Wesley A. Arend, Rebecca D. Mangold, Christopher L. Riggins, Collin Groutte, Yeyetzi Rodriguez, Thomas C. Heard, Nick Menchaca, Janaye Williamson, Dusty McDonald, Daniel Daugherty, Monica McGarrity, Kevin W. Conway, Joshuah S. Perkin
Abstract Suckermouth armored catfishes (SACs; Loricariidae) have invaded waterbodies outside their native range globally. Population control methods, including removals and genetic biocontrols, may be enhanced through greater knowledge of sex discrimination, sex ratios, and potential sex bias among control methods. We investigated sexual dimorphism and population sex ratio for an invasive SAC population of Hypostomus sp. in the upper San Marcos River, Texas, USA as a means of advancing on‐going management of the population. Among 385 specimens obtained at random during a planned dewatering of a 100‐m reach of the river, the sex ratio was biased towards females (proportion of females = 0.60). Morphometric analyses of 105 females and 108 males based on a generalized boosted classification model (GBM) revealed elongated dorsal‐ and anal‐fins in males correctly classified sex for 83% of individuals (95% CI = 77–88%). Seven independent observers used results from the GBM to assign sex to 30 fish with average accuracy of 72% (range = 43–83%). Accuracy of the model and validation exercises was highest for fish >240 mm total length, the estimated length of reproductive maturity. Morphometrics based on dorsal‐ and anal‐fin sizes can be used to infer sex externally from hundreds of SACs removed per year to evaluate long‐term population management success.
摘要:吸吮口铠甲鲶鱼;蛭形蝇科(Loricariidae)已在全球范围内侵入其原生范围以外的水体。人口控制方法，包括清除和遗传生物控制，可以通过更多地了解性别歧视、性别比例和控制方法中潜在的性别偏见来加强。研究了美国德克萨斯州圣马科斯河上游一个入侵性SAC种群的两性二态性和种群性别比，以促进种群的持续管理。在规划的100米河段脱水过程中随机获得的385个样本中，性别比例偏向于雌性(雌性比例= 0.60)。基于广义增强分类模型(GBM)的105只雌性和108只雄性的形态计量学分析显示，83%的雄性个体正确地分类了伸长的背鳍和肛门鳍(95% CI = 77-88%)。7名独立观察员使用GBM的结果对30条鱼进行性别鉴定，平均准确率为72%(范围= 43-83%)。模型和验证练习的准确性是最高的鱼>240毫米的总长度，生殖成熟的估计长度。基于背鳍和肛鳍大小的形态计量学可用于从每年移除的数百个sac中推断外部性别，以评估长期种群管理的成功。
{"title":"Sexual dimorphism in an invasive population of suckermouth armored catfish: Implications for management","authors":"Wesley A. Arend, Rebecca D. Mangold, Christopher L. Riggins, Collin Groutte, Yeyetzi Rodriguez, Thomas C. Heard, Nick Menchaca, Janaye Williamson, Dusty McDonald, Daniel Daugherty, Monica McGarrity, Kevin W. Conway, Joshuah S. Perkin","doi":"10.1002/nafm.10951","DOIUrl":"https://doi.org/10.1002/nafm.10951","url":null,"abstract":"Abstract Suckermouth armored catfishes (SACs; Loricariidae) have invaded waterbodies outside their native range globally. Population control methods, including removals and genetic biocontrols, may be enhanced through greater knowledge of sex discrimination, sex ratios, and potential sex bias among control methods. We investigated sexual dimorphism and population sex ratio for an invasive SAC population of Hypostomus sp. in the upper San Marcos River, Texas, USA as a means of advancing on‐going management of the population. Among 385 specimens obtained at random during a planned dewatering of a 100‐m reach of the river, the sex ratio was biased towards females (proportion of females = 0.60). Morphometric analyses of 105 females and 108 males based on a generalized boosted classification model (GBM) revealed elongated dorsal‐ and anal‐fins in males correctly classified sex for 83% of individuals (95% CI = 77–88%). Seven independent observers used results from the GBM to assign sex to 30 fish with average accuracy of 72% (range = 43–83%). Accuracy of the model and validation exercises was highest for fish >240 mm total length, the estimated length of reproductive maturity. Morphometrics based on dorsal‐ and anal‐fin sizes can be used to infer sex externally from hundreds of SACs removed per year to evaluate long‐term population management success.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135015753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tawni B. Riepe, Zachary E. Hooley‐Underwood, Rebecca E. McDevitt, Alan Sralik, P. Cadmus
Streams used by Bluehead Suckers Catostomus discobolus experience variable water temperatures of high and low extremes and extreme rates of change. Acute and chronic laboratory temperature tests have been used to develop protective thermal criteria, but these methods do not allow for testing the lethality of temperature interactions with other stressors. For instance, fish density and temperature interactions are likely to occur during low‐flow periods with high densities of fish stranded in a stagnant pool; but standard thermal tests only included one fish.We examined the effect of two acclimation temperatures that represent field temperatures (8°C and 18°C) on hatch success and larval survival, and the critical thermal maximum (CTMax) and minimum temperatures (CTMin). We then investigated how the interaction of density (n = 1, n = 10, n = 25 fish per 2 L) and temperature influence CTMax or CTMin.We found maximum egg hatch success and larval survival at 18°C and the temperature range for Bluehead Sucker larvae at 18°C was 7.2 ± 1.6°C to 32.1 ± 2.4°C. However, when the density of the larvae was high (n = 25 per 2 L) the upper thermal limit significantly decreased by 5.9°C.Our results indicate higher fish densities negatively affect the tolerance of the fish to increased temperature. Thus, density and temperature interactions should be considered when developing protective temperature criteria.
蓝头吸盘虫(Catostomus disbolus)所使用的溪流经历了高、低极端和极端变化率的可变水温。急性和慢性实验室温度测试已用于制定保护性热标准，但这些方法不允许测试温度与其他应激源相互作用的致命性。例如，鱼类密度和温度的相互作用很可能发生在低流量时期，在停滞池中有高密度的鱼类搁浅;但标准的热测试只包括一条鱼。我们研究了代表田间温度(8°C和18°C)的两种驯化温度对孵化成功率和幼虫存活率的影响，以及临界热最大值(CTMax)和最低温度(CTMin)。然后，我们研究了密度(n = 1, n = 10, n = 25鱼/ 2 L)和温度的相互作用如何影响CTMax或CTMin。结果表明，在18℃条件下，蓝头吸盘幼虫的孵化成功率和存活率最高，18℃温度范围为7.2±1.6℃~ 32.1±2.4℃。然而，当幼虫密度较高(n = 25 / 2 L)时，温度上限显著降低5.9°C。我们的研究结果表明，较高的鱼类密度会对鱼类对温度升高的耐受性产生负面影响。因此，在制定保护温度标准时，应考虑密度和温度的相互作用。
{"title":"Increased density of Bluehead Sucker larvae decreases critical thermal maximum","authors":"Tawni B. Riepe, Zachary E. Hooley‐Underwood, Rebecca E. McDevitt, Alan Sralik, P. Cadmus","doi":"10.1002/nafm.10925","DOIUrl":"https://doi.org/10.1002/nafm.10925","url":null,"abstract":"Streams used by Bluehead Suckers Catostomus discobolus experience variable water temperatures of high and low extremes and extreme rates of change. Acute and chronic laboratory temperature tests have been used to develop protective thermal criteria, but these methods do not allow for testing the lethality of temperature interactions with other stressors. For instance, fish density and temperature interactions are likely to occur during low‐flow periods with high densities of fish stranded in a stagnant pool; but standard thermal tests only included one fish.We examined the effect of two acclimation temperatures that represent field temperatures (8°C and 18°C) on hatch success and larval survival, and the critical thermal maximum (CTMax) and minimum temperatures (CTMin). We then investigated how the interaction of density (n = 1, n = 10, n = 25 fish per 2 L) and temperature influence CTMax or CTMin.We found maximum egg hatch success and larval survival at 18°C and the temperature range for Bluehead Sucker larvae at 18°C was 7.2 ± 1.6°C to 32.1 ± 2.4°C. However, when the density of the larvae was high (n = 25 per 2 L) the upper thermal limit significantly decreased by 5.9°C.Our results indicate higher fish densities negatively affect the tolerance of the fish to increased temperature. Thus, density and temperature interactions should be considered when developing protective temperature criteria.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46157561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ahmed A. Elbassiouny, J. P. Fontenelle, P. Kočovský, N. Mandrak, N. Lovejoy
Silver Chub Macrhybopsis storeriana is a small riverine minnow endemic to North American fresh waters. Its range extends from the southern USA to southcentral Canada; the latter includes a rare lacustrine population in Lake Erie. Anthropogenic activities pose an immediate threat to several Silver Chub populations, currently categorized from special concern to threatened at the state level in the USA and federally and provincially not‐at‐risk to endangered in Canada. Several studies have examined the anthropogenic causes for the decline of Silver Chub populations, but conservation efforts have been hindered by the lack of knowledge of the population genetics of this species.Here, we provide an assessment of the genetic diversity of Silver Chub populations across the USA and Canada using a fast‐evolving mitochondrial gene, with particular focus on the Lake Erie population.We found the Lake Erie population to be divergent from all other populations, with nearly all the haplotypes sampled there being private.Our study provides genetic evidence that the Silver Chub population in Lake Erie could be considered a separate conservation unit.
{"title":"Genetic structure of the Silver Chub indicates distinctiveness of Lake Erie population","authors":"Ahmed A. Elbassiouny, J. P. Fontenelle, P. Kočovský, N. Mandrak, N. Lovejoy","doi":"10.1002/nafm.10888","DOIUrl":"https://doi.org/10.1002/nafm.10888","url":null,"abstract":"Silver Chub Macrhybopsis storeriana is a small riverine minnow endemic to North American fresh waters. Its range extends from the southern USA to southcentral Canada; the latter includes a rare lacustrine population in Lake Erie. Anthropogenic activities pose an immediate threat to several Silver Chub populations, currently categorized from special concern to threatened at the state level in the USA and federally and provincially not‐at‐risk to endangered in Canada. Several studies have examined the anthropogenic causes for the decline of Silver Chub populations, but conservation efforts have been hindered by the lack of knowledge of the population genetics of this species.Here, we provide an assessment of the genetic diversity of Silver Chub populations across the USA and Canada using a fast‐evolving mitochondrial gene, with particular focus on the Lake Erie population.We found the Lake Erie population to be divergent from all other populations, with nearly all the haplotypes sampled there being private.Our study provides genetic evidence that the Silver Chub population in Lake Erie could be considered a separate conservation unit.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46571445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Population demographics of trout were analyzed across multiple spatial scales to evaluate fishery resources in the three forks and main stem of the upper Snoqualmie River, Washington. Physical habitat and trout species compositions, relative abundances, and sizes were assessed through spatially continuous sampling of the watershed. Fish were also sampled at the segment scale (5–20 km) for more detailed but spatially intermediate assessments of species and genetic origin, size at age, and seasonal diet. To evaluate growth conditions during summer months, bioenergetics simulations of consumption by trout were run using summer water temperatures, and growth and diets were sampled at two life stages.We found high variability in longitudinal species compositions, genetic origins, relative abundances, and densities within and among forks. While annual growth generally decreased with distance upstream, summer growth efficiency consistently increased. Areal density estimates of age‐0 recruits in the North and Middle forks generally increased with segment elevation, whereas density of recruits was relatively low in upper elevations of the South Fork, where nonnative Westslope Cutthroat Trout Oncorhynchus clarkii lewisi were most abundant. Abundance of trout varied widely among the forks, and a native metapopulation of Coastal Cutthroat Trout Oncorhynchus clarkii clarkii was the most abundantly distributed species across interconnected main‐stem habitats.Factors affecting population demographics of trout at the riverscape scale included geologic barriers, habitat diversity, and stocking practices, while summer growth was primarily affected by water temperature. Merging riverscape‐ and intermediate‐scale sampling enhanced watershed‐scale inferences made from intermediate sampling while accounting for continuous variability. This design provided a holistic assessment of the trout resources that would not have been possible using either site‐specific sampling or continuous longitudinal surveys and provided a baseline assessment of trout resources in the upper Snoqualmie River watershed for continued management and conservation of the fishery.
{"title":"Multiscale population demographics and growth responses of trout in the upper Snoqualmie River watershed, Washington","authors":"J. Thompson, Nathanael C. Overman","doi":"10.1002/nafm.10928","DOIUrl":"https://doi.org/10.1002/nafm.10928","url":null,"abstract":"Population demographics of trout were analyzed across multiple spatial scales to evaluate fishery resources in the three forks and main stem of the upper Snoqualmie River, Washington. Physical habitat and trout species compositions, relative abundances, and sizes were assessed through spatially continuous sampling of the watershed. Fish were also sampled at the segment scale (5–20 km) for more detailed but spatially intermediate assessments of species and genetic origin, size at age, and seasonal diet. To evaluate growth conditions during summer months, bioenergetics simulations of consumption by trout were run using summer water temperatures, and growth and diets were sampled at two life stages.We found high variability in longitudinal species compositions, genetic origins, relative abundances, and densities within and among forks. While annual growth generally decreased with distance upstream, summer growth efficiency consistently increased. Areal density estimates of age‐0 recruits in the North and Middle forks generally increased with segment elevation, whereas density of recruits was relatively low in upper elevations of the South Fork, where nonnative Westslope Cutthroat Trout Oncorhynchus clarkii lewisi were most abundant. Abundance of trout varied widely among the forks, and a native metapopulation of Coastal Cutthroat Trout Oncorhynchus clarkii clarkii was the most abundantly distributed species across interconnected main‐stem habitats.Factors affecting population demographics of trout at the riverscape scale included geologic barriers, habitat diversity, and stocking practices, while summer growth was primarily affected by water temperature. Merging riverscape‐ and intermediate‐scale sampling enhanced watershed‐scale inferences made from intermediate sampling while accounting for continuous variability. This design provided a holistic assessment of the trout resources that would not have been possible using either site‐specific sampling or continuous longitudinal surveys and provided a baseline assessment of trout resources in the upper Snoqualmie River watershed for continued management and conservation of the fishery.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42874168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Peterson, Rex Thors, D. Frechette, J. Zydlewski
Sea Lamprey Petromyzon marinus provide important ecological services within their native range, such as nutrient cycling, and can also act as a prey source for other species. Adult Sea Lamprey must access freshwater rivers to spawn, and because of this they are susceptible to changes in river connectivity. Human‐made structures, such as dams, can exclude them from usable habitat. Sea Lamprey dam passage has not been extensively studied in Maine, despite Maine being within the native range of this species. The goals of this study were to evaluate upstream passage efficiency at the Milford Dam on the Penobscot River, Maine, and to provide comprehensive information about adult Sea Lamprey passage at five other dams throughout the Penobscot River watershed.In 2020–2021 we captured and tagged 150 Sea Lamprey at the Milford Dam, the lowest dam in the Penobscot River, Maine, and displaced them downstream to assess passage efficiency at this dam and five upstream dams. In 2020, 50 Sea Lamprey were released on the east shore of the river downstream of Milford Dam; in 2021, the east shore release was repeated with an additional 50 fish and another 50 fish were released on the west shore.Between 70–82% of Sea Lamprey were observed passing Milford Dam again after mean delay times of 9–11 days. The release location did not affect dam passage success or the amount of time that was required to locate and use the passage structures. Sea Lampreys from both release groups were equally likely to approach the entrance to the fishway upon returning to Milford Dam, despite the fishway being located against the eastern shore of the river. However, high flows shortly after release may have resulted in higher attraction to the fishway in 2020. Passage success at dams upstream of Milford was highly variable. All Sea Lamprey were able to successfully navigate past West Enfield Dam (100% passage, n = 63), whereas Brownsmill Dam apparently acted as a complete barrier to further migration (0% passage, n = 7). Fish from all years and release groups together had a median upstream migration distance of 38.8 km after fish had passed Milford Dam, and a maximum observed upstream travel distance of approximately 100 km, indicating that most tagged Sea Lamprey ended their migration in the vicinity of a dam.The results of this study indicate that Sea Lamprey have high passage efficiency at the Milford Dam and highlight areas within the Penobscot River basin—such as the Brownsmill Dam—where passage facilities are currently inadequate for Sea Lamprey.
{"title":"Adult Sea Lamprey approach and passage at the Milford Dam fishway, Penobscot River, Maine, United States","authors":"E. Peterson, Rex Thors, D. Frechette, J. Zydlewski","doi":"10.1002/nafm.10919","DOIUrl":"https://doi.org/10.1002/nafm.10919","url":null,"abstract":"Sea Lamprey Petromyzon marinus provide important ecological services within their native range, such as nutrient cycling, and can also act as a prey source for other species. Adult Sea Lamprey must access freshwater rivers to spawn, and because of this they are susceptible to changes in river connectivity. Human‐made structures, such as dams, can exclude them from usable habitat. Sea Lamprey dam passage has not been extensively studied in Maine, despite Maine being within the native range of this species. The goals of this study were to evaluate upstream passage efficiency at the Milford Dam on the Penobscot River, Maine, and to provide comprehensive information about adult Sea Lamprey passage at five other dams throughout the Penobscot River watershed.In 2020–2021 we captured and tagged 150 Sea Lamprey at the Milford Dam, the lowest dam in the Penobscot River, Maine, and displaced them downstream to assess passage efficiency at this dam and five upstream dams. In 2020, 50 Sea Lamprey were released on the east shore of the river downstream of Milford Dam; in 2021, the east shore release was repeated with an additional 50 fish and another 50 fish were released on the west shore.Between 70–82% of Sea Lamprey were observed passing Milford Dam again after mean delay times of 9–11 days. The release location did not affect dam passage success or the amount of time that was required to locate and use the passage structures. Sea Lampreys from both release groups were equally likely to approach the entrance to the fishway upon returning to Milford Dam, despite the fishway being located against the eastern shore of the river. However, high flows shortly after release may have resulted in higher attraction to the fishway in 2020. Passage success at dams upstream of Milford was highly variable. All Sea Lamprey were able to successfully navigate past West Enfield Dam (100% passage, n = 63), whereas Brownsmill Dam apparently acted as a complete barrier to further migration (0% passage, n = 7). Fish from all years and release groups together had a median upstream migration distance of 38.8 km after fish had passed Milford Dam, and a maximum observed upstream travel distance of approximately 100 km, indicating that most tagged Sea Lamprey ended their migration in the vicinity of a dam.The results of this study indicate that Sea Lamprey have high passage efficiency at the Milford Dam and highlight areas within the Penobscot River basin—such as the Brownsmill Dam—where passage facilities are currently inadequate for Sea Lamprey.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48770439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effectiveness of bycatch avoidance programs relies on changes in fishing behavior in response to spatiotemporal information on bycatch patterns. We evaluated effectiveness of a voluntary bycatch avoidance program in the US Sea Scallop Placopecten magellanicus fishery over the course of four years based on fishing behavior relative to bycatch advisories. We compared results from self‐reported catch to data from a mandatory observer program for participating and non‐participating vessels in the bycatch avoidance program. Significant associations between bycatch advisories and fishing locations indicated bycatch avoidance behavior, while accounting for the effect of sea scallop density on fishing location decisions. Evidence of avoidance behavior was stronger in earlier years of the program and varied spatially. Decreasing avoidance behavior coincided with revised bycatch management measures, which appear to have altered the incentives for bycatch avoidance. We found differences in the fishing behavior of fishing captains who participated in the bycatch avoidance program when Yellowtail Flounder Limanda ferruginea bycatch was perceived to threaten economic yield due to fishery closures. This case study addresses the analytical challenge of detecting bycatch avoidance behavior and relative effectiveness for bycatch mitigation.
{"title":"Evaluating bycatch avoidance in the US Atlantic Sea Scallop fishery","authors":"B. Lowman, C. O’Keefe, S. Cadrin","doi":"10.1002/nafm.10948","DOIUrl":"https://doi.org/10.1002/nafm.10948","url":null,"abstract":"The effectiveness of bycatch avoidance programs relies on changes in fishing behavior in response to spatiotemporal information on bycatch patterns. We evaluated effectiveness of a voluntary bycatch avoidance program in the US Sea Scallop Placopecten magellanicus fishery over the course of four years based on fishing behavior relative to bycatch advisories. We compared results from self‐reported catch to data from a mandatory observer program for participating and non‐participating vessels in the bycatch avoidance program. Significant associations between bycatch advisories and fishing locations indicated bycatch avoidance behavior, while accounting for the effect of sea scallop density on fishing location decisions. Evidence of avoidance behavior was stronger in earlier years of the program and varied spatially. Decreasing avoidance behavior coincided with revised bycatch management measures, which appear to have altered the incentives for bycatch avoidance. We found differences in the fishing behavior of fishing captains who participated in the bycatch avoidance program when Yellowtail Flounder Limanda ferruginea bycatch was perceived to threaten economic yield due to fishery closures. This case study addresses the analytical challenge of detecting bycatch avoidance behavior and relative effectiveness for bycatch mitigation.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46048386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. P. Madenjian, Patricia M. Dieter, T. J. Desorcie, Stephen A. Lengnick, T. P. O'Brien, Lynn M. Benes, Steven A. Farha, Benjamin S. Leonhardt
The Northern Refuge of Lake Michigan was established under the auspices of the Great Lakes Fishery Commission in 1985 as an additional step toward restoring a self‐sustaining Lake Trout Salvelinus namaycush population to the lake. The overall goal of our study was to assess progress toward Lake Trout rehabilitation in the Northern Refuge through 2021.We conducted annual (1992–2021) gill‐net surveys in the fall to assess the adult population and beam trawl surveys in the spring to assess naturally reproduced age‐0 Lake Trout.Spawner abundance averaged 45 fish • 305 m of gill net−1 • day−1 during 1992–1999, just 4 fish • 305 m of gill net−1 • day−1 during 2000–2014, and then 67 fish • 305 m of gill net−1 • day−1 during 2018–2021. Sea Lamprey Petromyzon marinus wounding rate decreased by nearly 90% between the 2000–2014 and 2015–2021 periods. The average annual mortality rate of adult Lake Trout decreased from 43% during the 1990s and 2000s to 22% during 2015–2021. All of these population dynamics were partly driven by changes in Lake Trout stocking rates, which declined by roughly 50% during 1994–1996 but then increased roughly twofold during 2006–2010 and remained at this higher level during 2010–2018. In 2021, early signs of natural recruitment of Lake Trout became evident. Beam trawling during June 2021 yielded a wild age‐0 Lake Trout, the first ever caught since the surveys began in 1992. In addition, 15 (4% of total catch) of the Lake Trout caught in the fall 2021 gill‐net survey were unclipped (wild) fish. Estimated ages of these wild fish indicated that natural recruitment had begun sometime around 2015.With Alewife Alosa pseudoharengus abundance in Lake Michigan at record low levels, Sea Lamprey wounding rate greatly reduced, and Lake Trout spawner abundance at relatively high levels, the outlook for Lake Trout rehabilitation in the Northern Refuge holds promise.
{"title":"Lake Trout population dynamics in the Northern Refuge of Lake Michigan: Importance of stocking rate","authors":"C. P. Madenjian, Patricia M. Dieter, T. J. Desorcie, Stephen A. Lengnick, T. P. O'Brien, Lynn M. Benes, Steven A. Farha, Benjamin S. Leonhardt","doi":"10.1002/nafm.10915","DOIUrl":"https://doi.org/10.1002/nafm.10915","url":null,"abstract":"The Northern Refuge of Lake Michigan was established under the auspices of the Great Lakes Fishery Commission in 1985 as an additional step toward restoring a self‐sustaining Lake Trout Salvelinus namaycush population to the lake. The overall goal of our study was to assess progress toward Lake Trout rehabilitation in the Northern Refuge through 2021.We conducted annual (1992–2021) gill‐net surveys in the fall to assess the adult population and beam trawl surveys in the spring to assess naturally reproduced age‐0 Lake Trout.Spawner abundance averaged 45 fish • 305 m of gill net−1 • day−1 during 1992–1999, just 4 fish • 305 m of gill net−1 • day−1 during 2000–2014, and then 67 fish • 305 m of gill net−1 • day−1 during 2018–2021. Sea Lamprey Petromyzon marinus wounding rate decreased by nearly 90% between the 2000–2014 and 2015–2021 periods. The average annual mortality rate of adult Lake Trout decreased from 43% during the 1990s and 2000s to 22% during 2015–2021. All of these population dynamics were partly driven by changes in Lake Trout stocking rates, which declined by roughly 50% during 1994–1996 but then increased roughly twofold during 2006–2010 and remained at this higher level during 2010–2018. In 2021, early signs of natural recruitment of Lake Trout became evident. Beam trawling during June 2021 yielded a wild age‐0 Lake Trout, the first ever caught since the surveys began in 1992. In addition, 15 (4% of total catch) of the Lake Trout caught in the fall 2021 gill‐net survey were unclipped (wild) fish. Estimated ages of these wild fish indicated that natural recruitment had begun sometime around 2015.With Alewife Alosa pseudoharengus abundance in Lake Michigan at record low levels, Sea Lamprey wounding rate greatly reduced, and Lake Trout spawner abundance at relatively high levels, the outlook for Lake Trout rehabilitation in the Northern Refuge holds promise.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44761180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. M. Goldsmith, A. Scheld, Christopher H. McGuire, C. Lobue
In recent years, electronic self‐reporting has emerged as a potentially powerful tool for timely collection of catch and effort data from recreational fisheries. Such approaches are particularly critical given that recreational fisheries contribute significantly to fishing mortality for popular marine fish species in North America and elsewhere. However, many self‐reporting programs are voluntary and struggle with angler recruitment and retention, while those that are mandatory have demonstrated mixed success with angler compliance. In this study, we surveyed Massachusetts anglers in the recreational fishery for Atlantic Bluefin Tuna Thunnus thynnus; anglers in this fishery are required to report all landings and dead discards, but compliance has historically been poor.The survey assessed respondents' Bluefin Tuna fishing experience and behavior, opinions about self‐reporting, and views on the effectiveness of various strategies to increase self‐reporting rates. Because we had access to past reporting history, we were able to compare responses between those who had previously reported Bluefin Tuna and those who had not.We achieved a response rate of 21.9%, and by comparing survey responses with past reporting history, we estimated a reporting compliance rate of only about 42%. Surprisingly, responses to survey questions generally did not differ markedly between reporters and nonreporters, although we did find evidence that those who complied with the self‐reporting requirement had less faith in the Bluefin Tuna fishery's management process. Among the top strategies identified by respondents to increase reporting compliance were (1) providing incentives; (2) providing behavioral “nudges,” such as reminders; (3) better educating anglers on the benefits of self‐reporting; (4) increasing the user‐friendliness of the reporting technology; and (5) the reframing of norms through leveraging leaders in the fishery.Our findings can help to inform self‐reporting and other citizen science approaches to maximize the quantity and quality of recreational data collected, in turn informing the sustainable management of this sector.
{"title":"Improving electronic reporting rates in the U.S. recreational fishery for Atlantic Bluefin Tuna","authors":"W. M. Goldsmith, A. Scheld, Christopher H. McGuire, C. Lobue","doi":"10.1002/nafm.10929","DOIUrl":"https://doi.org/10.1002/nafm.10929","url":null,"abstract":"In recent years, electronic self‐reporting has emerged as a potentially powerful tool for timely collection of catch and effort data from recreational fisheries. Such approaches are particularly critical given that recreational fisheries contribute significantly to fishing mortality for popular marine fish species in North America and elsewhere. However, many self‐reporting programs are voluntary and struggle with angler recruitment and retention, while those that are mandatory have demonstrated mixed success with angler compliance. In this study, we surveyed Massachusetts anglers in the recreational fishery for Atlantic Bluefin Tuna Thunnus thynnus; anglers in this fishery are required to report all landings and dead discards, but compliance has historically been poor.The survey assessed respondents' Bluefin Tuna fishing experience and behavior, opinions about self‐reporting, and views on the effectiveness of various strategies to increase self‐reporting rates. Because we had access to past reporting history, we were able to compare responses between those who had previously reported Bluefin Tuna and those who had not.We achieved a response rate of 21.9%, and by comparing survey responses with past reporting history, we estimated a reporting compliance rate of only about 42%. Surprisingly, responses to survey questions generally did not differ markedly between reporters and nonreporters, although we did find evidence that those who complied with the self‐reporting requirement had less faith in the Bluefin Tuna fishery's management process. Among the top strategies identified by respondents to increase reporting compliance were (1) providing incentives; (2) providing behavioral “nudges,” such as reminders; (3) better educating anglers on the benefits of self‐reporting; (4) increasing the user‐friendliness of the reporting technology; and (5) the reframing of norms through leveraging leaders in the fishery.Our findings can help to inform self‐reporting and other citizen science approaches to maximize the quantity and quality of recreational data collected, in turn informing the sustainable management of this sector.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47327111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Although piscicides are an important tool for native fish management, our understanding of native fish population dynamics posttreatment (i.e., in putatively vacant habitat) is limited.Here, we describe long‐term trends in size and abundance of Cutthroat Trout Oncorhynchus clarkii in Lower Boulder Lake and Boulder Creek (Montana).No significant differences were found before and after treatment with rotenone in mean length and population density in Boulder Creek. Posttreatment genetic samples from Boulder Lake and upper Boulder Creek consisted entirely of the Westslope Cutthroat Trout Oncorhynchus clarkii lewisi used to refound the population. Middle and lower Boulder Creek genetic samples contained 99.4% and 98.4% Westslope Cutthroat Trout, indicating that some nonnative (Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri hybrid) fish survived the treatment. Population demographics showed robust recovery posttreatment; however, genetic results revealed the limitations of a one‐time treatment—that is, an incomplete fish kill.We demonstrate that Cutthroat Trout populations achieve recovery after rotenone treatment in the long term, but one‐time rotenone treatments on large drainages often fail to totally eradicate populations. Therefore, managers should plan on multiple treatments and utilize environmental DNA to help achieve total removal of target species.
{"title":"Efficacy of one‐time rotenone application for Westslope Cutthroat Trout restoration in Boulder Creek, Montana","authors":"J. Lampton, Ryan P. Kovach, J. Dunnigan","doi":"10.1002/nafm.10918","DOIUrl":"https://doi.org/10.1002/nafm.10918","url":null,"abstract":"Although piscicides are an important tool for native fish management, our understanding of native fish population dynamics posttreatment (i.e., in putatively vacant habitat) is limited.Here, we describe long‐term trends in size and abundance of Cutthroat Trout Oncorhynchus clarkii in Lower Boulder Lake and Boulder Creek (Montana).No significant differences were found before and after treatment with rotenone in mean length and population density in Boulder Creek. Posttreatment genetic samples from Boulder Lake and upper Boulder Creek consisted entirely of the Westslope Cutthroat Trout Oncorhynchus clarkii lewisi used to refound the population. Middle and lower Boulder Creek genetic samples contained 99.4% and 98.4% Westslope Cutthroat Trout, indicating that some nonnative (Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri hybrid) fish survived the treatment. Population demographics showed robust recovery posttreatment; however, genetic results revealed the limitations of a one‐time treatment—that is, an incomplete fish kill.We demonstrate that Cutthroat Trout populations achieve recovery after rotenone treatment in the long term, but one‐time rotenone treatments on large drainages often fail to totally eradicate populations. Therefore, managers should plan on multiple treatments and utilize environmental DNA to help achieve total removal of target species.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47766614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Koob, L. Kerr, J. Mandelman, Michael P. Armstrong
A recent expansion of the northern stock of Black Sea Bass Centropristis striata into the northern Gulf of Maine raises questions about this species’ movement and population dynamics in this region. Determining the origin of these fish is essential, as dramatic changes in migration patterns or current population boundaries could have profound effects on stock assessment estimates and subsequent management regulations.In this study, we measured otolith core concentrations of stable isotopes (δ18O, δ13C) and trace element:calcium ratios (Mg:Ca, Mn:Ca, Cu:Ca, Zn:Ca, Ba:Ca, Sr:Ca) to assess the natal origin of Black Sea Bass that were caught off the coast of Maine. Spawning condition adults from southern New England (SNE) and the mid‐Atlantic Bight (MAB) were used to characterize the chemical fingerprint of these known spawning regions.Unique chemical fingerprints were identified for fish from SNE and the MAB, with high reclassification success using random forest analysis (16% error rate). The classification of Black Sea Bass of unknown origin that were caught in Maine waters indicated that 85% of the samples matched to SNE and 13% to the MAB, whereas one sample remained unclassified.Results from this study support the current management population separation of the northern stock of Black Sea Bass between SNE and the MAB and lends additional information to the understanding of this species’ movement into the northern Gulf of Maine. As fish stocks around the world continue to shift into new regions due to climate change, knowledge of their natal origin will be critical to long‐term sustainable management of this species.
{"title":"Using otolith microchemistry to determine natal origin of Black Sea Bass off the coast of Maine","authors":"E. Koob, L. Kerr, J. Mandelman, Michael P. Armstrong","doi":"10.1002/nafm.10927","DOIUrl":"https://doi.org/10.1002/nafm.10927","url":null,"abstract":"A recent expansion of the northern stock of Black Sea Bass Centropristis striata into the northern Gulf of Maine raises questions about this species’ movement and population dynamics in this region. Determining the origin of these fish is essential, as dramatic changes in migration patterns or current population boundaries could have profound effects on stock assessment estimates and subsequent management regulations.In this study, we measured otolith core concentrations of stable isotopes (δ18O, δ13C) and trace element:calcium ratios (Mg:Ca, Mn:Ca, Cu:Ca, Zn:Ca, Ba:Ca, Sr:Ca) to assess the natal origin of Black Sea Bass that were caught off the coast of Maine. Spawning condition adults from southern New England (SNE) and the mid‐Atlantic Bight (MAB) were used to characterize the chemical fingerprint of these known spawning regions.Unique chemical fingerprints were identified for fish from SNE and the MAB, with high reclassification success using random forest analysis (16% error rate). The classification of Black Sea Bass of unknown origin that were caught in Maine waters indicated that 85% of the samples matched to SNE and 13% to the MAB, whereas one sample remained unclassified.Results from this study support the current management population separation of the northern stock of Black Sea Bass between SNE and the MAB and lends additional information to the understanding of this species’ movement into the northern Gulf of Maine. As fish stocks around the world continue to shift into new regions due to climate change, knowledge of their natal origin will be critical to long‐term sustainable management of this species.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43443985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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