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Coll M, Bellido JM, Pennino MG, Albo-Puigserver M, Báez JC, Christensen V, Corrales X, Fernández-Corredor E, Giménez J, Julià L, Lloret-Lloret E, Macias D, Ouled-Cheikh J, Ramírez F, Sbragaglia V, Steenbeek J. Retrospective analysis of the pelagic ecosystem of the Western Mediterranean Sea: Drivers, changes and effects. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 907:167790. [PMID: 37871814 DOI: 10.1016/j.scitotenv.2023.167790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/29/2023] [Accepted: 10/10/2023] [Indexed: 10/25/2023]
Abstract
In the Western Mediterranean Sea, forage fishes have changed in abundance, body condition, growth, reproduction, and distribution in the last decades. Different hypotheses have been proposed to explain these changes, including increase in fishing mortality; changes in environmental conditions affecting species fitness, and planktonic productivity and quality; recovery of top predators; and increase in competitors. We investigated the main drivers and changes of the pelagic ecosystem and their effects using an ecosystem-based modelling approach. Specifically, we (1) quantified the potential historical contribution of various drivers of change, (2) investigated changes in temporal trends and spatial distributions of main ecosystem components, and (3) identified ecological consequences of these changes in top predator and competitors, their fisheries and ecosystem traits during 2000-2020. We updated an established Ecopath food-web model representing the Spanish and French Mediterranean sub-areas (GSA06 and GSA07) in 2000 with recent available data. We applied the temporal dynamic Ecosim module, and tested historical time series of fishing effort, fishing mortality and environmental factors as potential drivers. Observed biomass and landings of key species were used to validate model projections. A spatial-temporal Ecospace model was developed to project species distribution changes. Results showed historical biomass and catch changes driven by a combination of high fishing pressure and environmental change (i.e. increase in temperature and salinity, and decline in primary productivity). Small pelagic fish showed significant temporal changes and predicted shifts in their distributions, following a latitudinal gradient. Predators and competitors showed changes as well, displaying heterogeneous spatial patterns, while fisheries landings declined. Overall, results matched observations (e.g., decline of sardine, fluctuations of anchovy and increases in bluefin tuna) and illustrated the need to complement traditional assessments with integrative frameworks to move towards an ecosystem-based approach in the Mediterranean. They also highlighted important knowledge gaps to guide future research in the region.
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Affiliation(s)
- Marta Coll
- Institute of Marine Sciences (ICM-CSIC), Barcelona, Spain; Ecopath International Initiative (EII), Barcelona, Spain.
| | - José María Bellido
- Spanish Institute of Oceanography (IEO-CSIC, CO Baleares, CO Málaga, CO Murcia y CO Vigo), Spain
| | - Maria Grazia Pennino
- Spanish Institute of Oceanography (IEO-CSIC, CO Baleares, CO Málaga, CO Murcia y CO Vigo), Spain
| | - Marta Albo-Puigserver
- Spanish Institute of Oceanography (IEO-CSIC, CO Baleares, CO Málaga, CO Murcia y CO Vigo), Spain
| | - José Carlos Báez
- Spanish Institute of Oceanography (IEO-CSIC, CO Baleares, CO Málaga, CO Murcia y CO Vigo), Spain.; Instituto Iberoamericano de Desarrollo Sostenible (IIDS), Universidad Autónoma de Chile, Av. Alemania 1090. Temuco 4810101, Región de la Araucanía, Chile
| | - Villy Christensen
- Ecopath International Initiative (EII), Barcelona, Spain; Institute for the Oceans and Fisheries, The University of British Columbia, Vancouver, Canada
| | - Xavier Corrales
- AZTI, Marine Research Division, Basque Research and Technology Alliance (BRTA), Sukarrieta, Spain
| | | | - Joan Giménez
- Institute of Marine Sciences (ICM-CSIC), Barcelona, Spain
| | - Laura Julià
- Institute of Marine Sciences (ICM-CSIC), Barcelona, Spain
| | | | - Diego Macias
- European Commission, Joint Research Centre (JRC), Directorate D - Sustainable Resources, Ispra, Italy
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2
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Kiszka JJ, Caputo M, Vollenweider J, Heithaus MR, Aichienger Dias L, Garrison LP. Critically endangered Rice's whales (Balaenoptera ricei) selectively feed on high-quality prey in the Gulf of Mexico. Sci Rep 2023; 13:6710. [PMID: 37185970 PMCID: PMC10130045 DOI: 10.1038/s41598-023-33905-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 04/20/2023] [Indexed: 05/17/2023] Open
Abstract
Determining the drivers of prey selection in marine predators is critical when investigating ecosystem structure and function. The newly recognized Rice's whale (Balaenoptera ricei) is one of the most critically endangered large whales in the world and endemic to the industrialized Gulf of Mexico. Here, we investigated the drivers of resource selection by Rice's whales in relation to prey availability and energy density. Bayesian stable isotope (δ13C, δ15N) mixing models suggest that Rice's whales feed primarily on a schooling fish, Ariomma bondi (66.8% relative contribution). Prey selection using the Chesson's index revealed that active prey selection was found to be positive for three out of the four potential prey identified in the mixing model. A low degree of overlap between prey availability and diet inferred from the mixing model (Pianka Index: 0.333) suggests that prey abundance is not the primary driver of prey selection. Energy density data suggest that prey selection may be primarily driven by the energy content. Results from this study indicate that Rice's whales are selective predators consuming schooling prey with the highest energy content. Environmental changes in the region have the potential to influence prey species that would make them less available to Rice's whales.
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Affiliation(s)
- Jeremy J Kiszka
- Institute of Environment, Department of Biological Sciences, Florida International University, North Miami, FL, USA.
| | - Michelle Caputo
- Institute of Environment, Department of Biological Sciences, Florida International University, North Miami, FL, USA
- Department of Zoology and Entomology, Rhodes University, Grahamstown, South Africa
| | | | - Michael R Heithaus
- Institute of Environment, Department of Biological Sciences, Florida International University, North Miami, FL, USA
| | - Laura Aichienger Dias
- Marine Mammal and Turtle Division, Southeast Fisheries Science Center, National Marine Fisheries Service, NOAA, Miami, FL, USA
- Cooperative Institute for Marine and Atmospheric Studies, University of Miami, Miami, FL, USA
| | - Lance P Garrison
- Marine Mammal and Turtle Division, Southeast Fisheries Science Center, National Marine Fisheries Service, NOAA, Miami, FL, USA
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3
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The influence of prey availability on behavioral decisions and reproductive success of a central-place forager during lactation. J Theor Biol 2023; 560:111392. [PMID: 36572092 DOI: 10.1016/j.jtbi.2022.111392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 12/14/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
Marine central-place foragers are increasingly faced with altered prey landscapes, necessitating predictions of the impact of such changes on behavior, reproductive success, and population dynamics. We used state-dependent behavioral life history theory implemented via Stochastic Dynamic Programming (SDP) to explore the influence of changes in prey distribution and energy gain from foraging on the behavior and reproductive success of a central place forager during lactation. Our work is motivated by northern fur seals (Callorhinus ursinus) because of the ongoing population decline of the Eastern Pacific stock and projected declines in biomass of walleye pollock (Gadus chalcogrammus), a key fur seal prey species in the eastern Bering Sea. We also explored how changes in female and pup metabolic rates, body size, and lactation duration affected model output to provide insight into traits that might experience selective pressure in response to reductions in prey availability. Simulated females adopted a central-place foraging strategy after an initial extended period spent on land (4.7-8.3 days). Trip durations increased as the high energy prey patch moved farther from land or when the energy gain from foraging decreased. Increases in trip duration adversely affected pup growth rates and wean mass despite attempts to compensate by increasing land durations. Metabolic rate changes had the largest impacts on pup wean mass, with reductions in a pup's metabolic rate allowing females to successfully forage at distances of 600+ km from land for up to 15+ days. Our results indicate that without physiological adaptations, a rookery is unlikely to be viable if the primary foraging grounds are 400 km or farther from the rookery. To achieve pup growth rates characteristic of a population experiencing rapid growth, model results indicate the primary foraging grounds need to be <150 km from the rookery.
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4
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Dwyer GK, Stoffels RJ, Silvester E, Rees GN. Two wild carnivores selectively forage for prey but not amino acids. Sci Rep 2023; 13:3254. [PMID: 36828827 PMCID: PMC9958011 DOI: 10.1038/s41598-023-28231-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 01/16/2023] [Indexed: 02/26/2023] Open
Abstract
In nutritional ecology the intake target is the diet that maximises consumer fitness. A key hypothesis of nutritional ecology is that natural selection has acted upon the behavioural and physiological traits of consumers to result in them Selectively Consuming prey to match the Intake Target (SCIT). SCIT has been documented in some herbivores and omnivores, which experience strong heterogeneity in the nutritional quality of available foods. Although carnivores experience a prey community with a much more homogeneous nutrient composition, SCIT by carnivores has nevertheless been deemed highly likely by some researchers. Here we test for SCIT for micronutrients (amino acids) in two freshwater carnivores: the river blackfish and the two-spined blackfish. Although both blackfishes exhibited non-random consumption of prey from the environment, this resulted in non-random consumption of amino acids in only one species, the river blackfish. Non-random consumption of amino acids by river blackfish was not SCIT, but instead an artefact of habitat-specific foraging. We present hypotheses to explain why wild populations of freshwater carnivores may not exhibit SCIT for amino acids. Our work highlights the need for careful, critical tests of the hypotheses and assumptions of nutritional ecology and its application to wild populations.
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Affiliation(s)
- Georgia K Dwyer
- Centre for Regional and Rural Futures, Deakin University, Locked Bag 20000, Geelong, VIC, 3220, Australia.
| | - Rick J Stoffels
- National Institute of Water and Atmospheric Research, Riccarton, PO Box 8602, Christchurch, 8440, New Zealand
| | - Ewen Silvester
- Department of Ecology, Environment and Evolution, Centre for Freshwater Ecosystems, School of Life Sciences, La Trobe University, Wodonga, VIC, 3690, Australia
| | - Gavin N Rees
- CSIRO Land and Water, and Institute for Land, Water and Society, Charles Sturt University, PO Box 789, Albury, NSW, 2640, Australia
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Booth CG, Guilpin M, Darias-O’Hara AK, Ransijn JM, Ryder M, Rosen D, Pirotta E, Smout S, McHuron EA, Nabe-Nielsen J, Costa DP. Estimating energetic intake for marine mammal bioenergetic models. CONSERVATION PHYSIOLOGY 2023; 11:coac083. [PMID: 36756464 PMCID: PMC9900471 DOI: 10.1093/conphys/coac083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 11/08/2022] [Accepted: 12/21/2022] [Indexed: 06/18/2023]
Abstract
Bioenergetics is the study of how animals achieve energetic balance. Energetic balance results from the energetic expenditure of an individual and the energy they extract from their environment. Ingested energy depends on several extrinsic (e.g prey species, nutritional value and composition, prey density and availability) and intrinsic factors (e.g. foraging effort, success at catching prey, digestive processes and associated energy losses, and digestive capacity). While the focus in bioenergetic modelling is often on the energetic costs an animal incurs, the robust estimation of an individual's energy intake is equally critical for producing meaningful predictions. Here, we review the components and processes that affect energy intake from ingested gross energy to biologically useful net energy (NE). The current state of knowledge of each parameter is reviewed, shedding light on research gaps to advance this field. The review highlighted that the foraging behaviour of many marine mammals is relatively well studied via biologging tags, with estimates of success rate typically assumed for most species. However, actual prey capture success rates are often only assumed, although we note studies that provide approaches for its estimation using current techniques. A comprehensive collation of the nutritional content of marine mammal prey species revealed a robust foundation from which prey quality (comprising prey species, size and energy density) can be assessed, though data remain unavailable for many prey species. Empirical information on various energy losses following ingestion of prey was unbalanced among marine mammal species, with considerably more literature available for pinnipeds. An increased understanding and accurate estimate of each of the components that comprise a species NE intake are an integral part of bioenergetics. Such models provide a key tool to investigate the effects of disturbance on marine mammals at an individual and population level and to support effective conservation and management.
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Affiliation(s)
- Cormac G Booth
- Corresponding author: SMRU Consulting, Scottish Oceans Institute, University of St Andrews, East Sands, St Andrews, KY16 8LB, UK.
| | | | - Aimee-Kate Darias-O’Hara
- SMRU Consulting, Scottish Oceans Institute, University of St Andrews, East Sands, St Andrews, KY16 8LB, UK
| | - Janneke M Ransijn
- Sea Mammal Research Unit, Scottish Oceans Institute, East Sands, University of St. Andrews, St. Andrews, KY16 8LB, UK
| | - Megan Ryder
- SMRU Consulting, Scottish Oceans Institute, University of St Andrews, East Sands, St Andrews, KY16 8LB, UK
| | - Dave Rosen
- Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall,
Vancouver, BC V6T 1Z4, Canada
| | - Enrico Pirotta
- Centre for Research into Ecological and Environmental Modelling,
The Observatory, Buchanan
Gardens, University of St. Andrews, St. Andrews,
KY16 9LZ, UK
| | - Sophie Smout
- Sea Mammal Research Unit, Scottish Oceans Institute, East Sands, University of St. Andrews, St. Andrews, KY16 8LB, UK
| | - Elizabeth A McHuron
- Cooperative Institute for Climate, Ocean, and Ecosystem Studies, University of Washington, 3737 Brooklyn Ave NE, Seattle, WA, 98105, USA
| | - Jacob Nabe-Nielsen
- Marine Mammal Research, Department of Ecoscience, Aarhus University, Aarhus, DK-4000
Roskilde, Denmark
| | - Daniel P Costa
- Ecology and Evolutionary Biology Department, University of California Santa Cruz, 130
McAlister Way, Santa Cruz, CA, 95064, USA
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Energy content of krill and amphipods in the Barents Sea from summer to winter: variation across species and size. Polar Biol 2023. [DOI: 10.1007/s00300-023-03112-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
AbstractArctic zooplankton develop large energy reserves, as an adaptation to strong seasonality, making them valuable prey items. We quantified the energy content (kJ g−1 dry weight) of abundant krill (arcto-boreal, Thysanoessa inermis and boreal, Meganyctiphanes norvegica) and amphipods (Arctic, Themisto libellula and sub-Arctic-boreal, Themisto abyssorum) in the Barents Sea in late summer (August) and early winter (December). Variation in energy content was attributed to species-specific traits and body size categories, the latter in part as a proxy for ontogeny. T. inermis had the highest energy content, (Aug: 26.8 ± 1.5 (SD) kJ g−1) and remained similar from summer to winter. Energy content increased in M. norvegica and decreased in both amphipod species, with the lowest energy content being in T. abyssorum (Dec: 17.8 ± 0.8 kJ g−1). The effect of body size varied between species, with energy content increasing with size in T. inermis and T. libellula, and no change with size in M. norvegica and T. abyssorum. The reproductive stages of T. libellula differed in energy content, being highest in gravid females. Energy content varied with species’ dependence on energy storage. Our findings highlight how phylogenetically and morphologically similar prey items cannot necessarily be considered equal from a predator´s perspective. Energetically, the northern T. inermis was higher quality compared to the more southern M. norvegica, and mostly so during summer. Ecological models and management strategies should consider such variation in prey quality, especially as Arctic borealization is expected to change species composition and the energetic landscape for predators.
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7
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Chambault P, Blackwell SB, Heide-Jørgensen MP. Extremely low seasonal prey capture efficiency in a deep-diving whale, the narwhal. Biol Lett 2023; 19:20220423. [PMID: 36974666 PMCID: PMC9943871 DOI: 10.1098/rsbl.2022.0423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
Successful foraging is essential for individuals to maintain the positive energy balance required for survival and reproduction. Yet, prey capture efficiency is poorly documented in marine apex predators, especially deep-diving mammals. We deployed acoustic tags and stomach temperature pills in summer to collect concurrent information on presumed foraging activity (through buzz detection) and successful prey captures (through drops in stomach temperature), providing estimates of feeding efficiency in narwhals. Compared to the daily number of buzzes (707 ± 368), the daily rate of feeding events was particularly low in summer (19.8 ± 8.9) and only 8–14% of the foraging dives were successful (i.e. with a detectable prey capture). This extremely low success rate resulted in a very low daily food consumption rate (less than 0.5% of body mass), suggesting that narwhals rely on body reserves accumulated in winter to sustain year-round activities. The expected changes or disappearance of their wintering habitats in response to climate change may therefore have severe fitness consequences for narwhal populations.
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Affiliation(s)
- Philippine Chambault
- Greenland Institute of Natural Resources, Strandgade 91, 2, DK-1401 Copenhagen, Denmark,Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Susanna B. Blackwell
- Institute of Marine Sciences, University of California, Santa Cruz, CA, USA,Greeneridge Sciences Inc., Santa Barbara, CA, USA
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8
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Deep ocean drivers better explain habitat preferences of sperm whales Physeter macrocephalus than beaked whales in the Bay of Biscay. Sci Rep 2022; 12:9620. [PMID: 35688859 PMCID: PMC9187681 DOI: 10.1038/s41598-022-13546-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 05/25/2022] [Indexed: 11/09/2022] Open
Abstract
Species Distribution Models are commonly used with surface dynamic environmental variables as proxies for prey distribution to characterise marine top predator habitats. For oceanic species that spend lot of time at depth, surface variables might not be relevant to predict deep-dwelling prey distributions. We hypothesised that descriptors of deep-water layers would better predict the deep-diving cetacean distributions than surface variables. We combined static variables and dynamic variables integrated over different depth classes of the water column into Generalised Additive Models to predict the distribution of sperm whales Physeter macrocephalus and beaked whales Ziphiidae in the Bay of Biscay, eastern North Atlantic. We identified which variables best predicted their distribution. Although the highest densities of both taxa were predicted near the continental slope and canyons, the most important variables for beaked whales appeared to be static variables and surface to subsurface dynamic variables, while for sperm whales only surface and deep-water variables were selected. This could suggest differences in foraging strategies and in the prey targeted between the two taxa. Increasing the use of variables describing the deep-water layers would provide a better understanding of the oceanic species distribution and better assist in the planning of human activities in these habitats.
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9
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Danger M, Bec A, Spitz J, Perga M. Questioning the roles of resources nutritional quality in ecology. OIKOS 2022. [DOI: 10.1111/oik.09503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Michael Danger
- Univ. de Lorraine, CNRS, LIEC Metz France
- GRET (Groupe de Recherche en Ecologie Trophique), GDR 3716 CNRS INEE INRA Aubière France
- Inst. Universitaire de France (IUF) Paris France
| | - Alexandre Bec
- GRET (Groupe de Recherche en Ecologie Trophique), GDR 3716 CNRS INEE INRA Aubière France
- Univ. Clermont Auvergne, CNRS, LMGE Aubière France
| | - Jérôme Spitz
- GRET (Groupe de Recherche en Ecologie Trophique), GDR 3716 CNRS INEE INRA Aubière France
- Observatoire Pelagis, UAR 3462 La Rochelle Université/CNRS La Rochelle France
- CEBC, UMS 7372 La Rochelle Université/CNRS La Rochelle France
| | - Marie‐Elodie Perga
- GRET (Groupe de Recherche en Ecologie Trophique), GDR 3716 CNRS INEE INRA Aubière France
- Univ. of Lausanne, Inst. of Earth surface Dynamics Lausanne Switzerland
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10
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Gelippi M, Caraveo-Patiño J, Gauger MFW, Popp BN, Panigada S, Marcín-Medina R. Isotopic composition of the eastern gray whale epidermis indicates contribution of prey outside Arctic feeding grounds. Sci Rep 2022; 12:7055. [PMID: 35488113 PMCID: PMC9054758 DOI: 10.1038/s41598-022-10780-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 04/08/2022] [Indexed: 11/09/2022] Open
Abstract
Eastern gray whales' distribution range and plasticity in feeding behavior complicates the understanding of critical life-history such as pregnancy and lactation. Our goal was to determine if females who experienced gestation, gave birth, and lactated their calves, assimilated a high proportion of benthic amphipods from the Bering Sea, which are considered the species' main prey. We used Bayesian stable isotope mixing models to estimate the probability of contribution of food items sampled along the species' distributional range, using isotopic data on amphipods from the Bering Sea, mysids from Vancouver Island, and amphipods and polychaetes from Ojo de Liebre Lagoon. We sampled epidermal tissue from lactating females (n = 25) and calves (n = 34) and analyzed their carbon and nitrogen isotopic composition. Model outcome indicated that benthic amphipods from the Bering Sea were not the primary food for the eastern gray whale. Each mother performed a different feeding strategy, and prey from Vancouver Island were generally as important as that from the Bering Sea. Moreover, model results indicate a constant use of Ojo de Liebre Lagoon as a feeding ground. Our results appear to agree with previous studies that report continuous feeding by females to satisfy certain physiological requirements (e.g., fatty acids omega-6) during migration and breeding time. Future investigations of the isotopic composition of all those prey items that could be assimilated by the eastern gray whale emerge as critical. Both historical and recent information, that would provide insights in the species feeding ecology under past and present environmental conditions, should be considered as equally important to establish conservation and management plans.
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Affiliation(s)
- Michelle Gelippi
- Centro de Investigaciones Biológicas del Noroeste S.C., La Paz, B.C.S., México
| | | | - Marco F W Gauger
- Centro de Investigaciones Biológicas del Noroeste S.C., La Paz, B.C.S., México
| | - Brian N Popp
- Department of Earth Sciences, University of Hawaii at Manoa, Honolulu, HI, USA
| | | | - Rocío Marcín-Medina
- Asociación de Investigación y Conservación de Mamíferos Marinos y su Hábitat A.C., La Paz, B.C.S., México
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11
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Chouvelon T, Gilbert L, Caurant F, Méndez‐Fernandez P, Bustamante P, Brault‐Favrou M, Spitz J. Nutritional grouping of marine forage species reveals contrasted exposure of high trophic levels to essential micro‐nutrients. OIKOS 2022. [DOI: 10.1111/oik.08844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tiphaine Chouvelon
- Observatoire Pelagis, UAR 3462 La Rochelle Univ./CNRS La Rochelle France
- Ifremer, Unité Contamination Chimique des Écosystèmes Marins (CCEM) Nantes Cedex France
| | - Lola Gilbert
- Observatoire Pelagis, UAR 3462 La Rochelle Univ./CNRS La Rochelle France
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 La Rochelle Univ./CNRS Villiers‐en‐Bois France
| | - Florence Caurant
- Observatoire Pelagis, UAR 3462 La Rochelle Univ./CNRS La Rochelle France
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 La Rochelle Univ./CNRS Villiers‐en‐Bois France
| | | | - Paco Bustamante
- Littoral Environnement et Sociétés (LIENSs), UMR 7266 La Rochelle Univ./CNRS La Rochelle France
- Inst. Univ. de France (IUF) Paris France
| | - Maud Brault‐Favrou
- Littoral Environnement et Sociétés (LIENSs), UMR 7266 La Rochelle Univ./CNRS La Rochelle France
| | - Jérôme Spitz
- Observatoire Pelagis, UAR 3462 La Rochelle Univ./CNRS La Rochelle France
- Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 La Rochelle Univ./CNRS Villiers‐en‐Bois France
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12
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Campanini C, Albo-Puigserver M, Gérez S, Lloret-Lloret E, Giménez J, Pennino MG, Bellido JM, Colmenero AI, Coll M. Energy content of anchovy and sardine using surrogate calorimetry methods. MARINE ENVIRONMENTAL RESEARCH 2021; 172:105510. [PMID: 34717130 DOI: 10.1016/j.marenvres.2021.105510] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
European anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) are crucial species for the marine ecosystem of the Northwestern Mediterranean Sea. They account for a high percentage of fish landings and they represent an important economic income for the fishery sector. Concerns over their stock status are rising in recent years as biomass, growth, reproductive capacity, and body condition of both species are declining, with latitudinal variations. Therefore, there is an urgent need for a body condition monitoring scheme. Energy storage variability has important implications for both fish recruitment and population structure. Direct condition indices, such as energy density (ED) with bomb calorimetry, are highly reliable for measuring the energy content, but time-consuming. Alternatively, fatmeter analysis and relative condition index (Kn) have been proposed as effective indirect methods. The aim of this study is to test the application of fatmeter as a surrogate of bomb calorimetry to infer the energy content of sardine and anchovy. To validate its use, fatmeter values were compared with both ED and Kn values. Individuals of both species were sampled monthly for a year in order to assess seasonal variations in energy content. Our results highlight that fatmeter measurements are strongly correlated with calorimetry ED for sardine, while a weaker but significant correlation was found for anchovy. The observed differences between the two species are related to their breeding strategies. Based on this study, Kn cannot be considered a good proxy of the energy density of sardine, in particular during the resting period. By contrast, fatmeter analysis appears to be a faster and suitable method to evaluate the energy content of both species routinely. In addition, we provide a linear model to infer ED from fatmeter values for both small pelagic fish. Eventually, these findings could be used to implement body condition monitoring protocols and boost continuous large-scale monitoring.
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Affiliation(s)
- Claudia Campanini
- Department of Renewable Marine Resources, Institute of Marine Sciences (ICM-CSIC), Barcelona, 08003, Spain.
| | - Marta Albo-Puigserver
- Department of Renewable Marine Resources, Institute of Marine Sciences (ICM-CSIC), Barcelona, 08003, Spain; Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas, Faro, 8005-139, Portugal
| | - Sara Gérez
- Department of Renewable Marine Resources, Institute of Marine Sciences (ICM-CSIC), Barcelona, 08003, Spain
| | - Elena Lloret-Lloret
- Department of Renewable Marine Resources, Institute of Marine Sciences (ICM-CSIC), Barcelona, 08003, Spain
| | - Joan Giménez
- Department of Renewable Marine Resources, Institute of Marine Sciences (ICM-CSIC), Barcelona, 08003, Spain; MaREI Centre, Environmental Research Institute, University College Cork, Cork, P43 C573, Ireland
| | - Maria Grazia Pennino
- Fishery Department, Instituto Español de Oceanografía (IEO-CSIC). Centro Oceanográfico de Vigo. Subida a Radio Faro, 50-52, Vigo, Pontevedra, 36390, Spain
| | - José María Bellido
- Fishery Department, Instituto Español de Oceanografía (IEO-CSIC), Centro Oceanográfico de Murcia, San Pedro del Pinatar, 30740, Spain
| | - Ana I Colmenero
- Department of Renewable Marine Resources, Institute of Marine Sciences (ICM-CSIC), Barcelona, 08003, Spain
| | - Marta Coll
- Department of Renewable Marine Resources, Institute of Marine Sciences (ICM-CSIC), Barcelona, 08003, Spain
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13
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Nutritional status and prey energy density govern reproductive success in a small cetacean. Sci Rep 2021; 11:19201. [PMID: 34725464 PMCID: PMC8560860 DOI: 10.1038/s41598-021-98629-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 09/02/2021] [Indexed: 02/08/2023] Open
Abstract
A variety of mammals suppress reproduction when they experience poor physical condition or environmental harshness. In many marine mammal species, reproductive impairment has been correlated to polychlorinated biphenyls (PCBs), the most frequently measured chemical pollutants, while the relative importance of other factors remains understudied. We investigate whether reproductively active females abandon investment in their foetus when conditions are poor, exemplified using an extensively studied cetacean species; the harbour porpoise (Phocoena phocoena). Data on disease, fat and muscle mass and diet obtained from necropsies in The Netherlands were used as proxies of health and nutritional status and related to pregnancy and foetal growth. This was combined with published life history parameters for 16 other areas to correlate to parameters reflecting environmental condition: mean energy density of prey constituting diets (MEDD), cumulative human impact and PCB contamination. Maternal nutritional status had significant effects on foetal size and females in poor health had lower probabilities of being pregnant and generally did not sustain pregnancy throughout gestation. Pregnancy rates across the Northern Hemisphere were best explained by MEDD. We demonstrate the importance of having undisturbed access to prey with high energy densities in determining reproductive success and ultimately population size for small cetaceans.
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14
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Guo LW, McCormick SD, Schultz ET, Jordaan A. Direct and size-mediated effects of temperature and ration-dependent growth rates on energy reserves in juvenile anadromous alewives (Alosa pseudoharengus). JOURNAL OF FISH BIOLOGY 2021; 99:1236-1246. [PMID: 34101179 DOI: 10.1111/jfb.14824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 05/26/2021] [Accepted: 06/03/2021] [Indexed: 06/12/2023]
Abstract
Growth rate and energy reserves are important determinants of fitness and are governed by endogenous and exogenous factors. Thus, examining the influence of individual and multiple stressors on growth and energy reserves can help estimate population health under current and future conditions. In young anadromous fishes, freshwater habitat quality determines physiological state and fitness of juveniles emigrating to marine habitats. In this study, the authors tested how temperature and food availability affect survival, growth and energy reserves in juvenile anadromous alewives (Alosa pseudoharengus), a forage fish distributed along the eastern North American continent. Field-collected juvenile anadromous A. pseudoharengus were exposed for 21 days to one of two temperatures (21°C and 25°C) and one of two levels of food rations (1% or 2% tank biomass daily) and compared for differences in final size, fat mass-at-length, lean mass-at-length and energy density. Increased temperature and reduced ration both led to lower growth rates, and the effect of reduced ration was greater at higher temperature. Fat mass-at-length decreased with dry mass, and energy density increased with total length, suggesting size-based endogenous influences on energy reserves. Lower ration also directly decreased fat mass-at-length, lean mass-at-length and energy density. Given the fitness implications of size and energy reserves, temperature and food availability should be considered important indicators of nursery habitat quality and incorporated in A. pseudoharengus life-history models to improve forecasting of population health under climate change.
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Affiliation(s)
- Lian W Guo
- Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, Massachusetts, USA
| | - Stephen D McCormick
- US Geological Survey, Eastern Ecological Science Centre, Conte Research Laboratory, Turners Falls, Massachusetts, USA
- Department of Environmental Conservation, University of Massachusetts, Amherst, Massachusetts, USA
| | - Eric T Schultz
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Adrian Jordaan
- Department of Environmental Conservation, University of Massachusetts, Amherst, Massachusetts, USA
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15
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Virgili A, Hedon L, Authier M, Calmettes B, Claridge D, Cole T, Corkeron P, Dorémus G, Dunn C, Dunn TE, Laran S, Lehodey P, Lewis M, Louzao M, Mannocci L, Martínez-Cedeira J, Monestiez P, Palka D, Pettex E, Roberts JJ, Ruiz L, Saavedra C, Santos MB, Van Canneyt O, Bonales JAV, Ridoux V. Towards a better characterisation of deep-diving whales' distributions by using prey distribution model outputs? PLoS One 2021; 16:e0255667. [PMID: 34347854 PMCID: PMC8336804 DOI: 10.1371/journal.pone.0255667] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 07/21/2021] [Indexed: 11/28/2022] Open
Abstract
In habitat modelling, environmental variables are assumed to be proxies of lower trophic levels distribution and by extension, of marine top predator distributions. More proximal variables, such as potential prey fields, could refine relationships between top predator distributions and their environment. In situ data on prey distributions are not available over large spatial scales but, a numerical model, the Spatial Ecosystem And POpulation DYnamics Model (SEAPODYM), provides simulations of the biomass and production of zooplankton and six functional groups of micronekton at the global scale. Here, we explored whether generalised additive models fitted to simulated prey distribution data better predicted deep-diver densities (here beaked whales Ziphiidae and sperm whales Physeter macrocephalus) than models fitted to environmental variables. We assessed whether the combination of environmental and prey distribution data would further improve model fit by comparing their explanatory power. For both taxa, results were suggestive of a preference for habitats associated with topographic features and thermal fronts but also for habitats with an extended euphotic zone and with large prey of the lower mesopelagic layer. For beaked whales, no SEAPODYM variable was selected in the best model that combined the two types of variables, possibly because SEAPODYM does not accurately simulate the organisms on which beaked whales feed on. For sperm whales, the increase model performance was only marginal. SEAPODYM outputs were at best weakly correlated with sightings of deep-diving cetaceans, suggesting SEAPODYM may not accurately predict the prey fields of these taxa. This study was a first investigation and mostly highlighted the importance of the physiographic variables to understand mechanisms that influence the distribution of deep-diving cetaceans. A more systematic use of SEAPODYM could allow to better define the limits of its use and a development of the model that would simulate larger prey beyond 1,000 m would probably better characterise the prey of deep-diving cetaceans.
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Affiliation(s)
- Auriane Virgili
- Observatoire PELAGIS, UMS 3462 CNRS—La Rochelle Université, La Rochelle, France
| | - Laura Hedon
- Observatoire PELAGIS, UMS 3462 CNRS—La Rochelle Université, La Rochelle, France
| | - Matthieu Authier
- Observatoire PELAGIS, UMS 3462 CNRS—La Rochelle Université, La Rochelle, France
- ADERA, Pessac Cedex, Pessac, France
| | | | - Diane Claridge
- Bahamas Marine Mammal Research Organisation, Marsh Harbour, Abaco, Bahamas
| | - Tim Cole
- Protected Species Branch, NOAA Fisheries Northeast Fisheries Science, Woods Hole, Massachusetts, United States of America
| | - Peter Corkeron
- Protected Species Branch, NOAA Fisheries Northeast Fisheries Science, Woods Hole, Massachusetts, United States of America
| | - Ghislain Dorémus
- Observatoire PELAGIS, UMS 3462 CNRS—La Rochelle Université, La Rochelle, France
| | - Charlotte Dunn
- Bahamas Marine Mammal Research Organisation, Marsh Harbour, Abaco, Bahamas
| | - Tim E. Dunn
- Joint Nature Conservation Committee, Inverdee House, Aberdeen, United Kingdom
| | - Sophie Laran
- Observatoire PELAGIS, UMS 3462 CNRS—La Rochelle Université, La Rochelle, France
| | | | - Mark Lewis
- Protected Species Branch, NOAA Fisheries Northeast Fisheries Science, Woods Hole, Massachusetts, United States of America
| | - Maite Louzao
- AZTI, Marine Research, Basque Research and Technology Alliance (BRTA), Pasaia, Spain
| | - Laura Mannocci
- MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Sète, France
| | | | - Pascal Monestiez
- BioSP, INRA, Avignon, France
- Centre d’Etudes Biologiques de Chizé - La Rochelle, UMR 7372 CNRS—La Rochelle Université, Villiers-en-Bois, France
| | - Debra Palka
- Protected Species Branch, NOAA Fisheries Northeast Fisheries Science, Woods Hole, Massachusetts, United States of America
| | - Emeline Pettex
- ADERA, Pessac Cedex, Pessac, France
- Cohabys—ADERA, La Rochelle Université, La Rochelle, France
| | - Jason J. Roberts
- Marine Geospatial Ecology Laboratory, Duke University, Durham, North Carolina, United States of America
| | - Leire Ruiz
- AMBAR Elkartea Organisation, Bizkaia, Spain
| | - Camilo Saavedra
- Instituto Español de Oceanografía, Centro Oceanográfico de Vigo, Vigo, Spain
| | - M. Begoña Santos
- Instituto Español de Oceanografía, Centro Oceanográfico de Vigo, Vigo, Spain
| | - Olivier Van Canneyt
- Observatoire PELAGIS, UMS 3462 CNRS—La Rochelle Université, La Rochelle, France
| | | | - Vincent Ridoux
- Observatoire PELAGIS, UMS 3462 CNRS—La Rochelle Université, La Rochelle, France
- Centre d’Etudes Biologiques de Chizé - La Rochelle, UMR 7372 CNRS—La Rochelle Université, Villiers-en-Bois, France
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16
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Karlson AML, Gorokhova E, Gårdmark A, Pekcan-Hekim Z, Casini M, Albertsson J, Sundelin B, Karlsson O, Bergström L. Linking consumer physiological status to food-web structure and prey food value in the Baltic Sea. AMBIO 2020; 49:391-406. [PMID: 31168701 PMCID: PMC6965491 DOI: 10.1007/s13280-019-01201-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 05/01/2019] [Accepted: 05/08/2019] [Indexed: 06/09/2023]
Abstract
Declining physiological status in marine top consumers has been observed worldwide. We investigate changes in the physiological status and population/community traits of six consumer species/groups in the Baltic Sea (1993-2014), spanning four trophic levels and using metrics currently operational or proposed as indicators of food-web status. We ask whether the physiological status of consumers can be explained by food-web structure and prey food value. This was tested using partial least square regressions with status metrics for gray seal, cod, herring, sprat and the benthic predatory isopod Saduria as response variables, and abundance and food value of their prey, abundance of competitors and predators as predictors. We find evidence that the physiological status of cod, herring and sprat is influenced by competition, predation, and prey availability; herring and sprat status also by prey size. Our study highlights the need for management approaches that account for species interactions across multiple trophic levels.
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Affiliation(s)
- Agnes M. L. Karlson
- Department of Ecology, Environment and Plant Science, Stockholm University, Svante Arrhenius väg 21 A, 106 91 Stockholm, Sweden
- Stockholm University Baltic Sea Centre, Stockholm University, Stockholm, Sweden
| | - Elena Gorokhova
- Department of Environmental Science and Analytical Chemistry, Stockholm University, 106 91 Stockholm, Sweden
| | - Anna Gårdmark
- Department of Aquatic Resources, Institute of Coastal Research, Swedish University of Agricultural Sciences, Skolgatan 6, 742 42 Öregrund, Sweden
| | - Zeynep Pekcan-Hekim
- Department of Aquatic Resources, Institute of Coastal Research, Swedish University of Agricultural Sciences, Skolgatan 6, 742 42 Öregrund, Sweden
| | - Michele Casini
- Department of Aquatic Resources, Institute of Marine Research, Swedish University of Agricultural Sciences, Turistgatan 5, 453 30 Lysekil, Sweden
| | - Jan Albertsson
- Umeå Marine Science Centre, Umeå University, Norrbyn 557, 905 71 Hörnefors, Sweden
| | - Brita Sundelin
- Department of Environmental Science and Analytical Chemistry, Stockholm University, 106 91 Stockholm, Sweden
| | - Olle Karlsson
- Department of Environmental Research and Monitoring, Swedish Museum of Natural History, P.O. 50007, 104 05 Stockholm, Sweden
| | - Lena Bergström
- Department of Aquatic Resources, Institute of Coastal Research, Swedish University of Agricultural Sciences, Skolgatan 6, 742 42 Öregrund, Sweden
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17
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Machovsky-Capuska GE, Raubenheimer D. The Nutritional Ecology of Marine Apex Predators. ANNUAL REVIEW OF MARINE SCIENCE 2020; 12:361-387. [PMID: 31487471 DOI: 10.1146/annurev-marine-010318-095411] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Apex predators play pivotal roles in marine ecosystems, mediated principally through diet and nutrition. Yet, compared with terrestrial animals, the nutritional ecology of marine predators is poorly understood. One reason is that the field has adhered to an approach that evaluates diet principally in terms of energy gain. Studies in terrestrial systems, by contrast, increasingly adopt a multidimensional approach, the nutritional geometry framework, that distinguishes specific nutrients and calories. We provide evidence that a nutritional approach is likewise relevant to marine apex predators, then demonstrate how nutritional geometry can characterize the nutrient and energy content of marine prey. Next, we show how this framework can be used to reconceptualize ecological interactions via the ecological niche concept, and close with a consideration of its application to problems in marine predator research.
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Affiliation(s)
| | - David Raubenheimer
- Charles Perkins Centre, The University of Sydney, Sydney, New South Wales 2006, Australia;
- School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales 2006, Australia
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18
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Sotillo A, Baert JM, Müller W, Stienen EWM, Soares AMVM, Lens L. Time and energy costs of different foraging choices in an avian generalist species. MOVEMENT ECOLOGY 2019; 7:41. [PMID: 31908778 PMCID: PMC6937837 DOI: 10.1186/s40462-019-0188-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Accepted: 12/18/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Animals can obtain a higher foraging yield by optimizing energy expenditure or minimizing time costs. In this study, we assessed how individual variation in the relative use of marine and terrestrial foraging habitats relates to differences in the energy and time investments of an avian generalistic feeder (the Lesser Black-backed Gull, Larus fuscus), and how this changes during the course of the chick-rearing period. METHODS We analyzed 5 years of GPS tracking data collected at the colony of Zeebrugge (Belgium). Cost proxies for energy expenditure (overall dynamic body acceleration) and time costs (trip durations and time spent away from the colony), together with trip frequency, were analyzed against the relative use of the marine and terrestrial habitats. RESULTS The marine habitat was most often used by males and outside weekends, when fisheries are active. Marine trips implied higher energetic costs and lower time investments. As chicks became older, terrestrial trips became more prevalent, and trip frequency reached a peak towards 20 days after hatching of the first egg. Over a full chick rearing period, energy costs varied widely between individuals, but no trends were found across the marine foraging gradient. Conversely, a higher use of marine foraging implied lower overall amounts of time spent away from the colony. CONCLUSIONS Foraging habitat choice was related to overall time costs incurred by gulls, but not to energy costs. The effect of chick age on foraging habitat choice and effort may be driven by energy expenditure constraints on the amount of marine foraging that can be performed. If time is less constraining to them, Lesser Black-backed Gulls may meet the increasing chick demand for food by switching from high to low energy demanding foraging strategies.
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Affiliation(s)
- Alejandro Sotillo
- Department of Biology, Terrestrial Ecology Unit, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
- Department of Biology & CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal
| | - Jan M. Baert
- Department of Biology, Terrestrial Ecology Unit, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
- Department of Biology – Behavioural Ecology and Ecophysiology Group, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk, Antwerp Belgium
| | - Wendt Müller
- Department of Biology – Behavioural Ecology and Ecophysiology Group, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk, Antwerp Belgium
| | - Eric W. M. Stienen
- Research Institute for Nature and Forest (INBO), Herman Teirlinckgebouw, Havenlaan 88, 1000 Brussels, Belgium
| | - Amadeu M. V. M. Soares
- Department of Biology & CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal
| | - Luc Lens
- Department of Biology, Terrestrial Ecology Unit, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
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19
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Kadin M, Frederiksen M, Niiranen S, Converse SJ. Linking demographic and food-web models to understand management trade-offs. Ecol Evol 2019; 9:8587-8600. [PMID: 31410264 PMCID: PMC6686646 DOI: 10.1002/ece3.5385] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 05/13/2019] [Accepted: 05/18/2019] [Indexed: 11/17/2022] Open
Abstract
Alternatives in ecosystem-based management often differ with respect to trade-offs between ecosystem values. Ecosystem or food-web models and demographic models are typically employed to evaluate alternatives, but the approaches are rarely integrated to uncover conflicts between values. We applied multistate models to a capture-recapture dataset on common guillemots Uria aalge breeding in the Baltic Sea to identify factors influencing survival. The estimated relationships were employed together with Ecopath-with-Ecosim food-web model simulations to project guillemot survival under six future scenarios incorporating climate change. The scenarios were based on management alternatives for eutrophication and cod fisheries, issues considered top priority for regional management, but without known direct effects on the guillemot population. Our demographic models identified prey quantity (abundance and biomass of sprat Sprattus sprattus) as the main factor influencing guillemot survival. Most scenarios resulted in projections of increased survival, in the near (2016-2040) and distant (2060-2085) future. However, in the scenario of reduced nutrient input and precautionary cod fishing, guillemot survival was projected to be lower in both future periods due to lower sprat stocks. Matrix population models suggested a substantial decline of the guillemot population in the near future, 24% per 10 years, and a smaller reduction, 1.1% per 10 years, in the distant future. To date, many stakeholders and Baltic Sea governments have supported reduced nutrient input and precautionary cod fishing and implementation is underway. Negative effects on nonfocal species have previously not been uncovered, but our results show that the scenario is likely to negatively impact the guillemot population. Linking model results allowed identifying trade-offs associated with management alternatives. This information is critical to thorough evaluation by decision-makers, but not easily obtained by food-web models or demographic models in isolation. Appropriate datasets are often available, making it feasible to apply a linked approach for better-informed decisions in ecosystem-based management.
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Affiliation(s)
- Martina Kadin
- School of Aquatic and Fishery SciencesUniversity of WashingtonSeattleWashingtonUSA
- Swedish Museum of Natural HistoryStockholmSweden
| | | | - Susa Niiranen
- Stockholm Resilience CentreStockholm UniversityStockholmSweden
| | - Sarah J. Converse
- U.S. Geological SurveyWashington Cooperative Fish and Wildlife Research Unit, School of Environmental and Forest Sciences (SEFS) and School of Aquatic and Fishery Sciences (SAFS)University of WashingtonSeattleWashingtonUSA
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20
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Machovsky-Capuska GE, Miller MGR, Silva FRO, Amiot C, Stockin KA, Senior AM, Schuckard R, Melville D, Raubenheimer D. The nutritional nexus: Linking niche, habitat variability and prey composition in a generalist marine predator. J Anim Ecol 2018; 87:1286-1298. [DOI: 10.1111/1365-2656.12856] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 05/13/2018] [Indexed: 12/23/2022]
Affiliation(s)
- Gabriel E. Machovsky-Capuska
- Charles Perkins Centre; The University of Sydney; Sydney NSW Australia
- School of Life and Environmental Sciences; The University of Sydney; Sydney NSW Australia
| | - Mark G. R. Miller
- College of Science and Engineering and Centre for Tropical Environmental and Sustainability Science; James Cook University; Cairns QLD Australia
| | - Fabiola R. O. Silva
- School of Life and Environmental Sciences; The University of Sydney; Sydney NSW Australia
| | - Christophe Amiot
- Institute of Natural and Mathematical Sciences; Massey University; Auckland New Zealand
| | - Karen A. Stockin
- Institute of Natural and Mathematical Sciences; Massey University; Auckland New Zealand
| | - Alistair M. Senior
- Charles Perkins Centre; The University of Sydney; Sydney NSW Australia
- School of Mathematics and Statistics; The University of Sydney; Sydney NSW Australia
| | - Rob Schuckard
- Ornithological Society of New Zealand; Nelson New Zealand
| | - David Melville
- Ornithological Society of New Zealand; Nelson New Zealand
| | - David Raubenheimer
- Charles Perkins Centre; The University of Sydney; Sydney NSW Australia
- School of Life and Environmental Sciences; The University of Sydney; Sydney NSW Australia
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21
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Mensens C, De Laender F, Janssen CR, Rivera FC, Sabbe K, De Troch M. Selective and context-dependent effects of chemical stress across trophic levels at the basis of marine food webs. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:1342-1353. [PMID: 29698586 DOI: 10.1002/eap.1737] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 11/01/2017] [Accepted: 04/06/2018] [Indexed: 06/08/2023]
Abstract
Human activities increasingly impact the functioning of marine food webs, but anthropogenic stressors are seldom included in ecological study designs. Diet quality, as distinct from just diet quantity, has moreover rarely been highlighted in food web studies in a stress context. We measured the effects of metal and pesticide stress (copper and atrazine) on the contribution of a benthic intertidal diatom community to two processes that are key to the functioning of intertidal systems: biomass (diet quantity) and lipid (diet quality) production. We then examined if stressors affected diatom functioning by selectively targeting the species contributing most to functioning (selective stress effects) or by changing the species' functional contribution (context-dependent effects). Finally, we tested if stress-induced changes in diet quality altered the energy flow to the diatoms' main grazers (harpacticoid copepods). Diatom diet quantity was reduced by metal stress but not by low pesticide levels due to the presence of an atrazine-tolerant, mixotrophic species. Selective effects of the pesticide reduced diatom diet quality by 60% and 75% at low and high pesticide levels respectively, by shifting diatom community structure from dominance by lipid-rich species toward dominance by an atrazine-tolerant, but lipid-poor, species. Context-dependent effects did not affect individual diatom lipid content at low levels of both stressors, but caused diatoms to lose 40% of their lipids at high copper stress. Stress-induced changes in diet quality predicted the energy flow from the diatoms to their copepod consumers, which lost half of their lipids when feeding on diatoms grown under low and high pesticide and high metal stress. Selective pesticide effects were a more important threat for trophic energy transfer than context-dependent effects of both stressors, with shifts in diatom community structure affecting the energy flow to their copepod grazers at stress levels where no changes in diatom lipid content were detected.
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Affiliation(s)
- Christoph Mensens
- Biology Department, Marine Biology, Ghent University, Krijgslaan 281 - S8, 9000, Ghent, Belgium
- Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, Coupure Links 653, Building F, 9000, Ghent, Belgium
| | - Frederik De Laender
- Research Unit in Environmental and Evolutionary Biology, Biology Department, Université de Namur, Rue de Bruxelles 61, 5000, Namur, Belgium
| | - Colin R Janssen
- Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, Coupure Links 653, Building F, 9000, Ghent, Belgium
| | - Frances Camille Rivera
- Biology Department, Marine Biology, Ghent University, Krijgslaan 281 - S8, 9000, Ghent, Belgium
| | - Koen Sabbe
- Biology Department, Protistology and Aquatic Ecology, Ghent University, Krijgslaan 281 - S8, 9000, Ghent, Belgium
| | - Marleen De Troch
- Biology Department, Marine Biology, Ghent University, Krijgslaan 281 - S8, 9000, Ghent, Belgium
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22
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Scopel L, Diamond A. Predation and food–weather interactions drive colony collapse in a managed metapopulation of Arctic Terns (Sterna paradisaea). CAN J ZOOL 2018. [DOI: 10.1139/cjz-2016-0281] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Seabirds are considered bioindicators of bottom-up ecosystem processes, owing to seabirds’ dependence on marine prey. However, ground-nesting seabirds are susceptible to predation, which can limit their use as bioindicators. Machias Seal Island (MSI) supported the largest colony of Arctic Terns (Sterna paradisaea Pontoppidan, 1763) in the Gulf of Maine metapopulation, but prolonged breeding failure led ∼90% of terns to abandon the colony in 2006. We analyzed 12 years of food, weather, and predation data using logistic regression models to determine which had the strongest influence on breeding success. Food–weather interactions were important; under low rainfall, more euphausiids (northern krill, Meganyctiphanes norvegica (M. Sars, 1857)) in the diet increased breeding success, but euphausiids had a negative effect as rainfall became moderate or high. Predation by Herring Gulls (Larus argentatus Pontoppidan, 1763) increased following the cessation of lethal predator control; we identified a predation threshold of 25%, beyond which terns could not breed successfully. The collapse of MSI’s tern colony can be attributed entirely to gull predation. The breeding success of terns at MSI cannot be used as a bottom-up ecosystem bioindicator without accounting for predation. Managers of ground-nesting seabirds should consider predation and food as equally valid potential causes of population or reproductive declines.
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Affiliation(s)
- L.C. Scopel
- Atlantic Laboratory for Avian Research, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
- Atlantic Laboratory for Avian Research, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
| | - A.W. Diamond
- Atlantic Laboratory for Avian Research, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
- Atlantic Laboratory for Avian Research, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
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23
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Srinivasan M, Swannack TM, Grant WE, Rajan J, Würsig B. To feed or not to feed? Bioenergetic impacts of fear-driven behaviors in lactating dolphins. Ecol Evol 2017; 8:1384-1398. [PMID: 29375805 PMCID: PMC5773337 DOI: 10.1002/ece3.3732] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 10/26/2017] [Accepted: 11/22/2017] [Indexed: 11/25/2022] Open
Abstract
In mammals, lactation can be the most energetically expensive part of the reproductive cycle. Thus, when energy needs are compromised due to predation risk, environmental disturbance, or resource scarcity, future reproductive success can be impacted. In marine and terrestrial environments, foraging behavior is inextricably linked to predation risk. But quantification of foraging energetics for lactating animals under predation risk is less understood. In this study, we used a spatially explicit individual‐based model to study how changes in physiology (lactating or not) and the environment (predation risk) affect optimal behavior in dolphins. Specifically, we predicted that an adult dolphin without calf would incur lower relative energetic costs compared to a lactating dolphin with calf regardless of predation risk severity, antipredator behavior, or prey quality consumed. Under this state‐dependent analysis of risk approach, we found predation risk to be a stronger driver in affecting total energetic costs (foraging plus locomotor costs) than food quality for both dolphin types. Further, contrary to our hypothesis, after accounting for raised energy demands, a lactating dolphin with calf does not necessarily have higher relative‐to‐baseline costs than a dolphin without calf. Our results indicate that both a lactating (with calf) and non‐lactating dolphin incur lowered energetic costs under a risk‐averse behavioral scheme, but consequently suffer from lost foraging calories. A lactating dolphin with calf could be particularly worse off in lost foraging calories under elevated predation risk, heightened vigilance, and increased hiding time relative to an adult dolphin without calf. Further, hiding time in refuge could be more consequential than detection distance for both dolphin types in estimated costs and losses incurred. In conclusion, our study found that reproductive status is an important consideration in analyzing risk effects in mammals, especially in animals with lengthy lactation periods and those exposed to both biological and nonbiological stressors.
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Affiliation(s)
- Mridula Srinivasan
- Office of Science and Technology National Marine Fisheries Service (NMFS) Silver Spring MD USA
| | - Todd M Swannack
- U.S. Army Engineer Research and Development Center Vicksburg MS USA.,Department of Biology Texas State University San Marcos TX USA
| | - William E Grant
- Ecological Systems Laboratory, Department of Wildlife and Fisheries Sciences Texas A & M University College Station TX USA
| | - Jolly Rajan
- EcoLogik Consulting Group LLC Washington DC USA
| | - Bernd Würsig
- Department of Wildlife and Fisheries Sciences and Marine Biology Texas A & M University Galveston TX USA
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Additive effects of climate and fisheries drive ongoing declines in multiple albatross species. Proc Natl Acad Sci U S A 2017; 114:E10829-E10837. [PMID: 29158390 DOI: 10.1073/pnas.1618819114] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Environmental and anthropogenic factors often drive population declines in top predators, but how their influences may combine remains unclear. Albatrosses are particularly threatened. They breed in fast-changing environments, and their extensive foraging ranges expose them to incidental mortality (bycatch) in multiple fisheries. The albatross community at South Georgia includes globally important populations of three species that have declined by 40-60% over the last 35 years. We used three steps to deeply understand the drivers of such dramatic changes: (i) describe fundamental demographic rates using multievent models, (ii) determine demographic drivers of population growth using matrix models, and (iii) identify environmental and anthropogenic drivers using ANOVAs. Each species was affected by different processes and threats in their foraging areas during the breeding and nonbreeding seasons. There was evidence for two kinds of combined environmental and anthropogenic effects. The first was sequential; in wandering and black-browed albatrosses, high levels of bycatch have reduced juvenile and adult survival, then increased temperature, reduced sea-ice cover, and stronger winds are affecting the population recovery potential. The second was additive; in gray-headed albatrosses, not only did bycatch impact adult survival but also this impact was exacerbated by lower food availability in years following El Niño events. This emphasizes the need for much improved implementation of mitigation measures in fisheries and better enforcement of compliance. We hope our results not only help focus future management actions for these populations but also demonstrate the power of the modelling approach for assessing impacts of environmental and anthropogenic drivers in wild animal populations.
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Tompkins EM, Townsend HM, Anderson DJ. Decadal-scale variation in diet forecasts persistently poor breeding under ocean warming in a tropical seabird. PLoS One 2017; 12:e0182545. [PMID: 28832597 PMCID: PMC5568137 DOI: 10.1371/journal.pone.0182545] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Accepted: 07/17/2017] [Indexed: 11/19/2022] Open
Abstract
Climate change effects on population dynamics of natural populations are well documented at higher latitudes, where relatively rapid warming illuminates cause-effect relationships, but not in the tropics and especially the marine tropics, where warming has been slow. Here we forecast the indirect effect of ocean warming on a top predator, Nazca boobies in the equatorial Galápagos Islands, where rising water temperature is expected to exceed the upper thermal tolerance of a key prey item in the future, severely reducing its availability within the boobies' foraging envelope. From 1983 to 1997 boobies ate mostly sardines, a densely aggregated, highly nutritious food. From 1997 until the present, flying fish, a lower quality food, replaced sardines. Breeding success under the poor diet fell dramatically, causing the population growth rate to fall below 1, indicating a shrinking population. Population growth may not recover: rapid future warming is predicted around Galápagos, usually exceeding the upper lethal temperature and maximum spawning temperature of sardines within 100 years, displacing them permanently from the boobies' island-constrained foraging range. This provides rare evidence of the effect of ocean warming on a tropical marine vertebrate.
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Affiliation(s)
- Emily M Tompkins
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, United States of America
| | - Howard M Townsend
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, United States of America
- NOAA/NMFS/HC/Chesapeake Bay Office, Cooperative Oxford Lab, Oxford, Maryland, United States of America
| | - David J Anderson
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, United States of America
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Bennett KA, Robinson KJ, Moss SEW, Millward S, Hall AJ. Using blubber explants to investigate adipose function in grey seals: glycolytic, lipolytic and gene expression responses to glucose and hydrocortisone. Sci Rep 2017; 7:7731. [PMID: 28798409 PMCID: PMC5552887 DOI: 10.1038/s41598-017-06037-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 06/06/2017] [Indexed: 02/02/2023] Open
Abstract
Adipose tissue is fundamental to energy balance, which underpins fitness and survival. Knowledge of adipose regulation in animals that undergo rapid fat deposition and mobilisation aids understanding of their energetic responses to rapid environmental change. Tissue explants can be used to investigate adipose regulation in wildlife species with large fat reserves, when opportunities for organismal experimental work are limited. We investigated glucose removal, lactate, glycerol and NEFA accumulation in media, and metabolic gene expression in blubber explants from wild grey seals. Glycolysis was higher in explants incubated in 25 mM glucose (HG) for 24 h compared to controls (C: 5.5 mM glucose). Adipose-derived lactate likely contributes to high endogenous glucose production in seals. Lipolysis was not stimulated by HG or high hydrocortisone (HC: 500 nM hydrocortisone) and was lower in heavier animals. HC caused NEFA accumulation in media to decrease by ~30% relative to C in females, indicative of increased lipogenesis. Lipolysis was higher in males than females in C and HG conditions. Lower relative abundance of 11-β-hydroxysteroid dehydrogenase 1 mRNA in HG explants suggests glucose involvement in blubber cortisol sensitivity. Our findings can help predict energy balance responses to stress and nutritional state in seals, and highlight the use of explants to study fat tissue function in wildlife.
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Affiliation(s)
- Kimberley A Bennett
- Division of Science, School of Science Engineering and Technology, Abertay University, Bell St, Dundee, DD1 1HG, UK.
- Marine Biology and Ecology Research Centre, Plymouth University, Drake Circus, Plymouth, PL4 8AA, UK.
| | - Kelly J Robinson
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, KY16 8LB, UK
| | - Simon E W Moss
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, KY16 8LB, UK
| | - Sebastian Millward
- Marine Biology and Ecology Research Centre, Plymouth University, Drake Circus, Plymouth, PL4 8AA, UK
| | - Ailsa J Hall
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, KY16 8LB, UK
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Lamb JS, O'Reilly KM, Jodice PGR. Physical condition and stress levels during early development reflect feeding rates and predict pre- and post-fledging survival in a nearshore seabird. CONSERVATION PHYSIOLOGY 2016; 4:cow060. [PMID: 27957336 PMCID: PMC5146687 DOI: 10.1093/conphys/cow060] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 10/27/2016] [Accepted: 11/02/2016] [Indexed: 06/06/2023]
Abstract
The effects of acute environmental stressors on reproduction in wildlife are often difficult to measure because of the labour and disturbance involved in collecting accurate reproductive data. Stress hormones represent a promising option for assessing the effects of environmental perturbations on altricial young; however, it is necessary first to establish how stress levels are affected by environmental conditions during development and whether elevated stress results in reduced survival and recruitment rates. In birds, the stress hormone corticosterone is deposited in feathers during the entire period of feather growth, making it an integrated measure of background stress levels during development. We tested the utility of feather corticosterone levels in 3- to 4-week-old nestling brown pelicans (Pelecanus occidentalis) for predicting survival rates at both the individual and colony levels. We also assessed the relationship of feather corticosterone to nestling body condition and rates of energy delivery to nestlings. Chicks with higher body condition and lower corticosterone levels were more likely to fledge and to be resighted after fledging, whereas those with lower body condition and higher corticosterone levels were less likely to fledge or be resighted after fledging. Feather corticosterone was also associated with intracolony differences in survival between ground and elevated nest sites. Colony-wide, mean feather corticosterone predicted nest productivity, chick survival and post-fledging dispersal more effectively than did body condition, although these relationships were strongest before fledglings dispersed away from the colony. Both reproductive success and nestling corticosterone were strongly related to nutritional conditions, particularly meal delivery rates. We conclude that feather corticosterone is a powerful predictor of reproductive success and could provide a useful metric for rapidly assessing the effects of changes in environmental conditions, provided pre-existing baseline variation is monitored and understood.
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Affiliation(s)
- Juliet S. Lamb
- Department of Forestry and Environmental Conservation, and South Carolina Cooperative Fish and Wildlife Research Unit, G-27 Lehotsky Hall, Clemson University, Clemson, SC 29634, USA
| | - Kathleen M. O'Reilly
- Department of Biology, University of Portland, 5000 N Willamette Boulevard, Portland, OR 97203, USA
| | - Patrick G. R. Jodice
- US Geological Survey South Carolina Cooperative Fish and Wildlife Research Unit, and Department of Forestry and Environmental Conservation, G-27 Lehotsky Hall, Clemson, SC 29634, USA
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28
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Koehn LE, Essington TE, Marshall KN, Kaplan IC, Sydeman WJ, Szoboszlai AI, Thayer JA. Developing a high taxonomic resolution food web model to assess the functional role of forage fish in the California Current ecosystem. Ecol Modell 2016. [DOI: 10.1016/j.ecolmodel.2016.05.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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29
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Machovsky‐Capuska GE, Coogan SCP, Simpson SJ, Raubenheimer D. Motive for Killing: What Drives Prey Choice in Wild Predators? Ethology 2016. [DOI: 10.1111/eth.12523] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Gabriel E. Machovsky‐Capuska
- The Charles Perkins Centre The University of Sydney Sydney Australia
- Faculty of Veterinary Science The University of Sydney Sydney Australia
- School of Life and Environmental Sciences The University of Sydney Sydney Australia
| | - Sean C. P. Coogan
- The Charles Perkins Centre The University of Sydney Sydney Australia
- School of Life and Environmental Sciences The University of Sydney Sydney Australia
| | - Stephen J. Simpson
- The Charles Perkins Centre The University of Sydney Sydney Australia
- School of Life and Environmental Sciences The University of Sydney Sydney Australia
| | - David Raubenheimer
- The Charles Perkins Centre The University of Sydney Sydney Australia
- Faculty of Veterinary Science The University of Sydney Sydney Australia
- School of Life and Environmental Sciences The University of Sydney Sydney Australia
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30
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The Multidimensional Nutritional Niche. Trends Ecol Evol 2016; 31:355-365. [DOI: 10.1016/j.tree.2016.02.009] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 02/08/2016] [Accepted: 02/09/2016] [Indexed: 02/08/2023]
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31
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McClatchie S, Field J, Thompson AR, Gerrodette T, Lowry M, Fiedler PC, Watson W, Nieto KM, Vetter RD. Food limitation of sea lion pups and the decline of forage off central and southern California. ROYAL SOCIETY OPEN SCIENCE 2016; 3:150628. [PMID: 27069651 PMCID: PMC4821262 DOI: 10.1098/rsos.150628] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 02/02/2016] [Indexed: 05/18/2023]
Abstract
California sea lions increased from approximately 50 000 to 340 000 animals in the last 40 years, and their pups are starving and stranding on beaches in southern California, raising questions about the adequacy of their food supply. We investigated whether the declining sea lion pup weight at San Miguel rookery was associated with changes in abundance and quality of sardine, anchovy, rockfish and market squid forage. In the last decade off central California, where breeding female sea lions from San Miguel rookery feed, sardine and anchovy greatly decreased in biomass, whereas market squid and rockfish abundance increased. Pup weights fell as forage food quality declined associated with changes in the relative abundances of forage species. A model explained 67% of the variance in pup weights using forage from central and southern California and 81% of the variance in pup weights using forage from the female sea lion foraging range. A shift from high to poor quality forage for breeding females results in food limitation of the pups, ultimately flooding animal rescue centres with starving sea lion pups. Our study is unusual in using a long-term, fishery-independent dataset to directly address an important consequence of forage decline on the productivity of a large marine predator. Whether forage declines are environmentally driven, are due to a combination of environmental drivers and fishing removals, or are due to density-dependent interactions between forage and sea lions is uncertain. However, declining forage abundance and quality was coherent over a large area (32.5-38° N) for a decade, suggesting that trends in forage are environmentally driven.
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Affiliation(s)
- Sam McClatchie
- Fisheries Resources Division, Southwest Fisheries Science Center, NOAA Fisheries Service, 8901 La Jolla Shores Drive, La Jolla, CA 92037-1509, USA
- Author for correspondence: Sam McClatchie e-mail:
| | - John Field
- Fisheries Ecology Division, Southwest Fisheries Science Center, NOAA Fisheries Service, 110 Shaffer Road, Santa Cruz, CA 95062, USA
| | - Andrew R. Thompson
- Fisheries Resources Division, Southwest Fisheries Science Center, NOAA Fisheries Service, 8901 La Jolla Shores Drive, La Jolla, CA 92037-1509, USA
| | - Tim Gerrodette
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, NOAA Fisheries Service, 8901 La Jolla Shores Drive, La Jolla, CA 92037-1509, USA
| | - Mark Lowry
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, NOAA Fisheries Service, 8901 La Jolla Shores Drive, La Jolla, CA 92037-1509, USA
| | - Paul C. Fiedler
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, NOAA Fisheries Service, 8901 La Jolla Shores Drive, La Jolla, CA 92037-1509, USA
| | - William Watson
- Fisheries Resources Division, Southwest Fisheries Science Center, NOAA Fisheries Service, 8901 La Jolla Shores Drive, La Jolla, CA 92037-1509, USA
| | - Karen M. Nieto
- Water Resources Unit, Institute for Environment and Sustainability, European Commission Joint Research Centre, Ispra, Italy
| | - Russell D. Vetter
- Fisheries Resources Division, Southwest Fisheries Science Center, NOAA Fisheries Service, 8901 La Jolla Shores Drive, La Jolla, CA 92037-1509, USA
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Paleczny M, Hammill E, Karpouzi V, Pauly D. Population Trend of the World's Monitored Seabirds, 1950-2010. PLoS One 2015; 10:e0129342. [PMID: 26058068 PMCID: PMC4461279 DOI: 10.1371/journal.pone.0129342] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 05/07/2015] [Indexed: 11/18/2022] Open
Abstract
Seabird population changes are good indicators of long-term and large-scale change in marine ecosystems, and important because of their many impacts on marine ecosystems. We assessed the population trend of the world’s monitored seabirds (1950–2010) by compiling a global database of seabird population size records and applying multivariate autoregressive state-space (MARSS) modeling to estimate the overall population trend of the portion of the population with sufficient data (i.e., at least five records). This monitored population represented approximately 19% of the global seabird population. We found the monitored portion of the global seabird population to have declined overall by 69.7% between 1950 and 2010. This declining trend may reflect the global seabird population trend, given the large and apparently representative sample. Furthermore, the largest declines were observed in families containing wide-ranging pelagic species, suggesting that pan-global populations may be more at risk than shorter-ranging coastal populations.
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Affiliation(s)
- Michelle Paleczny
- University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
| | - Edd Hammill
- University of British Columbia, Vancouver, British Columbia, Canada
- School of the Environment, University of Technology, Sydney, Ultimo, New South Wales, 2007, Australia
| | | | - Daniel Pauly
- University of British Columbia, Vancouver, British Columbia, Canada
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Österblom H, Jouffray JB, Folke C, Crona B, Troell M, Merrie A, Rockström J. Transnational corporations as 'keystone actors' in marine ecosystems. PLoS One 2015; 10:e0127533. [PMID: 26017777 PMCID: PMC4446349 DOI: 10.1371/journal.pone.0127533] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/16/2015] [Indexed: 11/25/2022] Open
Abstract
Keystone species have a disproportionate influence on the structure and function of ecosystems. Here we analyze whether a keystone-like pattern can be observed in the relationship between transnational corporations and marine ecosystems globally. We show how thirteen corporations control 11-16% of the global marine catch (9-13 million tons) and 19-40% of the largest and most valuable stocks, including species that play important roles in their respective ecosystem. They dominate all segments of seafood production, operate through an extensive global network of subsidiaries and are profoundly involved in fisheries and aquaculture decision-making. Based on our findings, we define these companies as keystone actors of the Anthropocene. The phenomenon of keystone actors represents an increasingly important feature of the human-dominated world. Sustainable leadership by keystone actors could result in cascading effects throughout the entire seafood industry and enable a critical transition towards improved management of marine living resources and ecosystems.
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Affiliation(s)
- Henrik Österblom
- Stockholm Resilience Centre, Stockholm University, 106 91, Stockholm, Sweden
| | - Jean-Baptiste Jouffray
- Stockholm Resilience Centre, Stockholm University, 106 91, Stockholm, Sweden
- Global Economic Dynamics and the Biosphere Academy Programme, Royal Swedish Academy of Sciences, PO Box 50005, 104 05, Stockholm, Sweden
| | - Carl Folke
- Stockholm Resilience Centre, Stockholm University, 106 91, Stockholm, Sweden
- Global Economic Dynamics and the Biosphere Academy Programme, Royal Swedish Academy of Sciences, PO Box 50005, 104 05, Stockholm, Sweden
- Beijer Institute of Ecological Economics, Royal Swedish Academy of Sciences, PO Box 50005, 104 05, Stockholm, Sweden
| | - Beatrice Crona
- Stockholm Resilience Centre, Stockholm University, 106 91, Stockholm, Sweden
- Global Economic Dynamics and the Biosphere Academy Programme, Royal Swedish Academy of Sciences, PO Box 50005, 104 05, Stockholm, Sweden
| | - Max Troell
- Global Economic Dynamics and the Biosphere Academy Programme, Royal Swedish Academy of Sciences, PO Box 50005, 104 05, Stockholm, Sweden
- Beijer Institute of Ecological Economics, Royal Swedish Academy of Sciences, PO Box 50005, 104 05, Stockholm, Sweden
| | - Andrew Merrie
- Stockholm Resilience Centre, Stockholm University, 106 91, Stockholm, Sweden
| | - Johan Rockström
- Stockholm Resilience Centre, Stockholm University, 106 91, Stockholm, Sweden
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Kohl KD, Coogan SCP, Raubenheimer D. Do wild carnivores forage for prey or for nutrients? Bioessays 2015; 37:701-9. [DOI: 10.1002/bies.201400171] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Kevin D. Kohl
- Department of Biology; University of Utah; Salt Lake City UT USA
| | - Sean C. P. Coogan
- Charles Perkins Centre and School of Biological Sciences; University of Sydney; Sydney Australia
| | - David Raubenheimer
- Faculty of Veterinary Science and School of Biological Sciences; Charles Perkins Centre; University of Sydney; Sydney Australia
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35
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Spitz J, Becquet V, Rosen DAS, Trites AW. A nutrigenomic approach to detect nutritional stress from gene expression in blood samples drawn from Steller sea lions. Comp Biochem Physiol A Mol Integr Physiol 2015; 187:214-23. [PMID: 25700740 DOI: 10.1016/j.cbpa.2015.02.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 02/04/2015] [Accepted: 02/08/2015] [Indexed: 02/07/2023]
Abstract
Gene expression profiles are increasingly being used as biomarkers to detect the physiological responses of a number of species to disease, nutrition, and other stressors. However, little attention has been given to using gene expression to assess the stressors and physiological status of marine mammals. We sought to develop and validate a nutrigenomic approach to quantify nutritional stress in Steller sea lions (Eumetopias jubatus). We subjected 4 female Steller sea lions to 3 feeding regimes over 70-day trials (unrestricted food intake, acute nutritional stress, and chronic nutritional stress), and drew blood samples from each animal at the end of each feeding regime. We then extracted the RNA of white blood cells and measured the response of 8 genes known to react to diet restriction in terrestrial mammals. Overall, we found that the genomic response of Steller sea lions experiencing nutritional stress was consistent with how terrestrial mammals respond to dietary restrictions. Our nutritionally stressed sea lions down-regulated some cellular processes involved in immune response and oxidative stress, and up-regulated pro-inflammatory responses and metabolic processes. Nutrigenomics appears to be a promising means to monitor nutritional status and contribute to mitigation measures needed to assist in the recovery of Steller sea lions and other at-risk species of marine mammals.
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Affiliation(s)
- Jérôme Spitz
- Marine Mammal Research Unit, Fisheries Centre, University of British Columbia, 2202 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada.
| | - Vanessa Becquet
- Littoral Environnement et Sociétés, UMR 7266 Université de La Rochelle/CNRS, 2 rue Olympe de Gouges, 17042 La Rochelle, Cedex, France
| | - David A S Rosen
- Marine Mammal Research Unit, Fisheries Centre, University of British Columbia, 2202 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Andrew W Trites
- Marine Mammal Research Unit, Fisheries Centre, University of British Columbia, 2202 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
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36
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Lambert C, Mannocci L, Lehodey P, Ridoux V. Predicting cetacean habitats from their energetic needs and the distribution of their prey in two contrasted tropical regions. PLoS One 2014; 9:e105958. [PMID: 25162643 PMCID: PMC4146581 DOI: 10.1371/journal.pone.0105958] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 07/31/2014] [Indexed: 11/18/2022] Open
Abstract
To date, most habitat models of cetaceans have relied on static and oceanographic covariates, and very few have related cetaceans directly to the distribution of their prey, as a result of the limited availability of prey data. By simulating the distribution of six functional micronekton groups between the surface and ≃1,000 m deep, the SEAPODYM model provides valuable insights into prey distributions. We used SEAPODYM outputs to investigate the habitat of three cetacean guilds with increasing energy requirements: sperm and beaked whales, Globicephalinae and Delphininae. We expected High Energy Requirements cetaceans to preferentially forage in habitats of high prey biomass and/or production, where they might easily meet their high energetic needs, and Low Energy Requirements cetaceans to forage in habitats of either high or low prey biomass and/or production. Cetacean sightings were collected from dedicated aerial surveys in the South West Indian Ocean (SWIO) and French Polynesia (FP). We examined cetacean densities in relation to simulated distributions of their potential prey using Generalised Additive Models and predicted their habitats in both regions. Results supported their known diving abilities, with Delphininae mostly related to prey present in the upper layers of the water column, and Globicephalinae and sperm and beaked whales also related to prey present in deeper layers. Explained deviances ranged from 9% for sperm and beaked whales in the SWIO to 47% for Globicephalinae in FP. Delphininae and Globicephalinae appeared to select areas where high prey biomass and/or production were available at shallow depths. In contrast, sperm and beaked whales showed less clear habitat selection. Using simulated prey distributions as predictors in cetacean habitat models is crucial to understand their strategies of habitat selection in the three dimensions of the ocean.
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Affiliation(s)
- Charlotte Lambert
- Centre d'Études Biologiques de Chizé-La Rochelle, UMR 7372 Université de La Rochelle - CNRS, Institut du Littoral et de l'Environnement, La Rochelle, France
| | - Laura Mannocci
- Marine Geospatial Ecology Lab, Duke University West Campus, Durham, North Carolina, United States of America
| | - Patrick Lehodey
- MEMMS (Marine Ecosystems Modeling and Monitoring by Satellites), CLS, Space Oceanography Division, Ramonville, France
| | - Vincent Ridoux
- Centre d'Études Biologiques de Chizé-La Rochelle, UMR 7372 Université de La Rochelle - CNRS, Institut du Littoral et de l'Environnement, La Rochelle, France; Observatoire PELAGIS, UMS 3462 Université de La Rochelle - CNRS, Systèmes d'Observation pour la Conservation des Mammifères et des Oiseaux Marins, La Rochelle, France
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37
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Spitz J, Ridoux V, Brind'Amour A. Let's go beyond taxonomy in diet description: testing a trait-based approach to prey-predator relationships. J Anim Ecol 2014; 83:1137-48. [DOI: 10.1111/1365-2656.12218] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 03/11/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Jérôme Spitz
- Littoral Environnement & Sociétés; UMR 7266 Université de La Rochelle/CNRS; 17042 La Rochelle France
- Marine Mammal Research Unit; Fisheries Centre; University of British Columbia; 2202 Main Mall Vancouver BC V6T 1Z4 Canada
| | - Vincent Ridoux
- Observatoire PELAGIS - Système d'Observation pour la Conservation des Mammifères et Oiseaux Marins; UMS 3462; CNRS/Université de La Rochelle; 17071 La Rochelle France
- Centre d'études biologiques de Chizé - La Rochelle; UMR 7372; Université de La Rochelle/CNRS; 79360 Villiers en Bois France
| | - Anik Brind'Amour
- Ifremer; Département Écologie et Modèles pour l'Halieutique; Rue de l'île d'Yeu; BP 21105 44311 Nantes France
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Boersma PD, Rebstock GA. Climate change increases reproductive failure in Magellanic penguins. PLoS One 2014; 9:e85602. [PMID: 24489663 PMCID: PMC3906009 DOI: 10.1371/journal.pone.0085602] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 11/28/2013] [Indexed: 11/24/2022] Open
Abstract
Climate change is causing more frequent and intense storms, and climate models predict this trend will continue, potentially affecting wildlife populations. Since 1960 the number of days with >20 mm of rain increased near Punta Tombo, Argentina. Between 1983 and 2010 we followed 3496 known-age Magellanic penguin (Spheniscus magellanicus) chicks at Punta Tombo to determine how weather impacted their survival. In two years, rain was the most common cause of death killing 50% and 43% of chicks. In 26 years starvation killed the most chicks. Starvation and predation were present in all years. Chicks died in storms in 13 of 28 years and in 16 of 233 storms. Storm mortality was additive; there was no relationship between the number of chicks killed in storms and the numbers that starved (P = 0.75) or that were eaten (P = 0.39). However, when more chicks died in storms, fewer chicks fledged (P = 0.05, R2 = 0.14). More chicks died when rainfall was higher and air temperature lower. Most chicks died from storms when they were 9–23 days old; the oldest chick killed in a storm was 41 days old. Storms with heavier rainfall killed older chicks as well as more chicks. Chicks up to 70 days old were killed by heat. Burrow nests mitigated storm mortality (N = 1063). The age span of chicks in the colony at any given time increased because the synchrony of egg laying decreased since 1983, lengthening the time when chicks are vulnerable to storms. Climate change that increases the frequency and intensity of storms results in more reproductive failure of Magellanic penguins, a pattern likely to apply to many species breeding in the region. Climate variability has already lowered reproductive success of Magellanic penguins and is likely undermining the resilience of many other species.
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Affiliation(s)
- P. Dee Boersma
- Department of Biology, University of Washington, Seattle, Washington, United States of America
- Wildlife Conservation Society, Bronx, New York, United States of America
- * E-mail: .
| | - Ginger A. Rebstock
- Department of Biology, University of Washington, Seattle, Washington, United States of America
- Wildlife Conservation Society, Bronx, New York, United States of America
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Kowalczyk ND, Chiaradia A, Preston TJ, Reina RD. Linking dietary shifts and reproductive failure in seabirds: a stable isotope approach. Funct Ecol 2013. [DOI: 10.1111/1365-2435.12216] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nicole D. Kowalczyk
- School of Biological Sciences Monash University Clayton Victoria3800 Australia
| | - Andre Chiaradia
- School of Biological Sciences Monash University Clayton Victoria3800 Australia
- Research Department Phillip Island Nature Parks PO Box 97Cowes Victoria3922 Australia
| | - Tiana J. Preston
- School of Biological Sciences Monash University Clayton Victoria3800 Australia
| | - Richard D. Reina
- School of Biological Sciences Monash University Clayton Victoria3800 Australia
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40
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Spitz J, Jouma'a J. Variability in energy density of forage fishes from the Bay of Biscay (north-east Atlantic Ocean): reliability of functional grouping based on prey quality. JOURNAL OF FISH BIOLOGY 2013; 82:2147-2152. [PMID: 23731160 DOI: 10.1111/jfb.12142] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 03/29/2013] [Indexed: 06/02/2023]
Abstract
Energy densities of 670 fishes belonging to nine species were measured to evaluate intraspecific variability. Functional groups based on energy density appeared to be sufficiently robust to individual variability to provide a classification of forage fish quality applicable in a variety of ecological fields including ecosystem modelling.
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Affiliation(s)
- J Spitz
- Littoral Environnement et Sociétés, UMR 7266 Université de La Rochelle, CNRS, La Rochelle, France.
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41
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Bellingeri M, Vincenzi S. Robustness of empirical food webs with varying consumer's sensitivities to loss of resources. J Theor Biol 2013; 333:18-26. [PMID: 23685067 DOI: 10.1016/j.jtbi.2013.04.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 04/18/2013] [Accepted: 04/25/2013] [Indexed: 11/17/2022]
Abstract
Food web responses to species loss have been mostly studied in binary food webs, thus without accounting for the amount of energy transferred in consumer-resource interactions. We introduce an energetic criterion, called extinction threshold, for which a species goes secondarily extinct when a certain fraction of its incoming energy is lost. We study the robustness to random node loss of 10 food webs based on empirically-derived weightings. We use different extinction scenarios (random removal and from most- to least-connected species), and we simulate 10(5) replicates for each extinction threshold to account for stochasticity of extinction dynamics. We quantified robustness on the basis of how many additional species (i.e. secondary extinctions) were lost after the direct removal of species (i.e. primary extinctions). For all food webs, the expected robustness linearly decreases with extinction threshold, although a large variance in robustness is observed. The sensitivity of robustness to variations in extinction threshold increases with food web species richness and quantitative unweighted link density, while we observed a nonlinear relationship when the predictor is food web connectance and no relationship with the proportion of autotrophs.
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Affiliation(s)
- Michele Bellingeri
- Department of Physics, University of Parma, Viale Usberti 7/A, I-43124 Parma, Italy
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Luczak C, Beaugrand G, Lindley JA, Dewarumez JM, Dubois PJ, Kirby RR. Population dynamics in lesser black-backed gulls in the Netherlands support a North Sea regime shift. Biol Lett 2013; 9:20130127. [PMID: 23485878 PMCID: PMC3645047 DOI: 10.1098/rsbl.2013.0127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- C. Luczak
- Université d'Artois, IUFM, centre de Gravelines, 40, rue Victor Hugo, BP129, Gravelines 59820, France
- Centre National de la Recherche Scientifique, LOG UMR 8187, Université Lille 1, Wimereux, France
| | - G. Beaugrand
- Centre National de la Recherche Scientifique, LOG UMR 8187, Université Lille 1, Wimereux, France
| | - J. A. Lindley
- Sir Alister Hardy Foundation for Ocean Science, Plymouth, UK
| | - J.-M. Dewarumez
- Centre National de la Recherche Scientifique, LOG UMR 8187, Université Lille 1, Wimereux, France
| | - P. J. Dubois
- Centre National de la Recherche Scientifique, LOG UMR 8187, Université Lille 1, Wimereux, France
| | - R. R. Kirby
- Marine Institute, Plymouth University, Plymouth PL4 8AA, UK
- e-mail:
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Cost of living dictates what whales, dolphins and porpoises eat: the importance of prey quality on predator foraging strategies. PLoS One 2012. [PMID: 23185542 PMCID: PMC3503768 DOI: 10.1371/journal.pone.0050096] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Understanding the mechanisms that drive prey selection is a major challenge in foraging ecology. Most studies of foraging strategies have focused on behavioural costs, and have generally failed to recognize that differences in the quality of prey may be as important to predators as the costs of acquisition. Here, we tested whether there is a relationship between the quality of diets (kJ·g−1) consumed by cetaceans in the North Atlantic and their metabolic costs of living as estimated by indicators of muscle performance (mitochondrial density, n = 60, and lipid content, n = 37). We found that the cost of living of 11 cetacean species is tightly coupled with the quality of prey they consume. This relationship between diet quality and cost of living appears to be independent of phylogeny and body size, and runs counter to predictions that stem from the well-known scaling relationships between mass and metabolic rates. Our finding suggests that the quality of prey rather than the sheer quantity of food is a major determinant of foraging strategies employed by predators to meet their specific energy requirements. This predator-specific dependence on food quality appears to reflect the evolution of ecological strategies at a species level, and has implications for risk assessment associated with the consequences of changing the quality and quantities of prey available to top predators in marine ecosystems.
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Stable isotope analysis challenges wasp-waist food web assumptions in an upwelling pelagic ecosystem. Sci Rep 2012; 2:654. [PMID: 22977729 PMCID: PMC3440624 DOI: 10.1038/srep00654] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 08/24/2012] [Indexed: 11/17/2022] Open
Abstract
Eastern boundary currents are often described as ‘wasp-waist’ ecosystems in which one or few mid-level forage species support a high diversity of larger predators that are highly susceptible to fluctuations in prey biomass. The assumption of wasp-waist control has not been empirically tested in all such ecosystems. This study used stable isotope analysis to test the hypothesis of wasp-waist control in the southern California Current large marine ecosystem (CCLME). We analyzed prey and predator tissue for δ13C and δ15N and used Bayesian mixing models to provide estimates of CCLME trophic dynamics from 2007–2010. Our results show high omnivory, planktivory by some predators, and a higher degree of trophic connectivity than that suggested by the wasp-waist model. Based on this study period, wasp-waist models oversimplify trophic dynamics within the CCLME and potentially other upwelling, pelagic ecosystems. Higher trophic connectivity in the CCLME likely increases ecosystem stability and resilience to perturbations.
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Lewison R, Oro D, Godley B, Underhill L, Bearhop S, Wilson RP, Ainley D, Arcos JM, Boersma PD, Borboroglu PG, Boulinier T, Frederiksen M, Genovart M, González-Solís J, Green JA, Grémillet D, Hamer KC, Hilton GM, Hyrenbach KD, Martínez-Abraín A, Montevecchi WA, Phillips RA, Ryan PG, Sagar P, Sydeman WJ, Wanless S, Watanuki Y, Weimerskirch H, Yorio P. Research priorities for seabirds: improving conservation and management in the 21st century. ENDANGER SPECIES RES 2012. [DOI: 10.3354/esr00419] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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49
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Weis JS, Bergey L, Reichmuth J, Candelmo A. Living in a Contaminated Estuary: Behavioral Changes and Ecological Consequences for Five Species. Bioscience 2011. [DOI: 10.1525/bio.2011.61.5.6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Granadeiro JP, Phillips RA, Brickle P, Catry P. Albatrosses following fishing vessels: how badly hooked are they on an easy meal? PLoS One 2011; 6:e17467. [PMID: 21399696 PMCID: PMC3047564 DOI: 10.1371/journal.pone.0017467] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2010] [Accepted: 02/03/2011] [Indexed: 11/18/2022] Open
Abstract
Fisheries have major impacts on seabirds, both by changing food availability and by causing direct mortality of birds during trawling and longline setting. However, little is known about the nature and the spatial-temporal extent of the interactions between individual birds and vessels. By studying a system in which we had fine-scale data on bird movements and activity, and near real-time information on vessel distribution, we provide new insights on the association of a threatened albatross with fisheries. During early chick-rearing, black-browed albatrosses Thalassarche melanophris from two different colonies (separated by only 75 km) showed significant differences in the degree of association with fisheries, despite being nearly equidistant to the Falklands fishing fleet. Most foraging trips from either colony did not bring tracked individuals close to vessels, and proportionally little time and foraging effort was spent near ships. Nevertheless, a few individuals repeatedly visited fishing vessels, which may indicate they specialise on fisheries-linked food sources and so are potentially more vulnerable to bycatch. The evidence suggests that this population has little reliance on fisheries discards at a critical stage of its nesting cycle, and hence measures to limit fisheries waste on the Patagonian shelf that also reduce vessel attractiveness and the risk of incidental mortality, would be of high overall conservation benefit.
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Affiliation(s)
- José P Granadeiro
- CESAM, Museu Nacional de História Natural, Universidade de Lisboa, Lisboa, Portugal.
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