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Ivanova ES, Belova MA, Rumiantseva OY, Zudilova AA, Kopylov DS, Borisov MY, Komov VT. Effects of lipid extraction on stable isotope ratios of carbon and nitrogen in muscles of freshwater fish. ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2024; 60:162-173. [PMID: 38353149 DOI: 10.1080/10256016.2024.2317379] [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: 01/16/2024] [Accepted: 01/28/2024] [Indexed: 03/20/2024]
Abstract
The extraction of lipids by the Folch method from the muscles of all the fish studied led to statistically significant differences in the values of δ15N. At the same time, lipid extraction led to a statistically significant increase in δ13C in pike and roach, and to a statistically insignificant decrease in δ13C in perch and bream. Thus, lipid extraction cannot serve as a universal method of sample preparation for the analysis of the isotopic composition of carbon (13C/12C) and nitrogen (15N/14N) in fish muscles. The differences between the δ13C values in the samples before and after lipid extraction were statistically investigated by different models. It is shown that mathematical correction method models can be used, but the results are depending on the fish types.
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Affiliation(s)
- Elena S Ivanova
- Department of Biology, Cherepovets State University, Cherepovets, Russia
| | - Maria A Belova
- Department of Biology, Cherepovets State University, Cherepovets, Russia
| | | | - Alena A Zudilova
- Department of Biology, Cherepovets State University, Cherepovets, Russia
| | - Dmitry S Kopylov
- Department of Biology, Cherepovets State University, Cherepovets, Russia
- Borissiak Paleontological Institute, Russian Academy of Sciences, Moscow, Russia
| | - Michael Y Borisov
- Vologda Branch of the Federal State Budget Scientific Institution «Russian Federal Research Institute of Fisheries and Oceanography», Vologda, Russia
| | - Viktor T Komov
- Department of Biology, Cherepovets State University, Cherepovets, Russia
- Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, Russia
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Eggebo J, Groß J, Bengtson Nash S. Interpretation of southern hemisphere humpback whale diet via stable isotopes; implications of tissue-specific analysis. PLoS One 2023; 18:e0283330. [PMID: 37011067 PMCID: PMC10069779 DOI: 10.1371/journal.pone.0283330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 03/07/2023] [Indexed: 04/05/2023] Open
Abstract
Blubber and skin are commonly used tissues in stable isotope analysis for the purpose of investigating cetacean diet. Critical comparison of tissue-specific isotopic signals is, however, lacking resulting in uncertainty surrounding the representativeness and therefore utility of different tissues for accurate determination of recent foraging. This study used remotely biopsied blubber and skin tissues from southern hemisphere humpback whales for strategic comparison of δ13C and δ15N values. Samples were collected between 2008-2018 as part of long-term monitoring under the Humpback Whale Sentinel Program. Blubber tissues were lipid-extracted prior to analysis, whilst mathematical lipid-correction was performed on skin samples. Isotopic values from paired blubber and skin samples from the same individuals were compared to assess whether tissues could be used interchangeably for isotope analysis and dietary interpretation. Significant differences were observed for both δ13C and δ15N, flagging previously undocumented methodological considerations, and the need for method validation and standardisation in application of these approaches. This study therefore advances methodological aspects of cetacean dietary analysis. This is of elevated importance in the context of rapidly changing ocean ecosystems.
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Affiliation(s)
- June Eggebo
- Southern Ocean Persistent Organic Pollutants Program, Centre for Planetary Health and Food Security, School of Environment and Science, Griffith University, Nathan, QLD, Australia
| | - Jasmin Groß
- Southern Ocean Persistent Organic Pollutants Program, Centre for Planetary Health and Food Security, School of Environment and Science, Griffith University, Nathan, QLD, Australia
| | - Susan Bengtson Nash
- Southern Ocean Persistent Organic Pollutants Program, Centre for Planetary Health and Food Security, School of Environment and Science, Griffith University, Nathan, QLD, Australia
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Riverón S, Raoult V, Slip DJ, Harcourt RG. Lipid extraction has tissue-dependent effects on isotopic values (δ 34 S, δ 13 C, and δ 15 N) from different marine predators. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2022; 36:e9346. [PMID: 35737589 PMCID: PMC9539579 DOI: 10.1002/rcm.9346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 05/31/2022] [Accepted: 06/22/2022] [Indexed: 06/15/2023]
Abstract
RATIONALE The use of sulfur isotopes to study trophic ecology in marine ecosystems has increased in the past decade. Unlike other commonly used isotopes (e.g., carbon), sulfur can better discriminate benthic and pelagic productivity. However, how lipid extraction affects sulfur isotopic values has not been assessed, despite its frequent use to remove lipid effects on δ13 C values. METHODS We used white muscle and liver samples from two species of sharks and skin samples from two species of pinnipeds (sea lion and fur seal) to assess the effects of lipid extraction on stable isotope values for δ34 S, δ13 C, and δ15 N. Isotopic values were determined using a continuous flow-isotope ratio mass spectrometer coupled to an elemental analyzer. RESULTS Lipid extraction significantly decreased δ34 S values in shark tissues, more so for liver than muscle (-4.6 ± 0.9‰ vs -0.8 ± 0.3‰, average change), with nearly no change in their standard deviations. Lipid extraction did not affect δ34 S values from pinniped skin samples (0.2 ± 0.8‰, average change). After lipid extraction, consistent increases in δ13 C values (0.2‰-7.3‰) were detected as expected, especially in tissue with high lipid content (C:N >4). After lipid extraction, significant increases in δ15 N values (0.5‰-1.4‰) were found in shark muscle and liver tissues. For pinniped skin samples, δ15 N values were not significantly lower after lipid extraction (-0.4‰ to -0.1‰). CONCLUSIONS Lipid extraction did not have a strong impact on δ34 S values of shark muscle and pinniped skin (≤1‰). However, our results suggest it is essential to consider the effects of lipid extraction when interpreting results from δ34 S values of shark liver tissue, as they significantly depleted values relative to bulk tissue (~5‰). This may reflect selective removal of sulfolipids and glutathione present in higher concentrations in the liver than in muscle and skin and requires further investigation.
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Affiliation(s)
- Sabrina Riverón
- Marine Predator Research Group, School of Natural SciencesMacquarie UniversitySydneyNew South WalesAustralia
| | - Vincent Raoult
- School of Environmental and Life SciencesUniversity of NewcastleOurimbahNew South WalesAustralia
- Marine Ecology GroupSchool of Natural SciencesMacquarie UniversitySydneyNew South WalesAustralia
| | - David J. Slip
- Marine Predator Research Group, School of Natural SciencesMacquarie UniversitySydneyNew South WalesAustralia
- Taronga Institute of Science and LearningTaronga Conservation Society AustraliaSydneyNew South WalesAustralia
| | - Robert G. Harcourt
- Marine Predator Research Group, School of Natural SciencesMacquarie UniversitySydneyNew South WalesAustralia
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Too Close for Comfort? Isotopic Niche Segregation in New Zealand’s Odontocetes. BIOLOGY 2022; 11:biology11081179. [PMID: 36009806 PMCID: PMC9405429 DOI: 10.3390/biology11081179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 07/30/2022] [Accepted: 08/02/2022] [Indexed: 11/17/2022]
Abstract
Simple Summary We used carbon and nitrogen stable isotopes as ecological tracers to investigate isotopic niche overlap between 21 odontocete (toothed whale) species inhabiting neritic, mesopelagic, and bathypelagic waters. Results showed a clear niche separation for the bathypelagic Gray’s beaked whales (Mesoplodon grayi) and sperm whales (Physeter macrocephalus), but high isotopic niche overlap and potential interspecific competition for neritic and mesopelagic species. This study represents the first insights into the coexistence of odontocetes in a biodiverse hotspot and provides a critical baseline for a system already undergoing ecosystem changes via ocean warming and its subsequent effect on prey abundance and distribution. Abstract Species occurring in sympatry and relying on similar and limited resources may partition resource use to avoid overlap and interspecific competition. Aotearoa, New Zealand hosts an extraordinarily rich marine megafauna, including 50% of the world’s cetacean species. In this study, we used carbon and nitrogen stable isotopes as ecological tracers to investigate isotopic niche overlap between 21 odontocete (toothed whale) species inhabiting neritic, mesopelagic, and bathypelagic waters. Results showed a clear niche separation for the bathypelagic Gray’s beaked whales (Mesoplodon grayi) and sperm whales (Physeter macrocephalus), but high isotopic niche overlap and potential interspecific competition for neritic and mesopelagic species. For these species, competition could be reduced via temporal or finer-scale spatial segregation or differences in foraging behaviour. This study represents the first insights into the coexistence of odontocetes in a biodiverse hotspot. The data presented here provide a critical baseline to a system already ongoing ecosystem change via ocean warming and subsequent effects on prey abundance and distributions.
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Parra GJ, Wojtkowiak Z, Peters KJ, Cagnazzi D. Isotopic niche overlap between sympatric Australian snubfin and humpback dolphins. Ecol Evol 2022; 12:e8937. [PMID: 35646312 PMCID: PMC9130291 DOI: 10.1002/ece3.8937] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/08/2022] [Accepted: 04/25/2022] [Indexed: 11/11/2022] Open
Abstract
Ecological niche theory predicts the coexistence of closely related species is promoted by resource partitioning in space and time. Australian snubfin (Orcaella heinsohni) and humpback (Sousa sahulensis) dolphins live in sympatry throughout most of their range in northern Australian waters. We compared stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in their skin to investigate resource partitioning between these ecologically similar species. Skin samples were collected from live Australian snubfin (n = 31) and humpback dolphins (n = 23) along the east coast of Queensland in 2014–2015. Both species had similar δ13C and δ15N values and high (>50%) isotopic niche space overlap, suggesting that they feed at similar trophic levels, have substantial dietary overlap, and rely on similar basal food resources. Despite similarities, snubfin dolphins were more likely to have a larger δ15N value than humpback dolphins, indicating they may forage on a wider diversity of prey. Humpback dolphins were more likely to have a larger δ13C range suggesting they may forage on a wider range of habitats. Overall, results suggest that subtle differences in habitat use and prey selection are likely the principal resource partitioning mechanisms enabling the coexistence of Australian snubfin and humpback dolphins.
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Affiliation(s)
- Guido J. Parra
- Cetacean Ecology, Behavior and Evolution Lab College of Science and Engineering Flinders University Adelaide South Australia Australia
| | - Zachary Wojtkowiak
- Cetacean Ecology, Behavior and Evolution Lab College of Science and Engineering Flinders University Adelaide South Australia Australia
| | - Katharina J. Peters
- Evolutionary Genetics Group Department of Anthropology University of Zurich Zurich Switzerland
- School of Earth and Environment University of Canterbury Christchurch New Zealand
| | - Daniele Cagnazzi
- Marine Ecology Research Centre Faculty of Science and Engineering Southern Cross University Lismore New South Wales Australia
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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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Annasawmy P, Point D, Romanov EV, Bodin N. Mercury concentrations and stable isotope ratios (δ 13C and δ 15N) in pelagic nekton assemblages of the south-western Indian Ocean. MARINE POLLUTION BULLETIN 2022; 174:113151. [PMID: 34883442 DOI: 10.1016/j.marpolbul.2021.113151] [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: 06/29/2021] [Revised: 09/15/2021] [Accepted: 11/12/2021] [Indexed: 06/13/2023]
Abstract
Mercury (Hg) concentrations and stable isotope values (δ13C and δ15N) were investigated in micronekton collected from La Pérouse and MAD-Ridge seamounts, Reunion Island and the southern Mozambique Channel. Organisms occupying epipelagic habitats showed lower Hg concentrations relative to deeper dwelling benthopelagic ones. Increasing Hg concentrations with increasing body size were recorded in the Mozambique Channel and Reunion Island. Positive relationships were observed between Hg levels and δ15N values in pelagic nekton assemblages collected at MAD-Ridge seamount and the southern Mozambique Channel, suggesting biomagnification of Hg. Concentrations of Hg in organisms across the south-western Indian Ocean were within the same range of values. Total Hg concentrations depend on a range of factors linked to habitat range, body size and trophic position of the individuals. To our knowledge, this is the first study investigating the patterns of Hg concentrations in pelagic nekton assemblages from the south-western Indian Ocean.
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Affiliation(s)
- Pavanee Annasawmy
- Géosciences Environnement Toulouse (GET), UMR 5563 CNRS, IRD, UPS, CNES, Observatoire Midi Pyrénées (OMP), 31400 Toulouse, France.
| | - David Point
- Géosciences Environnement Toulouse (GET), UMR 5563 CNRS, IRD, UPS, CNES, Observatoire Midi Pyrénées (OMP), 31400 Toulouse, France
| | - Evgeny V Romanov
- Centre technique de recherche et de valorisation des milieux aquatiques (CITEB), 97420 Le Port, Île de la Réunion, France
| | - Nathalie Bodin
- Institut de Recherche pour le Développement (IRD), Fishing Port, Victoria, Mahé, Seychelles; Sustainable Ocean Seychelles, Beau Belle, Mahé, Seychelles
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Cloyed CS, Balmer BC, Schwacke LH, Wells RS, Berens McCabe EJ, Barleycorn AA, Allen JB, Rowles TK, Smith CR, Takeshita R, Townsend FI, Tumlin MC, Zolman ES, Carmichael RH. Interaction between dietary and habitat niche breadth influences cetacean vulnerability to environmental disturbance. Ecosphere 2021. [DOI: 10.1002/ecs2.3759] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Carl S. Cloyed
- Dauphin Island Sea Lab 101 Bienville Boulevard Dauphin Island Alabama 36608 USA
- Department of Marine Sciences University of South Alabama Mobile Alabama 36688 USA
| | - Brian C. Balmer
- National Marine Mammal Foundation 3419 Maybank Highway Johns Island South Carolina 29487 USA
| | - Lori H. Schwacke
- National Marine Mammal Foundation 3419 Maybank Highway Johns Island South Carolina 29487 USA
| | - Randall S. Wells
- Chicago Zoological Society’s Sarasota Dolphin Research Program, c/o Mote Marine Laboratory 1600 Ken Thompson Parkway Sarasota Florida 34236 USA
| | - Elizabeth J. Berens McCabe
- Chicago Zoological Society’s Sarasota Dolphin Research Program, c/o Mote Marine Laboratory 1600 Ken Thompson Parkway Sarasota Florida 34236 USA
| | - Aaron A. Barleycorn
- Chicago Zoological Society’s Sarasota Dolphin Research Program, c/o Mote Marine Laboratory 1600 Ken Thompson Parkway Sarasota Florida 34236 USA
| | - Jason B. Allen
- Chicago Zoological Society’s Sarasota Dolphin Research Program, c/o Mote Marine Laboratory 1600 Ken Thompson Parkway Sarasota Florida 34236 USA
| | - Teresa K. Rowles
- Office of Protected Resources National Marine Fisheries Service NOAA 1315 East West Highway Silver Spring Maryland 20910 USA
| | - Cynthia R. Smith
- National Marine Mammal Foundation 2240 Shelter Island Drive #200 San Diego California 92106 USA
| | - Ryan Takeshita
- National Marine Mammal Foundation 3419 Maybank Highway Johns Island South Carolina 29487 USA
| | - Forrest I. Townsend
- Bayside Hospital for Animals 251 Racetrack Road NE Fort Walton Beach Florida 32547 USA
| | - Mandy C. Tumlin
- Louisiana Department of Wildlife and Fisheries 2000 Quail Drive Baton Rouge Louisiana 70808 USA
| | - Eric S. Zolman
- National Marine Mammal Foundation 3419 Maybank Highway Johns Island South Carolina 29487 USA
| | - Ruth H. Carmichael
- Dauphin Island Sea Lab 101 Bienville Boulevard Dauphin Island Alabama 36608 USA
- Department of Marine Sciences University of South Alabama Mobile Alabama 36688 USA
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Groß J, Fry B, Burford MA, Bengtson Nash S. Assessing the effects of lipid extraction and lipid correction on stable isotope values (δ 13 C and δ 15 N) of blubber and skin from southern hemisphere humpback whales. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2021; 35:e9140. [PMID: 34097783 DOI: 10.1002/rcm.9140] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/26/2021] [Accepted: 06/04/2021] [Indexed: 06/12/2023]
Abstract
RATIONALE The coupled analysis of δ13 C and δ15 N stable isotope values of blubber and skin biopsy samples is widely used to study the diet of free-ranging cetaceans. Differences in the lipid content of these tissues can affect isotopic variability because lipids are depleted in 13 C, reducing the bulk tissue 13 C/12 C. This variability in carbon isotope values can be accounted for either by chemically extracting lipids from the tissue or by using mathematical lipid normalisation models. METHODS This study examines (a) the effects of chemical lipid extraction on δ13 C and δ15 N values in blubber and skin of southern hemisphere humpback whales, (b) whether chemical lipid extraction is more favourable than mathematical lipid correction and (c) which of the two tissues is more appropriate for dietary studies. Strategic comparisons were made between chemical lipid extraction and mathematical lipid correction and between blubber and skin tissue δ13 C and δ15 N values, as well as C:N ratios. Six existing mathematical normalisation models were tested for their efficacy in estimating lipid-free δ13 C for skin. RESULTS Both δ13 C and δ15 N values of lipid-extracted skin (δ13 C: -25.57‰, δ15 N: 6.83‰) were significantly higher than those of bulk skin (δ13 C: -26.97‰, δ15 N: 6.15‰). Five of the six tested lipid normalisation models had small error terms for predicting lipid-free δ13 C values. The average C:N ratio of lipid-extracted skin was within the lipid-free range reported in other studies, whereas the average C:N ratio of blubber was higher than previously reported. CONCLUSIONS These results highlight the need to account for lipids when analysing δ13 C and δ15 N values from the same sample. For optimised dietary assessments using parallel isotope analysis from a single sample, we recommend the use of unextracted skin tissue. δ15 N values should be obtained from unextracted skin, whereas δ13 C values may be adequately lipid corrected by a mathematical correction.
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Affiliation(s)
- Jasmin Groß
- Centre for Planetary Health and Food Security, Southern Ocean Persistent Organic Pollutants Program, Griffith University, Nathan, Queensland, Australia
| | - Brian Fry
- Australian Rivers Institute, Griffith University, Nathan, Queensland, Australia
| | - Michele A Burford
- Australian Rivers Institute, Griffith University, Nathan, Queensland, Australia
| | - Susan Bengtson Nash
- Centre for Planetary Health and Food Security, Southern Ocean Persistent Organic Pollutants Program, Griffith University, Nathan, Queensland, Australia
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Jory C, Lesage V, Leclerc A, Giard J, Iverson S, Bérubé M, Michaud R, Nozais C. Individual and population dietary specialization decline in fin whales during a period of ecosystem shift. Sci Rep 2021; 11:17181. [PMID: 34433851 PMCID: PMC8387503 DOI: 10.1038/s41598-021-96283-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 07/28/2021] [Indexed: 11/25/2022] Open
Abstract
This study sought to estimate the effect of an anthropogenic and climate-driven change in prey availability on the degree of individual and population specialization of a large marine predator, the fin whale (Balaenoptera physalus). We examined skin biopsies from 99 fin whales sampled in the St. Lawrence Estuary (Canada) over a nine year period (1998–2006) during which environmental change was documented. We analyzed stable isotope ratios in skin and fatty acid signatures in blubber samples of whales, as well as in seven potential prey species, and diet was quantitatively assessed using Bayesian isotopic models. An abrupt change in fin whale dietary niche coincided with a decrease in biomass of their predominant prey, Arctic krill (Thysanoessa spp.). This dietary niche widening toward generalist diets occurred in nearly 60% of sampled individuals. The fin whale population, typically composed of specialists of either krill or lipid-rich pelagic fishes, shifted toward one composed either of krill specialists or true generalists feeding on various zooplankton and fish prey. This change likely reduced intraspecific competition. In the context of the current “Atlantification” of northern water masses, our findings emphasize the importance of considering individual-specific foraging tactics and not only population or group average responses when assessing population resilience or when implementing conservation measures.
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Affiliation(s)
- Cabrol Jory
- Maurice Lamontagne Institute, Fisheries and Oceans Canada, Mont-Joli, QC, Canada.
| | - Véronique Lesage
- Maurice Lamontagne Institute, Fisheries and Oceans Canada, Mont-Joli, QC, Canada.,Département de Biologie, Chimie et Géographie, Québec-Océan, Université du Québec à Rimouski, Rimouski, QC, Canada
| | - Alexandra Leclerc
- Maurice Lamontagne Institute, Fisheries and Oceans Canada, Mont-Joli, QC, Canada.,Département de Biologie, Chimie et Géographie, Québec-Océan, Université du Québec à Rimouski, Rimouski, QC, Canada
| | - Janie Giard
- Groupe de Recherche et d'Éducation sur les Mammifères Marins, Tadoussac, QC, Canada
| | - Sara Iverson
- Department of Biology, Dalhousie University, Halifax, NS, Canada
| | - Martine Bérubé
- Marine Evolution and Conservation, Groningen Institute of Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands.,Centre for Coastal Studies, Provincetown, MA, USA
| | - Robert Michaud
- Groupe de Recherche et d'Éducation sur les Mammifères Marins, Tadoussac, QC, Canada
| | - Christian Nozais
- Département de Biologie, Chimie et Géographie, Québec-Océan, Université du Québec à Rimouski, Rimouski, QC, Canada
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Johnson KF, Davoren GK. Stable isotope analysis reveals that humpback whales ( Megaptera novaeangliae) primarily consume capelin ( Mallotus villosus) in coastal Newfoundland, Canada. CAN J ZOOL 2021. [DOI: 10.1139/cjz-2020-0257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
On the Newfoundland (Canada) foraging ground, humpback whales (Megaptera novaeangliae (Borowski, 1781)) are found associated with a dominant forage fish species, capelin (Mallotus villosus (Müller, 1776)), that experienced a population collapse in the early 1990s and has not recovered. Our primary goal was to reconstruct dietary proportions of humpback whales on their summer foraging grounds off the northeast coast of Newfoundland during July–August 2016 and 2017 using a Bayesian stable isotope mixing model (MixSiar). Modelled dietary proportions were similar in both years, with capelin comprising ∼90% of the diet. However, both δ13C and δ15N in humpback whale skin differed significantly between years, resulting in minimal isotopic niche overlap (9%). Lipid-extracted and nonlipid-extracted skin samples were used to develop a lipid normalization equation: Δ13C = –3.184 + 1.011(C:N). Overall, findings suggest that capelin is the primary prey type of humpback whales in coastal Newfoundland, despite the continued collapsed state of the capelin population. Findings also reiterate that dietary reconstruction from stable isotope analysis of cetacean skin can be misinterpreted without concurrently sampled isotopic ratios of potential prey types.
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Affiliation(s)
- Kelsey F. Johnson
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Gail K. Davoren
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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First evidence of interchange of humpback whales (Megaptera novaeangliae) between the Magellan Strait and Antarctic Peninsula feeding grounds. Polar Biol 2021. [DOI: 10.1007/s00300-021-02827-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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13
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Remili A, Gallego P, Pinzone M, Castro C, Jauniaux T, Garigliany MM, Malarvannan G, Covaci A, Das K. Humpback whales (Megaptera novaeangliae) breeding off Mozambique and Ecuador show geographic variation of persistent organic pollutants and isotopic niches. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 267:115575. [PMID: 33254700 DOI: 10.1016/j.envpol.2020.115575] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 08/27/2020] [Accepted: 08/28/2020] [Indexed: 06/12/2023]
Abstract
Humpback whales (Megaptera novaeangliae) from the Southern Hemisphere carry information on persistent organic pollutants (POPs) from their feeding zones in Antarctica to their breeding grounds, making this species a sentinel of contaminants accumulation in the Southern Ocean. This study aimed to evaluate driving factors, namely feeding areas, trophic level, and sex, affecting POP concentrations in the blubber of humpback whales breeding off Mozambique and off Ecuador. Biopsies of free-ranging humpback whales including blubber and skin were collected in 2014 and 2015 from Ecuador (n = 59) and in 2017 from Mozambique (n = 89). In both populations, HCB was the major contaminant followed by DDTs > CHLs > PCBs > HCHs > PBDEs. POP concentrations were significantly higher in males compared to females. HCB, DDTs, HCHs and PBDEs were significantly different between whales from the Mozambique population and the Ecuador population. Sex and feeding habits were important driving factors accounting for POP concentrations in Ecuador whales. The whales from our study had some of the lowest POP concentrations measured for humpback whales in the world. These whales fed predominantly on krill as reflected from the low δ13C and δ15N values measured in the skin. However, the isotopic niches of whales from Mozambique and Ecuador did not overlap indicating that the two populations are feeding in different areas of the Southern Ocean.
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Affiliation(s)
- Anaïs Remili
- Freshwater and Oceanic Sciences Unit of ReSearch (FOCUS - Oceanology), University of Liege, 4000, Liege, Belgium; Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, H9X 3V9, Canada
| | - Pierre Gallego
- Freshwater and Oceanic Sciences Unit of ReSearch (FOCUS - Oceanology), University of Liege, 4000, Liege, Belgium; Odyssea asbl., 37 rue du Nord, L-4260, Esch-sur-Alzette, Luxembourg
| | - Marianna Pinzone
- Freshwater and Oceanic Sciences Unit of ReSearch (FOCUS - Oceanology), University of Liege, 4000, Liege, Belgium
| | - Cristina Castro
- Pacific Whale Foundation Ecuador, Malecón Julio Izurieta y Abdón Calderón. Palo Santo Travel, Puerto López - Manabí - Ecuador
| | - Thierry Jauniaux
- Department of Pathology, Veterinary College, University of Liege, Sart Tilman B43, 4000, Liege, Belgium
| | - Mutien-Marie Garigliany
- Department of Pathology, Veterinary College, University of Liege, Sart Tilman B43, 4000, Liege, Belgium
| | - Govindan Malarvannan
- Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk, Belgium
| | - Adrian Covaci
- Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk, Belgium
| | - Krishna Das
- Freshwater and Oceanic Sciences Unit of ReSearch (FOCUS - Oceanology), University of Liege, 4000, Liege, Belgium.
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Gelippi M, Popp B, Gauger MFW, Caraveo-Patiño J. Tracing gestation and lactation in free ranging gray whales using the stable isotopic composition of epidermis layers. PLoS One 2020; 15:e0240171. [PMID: 33119639 PMCID: PMC7595409 DOI: 10.1371/journal.pone.0240171] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 09/22/2020] [Indexed: 11/22/2022] Open
Abstract
The isotopic composition of baleen whales' epidermis structural layers can give information about dietary change over time. This study investigated if epidermis layers integrated isotopic values that record physiological changes from gestation to lactation. Epidermis tissues (n = 43) were collected from free ranging lactating female gray whale and calves during the beginning of three breeding seasons. Modelling of δ13C and δ15N values show intra- and inter-individual differences based on epidermal layers, age class and year of sampling. The isotopic composition of mother-calf pairs is correlated, and the estimates of the maximum mother-to-calf isotopic difference was ~1.4‰ for δ13C and between 1 and 1.5‰ for δ15N values. Change in δ15N values among epidermal layers in calves was associated with the transition from fetus to consumption of maternal milk. It is here proposed when lactation influences calf epidermis, δ15N values decrease consistently from the outermost to the innermost layer. However, if a calf was born only few days before collection, epidermis integrates more variable δ15N patterns because gestation still affects the isotopic composition of the layers. The possibility of calculating mother-to-calf nitrogen isotope fractionation, and the regularity of changes between calf layer δ15N values, allowed results of an isotopic clock model to predict the age of each calf when sampled with its mother. This model has the potential to be a straightforward method to estimate the beginning of lactation, therefore calf birth date when direct observations are not feasible. The non-lethal remote collection of epidermis appears to be an effective tool for the study of the physiology of reproduction of baleen whales. The parallel study of the three epidermal structural layers highlighted the importance of considering the unique mother-calf pair physiological status at the time of sampling time when stable isotope results are interpreted.
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Affiliation(s)
- Michelle Gelippi
- Centro de Investigaciones Biológicas del Noroeste, La Paz, B.C.S., México
| | - Brian Popp
- Department of Earth Sciences, University of Hawaii at Manoa, Honolulu, HI, United States of America
| | - Marco F. W. Gauger
- Centro de Investigaciones Biológicas del Noroeste, La Paz, B.C.S., México
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15
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Smith KJ, Trueman CN, France CAM, Peterson MJ. Evaluation of two lipid removal methods for stable carbon and nitrogen isotope analysis in whale tissue. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8851. [PMID: 32492222 DOI: 10.1002/rcm.8851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 04/30/2020] [Accepted: 06/02/2020] [Indexed: 06/11/2023]
Abstract
RATIONALE The presence of lipids in animal tissues can influence the interpretation of stable isotope data, particularly in lipid-rich tissues such as the skin and muscle of marine mammals. The traditionally employed chloroform-methanol delipidation protocol has the potential to alter δ15 N values in proteinaceous tissues. Our objective was to determine whether the use of cyclohexane could be an alternative extraction method, effectively removing lipids without altering δ15 N values. METHODS Kidney, liver, muscle, and skin samples were collected from beach-cast Sowerby's beaked whales (Mesoplodon bidens). Control subsamples were processed without delipidation extraction, and duplicate subsamples were extracted with either chloroform-methanol or cyclohexane. δ13 C, δ15 N, and C:N values were determined by continuous-flow elemental analysis isotope ratio mass spectrometry. Paired Wilcoxon tests were used to evaluate the change in isotope ratios after extraction, and unpaired Wilcoxon tests were used to evaluate differences in isotope ratios between extractions. RESULTS Use of cyclohexane is an effective delipidation technique for tissues with low and moderate lipid content. Chemical delipidation influenced δ15 N values; extracted samples generally showed an increase in δ15 N values which varied from 0.0‰ to 1.7‰. Chloroform-methanol extraction resulted in alterations to δ15 N values greater than the analytical precision for all analyzed tissues. Changes to δ15 N values after cyclohexane extraction were at or near the analytical precision for liver and muscle but greater than the analytical precision for kidney and skin. CONCLUSIONS We recommend processing duplicate subsamples for stable isotope analysis, one with and one without extraction, in order to obtain accurate values for each isotope ratio. Prolonged chemical extractions are not necessary to effectively remove lipids. When samples are limited, we suggest using cyclohexane for tissues with low or moderate lipid content, and chloroform-methanol for lipid-rich tissues.
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Affiliation(s)
- Kerri J Smith
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, USA
- Department of Vertebrate Zoology, National Museum of Natural History, Washington, DC, USA
| | - Clive N Trueman
- Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, SO45 4PJ, UK
| | - Christine A M France
- Museum Conservation Institute, Smithsonian Institution, Suitland, MD, 20746, USA
| | - Markus J Peterson
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, USA
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Reisinger RR, Carpenter-Kling T, Connan M, Cherel Y, Pistorius PA. Foraging behaviour and habitat-use drives niche segregation in sibling seabird species. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200649. [PMID: 33047027 PMCID: PMC7540780 DOI: 10.1098/rsos.200649] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 08/17/2020] [Indexed: 06/11/2023]
Abstract
To mediate competition, similar sympatric species are assumed to use different resources, or the same but geographically separated resources. The two giant petrels (Macronectes spp.) are intriguing in that they are morphologically similar seabirds with overlapping diets and distributions. To better understand the mechanisms allowing their coexistence, we investigated intra- and interspecific niche segregation at Marion Island (Southern Indian Ocean), one of the few localities where they breed in sympatry. We used GPS tracks from 94 individuals and remote-sensed environmental data to quantify habitat use, combined with blood carbon and nitrogen stable isotope ratios from 90 individuals to characterize their foraging habitat and trophic ecology. Females of both species made distant at-sea foraging trips and fed at a similar trophic level. However, they used distinct pelagic habitats. By contrast, males of both species mainly foraged on or near land, resulting in significant sexual segregation, but high interspecific habitat and diet overlap. However, some males showed flexible behavioural strategies, also making distant, pelagic foraging trips. Using contemporaneous tracking, environmental and stable isotope data we provide a clear example of how sympatric sibling species can be segregated along different foraging behaviour dimensions.
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Affiliation(s)
- Ryan R. Reisinger
- Marine Apex Predator Research Unit, Institute for Coastal and Marine Research and Department of Zoology, Nelson Mandela University, South Campus, Port Elizabeth 6031, South Africa
- Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-La Rochelle Université, 79360 Villiers-en-Bois, France
- Institute for Marine Sciences, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Tegan Carpenter-Kling
- Marine Apex Predator Research Unit, Institute for Coastal and Marine Research and Department of Zoology, Nelson Mandela University, South Campus, Port Elizabeth 6031, South Africa
- DST/NRF Centre of Excellence at the FitzPatrick Institute of African Ornithology, Department of Zoology, Nelson Mandela University, Port Elizabeth, South Africa
| | - Maëlle Connan
- Marine Apex Predator Research Unit, Institute for Coastal and Marine Research and Department of Zoology, Nelson Mandela University, South Campus, Port Elizabeth 6031, South Africa
| | - Yves Cherel
- Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-La Rochelle Université, 79360 Villiers-en-Bois, France
| | - Pierre A. Pistorius
- Marine Apex Predator Research Unit, Institute for Coastal and Marine Research and Department of Zoology, Nelson Mandela University, South Campus, Port Elizabeth 6031, South Africa
- DST/NRF Centre of Excellence at the FitzPatrick Institute of African Ornithology, Department of Zoology, Nelson Mandela University, Port Elizabeth, South Africa
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Kratofil MA, Ylitalo GM, Mahaffy SD, West KL, Baird RW. Life history and social structure as drivers of persistent organic pollutant levels and stable isotopes in Hawaiian false killer whales (Pseudorca crassidens). THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 733:138880. [PMID: 32446048 DOI: 10.1016/j.scitotenv.2020.138880] [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: 03/12/2020] [Revised: 04/15/2020] [Accepted: 04/19/2020] [Indexed: 06/11/2023]
Abstract
False killer whales are long-lived, slow to mature, apex predators, and therefore susceptible to bioaccumulation of persistent organic pollutants (POPs). Hawaiian waters are home to three distinct populations: pelagic; Northwestern Hawaiian Islands (NWHI) insular; and main Hawaiian Islands (MHI) insular. Following a precipitous decline over recent decades, the MHI population was listed as "endangered" under the Endangered Species Act in 2012. This study assesses the risk of POP exposure to these populations by examining pollutant concentrations and ratios from blubber samples (n = 56) related to life history characteristics and MHI social clusters. Samples were analyzed for PCBs, DDTs, PBDEs, and some organochlorine pesticides. Skin samples (n = 52) were analyzed for stable isotopes δ13C and δ15N to gain insight into MHI false killer whale foraging ecology. Pollutant levels were similar among populations, although MHI whales had a significantly higher mean ratio of DDTs/PCBs than NWHI whales. The ∑PCB concentrations of 28 MHI individuals (68%) sampled were equal to or greater than suggested thresholds for deleterious health effects in marine mammals. The highest POP values among our samples were found in four stranded MHI animals. Eight of 24 MHI adult females have not been documented to have given birth; whether they have yet to reproduce, are reproductive senescent, or are experiencing reproductive dysfunction related to high POP exposure is unknown. Juvenile/sub-adults had significantly higher concentrations of certain contaminants than those measured in adults, and may be at greater risk of negative health effects during development. Multivariate analyses, POP ratios, and stable isotope ratios indicate varying risk of POP exposure, foraging locations and potentially prey items among MHI social clusters. Our findings provide invaluable insight into the ongoing risk POPs pose to the MHI population's viability, as well as consideration of risk for the NWHI and pelagic stocks.
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Affiliation(s)
| | - Gina M Ylitalo
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Association, 2725 Montlake Boulevard East, Seattle, WA 98112, USA.
| | - Sabre D Mahaffy
- Cascadia Research Collective, 218½ W. 4th Avenue, Olympia, WA 98501, USA.
| | - Kristi L West
- Hawai'i Institute of Marine Biology, PO Box 1346, Kaneohe, HI 96744, USA; Human Nutrition Food and Animal Sciences, College of Tropical Agriculture and Human Resources, 1955 East West Road, Ag Sci 216, Honolulu, HI 96822, USA.
| | - Robin W Baird
- Cascadia Research Collective, 218½ W. 4th Avenue, Olympia, WA 98501, USA; Hawai'i Institute of Marine Biology, PO Box 1346, Kaneohe, HI 96744, USA.
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18
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Jourdain E, Andvik C, Karoliussen R, Ruus A, Vongraven D, Borgå K. Isotopic niche differs between seal and fish-eating killer whales ( Orcinus orca) in northern Norway. Ecol Evol 2020; 10:4115-4127. [PMID: 32489635 PMCID: PMC7244801 DOI: 10.1002/ece3.6182] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 02/07/2020] [Accepted: 02/19/2020] [Indexed: 01/01/2023] Open
Abstract
Ecological diversity has been reported for killer whales (Orcinus orca) throughout the North Atlantic but patterns of prey specialization have remained poorly understood. We quantify interindividual dietary variations in killer whales (n = 38) sampled throughout the year in 2017-2018 in northern Norway using stable isotopic nitrogen (δ15N: 15N/14N) and carbon (δ13C: 13C/12C) ratios. A Gaussian mixture model assigned sampled individuals to three differentiated clusters, characterized by disparate nonoverlapping isotopic niches, that were consistent with predatory field observations: seal-eaters, herring-eaters, and lumpfish-eaters. Seal-eaters showed higher δ15N values (mean ± SD: 12.6 ± 0.3‰, range = 12.3-13.2‰, n = 10) compared to herring-eaters (mean ± SD: 11.7 ± 0.2‰, range = 11.4-11.9‰, n = 19) and lumpfish-eaters (mean ± SD: 11.6 ± 0.2‰, range = 11.3-11.9, n = 9). Elevated δ15N values for seal-eaters, regardless of sampling season, confirmed feeding at high trophic levels throughout the year. However, a wide isotopic niche and low measured δ15N values in the seal-eaters, compared to that of whales that would eat solely seals (δN-measured = 12.6 vs. δN-expected = 15.5), indicated a diverse diet that includes both fish and mammal prey. A narrow niche for killer whales sampled at herring and lumpfish seasonal grounds supported seasonal prey specialization reflective of local peaks in prey abundance for the two fish-eating groups. Our results, thus, show differences in prey specialization within this killer whale population in Norway and that the episodic observations of killer whales feeding on prey other than fish are a consistent behavior, as reflected in different isotopic niches between seal and fish-eating individuals.
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Affiliation(s)
| | - Clare Andvik
- Department of BiosciencesUniversity of OsloOsloNorway
| | | | - Anders Ruus
- Department of BiosciencesUniversity of OsloOsloNorway
- Norwegian Institute for Water ResearchOsloNorway
| | | | - Katrine Borgå
- Department of BiosciencesUniversity of OsloOsloNorway
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Wild LA, Mueter F, Witteveen B, Straley JM. Exploring variability in the diet of depredating sperm whales in the Gulf of Alaska through stable isotope analysis. ROYAL SOCIETY OPEN SCIENCE 2020; 7:191110. [PMID: 32269781 PMCID: PMC7137980 DOI: 10.1098/rsos.191110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 01/27/2020] [Indexed: 06/11/2023]
Abstract
Sperm whales interact with commercially important groundfish fisheries offshore in the Gulf of Alaska (GOA). This study aims to use stable isotope analysis to better understand the trophic variability of sperm whales and their potential prey, and to use dietary mixing models to estimate the importance of prey species to sperm whale diets. We analysed tissue samples from sperm whales and seven potential prey (five groundfish and two squid species). Samples were analysed for stable carbon and nitrogen isotope ratios, and diet composition was estimated using Bayesian isotopic mixing models. Mixing model results suggest that an isotopically combined sablefish/dogfish group, skates and rockfish make up the largest proportion of sperm whale diets (35%, 28% and 12%) in the GOA. The top prey items of whales that interact more frequently with fishing vessels consisted of skates (49%) and the sablefish/dogfish group (24%). This is the first known study to provide an isotopic baseline of adult male sperm whales and these adult groundfish and offshore squid species, and to assign contributions of prey to whale diets in the GOA. This study provides information to commercial fishermen and fisheries managers to better understand trophic connections of important commercial species.
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Affiliation(s)
- Lauren A. Wild
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 12101 Point Lena Loop, Juneau, AK 99801, USA
| | - Franz Mueter
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 12101 Point Lena Loop, Juneau, AK 99801, USA
| | - Briana Witteveen
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 12101 Point Lena Loop, Juneau, AK 99801, USA
| | - Janice M. Straley
- Department of Biology, University of Alaska Southeast, 1332 Seward Ave, Sitka, AK 99835, USA
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20
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Gauffier P, Borrell A, Silva MA, Víkingsson GA, López A, Giménez J, Colaço A, Halldórsson SD, Vighi M, Prieto R, de Stephanis R, Aguilar A. Wait your turn, North Atlantic fin whales share a common feeding ground sequentially. MARINE ENVIRONMENTAL RESEARCH 2020; 155:104884. [PMID: 32072986 DOI: 10.1016/j.marenvres.2020.104884] [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: 10/17/2019] [Revised: 01/10/2020] [Accepted: 01/19/2020] [Indexed: 06/10/2023]
Abstract
Highly migratory marine species pose a challenge for the identification of management units due to the absence of clear oceanographic barriers. The population structure of North Atlantic fin whales has been investigated since the start of whaling operations but is still the subject of an ongoing scientific debate. Here we measured stable isotopes of carbon, nitrogen and oxygen in skin samples collected from 151 individuals from western Iceland, Galicia (NW Spain), the Azores archipelago and the Strait of Gibraltar (SoG). We found spatiotemporal differences in stable isotope ratios suggesting that fin whales sampled in these four areas may share a common feeding ground within the Northeast Atlantic at different times during the year. Our results also suggest that SoG whales use this common feeding ground in summer but exploit Mediterranean resources during the winter months, further supporting the existence of a limited but current exchange of individuals between these two basins.
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Affiliation(s)
- Pauline Gauffier
- CIRCE, Cabeza de Manzaneda, 3, 11390, Pelayo, Algeciras, Spain; Department of Evolutionary Biology, Ecology and Environmental Sciences, IRBio, Faculty of Biology, University of Barcelona, 08028, Barcelona, Spain.
| | - Asunción Borrell
- Department of Evolutionary Biology, Ecology and Environmental Sciences, IRBio, Faculty of Biology, University of Barcelona, 08028, Barcelona, Spain
| | - Mónica A Silva
- Okeanos Centre & Institute of Marine Research (IMAR), University of the Azores, 9901-862, Horta, Portugal; Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA
| | - Gísli A Víkingsson
- Marine and Freshwater Research Institute, Skúlagata 4, 101, Reykjavík, Iceland
| | - Alfredo López
- Departamento de Biologia & CESAM, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal; Coordinadora para o Estudo dos Mamíferos Mariños (CEMMA), P.O. Box 15, 36380, Pontevedra, Gondomar, Spain
| | - Joan Giménez
- Institut de Ciències del Mar (ICM-CSIC), Passeig Maritim 37-49, 08003, Barcelona, Spain; MaREI Centre for Marine and Renewable Energy, Environmental Research Institute, Beaufort Building, University College Cork, Ringaskiddy, P43 C573 Cork, Ireland; School of Biological, Earth, and Environmental Sciences (BEES), University College Cork, Distillery Fields, North Mall, T23 N73K Cork, Ireland
| | - Ana Colaço
- Okeanos Centre & Institute of Marine Research (IMAR), University of the Azores, 9901-862, Horta, Portugal
| | | | - Morgana Vighi
- Department of Evolutionary Biology, Ecology and Environmental Sciences, IRBio, Faculty of Biology, University of Barcelona, 08028, Barcelona, Spain
| | - Rui Prieto
- Okeanos Centre & Institute of Marine Research (IMAR), University of the Azores, 9901-862, Horta, Portugal; MARE - Marine and Environmental Sciences Centre and IMAR, Institute of Marine Research, University of the Azores, 9901-862, Horta, Portugal
| | - Renaud de Stephanis
- CIRCE, Cabeza de Manzaneda, 3, 11390, Pelayo, Algeciras, Spain; Instituto Español de Oceanografía, Centro Oceanográfico de Málaga, Puerto Pesquero s/n, 29640 Fuengirola, Málaga, Spain
| | - Alex Aguilar
- Department of Evolutionary Biology, Ecology and Environmental Sciences, IRBio, Faculty of Biology, University of Barcelona, 08028, Barcelona, Spain
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Arostegui MC, Schindler DE, Holtgrieve GW. Does lipid-correction introduce biases into isotopic mixing models? Implications for diet reconstruction studies. Oecologia 2019; 191:745-755. [DOI: 10.1007/s00442-019-04525-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 10/09/2019] [Indexed: 12/11/2022]
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22
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Silva MA, Borrell A, Prieto R, Gauffier P, Bérubé M, Palsbøl PJ, Colaço A. Stable isotopes reveal winter feeding in different habitats in blue, fin and sei whales migrating through the Azores. ROYAL SOCIETY OPEN SCIENCE 2019; 6:181800. [PMID: 31598219 PMCID: PMC6731742 DOI: 10.1098/rsos.181800] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 07/23/2019] [Indexed: 06/10/2023]
Abstract
Knowing the migratory movements and behaviour of baleen whales is fundamental to understanding their ecology. We compared δ15N and δ13C values in the skin of blue (Balaenoptera musculus), fin (Balaenoptera physalus) and sei (Balaenoptera borealis) whales sighted in the Azores in spring with the values of potential prey from different regions within the North Atlantic using Bayesian mixing models to investigate their trophic ecology and migration patterns. Fin whale δ15N values were higher than those recorded in blue and sei whales, reflecting feeding at higher trophic levels. Whales' skin δ15N and δ13C values did not reflect prey from high-latitude summer foraging grounds; instead mixing models identified tropical or subtropical regions as the most likely feeding areas for all species during winter and spring. Yet, differences in δ13C values among whale species suggest use of different regions within this range. Blue and sei whales primarily used resources from the Northwest African upwelling and pelagic tropical/subtropical regions, while fin whales fed off Iberia. However, determining feeding habitats from stable isotope values remains difficult. In conclusion, winter feeding appears common among North Atlantic blue, fin and sei whales, and may play a crucial role in determining their winter distribution. A better understanding of winter feeding behaviour is therefore fundamental for the effective conservation of these species.
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Affiliation(s)
- Mónica A. Silva
- Okeanos Centre & Institute of Marine Research (IMAR), University of the Azores, 9901-862 Horta, Portugal
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Marine and Environmental Sciences Centre Açores (MARE), Department of Oceanography and Fisheries, 9901-862 Horta, Portugal
| | - Asunción Borrell
- Institute of Biodiversity Research (IRBio) & Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Rui Prieto
- Okeanos Centre & Institute of Marine Research (IMAR), University of the Azores, 9901-862 Horta, Portugal
- Marine and Environmental Sciences Centre Açores (MARE), Department of Oceanography and Fisheries, 9901-862 Horta, Portugal
| | - Pauline Gauffier
- Institute of Biodiversity Research (IRBio) & Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Martine Bérubé
- Groningen Institute of Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, The Netherlands
- Centre for Coastal Studies, Provincetown, MA 02657, USA
| | - Per J. Palsbøl
- Groningen Institute of Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, The Netherlands
- Centre for Coastal Studies, Provincetown, MA 02657, USA
| | - Ana Colaço
- Okeanos Centre & Institute of Marine Research (IMAR), University of the Azores, 9901-862 Horta, Portugal
- Marine and Environmental Sciences Centre Açores (MARE), Department of Oceanography and Fisheries, 9901-862 Horta, Portugal
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23
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Hidalgo-Reza M, Elorriaga-Verplancken FR, Aguíñiga-García S, Urbán R J. Impact of freezing and ethanol preservation techniques on the stable isotope analysis of humpback whale (Megaptera novaeangliae) skin. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2019; 33:789-794. [PMID: 30672617 DOI: 10.1002/rcm.8392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 01/15/2019] [Accepted: 01/16/2019] [Indexed: 06/09/2023]
Affiliation(s)
- Mariana Hidalgo-Reza
- Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Av. Ciudad Universitaria 3000, C.P. 04510, Coyoacán, Ciudad de México, Mexico
- Departamento de Ciencias Marinas y Costeras, Universidad Autónoma de Baja California Sur, Carretera al Sur KM 5.5, C.P. 23080, La Paz, Baja California Sur, Mexico
| | - Fernando R Elorriaga-Verplancken
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Ave. IPN s/n, Colonia Playa Palo de Santa Rita, Apartado Postal 592, La Paz, Baja California Sur, Mexico
| | - Sergio Aguíñiga-García
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Ave. IPN s/n, Colonia Playa Palo de Santa Rita, Apartado Postal 592, La Paz, Baja California Sur, Mexico
| | - Jorge Urbán R
- Departamento de Ciencias Marinas y Costeras, Universidad Autónoma de Baja California Sur, Carretera al Sur KM 5.5, C.P. 23080, La Paz, Baja California Sur, Mexico
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24
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Clark CT, Horstmann L, Misarti N. Lipid normalization and stable isotope discrimination in Pacific walrus tissues. Sci Rep 2019; 9:5843. [PMID: 30971722 PMCID: PMC6458160 DOI: 10.1038/s41598-019-42095-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 03/11/2019] [Indexed: 11/09/2022] Open
Abstract
Analysis of stable carbon and nitrogen isotope values (δ13C and δ15N) of animal tissues can provide important information about diet, physiology, and movements. Interpretation of δ13C and δ15N values, however, is influenced by factors such as sample lipid content, tissue-specific isotope discrimination, and tissue turnover rates, which are typically species- and tissue-specific. In this study, we generated lipid normalization models for δ13C and investigated the effects of chemical lipid extractions on δ13C and δ15N in Pacific walrus (Odobenus rosmarus divergens) muscle, liver, and skin. We also evaluated tissue-specific isotope discrimination in walrus muscle, liver, skin, and bone collagen. Mean δ13Clipid-free of skin and bone collagen were similar, as were mean δ15N of muscle and liver. All other tissues differed significantly for both isotopes. Differences in δ13Clipid-free and δ15N among tissues agreed with published estimates of marine mammal tissue-specific isotope discrimination factors, with the exception of skin. The results of this work will allow researchers to gain a clearer understanding of walrus diet and the structure of Arctic food webs, while also making it possible to directly compare the results of contemporary walrus isotope research with those of historic and paleoecological studies.
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Affiliation(s)
- Casey T Clark
- Water and Environmental Research Center, University of Alaska Fairbanks, 1764 Tanana Loop, Fairbanks, Alaska, 99775-5860, USA. .,College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 2150 Koyukuk Drive, Fairbanks, Alaska, 99775-7220, USA.
| | - Lara Horstmann
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, 2150 Koyukuk Drive, Fairbanks, Alaska, 99775-7220, USA
| | - Nicole Misarti
- Water and Environmental Research Center, University of Alaska Fairbanks, 1764 Tanana Loop, Fairbanks, Alaska, 99775-5860, USA
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25
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Weldrick CK, Trebilco R, Swadling KM. Can lipid removal affect interpretation of resource partitioning from stable isotopes in Southern Ocean pteropods? RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2019; 33:569-578. [PMID: 30635929 DOI: 10.1002/rcm.8384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 12/29/2018] [Accepted: 01/03/2019] [Indexed: 06/09/2023]
Abstract
RATIONALE Stable isotope analysis (SIA) is a powerful tool to estimate dietary links between polar zooplankton. However, the presence of highly variable 12 C-rich lipids may skew estimations as they are depleted in 13 C relative to proteins and carbohydrates, consequently masking carbon signals from food sources. Lipid effects on pteropod-specific values requires examining, since accounting for lipids is rarely conducted among the few existing pteropod-related SIA studies. It is currently unclear whether lipid correction is necessary prior to SIA of pteropods. METHODS Whole bodies of three species of pteropods (Clio pyramidata f. sulcata, Clione limacina antarctica, and Spongiobranchaea australis) sampled from the Southern Ocean were lipid-extracted chemically to test the effects on δ13 C and δ15 N values (n = 38 individuals in total). We determined the average change in δ13 C values for each treatment, and compared this offset with those from published normalization models. We tested lipid correction effects on isotopic niche dispersion metrics to compare interpretations surrounding food web dynamics. RESULTS Pteropods with lipids removed had δ13 C values up to 4.5‰ higher than bulk samples. However, lipid extraction also produced higher δ15 N values than bulk samples. Isotopic niche overlaps between untreated pteropods and their potential food sources were significantly different from overlaps generated between lipid-corrected pteropods and their potential food sources. Data converted using several published normalization models did not reveal significant differences among various calculated niche metrics, including standard ellipse and total area. CONCLUSIONS We recommend accounting for lipids via chemical extraction or mathematical normalization before applying SIA to calculate ecological niche metrics, particularly for organisms with moderate to high lipid content such as polar pteropods. Failure to account for lipids may result in misinterpretations of niche dimensions and overlap and, consequently, trophic interactions.
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Affiliation(s)
- Christine K Weldrick
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, Tasmania, 7001, Australia
- Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania, 7001, Australia
| | - Rowan Trebilco
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, Tasmania, 7001, Australia
- Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania, 7001, Australia
| | - Kerrie M Swadling
- Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, Tasmania, 7001, Australia
- Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania, 7001, Australia
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26
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Drago M, Franco-Trecu V, Segura AM, Valdivia M, González EM, Aguilar A, Cardona L. Mouth gape determines the response of marine top predators to long-term fishery-induced changes in food web structure. Sci Rep 2018; 8:15759. [PMID: 30361482 PMCID: PMC6202337 DOI: 10.1038/s41598-018-34100-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 10/11/2018] [Indexed: 11/09/2022] Open
Abstract
Here, we analyse changes throughout time in the isotopic niche of the Franciscana dolphin (Pontoporia blainvillei), the South American fur seal (Arctocephalus australis) and the South American sea lion (Otaria flavescens) from the Río de la Plata estuary and adjacent Atlantic Ocean to test the hypothesis that fishing may modify the diet of small-gape predators by reducing the average size of prey. The overall evidence, from stable isotope and stomach contents analyses, reveals major changes in resource partitioning between the three predators considered, mainly because of an increased access of Franciscana dolphins to juvenile demersal fishes. These results are consistent with the changes in the length distribution of demersal fish species resulting from fishing and suggest that Franciscana dolphin has been the most benefited species of the three marine mammal species considered because of its intermediate mouth gape. In conclusion, the impact of fishing on marine mammals goes beyond the simple reduction in prey biomass and is highly dependent on the mouth gape of the species involved.
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Affiliation(s)
- Massimiliano Drago
- IRBio and Department of Evolutive Biology, Ecology and Environmental Sciences, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
| | - Valentina Franco-Trecu
- Department of Ecology and Evolution, Faculty of Sciences, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay
| | - Angel M Segura
- Modelization and Analysis of Natural Resources (MAREN), Centro Universitario Regional Este (CURE), Universidad de la República, Ruta 9, km 208, 27000, Rocha, Uruguay.,National Museum of Natural History (MNHN), 25 de Mayo 582, 11000, Montevideo, Uruguay
| | - Meica Valdivia
- National Museum of Natural History (MNHN), 25 de Mayo 582, 11000, Montevideo, Uruguay
| | - Enrique M González
- National Museum of Natural History (MNHN), 25 de Mayo 582, 11000, Montevideo, Uruguay
| | - Alex Aguilar
- IRBio and Department of Evolutive Biology, Ecology and Environmental Sciences, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
| | - Luis Cardona
- IRBio and Department of Evolutive Biology, Ecology and Environmental Sciences, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
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Wild LA, Chenoweth EM, Mueter FJ, Straley JM. Evidence for dietary time series in layers of cetacean skin using stable carbon and nitrogen isotope ratios. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2018; 32:1425-1438. [PMID: 29777550 PMCID: PMC6097889 DOI: 10.1002/rcm.8168] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 05/05/2018] [Accepted: 05/06/2018] [Indexed: 05/22/2023]
Abstract
RATIONALE Stable isotope analysis integrates diet information over a time period specific to the type of tissue sampled. For metabolically active skin of free-ranging cetaceans, cells are generated at the basal layer of the skin and migrate outward until they eventually slough off, suggesting potential for a dietary time series. METHODS Skin samples from cetaceans were analyzed using continuous-flow elemental analyzer isotope ratio mass spectrometry. We used ANOVAs to compare the variability of δ13 C and δ15 N values within and among layers and columns ("cores") of the skin of a fin, humpback, and sperm whale. We then used mixed-effects models to analyze isotopic variability among layers of 28 sperm whale skin samples, over the course of a season and among years. RESULTS We found layer to be a significant predictor of δ13 C values in the sperm whale's skin, and δ15 N values in the humpback whale's skin. There was no evidence for significant differences in δ15 N or δ13 C values among cores for any species. Mixed-effects models selected layer and day of the year as significant predictors of δ13 C and δ15 N values in sperm whale skin across individuals sampled during the summer months in the Gulf of Alaska. CONCLUSIONS These results suggest that skin samples from cetaceans may be subsampled to reflect diet during a narrower time period; specifically different layers of skin may contain a dietary time series. This underscores the importance of selecting an appropriate portion of skin to analyze based on the species and objectives of the study.
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Affiliation(s)
- Lauren A. Wild
- University of Alaska Fairbanks, Juneau, AK 99801 USA
- Corresponding author;
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28
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Borrell A, Saiz L, Víkingsson GA, Gaufier P, López Fernández A, Aguilar A. Fin whales as bioindicators of multi-decadal change in carbon and oxygen stable isotope shifts in the North Atlantic. MARINE ENVIRONMENTAL RESEARCH 2018; 138:129-134. [PMID: 29724493 DOI: 10.1016/j.marenvres.2018.04.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 04/19/2018] [Accepted: 04/23/2018] [Indexed: 06/08/2023]
Abstract
Global changes, and particularly the massive release of CO2 to the atmosphere and subsequent global warming, have altered the baselines of carbon and oxygen stable isotopic ratios. Temporal shifts in these baselines can be advantageously monitored through cetacean skin samples because these animals are highly mobile and therefore integrate in their tissues the heterogeneity of local environmental signals. In this study, we examine variation of δ13C and δ18O values in the skin of fin whales sampled over three decades in two different North Atlantic feeding grounds: west Iceland and northwest Spain. These locations are situated about 2700 km apart and thus represent a wide latitudinal range within the North Atlantic Ocean. The δ13C decrease in both areas is attributed to the burning of fossil fuels and increased deforestation worldwide, the so-called Suess effect. The dissimilarity in the magnitude of the shift between the two areas is coincidental with previous information on local shifts and lies within the ranges of variation observed. δ18O values experienced a minimal, yet significant change in fin whales from W Iceland (a decline of -0.44‰ between 1986 and 2013) but not in those from NW Spain. This is in concordance with a higher rise in temperatures in the former area than in the latter. The study validates the use of cetacean skin to monitor temporal and geographical shifts in stable isotopic values and alerts that, when applying this tool to ecological research, comparisons between sample sets should take into account temporal and latitudinal scales.
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Affiliation(s)
- A Borrell
- Institute of Biodiversity Research (IRBio), Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain.
| | - L Saiz
- Institute of Biodiversity Research (IRBio), Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - G A Víkingsson
- Marine and Freshwater Research Institute, P. O. Box 1390, Skúlagata 4, 121 Reykjavík, Iceland
| | - P Gaufier
- Conservation, Information and Research on Cetaceans (CIRCE), Cabeza de Manzaneda, 3, 11390 Pelayo-Algeciras (Cadiz), Spain
| | - A López Fernández
- Coordinadora para o Estudo dos Mamíferos Mariños (CEMMA), P.O. Box 15, 36380 Pontevedra, Gondomar, Spain
| | - A Aguilar
- Institute of Biodiversity Research (IRBio), Department of Evolutionary Biology, Ecology and Environmental Sciences, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
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29
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Eisenmann P, Fry B, Mazumder D, Jacobsen G, Holyoake CS, Coughran D, Bengtson Nash S. Radiocarbon as a Novel Tracer of Extra-Antarctic Feeding in Southern Hemisphere Humpback Whales. Sci Rep 2017; 7:4366. [PMID: 28663586 PMCID: PMC5491506 DOI: 10.1038/s41598-017-04698-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 05/19/2017] [Indexed: 11/17/2022] Open
Abstract
Bulk stable isotope analysis provides information regarding food web interactions, and has been applied to several cetacean species for the study of migration ecology. One limitation in bulk stable isotope analysis arises when a species, such as Southern hemisphere humpback whales, utilises geographically distinct food webs with differing isotopic baselines. Migrations to areas with different baselines can result in isotopic changes that mimic changes in feeding relations, leading to ambiguous food web interpretations. Here, we demonstrate the novel application of radiocarbon measurement for the resolution of such ambiguities. Radiocarbon was measured in baleen plates from humpback whales stranded in Australia between 2007 and 2013, and in skin samples collected in Australia and Antarctica from stranded and free-ranging animals. Radiocarbon measurements showed lower values for Southern Ocean feeding than for extra-Antarctic feeding in Australian waters. While the whales mostly relied on Antarctic-derived energy stores during their annual migration, there was some evidence of feeding within temperate zone waters in some individuals. This work, to our knowledge, provides the first definitive biochemical evidence for supplementary feeding by southern hemisphere humpback whales within temperate waters during migration. Further, the work contributes a powerful new tool (radiocarbon) for tracing source regions and geographical feeding.
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Affiliation(s)
- Pascale Eisenmann
- Griffith University, Environmental Futures Research Institute (EFRI), Southern Ocean Persistent Organic Pollutants (SOPOPP), Brisbane, QLD 4111, Australia.
| | - Brian Fry
- Griffith University, Australian Rivers Institute (ARI), Brisbane, QLD 4111, Australia
| | - Debashish Mazumder
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia
| | - Geraldine Jacobsen
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia
| | | | - Douglas Coughran
- Department of Parks and Wildlife, Kensington, WA 6151, Australia
| | - Susan Bengtson Nash
- Griffith University, Environmental Futures Research Institute (EFRI), Southern Ocean Persistent Organic Pollutants (SOPOPP), Brisbane, QLD 4111, Australia
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30
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Das K, Holleville O, Ryan C, Berrow S, Gilles A, Ody D, Michel LN. Isotopic niches of fin whales from the Mediterranean Sea and the Celtic Sea (North Atlantic). MARINE ENVIRONMENTAL RESEARCH 2017; 127:75-83. [PMID: 28390660 DOI: 10.1016/j.marenvres.2017.03.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 01/25/2017] [Accepted: 03/19/2017] [Indexed: 06/07/2023]
Abstract
The fin whale (Balaenoptera physalus) is the most abundant and widespread mysticete species in the Mediterranean Sea, found mostly in deep, offshore waters of the western and central portion of the region. In the Mediterranean, this species is known to feed mainly on krill, in contrast to its Atlantic counterpart, which displays a more diversified diet. The International Whaling Commission recognizes several managements units in the Atlantic and the Mediterranean Sea and the connectivity between these populations is still being debated. Questions remain about inter-individual feeding strategies and trophic ecology. The goal of this study was to compare isotopic niches of fin whales from the Mediterranean Sea and the Celtic Sea (North Atlantic). δ13C and δ15N values were analysed in 136 skin biopsies from free-ranging Mediterranean fin whales sampled in 2010 and 2011 during campaigns at sea. δ13C and δ15N values ranged from -20.4 to -17.1‰ and from 5.9 to 8.9‰, respectively. These values are in good agreement with those estimated previously from baleen plates from Mediterranean and North Atlantic fin whales. The narrow isotopic niche width of the Mediterranean fin whale (Standard Ellipses area SEAc) compared to the North Atlantic fin whale raises many concerns in the context of global changes and long-term consequences. One could indeed expect that species displaying narrow niches would be more susceptible to ecosystem fragmentation and other anthropogenic impacts.
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Affiliation(s)
- Krishna Das
- Laboratory of Oceanology-MARE, University of Liege, Belgium.
| | | | - Conor Ryan
- Marine and Freshwater Research Centre, Galway-Mayo Institute of Technology, Galway, Ireland; Irish Whale and Dolphin Group, Merchant's Quay, Kilrush, Co. Clare, Ireland
| | - Simon Berrow
- Marine and Freshwater Research Centre, Galway-Mayo Institute of Technology, Galway, Ireland; Irish Whale and Dolphin Group, Merchant's Quay, Kilrush, Co. Clare, Ireland
| | - Anita Gilles
- Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstraße 6, D-25761 Büsum, Germany
| | - Denis Ody
- WWF-France, 6 Rue des Fabres, 13001 Marseille, France
| | - Loïc N Michel
- Laboratory of Oceanology-MARE, University of Liege, Belgium
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31
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Busquets-Vass G, Newsome SD, Calambokidis J, Serra-Valente G, Jacobsen JK, Aguíñiga-García S, Gendron D. Estimating blue whale skin isotopic incorporation rates and baleen growth rates: Implications for assessing diet and movement patterns in mysticetes. PLoS One 2017; 12:e0177880. [PMID: 28562625 PMCID: PMC5451050 DOI: 10.1371/journal.pone.0177880] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 05/04/2017] [Indexed: 11/19/2022] Open
Abstract
Stable isotope analysis in mysticete skin and baleen plates has been repeatedly used to assess diet and movement patterns. Accurate interpretation of isotope data depends on understanding isotopic incorporation rates for metabolically active tissues and growth rates for metabolically inert tissues. The aim of this research was to estimate isotopic incorporation rates in blue whale skin and baleen growth rates by using natural gradients in baseline isotope values between oceanic regions. Nitrogen (δ15N) and carbon (δ13C) isotope values of blue whale skin and potential prey were analyzed from three foraging zones (Gulf of California, California Current System, and Costa Rica Dome) in the northeast Pacific from 1996–2015. We also measured δ15N and δ13C values along the lengths of baleen plates collected from six blue whales stranded in the 1980s and 2000s. Skin was separated into three strata: basale, externum, and sloughed skin. A mean (±SD) skin isotopic incorporation rate of 163±91 days was estimated by fitting a generalized additive model of the seasonal trend in δ15N values of skin strata collected in the Gulf of California and the California Current System. A mean (±SD) baleen growth rate of 15.5±2.2 cm y-1 was estimated by using seasonal oscillations in δ15N values from three whales. These oscillations also showed that individual whales have a high fidelity to distinct foraging zones in the northeast Pacific across years. The absence of oscillations in δ15N values of baleen sub-samples from three male whales suggests these individuals remained within a specific zone for several years prior to death. δ13C values of both whale tissues (skin and baleen) and potential prey were not distinct among foraging zones. Our results highlight the importance of considering tissue isotopic incorporation and growth rates when studying migratory mysticetes and provide new insights into the individual movement strategies of blue whales.
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Affiliation(s)
- Geraldine Busquets-Vass
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur, Mexico
| | - Seth D. Newsome
- Biology Department, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - John Calambokidis
- Cascadia Research Collective, Olympia, Washington, United States of America
| | - Gabriela Serra-Valente
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla, California, United States of America
| | - Jeff K. Jacobsen
- Vertebrate Museum, Department of Biological Sciences, Humboldt State University, Arcata, California, United States of America
| | - Sergio Aguíñiga-García
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur, Mexico
| | - Diane Gendron
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur, Mexico
- * E-mail:
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32
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Drago M, Cardona L, Franco-Trecu V, Crespo EA, Vales DG, Borella F, Zenteno L, Gonzáles EM, Inchausti P. Isotopic niche partitioning between two apex predators over time. J Anim Ecol 2017; 86:766-780. [PMID: 28326539 DOI: 10.1111/1365-2656.12666] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 03/01/2017] [Indexed: 11/26/2022]
Abstract
Stable isotope analyses have become an important tool in reconstructing diets, analysing resource use patterns, elucidating trophic relations among predators and understanding the structure of food webs. Here, we use stable carbon and nitrogen isotope ratios in bone collagen to reconstruct and compare the isotopic niches of adult South American fur seals (Arctocephalus australis; n = 86) and sea lions (Otaria flavescens; n = 49) - two otariid species with marked morphological differences - in the Río de la Plata estuary (Argentina - Uruguay) and the adjacent Atlantic Ocean during the second half of the 20th century and the beginning of the 21st century. Samples from the middle Holocene (n = 7 fur seals and n = 5 sea lions) are also included in order to provide a reference point for characterizing resource partitioning before major anthropogenic modifications of the environment. We found that the South American fur seals and South American sea lions had distinct isotopic niches during the middle Holocene. Isotopic niche segregation was similar at the beginning of the second half of the 20th century, but has diminished over time. The progressive convergence of the isotopic niches of these two otariids during the second half of the 20th century and the beginning of the 21st century is most likely due to the increased reliance of South American fur seals on demersal prey. This recent dietary change in South American fur seals can be explained by at least two non-mutually exclusive mechanisms: (i) the decrease in the abundance of sympatric South American sea lions as a consequence of small colony size and high pup mortality resulting from commercial sealing; and (ii) the decrease in the average size of demersal fishes due to intense fishing of the larger class sizes, which may have increased their accessibility to those eared seals with a smaller mouth gape, that is, South American fur seals of both sexes and female South American sea lions.
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Affiliation(s)
- Massimiliano Drago
- Departamento de Ecología & Evolución, Centro Universitario Regional Este (CURE), Universidad de la República, Tacuarembó s/n, 20000, Maldonado, Uruguay
| | - Luis Cardona
- IRBio y Departamento de Biología Evolutiva, Ecología y Ciencias Ambientales, Universidad de Barcelona, Av. Diagonal 643, 08028, Barcelona, España
| | - Valentina Franco-Trecu
- Departamento de Ecología & Evolución, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay
| | - Enrique A Crespo
- Laboratorio de Mamíferos Marinos, Centro para el Estudio de Sistemas Marinos (CESIMAR - CCT CONICET-CENPAT), Blvd. Brown 2915, U9120ACD, Puerto Madryn, Argentina.,Universidad Nacional de la Patagonia, Blvd. Brown 3600, U9120ACD, Puerto Madryn, Argentina
| | - Damián G Vales
- Laboratorio de Mamíferos Marinos, Centro para el Estudio de Sistemas Marinos (CESIMAR - CCT CONICET-CENPAT), Blvd. Brown 2915, U9120ACD, Puerto Madryn, Argentina
| | - Florencia Borella
- Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano (INCUAPA-CONICET), Universidad Nacional del Centro, Av. Del Valle 5737, B7400JWI, Olavarría, Argentina
| | - Lisette Zenteno
- IRBio y Departamento de Biología Evolutiva, Ecología y Ciencias Ambientales, Universidad de Barcelona, Av. Diagonal 643, 08028, Barcelona, España
| | - Enrique M Gonzáles
- Museo Nacional de Historia Natural, 25 de Mayo 582, 11000, Montevideo, Uruguay
| | - Pablo Inchausti
- Departamento de Ecología & Evolución, Centro Universitario Regional Este (CURE), Universidad de la República, Tacuarembó s/n, 20000, Maldonado, Uruguay
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33
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Das K, Malarvannan G, Dirtu A, Dulau V, Dumont M, Lepoint G, Mongin P, Covaci A. Linking pollutant exposure of humpback whales breeding in the Indian Ocean to their feeding habits and feeding areas off Antarctica. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 220:1090-1099. [PMID: 27884466 DOI: 10.1016/j.envpol.2016.11.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 11/10/2016] [Accepted: 11/10/2016] [Indexed: 06/06/2023]
Abstract
Humpback whales, Megaptera novaeangliae, breeding off la Reunion Island (Indian Ocean) undergo large-scale seasonal migrations between summer feeding grounds near Antarctica and their reproductive winter grounds in the Indian Ocean. The main scope of the current study was to investigate chemical exposure of humpback whales breeding in the Indian Ocean by providing the first published data on this breeding stock concerning persistent organic pollutants (POPs), namely polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), DDT and its metabolites (DDTs), chlordane compounds (CHLs), polybrominated diphenyl ethers (PBDEs), and methoxylated PBDEs (MeO-PBDEs). Analyses of stable isotopes δ13C and δ15N in skin resulted in further insight in their feeding ecology, which was in agreement with a diet focused mainly on low trophic level prey species, such as krill from Antarctica. POPs were measured in all humpback whales in the order of HCB > DDTs > CHLs > HCHs > PCBs > PBDEs > MeO-BDEs. HCB (median: 24 ng g-1 lw) and DDTs (median: 7.7 ng g-1 lw) were the predominant compounds in all whale biopsies. Among DDT compounds, p,p'-DDE was the major organohalogenated pollutant, reflecting its long-term accumulation in humpback whales. Significantly lower concentrations of HCB and DDTs were found in females than in males (p < 0.001). Other compounds were similar between the two genders (p > 0.05). Differences in the HCB and DDTs suggested gender-specific transfer of some compounds to the offspring. POP concentrations were lower than previously reported results for humpback whales sampled near the Antarctic Peninsula, suggesting potential influence of their nutritional status and may indicate different exposures of the whales according to their feeding zones. Further investigations are required to assess exposure of southern humpback whales throughout their feeding zones.
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Affiliation(s)
- Krishna Das
- Laboratory of Oceanology-MARE, University of Liege, 4000 Liege, Belgium.
| | - Govindan Malarvannan
- Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Alin Dirtu
- Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium; Department of Chemistry, "Al. I. Cuza" University of Iasi, 700506 Iasi, Romania
| | - Violaine Dulau
- Groupe Local d'Observation et d'Identification des Cétacés (GLOBICE), 30 Chemin Parc Cabris, Grand Bois, 97 410 Saint Pierre, Reunion
| | - Magali Dumont
- Laboratory of Oceanology-MARE, University of Liege, 4000 Liege, Belgium
| | - Gilles Lepoint
- Laboratory of Oceanology-MARE, University of Liege, 4000 Liege, Belgium
| | - Philippe Mongin
- BNOI-ONCFS, Parc de la Providence, 97400 Saint-Denis, Reunion
| | - Adrian Covaci
- Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
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Tatsch ACC, Secchi ER, Botta S. Effects of acidification, lipid removal and mathematical normalization on carbon and nitrogen stable isotope compositions in beaked whale (Ziphiidae) bone. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2016; 30:460-466. [PMID: 26754138 DOI: 10.1002/rcm.7457] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 10/28/2015] [Accepted: 10/29/2015] [Indexed: 06/05/2023]
Abstract
RATIONALE The analysis of stable isotopes in tissues such as teeth and bones has been used to study long-term trophic ecology and habitat use in marine mammals. However, carbon isotope ratios (δ(13) C values) can be altered by the presence of (12) C-rich lipids and carbonates. Lipid extraction and acidification are common treatments used to remove these compounds. The impact of lipids and carbonates on carbon and nitrogen isotope ratios (δ(15) N values), however, varies among tissues and/or species, requiring taxon-specific protocols to be developed. METHODS The effects of lipid extraction and acidification and their interaction on carbon and nitrogen isotope values were studied for beaked whale (Ziphiidae) bone samples. δ(13) C and δ(15) N values were determined in quadruplicate samples: control, lipid-extracted, acidified and lipid-extracted followed by acidification. Samples were analyzed by means of elemental analysis isotope ratio mass spectrometry. Furthermore, the efficiency of five mathematical models developed for estimating lipid-normalized δ(13) C values from untreated δ(13) C values was tested. RESULTS Significant increases in δ(13) C values were observed after lipid extraction. No significant changes in δ(13) C values were found in acidified samples. An interaction between both treatments was demonstrated for δ(13) C but not for δ(15) N values. No change was observed in δ(15) N values for lipid-extracted and/or acidified samples. Although all tested models presented good predictive power to estimate lipid-free δ(13) C values, linear models performed best. CONCLUSIONS Given the observed changes in δ(13) C values after lipid extraction, we recommend a priori lipid extraction or a posteriori lipid normalization, through simple linear models, for beaked whale bones. Furthermore, acidification seems to be an unnecessary step before stable isotope analysis, at least for bone samples of ziphiids. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Ana Carolina C Tatsch
- Programa de Pós-Graduação em Oceanografia Biológica, Instituto de Oceanografia, Universidade Federal do Rio Grande, 96203-900, Rio Grande, RS, Brazil
- Laboratório de Ecologia e Conservação da Megafauna Marinha - ECOMEGA, Instituto de Oceanografia, Universidade Federal do Rio Grande, 96203-900, Rio Grande, RS, Brazil
| | - Eduardo R Secchi
- Programa de Pós-Graduação em Oceanografia Biológica, Instituto de Oceanografia, Universidade Federal do Rio Grande, 96203-900, Rio Grande, RS, Brazil
- Laboratório de Ecologia e Conservação da Megafauna Marinha - ECOMEGA, Instituto de Oceanografia, Universidade Federal do Rio Grande, 96203-900, Rio Grande, RS, Brazil
| | - Silvina Botta
- Programa de Pós-Graduação em Oceanografia Biológica, Instituto de Oceanografia, Universidade Federal do Rio Grande, 96203-900, Rio Grande, RS, Brazil
- Laboratório de Ecologia e Conservação da Megafauna Marinha - ECOMEGA, Instituto de Oceanografia, Universidade Federal do Rio Grande, 96203-900, Rio Grande, RS, Brazil
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Drago M, Franco-Trecu V, Cardona L, Inchausti P, Tapia W, Páez-Rosas D. Stable Isotopes Reveal Long-Term Fidelity to Foraging Grounds in the Galapagos Sea Lion (Zalophus wollebaeki). PLoS One 2016; 11:e0147857. [PMID: 26808381 PMCID: PMC4725682 DOI: 10.1371/journal.pone.0147857] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 01/08/2016] [Indexed: 11/30/2022] Open
Abstract
Most otariids have colony-specific foraging areas during the breeding season, when they behave as central place foragers. However, they may disperse over broad areas after the breeding season and individuals from different colonies may share foraging grounds at that time. Here, stable isotope ratios in the skull bone of adult Galapagos sea lions (Zalophus wollebaeki) were used to assess the long-term fidelity of both sexes to foraging grounds across the different regions of the Galapagos archipelago. Results indicated that the stable isotope ratios (δ13C and δ15N) of sea lion bone significantly differed among regions of the archipelago, without any significant difference between sexes and with a non significant interaction between sex and region. Moreover, standard ellipses, estimated by Bayesian inference and used as a measure of the isotopic resource use area at the population level, overlapped widely for the sea lions from the southern and central regions, whereas the overlap of the ellipses for sea lions from the central and western regions was small and non-existing for those from the western and southern regions. These results suggest that males and females from the same region within the archipelago use similar foraging grounds and have similar diets. Furthermore, they indicate that the exchange of adults between regions is limited, thus revealing a certain degree of foraging philopatry at a regional scale within the archipelago. The constraints imposed on males by an expanded reproductive season (~ 6 months), resulting from the weak reproductive synchrony among females, and those imposed on females by a very long lactation period (at least one year but up to three years), may explain the limited mobility of adult Galapagos sea lions of both sexes across the archipelago.
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Affiliation(s)
- Massimiliano Drago
- Programa PROMETEO-SENESCYT, Secretaría de Educación Superior, Ciencia, Tecnología e Innovación, Quito, Ecuador
- Department of Ecology & Evolution, Centro Universitario Regional Este (CURE), University of the Republic (UdeLaR), Maldonado, Uruguay
- * E-mail:
| | - Valentina Franco-Trecu
- Department of Ecology & Evolution, Faculty of Sciences, University of the Republic (UdeLaR), Montevideo, Uruguay
| | - Luis Cardona
- Department of Animal Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Pablo Inchausti
- Department of Ecology & Evolution, Centro Universitario Regional Este (CURE), University of the Republic (UdeLaR), Maldonado, Uruguay
| | - Washington Tapia
- Department of Applied Research, Galapagos National Park Service, Puerto Ayora, Galápagos, Ecuador
- Galapagos Conservancy, Santa Cruz, Galápagos, Ecuador
| | - Diego Páez-Rosas
- Universidad San Francisco de Quito (USFQ) and Galapagos Science Center, San Cristóbal, Galápagos, Ecuador
- Dirección Parque Nacional Galápagos, Unidad Técnica Operativa San Cristóbal, Galápagos, Ecuador
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Kavembe GD, Kautt AF, Machado-Schiaffino G, Meyer A. Eco-morphological differentiation in Lake Magadi tilapia, an extremophile cichlid fish living in hot, alkaline and hypersaline lakes in East Africa. Mol Ecol 2016; 25:1610-25. [DOI: 10.1111/mec.13461] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 11/01/2015] [Accepted: 11/03/2015] [Indexed: 12/25/2022]
Affiliation(s)
- Geraldine D. Kavembe
- Chair in Zoology and Evolutionary Biology; Department of Biology; University of Konstanz; Universitätsstrasse 10 78457 Konstanz Germany
- Department of Biology; School of Pure and Applied Sciences; South Eastern Kenya University; P. O. Box 170 90200 Kitui Kenya
| | - Andreas F. Kautt
- Chair in Zoology and Evolutionary Biology; Department of Biology; University of Konstanz; Universitätsstrasse 10 78457 Konstanz Germany
- International Max Planck Research School for Organismal Biology; University of Konstanz; Universitätsstrasse 10 78457 Konstanz Germany
| | - Gonzalo Machado-Schiaffino
- Chair in Zoology and Evolutionary Biology; Department of Biology; University of Konstanz; Universitätsstrasse 10 78457 Konstanz Germany
| | - Axel Meyer
- Chair in Zoology and Evolutionary Biology; Department of Biology; University of Konstanz; Universitätsstrasse 10 78457 Konstanz Germany
- International Max Planck Research School for Organismal Biology; University of Konstanz; Universitätsstrasse 10 78457 Konstanz Germany
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Sardenne F, Ménard F, Degroote M, Fouché E, Guillou G, Lebreton B, Hollanda SJ, Bodin N. Methods of lipid-normalization for multi-tissue stable isotope analyses in tropical tuna. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2015; 29:1253-1267. [PMID: 26395609 DOI: 10.1002/rcm.7215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 04/13/2015] [Accepted: 04/17/2015] [Indexed: 06/05/2023]
Abstract
RATIONALE The bias associated with lipid contents in fish tissues is a recalcitrant topic for trophic studies using stable isotopes. Lipids are depleted in the heavy carbon isotope ((13)C) and the lipid content varies considerably among species, tissues and in both time and space. We have applied and assessed different correction methods for tropical tuna tissues. METHODS We tested two types of normalization methods to deal with variable lipid content in liver, gonads, and white and red muscles of yellowfin, bigeye and skipjack tuna: a chemical extraction using dichloromethane and a mathematical correction based on three modeling approaches (linear, non-linear and mass balance models). We measured isotopic ratios of bulk and lipid-free tissues and assessed the predictive ability of the correction models with the lipid-free measurements. The parameters of the models were estimated from our dataset and from results from published studies on other species. RESULTS Comparison between bulk, lipid-free and lipid-corrected isotopic ratios demonstrated that (1) chemical extraction using dichloromethane did not affect δ(15)N values; (2) the change in δ(13)C values after extraction was tissue-specific; (3) lipid-normalization models using published parameter estimates failed to predict lipid-corrected δ(13)C values; and (4) linear and non-linear models using parameters estimated for each tissue from our dataset provided accurate δ(13)C predictions for all tissues, and mass balance model for white muscle only. CONCLUSIONS Models using published estimates for parameters from other species cannot be used. Based on a range of lipid content that do not exceed 45%, we recommend the linear model to correct the bulk δ(13)C values in the investigated tissues but the parameters have to be estimated from a proportion of the original data for which chemical extraction is required and the isotopic values of bulk and lipid-free tissues are measured.
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Affiliation(s)
- Fany Sardenne
- IRD, UMR MARine Biodiversity Exploitation and Conservation (MARBEC), Avenue Jean Monnet, Sète, France
- IRD, UMR MARine Biodiversity Exploitation and Conservation (MARBEC), Fishing Port, Victoria, Seychelles
| | - Frédéric Ménard
- IRD, Mediterranean Institute of Oceanography (MIO), Aix-Marseille Université/CNRS/IRD/Université de Toulon, 13288, Marseille, France
| | - Maxime Degroote
- IRD, UMR MARine Biodiversity Exploitation and Conservation (MARBEC), Avenue Jean Monnet, Sète, France
| | - Edwin Fouché
- IRD, UMR MARine Biodiversity Exploitation and Conservation (MARBEC), Avenue Jean Monnet, Sète, France
- INRA, UMR TOXALIM (Research Centre in Food Toxicology), Toulouse, France
| | - Gaël Guillou
- CNRS-Université de la Rochelle, UMR Littoral Environnement et Sociétés (LIENSs), 2 rue Olympe de Gouges, 17000, La Rochelle, France
| | - Benoit Lebreton
- CNRS-Université de la Rochelle, UMR Littoral Environnement et Sociétés (LIENSs), 2 rue Olympe de Gouges, 17000, La Rochelle, France
| | | | - Nathalie Bodin
- IRD, UMR MARine Biodiversity Exploitation and Conservation (MARBEC), Fishing Port, Victoria, Seychelles
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Yurkowski DJ, Hussey NE, Semeniuk C, Ferguson SH, Fisk AT. Effects of lipid extraction and the utility of lipid normalization models on δ13C and δ15N values in Arctic marine mammal tissues. Polar Biol 2014. [DOI: 10.1007/s00300-014-1571-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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The effect of acidification and the combined effects of acidification/lipid extraction on carbon stable isotope ratios for sub-arctic and arctic marine zooplankton species. Polar Biol 2014. [DOI: 10.1007/s00300-014-1540-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Fry B. Using stable CNS isotopes to evaluate estuarine fisheries condition and health. ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2013; 49:295-304. [PMID: 23781903 DOI: 10.1080/10256016.2013.783830] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Humans are modifying estuaries of the coastal zone and ecologists have begun measuring ecosystem responses in an attempt to preserve natural ecological conditions and health. Traditional approaches to assessing structural and functional responses of coastal systems include measures of species composition and water quality, but fisheries assessments are often left out because of the perception that fisheries species are too mobile and cannot easily be linked to local conditions. Stable isotopes have emerged as a new and useful way to understand movements and productivity of mobile shrimp and fish species across estuarine seascapes. Two case studies from Louisiana, USA, suggest that estuaries with healthy fishery food webs might be identified using isotope indicators that show low anthropogenic N inputs, strong benthic contributions, and moderate to high fisheries residency and productivity in marsh and mid- salinity areas.
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Affiliation(s)
- Brian Fry
- a Australian Rivers Institute, Griffith University , Nathan , Queensland , Australia 4111
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