M.D. Hocking, S.G. Faulkner, E. Vogt, K. Akaoka, A. Harwood, T. Hatfield, F. Lewis
{"title":"Reply to “Comment: Surprising salmonid response to water diversion at four run-of-river hydroelectric projects in British Columbia”","authors":"M.D. Hocking, S.G. Faulkner, E. Vogt, K. Akaoka, A. Harwood, T. Hatfield, F. Lewis","doi":"10.1139/cjfas-2023-0153","DOIUrl":"https://doi.org/10.1139/cjfas-2023-0153","url":null,"abstract":"","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42737254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Although the authors have completed an ambitious long-term field experiment involving the effects of water diversion on fish and invertebrates inhabiting steep mountain stream ecosystems, certain aspects of their study design and their interpretations create doubt and skepticism. Additional information is required on how the authors addressed challenging aspects of the research environment and how the sample sites were configured. A substantial decrease in water velocity during the treatment phase may have impacted capture probability. The authors downplay challenges of electrofishing in streams with extremely low conductivity. The authors do not discuss the potential effects of the dams at the boundary between the control and treatment sites, which may include entrainment and migration obstruction. The authors identify opportunities to extrapolate their findings to other systems but have not sufficiently characterized the environment and limiting factors within their study sites to facilitate extrapolation to different ecosystems. Additional work is required to explain how the alterations in this environment contributed to the increase in fish biomass that was observed.
{"title":"Comment: Surprising salmonid response to water diversion at four run-of-river hydroelectric projects in British Columbia","authors":"Richard J. McCleary, Ronald A. Ptolemy","doi":"10.1139/cjfas-2022-0291","DOIUrl":"https://doi.org/10.1139/cjfas-2022-0291","url":null,"abstract":"Although the authors have completed an ambitious long-term field experiment involving the effects of water diversion on fish and invertebrates inhabiting steep mountain stream ecosystems, certain aspects of their study design and their interpretations create doubt and skepticism. Additional information is required on how the authors addressed challenging aspects of the research environment and how the sample sites were configured. A substantial decrease in water velocity during the treatment phase may have impacted capture probability. The authors downplay challenges of electrofishing in streams with extremely low conductivity. The authors do not discuss the potential effects of the dams at the boundary between the control and treatment sites, which may include entrainment and migration obstruction. The authors identify opportunities to extrapolate their findings to other systems but have not sufficiently characterized the environment and limiting factors within their study sites to facilitate extrapolation to different ecosystems. Additional work is required to explain how the alterations in this environment contributed to the increase in fish biomass that was observed.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45059316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Katja Mäkinen, M. Rajasilta, S. Ruuskanen, Tiia Karpela, Aarne O. Lauerma, Johannes Sahlstén
Temperature modifies the reproductive success of fish, yet, in many species, we lack the information on its role in the early development. In this study, the effect of temperature on the relation between maternal traits (length, age, somatic condition, and muscle lipid and ovarian thyroid hormone concentrations), egg quality (fertilization success, development rate, mortality, and hatching success), and offspring traits (size-at-hatch, yolk sac size, and proportion of malformations) were studied in Baltic herring (Clupea harengus membras) in the northern Baltic Sea. The experiments were conducted at an ambient temperature of 7°C and at an elevated temperature of 14°C using 5 to 15 females and 3 replicates per female. The results indicate that elevated temperature may result in a faster developmental rate, a lower early-stage mortality and hatching success, smaller size-at-hatch, a larger yolk sac size and a higher amount of larval malformations when compared to an ambient temperature. The egg and offspring traits were also associated with the maternal traits, indicating especially that thyroid hormones play a mediating role in the physiological processes.
{"title":"Effects of incubation temperature and maternal phenotype on Baltic herring (Clupea harengus membras) eggs and larvae: An experimental study","authors":"Katja Mäkinen, M. Rajasilta, S. Ruuskanen, Tiia Karpela, Aarne O. Lauerma, Johannes Sahlstén","doi":"10.1139/cjfas-2023-0032","DOIUrl":"https://doi.org/10.1139/cjfas-2023-0032","url":null,"abstract":"Temperature modifies the reproductive success of fish, yet, in many species, we lack the information on its role in the early development. In this study, the effect of temperature on the relation between maternal traits (length, age, somatic condition, and muscle lipid and ovarian thyroid hormone concentrations), egg quality (fertilization success, development rate, mortality, and hatching success), and offspring traits (size-at-hatch, yolk sac size, and proportion of malformations) were studied in Baltic herring (Clupea harengus membras) in the northern Baltic Sea. The experiments were conducted at an ambient temperature of 7°C and at an elevated temperature of 14°C using 5 to 15 females and 3 replicates per female. The results indicate that elevated temperature may result in a faster developmental rate, a lower early-stage mortality and hatching success, smaller size-at-hatch, a larger yolk sac size and a higher amount of larval malformations when compared to an ambient temperature. The egg and offspring traits were also associated with the maternal traits, indicating especially that thyroid hormones play a mediating role in the physiological processes.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42373189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chuansong Liao, Jiacheng Wang, S. B. Correa, Jixin Yu, Rui Yang, Jing Yuan, Wei Li, Shaowen Ye, Chuanbo Guo, Jiashou Liu
The impoundment of the Yangtze River and construction of the Three Gorges Dam and Reservoir created an unnatural flow regime with a 30 m water-level fluctuation and four artificial seasons that differ from the river's natural flow-regime timing. Using stable isotopes, we selected 15 common benthic fish species representing five trophic guilds to analyze seasonal variation in production sources, trophic niche width, and niche overlap. We hypothesized that, similarly to a natural flow regime, artificial hydrological seasons effectively influence fish trophic niches. We found consistency in seasonal shifts in the contribution of aquatic and terrestrial producers to fish biomass. δ13C and δ15N depicted seasonal changes in intra-guild trophic niche width and intra- and inter-guild niche overlap. Considering that the Three Gorges Reservoir's flow regime is artificially regulated, our findings suggest that water level fluctuation is one of the key mechanisms driving such trophic shifts and allowing multiple species to coexist. Given the increased cascaded large reservoir construction and the concomitant creation of unnatural flow regimes in large rivers worldwide, these findings are timely. Our findings contribute to improving water level management by optimizing rhythmicity while balancing flood control and fish protection.
{"title":"Artificial water level fluctuation modulates trophic niches of benthic fish assemblages in one of the world's largest reservoirs","authors":"Chuansong Liao, Jiacheng Wang, S. B. Correa, Jixin Yu, Rui Yang, Jing Yuan, Wei Li, Shaowen Ye, Chuanbo Guo, Jiashou Liu","doi":"10.1139/cjfas-2023-0114","DOIUrl":"https://doi.org/10.1139/cjfas-2023-0114","url":null,"abstract":"The impoundment of the Yangtze River and construction of the Three Gorges Dam and Reservoir created an unnatural flow regime with a 30 m water-level fluctuation and four artificial seasons that differ from the river's natural flow-regime timing. Using stable isotopes, we selected 15 common benthic fish species representing five trophic guilds to analyze seasonal variation in production sources, trophic niche width, and niche overlap. We hypothesized that, similarly to a natural flow regime, artificial hydrological seasons effectively influence fish trophic niches. We found consistency in seasonal shifts in the contribution of aquatic and terrestrial producers to fish biomass. δ13C and δ15N depicted seasonal changes in intra-guild trophic niche width and intra- and inter-guild niche overlap. Considering that the Three Gorges Reservoir's flow regime is artificially regulated, our findings suggest that water level fluctuation is one of the key mechanisms driving such trophic shifts and allowing multiple species to coexist. Given the increased cascaded large reservoir construction and the concomitant creation of unnatural flow regimes in large rivers worldwide, these findings are timely. Our findings contribute to improving water level management by optimizing rhythmicity while balancing flood control and fish protection.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45111540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Early life-history properties reveal a considerable variation among riverine fish species and may play a major role in the downstream drift of larval fish. This role, however, remains largely unexplored. Assemblages of drifting fish larvae and their condition during the peak seasons were analyzed along a cross-section from littoral to midstream zones in a free-flowing section in the middle Yangtze River. Assemblage structure and larval body injuries revealed pronounced transverse patterns. These patterns were mainly explained by hydraulic gradients. Highest species occurrence was recorded in the littoral zone. Larval abundance of most species and larval body injury rates were higher in littoral and sublittoral zones. Relative inshore and nearshore larval abundance revealed a significant negative relationship with species-specific initial body size, and varied among species. Larval abundance, body injury rate and feeding intensity were all higher at night. Our findings revealed considerable habitat preferences of drifting larval fish and suggest important adaptations for reducing starvation- and predation risks. These factors should be considered in species conservation and river management.
{"title":"Species-specific adaptations, individual condition, and life-history-induced dispersal strategies of fish larvae along a transverse gradient in a large river","authors":"Zhen Wang, H. Keckeis, Fei Cheng, S. Xie","doi":"10.1139/cjfas-2023-0078","DOIUrl":"https://doi.org/10.1139/cjfas-2023-0078","url":null,"abstract":"Early life-history properties reveal a considerable variation among riverine fish species and may play a major role in the downstream drift of larval fish. This role, however, remains largely unexplored. Assemblages of drifting fish larvae and their condition during the peak seasons were analyzed along a cross-section from littoral to midstream zones in a free-flowing section in the middle Yangtze River. Assemblage structure and larval body injuries revealed pronounced transverse patterns. These patterns were mainly explained by hydraulic gradients. Highest species occurrence was recorded in the littoral zone. Larval abundance of most species and larval body injury rates were higher in littoral and sublittoral zones. Relative inshore and nearshore larval abundance revealed a significant negative relationship with species-specific initial body size, and varied among species. Larval abundance, body injury rate and feeding intensity were all higher at night. Our findings revealed considerable habitat preferences of drifting larval fish and suggest important adaptations for reducing starvation- and predation risks. These factors should be considered in species conservation and river management.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49046754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Successful management of imperiled anadromous salmon stocks requires understanding how salmon will respond to a changing climate across their extensive ranges. Though largely unused for anadromous salmon to date, Environmental Niche Models (ENMs) can provide a strong foundation for estimating where and how much habitat will likely remain favourable. We applied a comprehensive suite of ENM statistical approaches to five Pacific salmon species, focusing on freshwater spawning and natal rearing habitat as critical for population survival but also highly susceptible to a changing climate. We developed ENMs for spawning ranges across British Columbia (BC), Canada and western US, and projected future scenarios for BC. Projections indicated net expansion of favourable spawning habitat across species in BC, with the most change occurring by 2060. However, shifts in favourable habitat varied greatly geographically and by species, with notable reductions in coastal and southern interior streams. Our results provide a basis for identifying important changes in spawning and natal rearing habitat conditions to help inform priorities for restoration and protection actions.
{"title":"Predicting favourable streams for anadromous salmon spawning and natal rearing under climate change","authors":"Josephine C. Iacarella, J. D. Weller","doi":"10.1139/cjfas-2023-0096","DOIUrl":"https://doi.org/10.1139/cjfas-2023-0096","url":null,"abstract":"Successful management of imperiled anadromous salmon stocks requires understanding how salmon will respond to a changing climate across their extensive ranges. Though largely unused for anadromous salmon to date, Environmental Niche Models (ENMs) can provide a strong foundation for estimating where and how much habitat will likely remain favourable. We applied a comprehensive suite of ENM statistical approaches to five Pacific salmon species, focusing on freshwater spawning and natal rearing habitat as critical for population survival but also highly susceptible to a changing climate. We developed ENMs for spawning ranges across British Columbia (BC), Canada and western US, and projected future scenarios for BC. Projections indicated net expansion of favourable spawning habitat across species in BC, with the most change occurring by 2060. However, shifts in favourable habitat varied greatly geographically and by species, with notable reductions in coastal and southern interior streams. Our results provide a basis for identifying important changes in spawning and natal rearing habitat conditions to help inform priorities for restoration and protection actions.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49105004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Hermann, L. Hammer, N. Hussey, M. Marcoux, K. Hedges, R. Walter, N. Furey
Environments change across space and time, often requiring organisms to exhibit behavioral responses. In the Arctic, migratory consumers are motivated by spring resources to follow receding ice; however, resident species’ responses to this ephemeral productivity are less well understood. We characterized the movement behaviors of relatively sedentary Arctic species of sculpin (Myoxocephalus spp.) in Tremblay Sound, Nunavut, Canada. Movements of individuals (n = 60) captured during the ice-free periods of 2017-2019 were monitored year-round via an array of acoustic telemetry receivers (n = 37). Telemetry data confirmed year-round residency within the Sound, yet sculpins were consistently more active and wider ranging during the ice-free period versus the ice-covered winters. Sequence analysis revealed distinct patterns of activity differentiated primarily by regional associations. Together, these results indicate sculpin are highly sedentary, but move more during the ice-free season, suggesting the importance of the seasonal productivity pulse to these fish. As resident species adapted to exploit the conditions within their local environment, sculpin provide a valuable indicator species to monitor coastal and benthic Arctic ecosystems that are experiencing rapid change.
{"title":"Year-round monitoring of Arctic species of sculpin to identify residency and seasonality of movement behavior","authors":"N. Hermann, L. Hammer, N. Hussey, M. Marcoux, K. Hedges, R. Walter, N. Furey","doi":"10.1139/cjfas-2023-0042","DOIUrl":"https://doi.org/10.1139/cjfas-2023-0042","url":null,"abstract":"Environments change across space and time, often requiring organisms to exhibit behavioral responses. In the Arctic, migratory consumers are motivated by spring resources to follow receding ice; however, resident species’ responses to this ephemeral productivity are less well understood. We characterized the movement behaviors of relatively sedentary Arctic species of sculpin (Myoxocephalus spp.) in Tremblay Sound, Nunavut, Canada. Movements of individuals (n = 60) captured during the ice-free periods of 2017-2019 were monitored year-round via an array of acoustic telemetry receivers (n = 37). Telemetry data confirmed year-round residency within the Sound, yet sculpins were consistently more active and wider ranging during the ice-free period versus the ice-covered winters. Sequence analysis revealed distinct patterns of activity differentiated primarily by regional associations. Together, these results indicate sculpin are highly sedentary, but move more during the ice-free season, suggesting the importance of the seasonal productivity pulse to these fish. As resident species adapted to exploit the conditions within their local environment, sculpin provide a valuable indicator species to monitor coastal and benthic Arctic ecosystems that are experiencing rapid change.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42978538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
David Páez, J. Gregg, A. Mackenzie, Sophie Hall, P. Hershberger
We characterized a natural sea louse epizootic of Caligus clemensi and the effects of parasitism on Pacific herring Clupea pallasii in Port Angeles Harbor, WA, USA. Infestation prevalence on newly metamorphosed age 0 Pacific herring reached 100% prevalence by mid-August. At this time, the mean louse intensity was 4.6 lice / fish, and a positive correlation occurred between louse intensity and herring body length. The epizootic then waned, with infestation prevalence decreasing to less than 25% and the mean parasite intensity falling below 1 louse. While skin injuries were not detected, motile lice preferentially aggregated around head and anterior dorsal areas. However, louse tropism became evenly distributed over the body as the parasite intensity increased. Louse-induced mortality in herring was negligible in controlled experiments. These results indicate that C. clemensi epizootics reach high prevalence, but also fade from mid-summer to early fall. The predominant presence of motile copepod stages suggests that the epizootic fades because lice complete their life cycle and dislodge from the host; however, multiple explanations for epidemic fading are possible.
{"title":"Characteristics of a sea louse (Caligus clemensi) epizootic in wild Pacific herring (Clupea pallasii)","authors":"David Páez, J. Gregg, A. Mackenzie, Sophie Hall, P. Hershberger","doi":"10.1139/cjfas-2023-0070","DOIUrl":"https://doi.org/10.1139/cjfas-2023-0070","url":null,"abstract":"We characterized a natural sea louse epizootic of Caligus clemensi and the effects of parasitism on Pacific herring Clupea pallasii in Port Angeles Harbor, WA, USA. Infestation prevalence on newly metamorphosed age 0 Pacific herring reached 100% prevalence by mid-August. At this time, the mean louse intensity was 4.6 lice / fish, and a positive correlation occurred between louse intensity and herring body length. The epizootic then waned, with infestation prevalence decreasing to less than 25% and the mean parasite intensity falling below 1 louse. While skin injuries were not detected, motile lice preferentially aggregated around head and anterior dorsal areas. However, louse tropism became evenly distributed over the body as the parasite intensity increased. Louse-induced mortality in herring was negligible in controlled experiments. These results indicate that C. clemensi epizootics reach high prevalence, but also fade from mid-summer to early fall. The predominant presence of motile copepod stages suggests that the epizootic fades because lice complete their life cycle and dislodge from the host; however, multiple explanations for epidemic fading are possible.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46556388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Vaisvil, M. Willmes, E. J. Enriquez, Z. Klein, C. Caldwell
Largemouth Bass Micropterus salmoides, a popular warm water sport fish, is routinely stocked in reservoirs throughout the USA to augment wild populations. Evaluating if these supplementations are successful requires distinguishing hatchery-sourced fish from their wild counterparts. From 2011 to 2019, over 467,000 Largemouth Bass fingerlings were stocked from multiple hatchery sources into a large southwestern reservoir (Elephant Butte Reservoir, New Mexico USA) to supplement the sportfish population. To identify hatchery-sourced Largemouth Bass, we measured strontium isotope ratios (87Sr/86Sr) and determined ages using otoliths and dorsal spines. Otolith analysis of 169 fish classified 92.9% (n = 159) to the reservoir with few fish of hatchery origin (2 from Arkansas, 1.2% and 1 from Montana, 0.6%). While stocking over 467,000 fingerlings across eight years appears to reflect negligible stocking success, it is likely that low and variable stocking densities (average 3.0, range 0.29–7.77 fish/ha) likely contributed to the low stocking success in Elephant Butte Reservoir. Dorsal fin spines did not yield accurate age reconstructions and their 87Sr/86Sr were affected by matrix interferences preventing source assignments.
{"title":"A needle in a haystack: Strontium isotopes (87Sr/86Sr) in otoliths identify origin of Largemouth Bass from a large Southwest reservoir","authors":"A. Vaisvil, M. Willmes, E. J. Enriquez, Z. Klein, C. Caldwell","doi":"10.1139/cjfas-2023-0148","DOIUrl":"https://doi.org/10.1139/cjfas-2023-0148","url":null,"abstract":"Largemouth Bass Micropterus salmoides, a popular warm water sport fish, is routinely stocked in reservoirs throughout the USA to augment wild populations. Evaluating if these supplementations are successful requires distinguishing hatchery-sourced fish from their wild counterparts. From 2011 to 2019, over 467,000 Largemouth Bass fingerlings were stocked from multiple hatchery sources into a large southwestern reservoir (Elephant Butte Reservoir, New Mexico USA) to supplement the sportfish population. To identify hatchery-sourced Largemouth Bass, we measured strontium isotope ratios (87Sr/86Sr) and determined ages using otoliths and dorsal spines. Otolith analysis of 169 fish classified 92.9% (n = 159) to the reservoir with few fish of hatchery origin (2 from Arkansas, 1.2% and 1 from Montana, 0.6%). While stocking over 467,000 fingerlings across eight years appears to reflect negligible stocking success, it is likely that low and variable stocking densities (average 3.0, range 0.29–7.77 fish/ha) likely contributed to the low stocking success in Elephant Butte Reservoir. Dorsal fin spines did not yield accurate age reconstructions and their 87Sr/86Sr were affected by matrix interferences preventing source assignments.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48132364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Random utility models have been widely used to model spatial choice within fisheries, but less attention has been paid to modeling participation and movement between fisheries. Fishers may switch fisheries in response to time closures or changes in profitability potentially creating management implications for those fisheries as well as the fishery with the closure. We used a random utility maximization framework to model participation, fishery choice, and location choice for a large fleet of West Coast salmon trollers, many of which also participate in other fisheries. We used the model to demonstrate substitution effects across fisheries due to spatial policies implemented in the salmon fishery. Our work suggests spatial management of a single fishery needs to take into consideration fishers’ full choice set to predict behavioral responses to spatial policies. Our analysis also provides insights into how fishers construct multifishery harvest strategies that enable them to more fully use capital or adjust to closures or changes in relative profitability.
{"title":"Fishery Participation and Location Choice Model: The West Coast Salmon Troll Commercial Fishery","authors":"Smit Vasquez Caballero, G. Sylvia, D. Holland","doi":"10.1139/cjfas-2023-0001","DOIUrl":"https://doi.org/10.1139/cjfas-2023-0001","url":null,"abstract":"Random utility models have been widely used to model spatial choice within fisheries, but less attention has been paid to modeling participation and movement between fisheries. Fishers may switch fisheries in response to time closures or changes in profitability potentially creating management implications for those fisheries as well as the fishery with the closure. We used a random utility maximization framework to model participation, fishery choice, and location choice for a large fleet of West Coast salmon trollers, many of which also participate in other fisheries. We used the model to demonstrate substitution effects across fisheries due to spatial policies implemented in the salmon fishery. Our work suggests spatial management of a single fishery needs to take into consideration fishers’ full choice set to predict behavioral responses to spatial policies. Our analysis also provides insights into how fishers construct multifishery harvest strategies that enable them to more fully use capital or adjust to closures or changes in relative profitability.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47555108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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