Abstract Objective Given the limited information on population dynamics of Gafftopsail Catfish Bagre marinus in the western Gulf of Mexico, the objectives of this study were to determine the status of this species in Texas estuaries by assessing trends in relative abundance, length, and habitat preferences from fishery‐independent trawl (juvenile) and gill net (adult) data as well as angler harvest trends from fishery dependent creel surveys collected in all Texas estuaries. Methods Fishery independent and dependent monitoring data were collected by Texas Parks and Wildlife Department in all major bay systems of the Texas coast from 1983‐2022. Linear trend analysis was used to assess trends across the full timeseries and all major bay systems for both juvenile and adult specimens and for total recreational harvest. Boosted regression tree analysis was used to assess habitat preference for both juveniles and adults. Result Both juvenile and adult catch rates consistently increased in most Texas estuaries, with the most extreme increases occurring in central Texas coast estuaries beginning in the early 2000's. During the same timeframe, mean lengths of adult specimens significantly decreased in many of the same estuaries. Habitat suitability analysis suggested that Gafftopsail Catfish were primarily influenced by salinity, though they still exist across a very broad range of salinity conditions. Angler catch rates showed some localized patterns of increasing or decreasing trends, though they generally did not follow fishery independent trends for most estuaries. Conclusion These trends interpreted in the context of the known trophic role of Gafftopsail Catfish imply the potential for larger ecosystem‐level effects on both prey organisms and competitors. A more thorough awareness of these trends and potential interactions should help fisheries managers operate in an ecosystem‐based context when investigating population dynamics and recommending management strategies.
{"title":"Gafftopsail Catfish in Texas Estuaries: Population Trends and Ecosystem Implications","authors":"Lydia Cates, Stephen Hale, Zachary Olsen","doi":"10.1002/nafm.10967","DOIUrl":"https://doi.org/10.1002/nafm.10967","url":null,"abstract":"Abstract Objective Given the limited information on population dynamics of Gafftopsail Catfish Bagre marinus in the western Gulf of Mexico, the objectives of this study were to determine the status of this species in Texas estuaries by assessing trends in relative abundance, length, and habitat preferences from fishery‐independent trawl (juvenile) and gill net (adult) data as well as angler harvest trends from fishery dependent creel surveys collected in all Texas estuaries. Methods Fishery independent and dependent monitoring data were collected by Texas Parks and Wildlife Department in all major bay systems of the Texas coast from 1983‐2022. Linear trend analysis was used to assess trends across the full timeseries and all major bay systems for both juvenile and adult specimens and for total recreational harvest. Boosted regression tree analysis was used to assess habitat preference for both juveniles and adults. Result Both juvenile and adult catch rates consistently increased in most Texas estuaries, with the most extreme increases occurring in central Texas coast estuaries beginning in the early 2000's. During the same timeframe, mean lengths of adult specimens significantly decreased in many of the same estuaries. Habitat suitability analysis suggested that Gafftopsail Catfish were primarily influenced by salinity, though they still exist across a very broad range of salinity conditions. Angler catch rates showed some localized patterns of increasing or decreasing trends, though they generally did not follow fishery independent trends for most estuaries. Conclusion These trends interpreted in the context of the known trophic role of Gafftopsail Catfish imply the potential for larger ecosystem‐level effects on both prey organisms and competitors. A more thorough awareness of these trends and potential interactions should help fisheries managers operate in an ecosystem‐based context when investigating population dynamics and recommending management strategies.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136185413","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}
B. L. Jensen, R. C. Johnson, J. J. Duda, C. O. Ostberg, T. J. Code, J. H. Mclean, K. D. Stenberg, K. A. Larsen, M. S. Hoy, D. A. Beauchamp
Abstract Objective In the Pacific Northwest (USA), Pacific salmon Oncorhynchus spp. populations have been declining significantly for decades, prompting stakeholders to respond with a variety of conservation and restoration measures. One such measure being considered in the Skagit River basin (Washington, USA) is the introduction of steelhead Oncorhynchus mykiss (anadromous Rainbow Trout) above the impassable Gorge, Diablo, and Ross dams to bolster their populations. Because freshwater growth is key to survival at subsequent life stages, we evaluated current trends in size and growth of Rainbow Trout among key tributaries to Gorge, Diablo, and Ross reservoirs using empirical data collection and bioenergetics modeling. Methods For nine candidate streams, a bioenergetics model was used to assess how temperature and prey consumption affected growth performance of Rainbow Trout between annuli 1 and 2, and 2 and 3. Thermal scenarios were created to evaluate how fish growth responded to temperature variability while total annual consumption was constrained within empirical growth estimates. We then compared these results to back‐calculated size thresholds established by size‐at‐age observed in wild steelhead adults that returned to the Skagit River below the dams. Result Of the streams proposed for introductions, there was one instance (McMillan Creek) in the nominal simulations where growth met or exceeded the size at annulus 2 or 3 of a returning adult steelhead (24.9 g at annulus 2 and 50.3 g at annulus 3). Modeled growth under different thermal scenarios showed that colder temperatures (0.1–10.7°C, Canyon Creek) produced higher growth than under the nominal or warm scenarios (2.0–15.3°C, Canyon Creek), as well as one additional tributary where size at annulus 2 or 3 (±2 SE) was comparable to the threshold established by adult steelhead below the dams (Big Beaver Creek, annulus 3). Conclusion These results suggest Rainbow Trout growth is most limited by prey availability in the examined upper Skagit tributaries.
{"title":"Growth performance of Rainbow Trout in reservoir tributaries and implications for steelhead growth potential above Skagit River dams","authors":"B. L. Jensen, R. C. Johnson, J. J. Duda, C. O. Ostberg, T. J. Code, J. H. Mclean, K. D. Stenberg, K. A. Larsen, M. S. Hoy, D. A. Beauchamp","doi":"10.1002/nafm.10944","DOIUrl":"https://doi.org/10.1002/nafm.10944","url":null,"abstract":"Abstract Objective In the Pacific Northwest (USA), Pacific salmon Oncorhynchus spp. populations have been declining significantly for decades, prompting stakeholders to respond with a variety of conservation and restoration measures. One such measure being considered in the Skagit River basin (Washington, USA) is the introduction of steelhead Oncorhynchus mykiss (anadromous Rainbow Trout) above the impassable Gorge, Diablo, and Ross dams to bolster their populations. Because freshwater growth is key to survival at subsequent life stages, we evaluated current trends in size and growth of Rainbow Trout among key tributaries to Gorge, Diablo, and Ross reservoirs using empirical data collection and bioenergetics modeling. Methods For nine candidate streams, a bioenergetics model was used to assess how temperature and prey consumption affected growth performance of Rainbow Trout between annuli 1 and 2, and 2 and 3. Thermal scenarios were created to evaluate how fish growth responded to temperature variability while total annual consumption was constrained within empirical growth estimates. We then compared these results to back‐calculated size thresholds established by size‐at‐age observed in wild steelhead adults that returned to the Skagit River below the dams. Result Of the streams proposed for introductions, there was one instance (McMillan Creek) in the nominal simulations where growth met or exceeded the size at annulus 2 or 3 of a returning adult steelhead (24.9 g at annulus 2 and 50.3 g at annulus 3). Modeled growth under different thermal scenarios showed that colder temperatures (0.1–10.7°C, Canyon Creek) produced higher growth than under the nominal or warm scenarios (2.0–15.3°C, Canyon Creek), as well as one additional tributary where size at annulus 2 or 3 (±2 SE) was comparable to the threshold established by adult steelhead below the dams (Big Beaver Creek, annulus 3). Conclusion These results suggest Rainbow Trout growth is most limited by prey availability in the examined upper Skagit tributaries.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135858318","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}
Abstract Objective Environmental DNA (eDNA) metabarcoding has become an important method for inventorying and monitoring biota in aquatic systems. The Texas Parks and Wildlife Department conducts regular fishery‐independent sampling of biotic communities using traditional sampling gears, such as gill nets and bag seines, in all of the major estuaries of adjacent to the Gulf of Mexico in Texas. Previous studies have shown that eDNA approaches can complement traditional sampling methods. Methods We compared fish community structure data in the Cedar Lakes estuary system obtained with traditional sampling gears with data obtained using eDNA sampling using a small sequence of mitochondrial 12S ribosomal RNA gene and a validated taxonomic reference file. Result For spring and fall of 2022, eDNA metabarcoding detected a larger number of species than either bag seines or gill nets. Species richness detected via eDNA in two seasons in a single year was comparable with the species richness of agency’s historical record based on traditional gears for Cedar Lakes. Conclusion Seasonal and spatial variation in species richness was similar between traditional and eDNA sampling; however, eDNA metabarcoding allowed detection of several species that would be difficult or impossible to capture with either bag seines or gill nets. We observed two limitations of eDNA metabarcoding. Read depth was not a good index of relative abundance, which limits our ability to infer relative biomass using single samples. Secondly, we observed detection bias in our eDNA results. Specifically, eDNA failed to detect two species of elasmobranchs present when water sampling was performed and eDNA also performed poorly compared to traditional sampling gears for some species of bony fishes. Despite these limitations, eDNA metabarcoding proved to be an efficient and cost‐effective alternative and compliment to traditional fisheries sampling gears for fishery‐independent monitoring of community structure and composition in estuaries of the Gulf of Mexico.
摘要目的环境DNA元条形码(Environmental DNA metabarcoding, eDNA)已成为水生生物区系清查和监测的重要方法。德克萨斯州公园和野生动物部在德克萨斯州墨西哥湾附近的所有主要河口，使用传统的采样装置，如刺网和袋式围网，对生物群落进行定期的渔业独立采样。先前的研究表明，eDNA方法可以补充传统的采样方法。方法将传统采样方法获得的雪松湖河口系统鱼类群落结构数据与利用线粒体12S核糖体RNA基因小序列和经过验证的分类参考文件进行eDNA采样获得的数据进行比较。结果2022年春季和秋季，eDNA元条形码检测到的鱼种数量高于袋网和刺网。通过eDNA在一年中两个季节检测到的物种丰富度与机构基于传统年轮的历史记录的物种丰富度相当。结论传统取样和eDNA取样物种丰富度的季节和空间变化相似;然而，eDNA元条形码可以检测到一些用围网或刺网很难或不可能捕获的物种。我们观察到eDNA元条形码的两个局限性。阅读深度不是一个很好的相对丰度指标，这限制了我们使用单个样本推断相对生物量的能力。其次，我们在我们的eDNA结果中观察到检测偏差。具体来说，在进行水样取样时，eDNA未能检测到两种板鳃类，并且与传统取样装置相比，eDNA对某些硬骨鱼类的表现也很差。尽管存在这些限制，eDNA元条形码被证明是一种高效且具有成本效益的替代方案，并补充了传统渔业采样装置，用于对墨西哥湾河口的群落结构和组成进行渔业独立监测。
{"title":"Environmental <scp>DNA</scp> compliments traditional sampling for monitoring fish communities in a Texas estuary","authors":"Damon Williford, Polly Hajovsky, Joel Anderson","doi":"10.1002/nafm.10937","DOIUrl":"https://doi.org/10.1002/nafm.10937","url":null,"abstract":"Abstract Objective Environmental DNA (eDNA) metabarcoding has become an important method for inventorying and monitoring biota in aquatic systems. The Texas Parks and Wildlife Department conducts regular fishery‐independent sampling of biotic communities using traditional sampling gears, such as gill nets and bag seines, in all of the major estuaries of adjacent to the Gulf of Mexico in Texas. Previous studies have shown that eDNA approaches can complement traditional sampling methods. Methods We compared fish community structure data in the Cedar Lakes estuary system obtained with traditional sampling gears with data obtained using eDNA sampling using a small sequence of mitochondrial 12S ribosomal RNA gene and a validated taxonomic reference file. Result For spring and fall of 2022, eDNA metabarcoding detected a larger number of species than either bag seines or gill nets. Species richness detected via eDNA in two seasons in a single year was comparable with the species richness of agency’s historical record based on traditional gears for Cedar Lakes. Conclusion Seasonal and spatial variation in species richness was similar between traditional and eDNA sampling; however, eDNA metabarcoding allowed detection of several species that would be difficult or impossible to capture with either bag seines or gill nets. We observed two limitations of eDNA metabarcoding. Read depth was not a good index of relative abundance, which limits our ability to infer relative biomass using single samples. Secondly, we observed detection bias in our eDNA results. Specifically, eDNA failed to detect two species of elasmobranchs present when water sampling was performed and eDNA also performed poorly compared to traditional sampling gears for some species of bony fishes. Despite these limitations, eDNA metabarcoding proved to be an efficient and cost‐effective alternative and compliment to traditional fisheries sampling gears for fishery‐independent monitoring of community structure and composition in estuaries of the Gulf of Mexico.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136358964","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}
John M. Caldwell, Summer M. Burdick, Jacob R. Krause, Alta C. Harris
Abstract Objective High juvenile mortality prevents recruitment into the adult populations of endangered Shortnose Sucker Chasmistes brevirostris and Lost River Sucker Deltistes luxatus in Upper Klamath Lake, Oregon. To address the lack of recruitment, the U.S. Fish and Wildlife Service implemented the Sucker Assisted Rearing Program (SARP). Managers developing the rearing program lack information about how length at release relates to survival. To determine how initial length affects survival of captively reared juvenile suckers, we introduced juvenile suckers from the SARP into three net‐pens in Upper Klamath Lake. Methods The juvenile suckers ranged from 102 to 284 mm standard length, and each fish was tagged with a passive integrated transponder (PIT) tag. Fish were monitored continuously by PIT antennas and mortality was inferred when movements ceased. Result Estimated survival over 57 days was high in all net‐pens (0.79–1.00) and remained high at two net‐pens for 76 and 86 days. Adjusted survival curves resulting from a stratified Cox model with standard length as a covariate, indicated that length positively influenced predicted survival by as much as 41% at one site. During the study, pH and dissolved oxygen regularly exceeded no‐effect thresholds at two sites and briefly reached lethal thresholds at the same two sites but did not coincide with the observed mortalities. Slower growth and the lowest survival were observed at the third site, where water quality never exceeded thresholds. Conclusion A larger release size and the location of the net‐pen can improve the survivability of juvenile suckers in net‐pens in Upper Klamath Lake.
摘要目的俄勒冈州上克拉马斯湖濒危物种短鼻吸鱼Chasmistes brevirostris和Lost River Sucker Deltistes luxatus幼鱼的高死亡率阻碍了它们进入成年种群。为了解决招募不足的问题，美国鱼类和野生动物管理局实施了吸盘辅助饲养计划(SARP)。开发饲养计划的管理者缺乏关于放生长度与生存的关系的信息。为了确定初始长度如何影响人工饲养的吸盘鱼幼鱼的生存，我们将来自SARP的吸盘鱼幼鱼引入上克拉马斯湖的三个网栏中。方法采用标准长度为102 ~ 284 mm的幼鱼吸盘，每条鱼均采用被动式集成应答器(PIT)标签。由PIT天线连续监测鱼类，并在运动停止时推断死亡率。结果57天的估计存活率在所有净栏中都很高(0.79-1.00)，在76天和86天的两个净栏中仍然很高。以标准长度为协变量的分层Cox模型得出的调整生存曲线表明，在一个位点，长度对预测生存的影响高达41%。在研究期间，两个地点的pH值和溶解氧定期超过无影响阈值，并在同一两个地点短暂达到致死阈值，但与观察到的死亡率不一致。在水质从未超过阈值的第三个地点观察到较慢的生长和最低的存活率。结论加大放生规模和设置网栏可以提高上克拉马斯湖网栏中吸盘鱼幼鱼的存活率。
{"title":"Does release size into net‐pens affect survival of captively reared juvenile endangered suckers in Upper Klamath Lake?","authors":"John M. Caldwell, Summer M. Burdick, Jacob R. Krause, Alta C. Harris","doi":"10.1002/nafm.10933","DOIUrl":"https://doi.org/10.1002/nafm.10933","url":null,"abstract":"Abstract Objective High juvenile mortality prevents recruitment into the adult populations of endangered Shortnose Sucker Chasmistes brevirostris and Lost River Sucker Deltistes luxatus in Upper Klamath Lake, Oregon. To address the lack of recruitment, the U.S. Fish and Wildlife Service implemented the Sucker Assisted Rearing Program (SARP). Managers developing the rearing program lack information about how length at release relates to survival. To determine how initial length affects survival of captively reared juvenile suckers, we introduced juvenile suckers from the SARP into three net‐pens in Upper Klamath Lake. Methods The juvenile suckers ranged from 102 to 284 mm standard length, and each fish was tagged with a passive integrated transponder (PIT) tag. Fish were monitored continuously by PIT antennas and mortality was inferred when movements ceased. Result Estimated survival over 57 days was high in all net‐pens (0.79–1.00) and remained high at two net‐pens for 76 and 86 days. Adjusted survival curves resulting from a stratified Cox model with standard length as a covariate, indicated that length positively influenced predicted survival by as much as 41% at one site. During the study, pH and dissolved oxygen regularly exceeded no‐effect thresholds at two sites and briefly reached lethal thresholds at the same two sites but did not coincide with the observed mortalities. Slower growth and the lowest survival were observed at the third site, where water quality never exceeded thresholds. Conclusion A larger release size and the location of the net‐pen can improve the survivability of juvenile suckers in net‐pens in Upper Klamath Lake.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136359238","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}
Joshuah S. Perkin, Shannon K. Brewer, Anthony A. Echelle, Patrick M. Kočovský
Impact statement Twelve recognized species in genus Macrhybopsis are distributed across Canada, Mexico, and the United States. Most chubs have elevated conservation concerns at international, national, or state/province levels, but management intervention might reverse their trajectory of decline.
{"title":"Avoiding a macabre future for <i>Macrhybopsis</i>—A special section on improving management and conservation of chubs","authors":"Joshuah S. Perkin, Shannon K. Brewer, Anthony A. Echelle, Patrick M. Kočovský","doi":"10.1002/nafm.10950","DOIUrl":"https://doi.org/10.1002/nafm.10950","url":null,"abstract":"Impact statement Twelve recognized species in genus Macrhybopsis are distributed across Canada, Mexico, and the United States. Most chubs have elevated conservation concerns at international, national, or state/province levels, but management intervention might reverse their trajectory of decline.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135197763","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}
Alexa N. Maine, Mary L. Moser, Aaron D. Jackson, Frank Wilhelm
Abstract Objective The Pacific Lamprey Entosphenus tridentatus is a First Food for members of the Confederated Tribes of the Umatilla Indian Reservation and other Columbia Plateau tribes in the Pacific Northwest. Declines in Pacific Lamprey abundance have prompted restoration efforts, including development of artificial propagation. Laboratory rearing of larvae has focused on maximizing survival and growth to conserve resources and increase production. To test the hypothesis that bacterial supplements increased the survival and growth of first‐feeding larval Pacific Lamprey, we conducted two controlled experiments. Methods First, a probiotic supplement (EPI‐CIN G2; Epicore, Bionetworks) was added to a standard food ration (yeast and Otohime mix) at two levels (2 and 5 mg/L) in a replicated, randomized design. Result Growth at 10 weeks was measured, and larvae that were fed probiotics at both levels grew significantly faster (2 mg/L: 11.0 μm/day; 5 mg/L: 13.3 μm/day) than controls that were fed the standard ration alone (6.6 μm/day). Larvae that received the probiotic supplement also had a higher survival (2 mg/L: 36%; 5 mg/L: 44%) than those fed the standard ration (24%). Next, a different cohort of larval lamprey was fed the same two levels of probiotic (at the same rate as in the first experiment), but the lamprey was kept in larger rearing pans and were fed for 28 weeks. Overall growth rates in the second experiment (2 mg/L: 4.6 μm/day; 5 mg/L: 5.7 μm/day; control 3.4 μm/day) were lower than those in the first experiment, but growth and survival (2 mg/L: 71.4%; 5 mg/L: 78.6%; control: 55.7%) were both highest in the treatments with probiotic. Moreover, in both experiments, we observed the highest growth in the probiotic treatments that also had high larval density. Conclusion This suggests that probiotics may help to overcome density‐dependent growth, which is a common problem in lamprey culture. Successful artificial propagation and culture of Pacific Lamprey are vital to the long‐term restoration goals for this imperiled First Food.
{"title":"Probiotics improve survival and growth of larval Pacific Lamprey in laboratory culture","authors":"Alexa N. Maine, Mary L. Moser, Aaron D. Jackson, Frank Wilhelm","doi":"10.1002/nafm.10923","DOIUrl":"https://doi.org/10.1002/nafm.10923","url":null,"abstract":"Abstract Objective The Pacific Lamprey Entosphenus tridentatus is a First Food for members of the Confederated Tribes of the Umatilla Indian Reservation and other Columbia Plateau tribes in the Pacific Northwest. Declines in Pacific Lamprey abundance have prompted restoration efforts, including development of artificial propagation. Laboratory rearing of larvae has focused on maximizing survival and growth to conserve resources and increase production. To test the hypothesis that bacterial supplements increased the survival and growth of first‐feeding larval Pacific Lamprey, we conducted two controlled experiments. Methods First, a probiotic supplement (EPI‐CIN G2; Epicore, Bionetworks) was added to a standard food ration (yeast and Otohime mix) at two levels (2 and 5 mg/L) in a replicated, randomized design. Result Growth at 10 weeks was measured, and larvae that were fed probiotics at both levels grew significantly faster (2 mg/L: 11.0 μm/day; 5 mg/L: 13.3 μm/day) than controls that were fed the standard ration alone (6.6 μm/day). Larvae that received the probiotic supplement also had a higher survival (2 mg/L: 36%; 5 mg/L: 44%) than those fed the standard ration (24%). Next, a different cohort of larval lamprey was fed the same two levels of probiotic (at the same rate as in the first experiment), but the lamprey was kept in larger rearing pans and were fed for 28 weeks. Overall growth rates in the second experiment (2 mg/L: 4.6 μm/day; 5 mg/L: 5.7 μm/day; control 3.4 μm/day) were lower than those in the first experiment, but growth and survival (2 mg/L: 71.4%; 5 mg/L: 78.6%; control: 55.7%) were both highest in the treatments with probiotic. Moreover, in both experiments, we observed the highest growth in the probiotic treatments that also had high larval density. Conclusion This suggests that probiotics may help to overcome density‐dependent growth, which is a common problem in lamprey culture. Successful artificial propagation and culture of Pacific Lamprey are vital to the long‐term restoration goals for this imperiled First Food.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135251457","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}
William T. Samuel, Lauren E. Yancy, Elizabeth G. Hinkle, Jeffrey A. Falke
Abstract Objective Some Graylings ( Thymallus spp.) possess an elongated dorsal fin and other morphological traits that can be sexually dimorphic as demonstrated in European Grayling T. thymallu s. North American Arctic Grayling T. arcticus are assumed to follow these trends, but decisive evidence is lacking. This study aimed to determine whether sexually dimorphic characteristics, including posterior dorsal height, of Arctic Grayling in Interior Alaska can be used to accurately predict fish sex. Methods We used computer imaging software to measure 22 morphometrics on 97 Arctic Grayling of known sex from streams in Interior Alaska and developed a set of binomial models to evaluate the validity of morphometrics as predictors of Arctic Grayling sex. Result Posterior dorsal height was a reasonably accurate predictor of sex (~90% accurate at fork lengths ≥ 300 mm), although models containing additional morphometrics were more accurate (100% accuracy at fork lengths ≥ 250 mm). Conclusion This study presents an affordable, non‐invasive, and replicable method for non‐lethal determination of Arctic Grayling sex using digital images from the field, with potential application to other salmonids.
{"title":"Validating morphometrics as a non‐lethal tool to determine Arctic Grayling sex.","authors":"William T. Samuel, Lauren E. Yancy, Elizabeth G. Hinkle, Jeffrey A. Falke","doi":"10.1002/nafm.10956","DOIUrl":"https://doi.org/10.1002/nafm.10956","url":null,"abstract":"Abstract Objective Some Graylings ( Thymallus spp.) possess an elongated dorsal fin and other morphological traits that can be sexually dimorphic as demonstrated in European Grayling T. thymallu s. North American Arctic Grayling T. arcticus are assumed to follow these trends, but decisive evidence is lacking. This study aimed to determine whether sexually dimorphic characteristics, including posterior dorsal height, of Arctic Grayling in Interior Alaska can be used to accurately predict fish sex. Methods We used computer imaging software to measure 22 morphometrics on 97 Arctic Grayling of known sex from streams in Interior Alaska and developed a set of binomial models to evaluate the validity of morphometrics as predictors of Arctic Grayling sex. Result Posterior dorsal height was a reasonably accurate predictor of sex (~90% accurate at fork lengths ≥ 300 mm), although models containing additional morphometrics were more accurate (100% accuracy at fork lengths ≥ 250 mm). Conclusion This study presents an affordable, non‐invasive, and replicable method for non‐lethal determination of Arctic Grayling sex using digital images from the field, with potential application to other salmonids.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135197768","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}
Abstract Objective Water temperature is perhaps the single‐most important environmental driver of fish populations. The strong relationship between fish and water temperature allows fisheries managers to make predictions about the influence of temperature on fishes under both current and future climatic conditions. These predictions are more robust if based on year‐round and long‐term data. However, water temperature data are commonly compromised or lost altogether when data‐logging temperature sensors are damaged or go missing. In recognition of the need for reliable ways to collect long‐term, year‐round temperature data, we designed, implemented, and tested a durable but cryptic logger deployment and retrieval system. Methods We used metal housings and stakes to protect and anchor temperature loggers on the streambed and, when necessary, used a metal detector to assist with logger recovery. We then evaluated logger recovery rates across 12 years and 312 deployments at 85 sites in first‐ to ninth‐order Rocky Mountain streams and rivers. Result Although we recovered only 73% of loggers with traditional means of retrieval (e.g., GPS or photo), presumably owing to the inconspicuous nature of our metal housings and streambed anchor stakes, we recovered 96% of loggers when a metal detector was also used. Ordinal and binary logistic regression revealed that a metal detector was especially beneficial when trying to recover loggers from unfamiliar monitoring sites or those deployed for long periods of time (years). Conclusion Our methods could be replicated for a reliable and inexpensive approach to acquiring year‐round stream temperature data.
{"title":"An inexpensive method for reliable recovery of stream temperature data","authors":"Kevin B. Rogers, Brian W. Hodge","doi":"10.1002/nafm.10930","DOIUrl":"https://doi.org/10.1002/nafm.10930","url":null,"abstract":"Abstract Objective Water temperature is perhaps the single‐most important environmental driver of fish populations. The strong relationship between fish and water temperature allows fisheries managers to make predictions about the influence of temperature on fishes under both current and future climatic conditions. These predictions are more robust if based on year‐round and long‐term data. However, water temperature data are commonly compromised or lost altogether when data‐logging temperature sensors are damaged or go missing. In recognition of the need for reliable ways to collect long‐term, year‐round temperature data, we designed, implemented, and tested a durable but cryptic logger deployment and retrieval system. Methods We used metal housings and stakes to protect and anchor temperature loggers on the streambed and, when necessary, used a metal detector to assist with logger recovery. We then evaluated logger recovery rates across 12 years and 312 deployments at 85 sites in first‐ to ninth‐order Rocky Mountain streams and rivers. Result Although we recovered only 73% of loggers with traditional means of retrieval (e.g., GPS or photo), presumably owing to the inconspicuous nature of our metal housings and streambed anchor stakes, we recovered 96% of loggers when a metal detector was also used. Ordinal and binary logistic regression revealed that a metal detector was especially beneficial when trying to recover loggers from unfamiliar monitoring sites or those deployed for long periods of time (years). Conclusion Our methods could be replicated for a reliable and inexpensive approach to acquiring year‐round stream temperature data.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135250738","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}
Steven P. Griffeth, Krista D. Baker, Darrell R. J. Mullowney
Abstract Objective The snow crab Chionoecetes opilio resource in Assessment Division 2HJ has experienced prolonged high exploitation rates and reduced exploitable biomass over the past two decades. We aimed to explore whether this poor state of the resource is associated with spatial management changes made in 2003 and 2013. Methods We tested for differences in fishery performance trends before and after the implementation of spatial management which include standardized CPUE, spatial extent of fishing effort, and size at maturity of male snow crabs. Result The results show that spatial regulatory changes were successful in increasing fishery catch rates in the short term but that chronic high exploitation eventually overrode these gains, with contracted fishing patterns leading to increased localized depletion rates on dominant stock components. This ultimately culminated in a downward shift in size at maturity and other concerning biological outcomes. Conclusion The analysis demonstrates spatial management measures contributed to the present poor state of Assessment Division 2HJ snow crab and that such measures should serve as complements to—not replacements for—stringent quota control.
{"title":"Short‐term fishery gains mask long‐term resource pains: Spatial fisheries management changes promote hyperstable <scp>CPUE</scp> in Labrador snow crab <i>Chionoecetes opilio</i> during a period of heavy exploitation","authors":"Steven P. Griffeth, Krista D. Baker, Darrell R. J. Mullowney","doi":"10.1002/nafm.10934","DOIUrl":"https://doi.org/10.1002/nafm.10934","url":null,"abstract":"Abstract Objective The snow crab Chionoecetes opilio resource in Assessment Division 2HJ has experienced prolonged high exploitation rates and reduced exploitable biomass over the past two decades. We aimed to explore whether this poor state of the resource is associated with spatial management changes made in 2003 and 2013. Methods We tested for differences in fishery performance trends before and after the implementation of spatial management which include standardized CPUE, spatial extent of fishing effort, and size at maturity of male snow crabs. Result The results show that spatial regulatory changes were successful in increasing fishery catch rates in the short term but that chronic high exploitation eventually overrode these gains, with contracted fishing patterns leading to increased localized depletion rates on dominant stock components. This ultimately culminated in a downward shift in size at maturity and other concerning biological outcomes. Conclusion The analysis demonstrates spatial management measures contributed to the present poor state of Assessment Division 2HJ snow crab and that such measures should serve as complements to—not replacements for—stringent quota control.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134944496","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}
Erica Stegens, Daniel D. Wiegmann, Lisa M. Angeloni, Jeffrey R. Baylis, Robert A. S. Laroche, Steven P. Newman, Scott P. Egan, Greg G. Sass, Kelly L. Weinersmith
Abstract Fish population surveys in north‐temperate lakes are often conducted in the fall or spring when individuals are easy to capture with traditional fisheries techniques. Because some fishes are preparing to spawn or are spawning during these seasons, there is a critical need to better understand the potential influences of these surveys on decisions related to fish reproduction. We tested whether spring mark‐recapture surveys using fyke nets followed by electrofishing affect reproductive behaviors of male Smallmouth Bass Micropterus dolomieu in a northern Wisconsin lake. Fyke‐netting, electrofishing, and whole‐lake nest snorkeling surveys were conducted during 2001‐2008, and Floy‐tagged males were tracked across years to test whether capture in the fyke nets only, or capture in the electrofishing survey influenced inter‐year nest site fidelity and reproductive timing. The mark‐recapture surveys were conducted preceding Smallmouth Bass spawning, and returning males caught in the electrofishing survey nested ~50 m farther from their prior year's nest than both males captured only in fyke nets and males that were captured by neither method. Average inter‐year nest distances were ~200 m and median inter‐year nest distances were ~90 m for males not captured in the electrofishing survey. Electrofishing and fyke netting did not influence timing of reproduction. Spring electrofishing surveys for Smallmouth Bass have the potential to displace breeding males from preferred nesting habitats. If displacement negatively influences fitness (i.e., age‐0 survivorship to maturation), spring electrofishing surveys would not be recommended for assessing Smallmouth Bass populations. However, spring population surveys often occur soon after ice off, and surveys conducted at these colder temperatures are typically less stressful and less likely to result in mortality. Future research should test for fitness implications of reduced nest site fidelity following electrofishing in Smallmouth Bass, while considering potential fitness trade‐offs if surveys are moved later in the year.
{"title":"Mark‐Recapture Surveys Impact Nest Site Fidelity but not Reproductive Timing of Male Smallmouth Bass","authors":"Erica Stegens, Daniel D. Wiegmann, Lisa M. Angeloni, Jeffrey R. Baylis, Robert A. S. Laroche, Steven P. Newman, Scott P. Egan, Greg G. Sass, Kelly L. Weinersmith","doi":"10.1002/nafm.10964","DOIUrl":"https://doi.org/10.1002/nafm.10964","url":null,"abstract":"Abstract Fish population surveys in north‐temperate lakes are often conducted in the fall or spring when individuals are easy to capture with traditional fisheries techniques. Because some fishes are preparing to spawn or are spawning during these seasons, there is a critical need to better understand the potential influences of these surveys on decisions related to fish reproduction. We tested whether spring mark‐recapture surveys using fyke nets followed by electrofishing affect reproductive behaviors of male Smallmouth Bass Micropterus dolomieu in a northern Wisconsin lake. Fyke‐netting, electrofishing, and whole‐lake nest snorkeling surveys were conducted during 2001‐2008, and Floy‐tagged males were tracked across years to test whether capture in the fyke nets only, or capture in the electrofishing survey influenced inter‐year nest site fidelity and reproductive timing. The mark‐recapture surveys were conducted preceding Smallmouth Bass spawning, and returning males caught in the electrofishing survey nested ~50 m farther from their prior year's nest than both males captured only in fyke nets and males that were captured by neither method. Average inter‐year nest distances were ~200 m and median inter‐year nest distances were ~90 m for males not captured in the electrofishing survey. Electrofishing and fyke netting did not influence timing of reproduction. Spring electrofishing surveys for Smallmouth Bass have the potential to displace breeding males from preferred nesting habitats. If displacement negatively influences fitness (i.e., age‐0 survivorship to maturation), spring electrofishing surveys would not be recommended for assessing Smallmouth Bass populations. However, spring population surveys often occur soon after ice off, and surveys conducted at these colder temperatures are typically less stressful and less likely to result in mortality. Future research should test for fitness implications of reduced nest site fidelity following electrofishing in Smallmouth Bass, while considering potential fitness trade‐offs if surveys are moved later in the year.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135739495","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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