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Ryberg MP, Christensen A, Jørgensen C, Neuenfeldt S, Skov PV, Behrens JW. Bioenergetics modelling of growth processes in parasitized Eastern Baltic cod ( Gadus morhua L.). CONSERVATION PHYSIOLOGY 2023; 11:coad007. [PMID: 36911046 PMCID: PMC9999110 DOI: 10.1093/conphys/coad007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 02/03/2023] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
Changes in physiological processes can reveal how individuals respond to environmental stressors. It can be difficult to link physiological responses to changes in vital rates such as growth, reproduction and survival. Here, bioenergetics modelling can aid in understanding non-intuitive outcomes from stressor combinations. Building on an established bioenergetics model, we examine the potential effects of parasite infection on growth rate and body condition. Parasites represent an overlooked biotic factor, despite their known effects on the physiology of the host organism. As a case study, we use the host-parasite system of Eastern Baltic cod (Gadus morhua) infected with the parasitic nematode Contraceacum osculatum. Eastern Baltic cod have during the past decade experienced increasing infection loads with C. osculatum that have been shown to lead to physiological changes. We hypothesized that infection with parasites affects cod growth negatively as previous studies reveal that the infections lead to reduced energy turnover, severe liver disease and reduced nutritional condition. To test this, we implemented new variables into the bioenergetics model representing the physiological changes in infected fish and parameterized these based on previous experimental data. We found that growth rate and body condition decreased with increased infection load. Highly infected cod reach a point of no return where their energy intake cannot maintain a surplus energy balance, which may eventually lead to induced mortality. In conclusion, parasite infections cannot be ignored when assessing drivers of fish stock dynamics.
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Affiliation(s)
- Marie Plambech Ryberg
- National Institute of Aquatic Resources, Technical University of Denmark (DTU Aqua), Kemitorvet, Building 202,
Kgs. Lyngby 2800, Denmark
| | - Asbjørn Christensen
- National Institute of Aquatic Resources, Technical University of Denmark (DTU Aqua), Kemitorvet, Building 202,
Kgs. Lyngby 2800, Denmark
| | - Christian Jørgensen
- Department of Biological Sciences, University of Bergen, Thormøhlens Gate 53 A/B, 5006 Bergen, Norway
| | - Stefan Neuenfeldt
- National Institute of Aquatic Resources, Technical University of Denmark (DTU Aqua), Kemitorvet, Building 202,
Kgs. Lyngby 2800, Denmark
| | - Peter V Skov
- National Institute of Aquatic Resources, Technical University of Denmark (DTU Aqua), Willemoesvej 2, Hirtshals 9850, Denmark
| | - Jane W Behrens
- National Institute of Aquatic Resources, Technical University of Denmark (DTU Aqua), Kemitorvet, Building 202,
Kgs. Lyngby 2800, Denmark
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Strait JT, Eby LA, Kovach RP, Muhlfeld CC, Boyer MC, Amish SJ, Smith S, Lowe WH, Luikart G. Hybridization alters growth and migratory life-history expression of native trout. Evol Appl 2021; 14:821-833. [PMID: 33767755 PMCID: PMC7980306 DOI: 10.1111/eva.13163] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/25/2020] [Accepted: 10/12/2020] [Indexed: 11/29/2022] Open
Abstract
Human-mediated hybridization threatens many native species, but the effects of introgressive hybridization on life-history expression are rarely quantified, especially in vertebrates. We quantified the effects of non-native rainbow trout admixture on important life-history traits including growth and partial migration behavior in three populations of westslope cutthroat trout over five years. Rainbow trout admixture was associated with increased summer growth rates in all populations and decreased spring growth rates in two populations with cooler spring temperatures. These results indicate that non-native admixture may increase growth under warmer conditions, but cutthroat trout have higher growth rates during cooler periods. Non-native admixture consistently increased expression of migratory behavior, suggesting that there is a genomic basis for life-history differences between these species. Our results show that effects of interspecific hybridization on fitness traits can be the product of genotype-by-environment interactions even when there are minor differences in environmental optima between hybridizing species. These results also indicate that while environmentally mediated traits like growth may play a role in population-level consequences of admixture, strong genetic influences on migratory life-history differences between these species likely explains the continued spread of non-native hybridization at the landscape-level, despite selection against hybrids at the population-level.
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Affiliation(s)
- Jeffrey T. Strait
- Wildlife Biology Program, W.A. Franke College of Forestry and ConservationUniversity of MontanaMissoulaMTUSA
- Flathead Lake Biological Station, Fish and Wildlife Genomics GroupDivision of Biological SciencesUniversity of MontanaPolsonMTUSA
| | - Lisa A. Eby
- Wildlife Biology Program, W.A. Franke College of Forestry and ConservationUniversity of MontanaMissoulaMTUSA
| | - Ryan P. Kovach
- Montana Fish, Wildlife, and ParksUniversity of Montana Fish Conservation Genetics LabMissoulaMTUSA
| | - Clint C. Muhlfeld
- Flathead Lake Biological Station, Fish and Wildlife Genomics GroupDivision of Biological SciencesUniversity of MontanaPolsonMTUSA
- U.S. Geological SurveyNorthern Rocky Mountain Science CenterGlacier National ParkWest GlacierMTUSA
| | | | - Stephen J. Amish
- Flathead Lake Biological Station, Fish and Wildlife Genomics GroupDivision of Biological SciencesUniversity of MontanaPolsonMTUSA
| | - Seth Smith
- Flathead Lake Biological Station, Fish and Wildlife Genomics GroupDivision of Biological SciencesUniversity of MontanaPolsonMTUSA
| | - Winsor H. Lowe
- Division of Biological SciencesUniversity of MontanaMissoulaMTUSA
| | - Gordon Luikart
- Flathead Lake Biological Station, Fish and Wildlife Genomics GroupDivision of Biological SciencesUniversity of MontanaPolsonMTUSA
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Caldwell TJ, Chandra S, Feher K, Simmons JB, Hogan Z. Ecosystem response to earlier ice break-up date: Climate-driven changes to water temperature, lake-habitat-specific production, and trout habitat and resource use. GLOBAL CHANGE BIOLOGY 2020; 26:5475-5491. [PMID: 32602183 DOI: 10.1111/gcb.15258] [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: 03/04/2019] [Revised: 05/19/2020] [Accepted: 06/06/2020] [Indexed: 06/11/2023]
Abstract
Climate warming has yielded earlier ice break-up dates in recent decades for lakes leading to water temperature increases, altered habitat, and both increases and decreases to ecosystem productivity. Within lakes, the effect of climate warming on secondary production in littoral and pelagic habitats remains unclear. The intersection of changing habitat productivity and warming water temperatures on salmonids is important for understanding how climate warming will impact mountain ecosystems. We develop and test a conceptual model that expresses how earlier ice break-up dates influence within lake habitat production, water temperatures and the habitat utilized by, resources obtained and behavior of salmonids in a mountain lake. We measured zoobenthic and zooplankton production from the littoral and pelagic habitats, thermal conditions, and the habitat use, resource use, and fitness of Brook Trout (Salvelinus fontinalis). We show that earlier ice break-up conditions created a "resource-rich" littoral-benthic habitat with increases in zoobenthic production compared to the pelagic habitat which decreased in zooplankton production. Despite the increases in littoral-benthic food resources, trout did not utilize littoral habitat or zoobenthic resources due to longer durations of warm water temperatures in the littoral zone. In addition, 87% of their resources were supported by the pelagic habitat during periods with earlier ice break-up when pelagic resources were least abundant. The decreased reliance on littoral-benthic resources during earlier ice break-up caused reduced fitness (mean reduction of 12 g) to trout. Our data show that changes to ice break-up drive multi-directional results for resource production within lake habitats and increase the duration of warmer water temperatures in food-rich littoral habitats. The increased duration of warmer littoral water temperatures reduces the use of energetically efficient habitats culminating in decreased trout fitness.
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Affiliation(s)
- Timothy J Caldwell
- Ecology, Evolution and Conservation Biology Graduate Program, University of Nevada, Reno, NV, USA
- Department of Biology, College of Science, University of Nevada, Reno, NV, USA
| | - Sudeep Chandra
- Ecology, Evolution and Conservation Biology Graduate Program, University of Nevada, Reno, NV, USA
- Department of Biology, College of Science, University of Nevada, Reno, NV, USA
- Global Water Center, University of Nevada, Reno, NV, USA
| | - Karly Feher
- Department of Biology, College of Science, University of Nevada, Reno, NV, USA
| | - James B Simmons
- Ecology, Evolution and Conservation Biology Graduate Program, University of Nevada, Reno, NV, USA
- Department of Biology, College of Science, University of Nevada, Reno, NV, USA
| | - Zeb Hogan
- Department of Biology, College of Science, University of Nevada, Reno, NV, USA
- Global Water Center, University of Nevada, Reno, NV, USA
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Haskell CA, Beauchamp DA, Bollens SM. Linking functional response and bioenergetics to estimate juvenile salmon growth in a reservoir food web. PLoS One 2017; 12:e0185933. [PMID: 29020032 PMCID: PMC5636121 DOI: 10.1371/journal.pone.0185933] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 09/21/2017] [Indexed: 11/18/2022] Open
Abstract
Juvenile salmon (Oncorhynchus spp.) use of reservoir food webs is understudied. We examined the feeding behavior of subyearling Chinook salmon (O. tshawytscha) and its relation to growth by estimating the functional response of juvenile salmon to changes in the density of Daphnia, an important component of reservoir food webs. We then estimated salmon growth across a broad range of water temperatures and daily rations of two primary prey, Daphnia and juvenile American shad (Alosa sapidissima) using a bioenergetics model. Laboratory feeding experiments yielded a Type-II functional response curve: C = 29.858 P *(4.271 + P)-1 indicating that salmon consumption (C) of Daphnia was not affected until Daphnia densities (P) were < 30 · L-1. Past field studies documented Daphnia densities in lower Columbia River reservoirs of < 3 · L-1 in July but as high as 40 · L-1 in August. Bioenergetics modeling indicated that subyearlings could not achieve positive growth above 22°C regardless of prey type or consumption rate. When feeding on Daphnia, subyearlings could not achieve positive growth above 20°C (water temperatures they commonly encounter in the lower Columbia River during summer). At 16–18°C, subyearlings had to consume about 27,000 Daphnia · day-1 to achieve positive growth. However, when feeding on juvenile American shad, subyearlings had to consume 20 shad · day-1 at 16–18°C, or at least 25 shad · day-1 at 20°C to achieve positive growth. Using empirical consumption rates and water temperatures from summer 2013, subyearlings exhibited negative growth during July (-0.23 to -0.29 g · d-1) and August (-0.05 to -0.07 g · d-1). By switching prey from Daphnia to juvenile shad which have a higher energy density, subyearlings can partially compensate for the effects of higher water temperatures they experience in the lower Columbia River during summer. However, achieving positive growth as piscivores requires subyearlings to feed at higher consumption rates than they exhibited empirically. While our results indicate compromised growth in reservoir habitats, the long-term repercussions to salmon populations in the Columbia River Basin are unknown.
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Affiliation(s)
- Craig A. Haskell
- U.S. Geological Survey, Western Fisheries Research Center, Cook, Washington, United States of America
- * E-mail:
| | - David A. Beauchamp
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, Washington, United States of America
| | - Stephen M. Bollens
- Washington State University, School of the Environment and School of Biological Sciences, Vancouver, Washington, United States of America
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