Christopher W. Schwinghamer, Kyle J. Hartman, Amy B. Welsh
ObjectivePopulations of eastern Brook Trout Salvelinus fontinalis face threats from several sources, such as habitat fragmentation, climate change, and competition with introduced salmonids. As a native species, understanding how these populations will respond to disturbances is paramount to their management and effective conservation. A population's ability to respond to disturbance, its resilience, is influenced by several factors. One such group of factors is population genetics.MethodsWe calculated population resilience metrics based on transient dynamics using population projection matrix models. Long‐term demographic data from 23 headwater stream Brook Trout populations were used to parameterize models. Genetic data were collected, and genetic indices were calculated. Partial redundancy analysis was then used to evaluate relationships between resilience metrics and genetic indices.ResultInbreeding coefficient, rarefied allelic richness, pairwise genetic differentiation (FST), and effective population size were all found to be important variables in predicting resilience.ConclusionOur results suggest that genetic isolation may increase the demographic resilience in Brook Trout through faster generation times and higher juvenile survival, but this likely comes at the cost of increased extinction risk and truncated size structures. Genetic indices can provide insight into gene flow between populations, thus the relationship between population connectivity and resilience. Given the importance of connectivity to population resilience, restoring and maintaining movement corridors could affect resilience in headwater Brook Trout populations.
{"title":"Genetic predictors of population resilience: A case study of native Brook Trout in headwater streams","authors":"Christopher W. Schwinghamer, Kyle J. Hartman, Amy B. Welsh","doi":"10.1002/nafm.11003","DOIUrl":"https://doi.org/10.1002/nafm.11003","url":null,"abstract":"ObjectivePopulations of eastern Brook Trout <jats:italic>Salvelinus fontinalis</jats:italic> face threats from several sources, such as habitat fragmentation, climate change, and competition with introduced salmonids. As a native species, understanding how these populations will respond to disturbances is paramount to their management and effective conservation. A population's ability to respond to disturbance, its resilience, is influenced by several factors. One such group of factors is population genetics.MethodsWe calculated population resilience metrics based on transient dynamics using population projection matrix models. Long‐term demographic data from 23 headwater stream Brook Trout populations were used to parameterize models. Genetic data were collected, and genetic indices were calculated. Partial redundancy analysis was then used to evaluate relationships between resilience metrics and genetic indices.ResultInbreeding coefficient, rarefied allelic richness, pairwise genetic differentiation (<jats:italic>F</jats:italic><jats:sub>ST</jats:sub>), and effective population size were all found to be important variables in predicting resilience.ConclusionOur results suggest that genetic isolation may increase the demographic resilience in Brook Trout through faster generation times and higher juvenile survival, but this likely comes at the cost of increased extinction risk and truncated size structures. Genetic indices can provide insight into gene flow between populations, thus the relationship between population connectivity and resilience. Given the importance of connectivity to population resilience, restoring and maintaining movement corridors could affect resilience in headwater Brook Trout populations.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"10 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140835430","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}
M. Todd Driscoll, Jacob D. Norman, Daniel L. Bennett, Brian K. Metz, David R. Smith
ObjectiveAngler complaints regarding perceived declines in angling quality prompted research to examine the home range, movement, water depth use, and structural habitat use and selection of the Largemouth Bass complex (LBC; Largemouth Bass Micropterus nigricans, Florida Bass M. salmoides, and Largemouth Bass × Florida Bass hybrids) in Toledo Bend and Lake Fork reservoirs, Texas.MethodsA total of 21 LBC individuals at Toledo Bend Reservoir (386–604 mm total length [TL]) and 22 LBC fish at Lake Fork Reservoir (364–545 mm TL) were implanted with radio transmitters and tracked over a 2‐year period.ResultAt both reservoirs, LBC home range areas were small (<50 ha) and overall movement was low (~40–100 m/week). Fish primarily occupied water column depths of less than 2 m in both reservoirs and were found in the shallowest depths during the spring. Although overall structural habitat occurrence and selection of LBC fish varied between reservoirs, primarily due to differences at shorelines and creeks (two times higher in Toledo Bend Reservoir) and drops (three times higher in Lake Fork Reservoir), fish selected for the shoreline, drops, points, and creeks in both reservoirs, while drains and flats reflected avoidance. Seasonally, habitat occurrence of LBC fish varied at Toledo Bend Reservoir, primarily due to differences in shoreline use, and flats had the highest fish occurrences during all seasons. At Lake Fork Reservoir, LBC occurrences at flats and drops were high and similar during all seasons.ConclusionOur estimates of small LBC home ranges and low movement in these large reservoirs were generally similar to those reported in previous studies, regardless of reservoir size. Fish preferred structural habitat types with abrupt slopes, were primarily located offshore, and occupied water column depths that are commonly targeted by LBC anglers.
{"title":"Movement, home range, and structural habitat use of the Largemouth Bass complex in two large Texas reservoirs","authors":"M. Todd Driscoll, Jacob D. Norman, Daniel L. Bennett, Brian K. Metz, David R. Smith","doi":"10.1002/nafm.10996","DOIUrl":"https://doi.org/10.1002/nafm.10996","url":null,"abstract":"ObjectiveAngler complaints regarding perceived declines in angling quality prompted research to examine the home range, movement, water depth use, and structural habitat use and selection of the Largemouth Bass complex (LBC; Largemouth Bass <jats:italic>Micropterus nigricans</jats:italic>, Florida Bass <jats:italic>M. salmoides</jats:italic>, and Largemouth Bass × Florida Bass hybrids) in Toledo Bend and Lake Fork reservoirs, Texas.MethodsA total of 21 LBC individuals at Toledo Bend Reservoir (386–604 mm total length [TL]) and 22 LBC fish at Lake Fork Reservoir (364–545 mm TL) were implanted with radio transmitters and tracked over a 2‐year period.ResultAt both reservoirs, LBC home range areas were small (<50 ha) and overall movement was low (~40–100 m/week). Fish primarily occupied water column depths of less than 2 m in both reservoirs and were found in the shallowest depths during the spring. Although overall structural habitat occurrence and selection of LBC fish varied between reservoirs, primarily due to differences at shorelines and creeks (two times higher in Toledo Bend Reservoir) and drops (three times higher in Lake Fork Reservoir), fish selected for the shoreline, drops, points, and creeks in both reservoirs, while drains and flats reflected avoidance. Seasonally, habitat occurrence of LBC fish varied at Toledo Bend Reservoir, primarily due to differences in shoreline use, and flats had the highest fish occurrences during all seasons. At Lake Fork Reservoir, LBC occurrences at flats and drops were high and similar during all seasons.ConclusionOur estimates of small LBC home ranges and low movement in these large reservoirs were generally similar to those reported in previous studies, regardless of reservoir size. Fish preferred structural habitat types with abrupt slopes, were primarily located offshore, and occupied water column depths that are commonly targeted by LBC anglers.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"2013 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140623260","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}
Meredith B. Pfennig, Derek P. Crane, Nate G. Smith, Dave L. Buckmeier
ObjectiveAge estimation methods have not been validated for many species. Thus, we focused this age estimation study on four species from central Texas: the Guadalupe Bass Micropterus treculii, Channel Catfish Ictalurus punctatus, Gray Redhorse Moxostoma congestum, and Redbreast Sunfish Lepomis auritus. Our objectives for each species were to (1) investigate whether increments form annually in otoliths, fin rays, or spines; (2) determine the seasonal timing of zone deposition in each calcified structure; and (3) compare age estimates between otoliths and fin rays or spines.MethodsFish were sampled from central Texas waters and injected with oxytetracycline (OTC) quarterly in 2021. In July 2022, otoliths and fin rays or spines were collected to determine whether the increments formed annually and to estimate age.ResultOn average, two readers identified the correct number of annuli after the OTC mark in at least 95% of Gray Redhorse, Guadalupe Bass, and Redbreast Sunfish otoliths but in only 69% of Channel Catfish otoliths. However, the more experienced reader identified the correct number of annuli in at least 95% of otoliths from age‐2–4 Channel Catfish. Compared to otoliths, the correct number of annuli after the OTC mark was identified in a smaller percentage of fin rays or spines (47–62%). The probability of identifying the correct number of annuli after the OTC mark differed between the two readers for all spines and fin rays. Age difference plots revealed that age estimates based on fin rays or spines were either overestimated or underestimated compared to otolith‐based ages for all species.ConclusionWe consider annual increment formation in otoliths to be validated for all age‐classes of Gray Redhorse, Guadalupe Bass, and Redbreast Sunfish examined and for ages 2–4 of Channel Catfish. Differences in correctness between readers were most likely due to differences in age estimation experience. Given the level of error observed in our study, caution is advised if using age estimates from unvalidated structures and species.
{"title":"Age estimation and validation in otoliths, spines, and fin rays from four central Texas fishes","authors":"Meredith B. Pfennig, Derek P. Crane, Nate G. Smith, Dave L. Buckmeier","doi":"10.1002/nafm.10997","DOIUrl":"https://doi.org/10.1002/nafm.10997","url":null,"abstract":"ObjectiveAge estimation methods have not been validated for many species. Thus, we focused this age estimation study on four species from central Texas: the Guadalupe Bass <jats:italic>Micropterus treculii</jats:italic>, Channel Catfish <jats:italic>Ictalurus punctatus</jats:italic>, Gray Redhorse <jats:italic>Moxostoma congestum</jats:italic>, and Redbreast Sunfish <jats:italic>Lepomis auritus</jats:italic>. Our objectives for each species were to (1) investigate whether increments form annually in otoliths, fin rays, or spines; (2) determine the seasonal timing of zone deposition in each calcified structure; and (3) compare age estimates between otoliths and fin rays or spines.MethodsFish were sampled from central Texas waters and injected with oxytetracycline (OTC) quarterly in 2021. In July 2022, otoliths and fin rays or spines were collected to determine whether the increments formed annually and to estimate age.ResultOn average, two readers identified the correct number of annuli after the OTC mark in at least 95% of Gray Redhorse, Guadalupe Bass, and Redbreast Sunfish otoliths but in only 69% of Channel Catfish otoliths. However, the more experienced reader identified the correct number of annuli in at least 95% of otoliths from age‐2–4 Channel Catfish. Compared to otoliths, the correct number of annuli after the OTC mark was identified in a smaller percentage of fin rays or spines (47–62%). The probability of identifying the correct number of annuli after the OTC mark differed between the two readers for all spines and fin rays. Age difference plots revealed that age estimates based on fin rays or spines were either overestimated or underestimated compared to otolith‐based ages for all species.ConclusionWe consider annual increment formation in otoliths to be validated for all age‐classes of Gray Redhorse, Guadalupe Bass, and Redbreast Sunfish examined and for ages 2–4 of Channel Catfish. Differences in correctness between readers were most likely due to differences in age estimation experience. Given the level of error observed in our study, caution is advised if using age estimates from unvalidated structures and species.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"19 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140614223","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}
Benjamin C. Kissinger, Michael G. Sullivan, Andrew J. Paul, Adrian Meinke, John Post
Translocations have increased in recent years to aid in species recovery efforts. This includes translocations outside of species' historical distribution, where threats are less severe. One candidate species for translocation is the Bull Trout Salvelinus confluentus, but few examples of successful translocations (re-establishment or range expansion) have been documented. Here, we describe an example in which 63 Bull Trout were translocated in 1987 to establish a population in fishless Marie Lake, Alberta.
{"title":"Establishment of Bull Trout in a previously fishless subalpine lake by translocation","authors":"Benjamin C. Kissinger, Michael G. Sullivan, Andrew J. Paul, Adrian Meinke, John Post","doi":"10.1002/nafm.10989","DOIUrl":"https://doi.org/10.1002/nafm.10989","url":null,"abstract":"Translocations have increased in recent years to aid in species recovery efforts. This includes translocations outside of species' historical distribution, where threats are less severe. One candidate species for translocation is the Bull Trout <i>Salvelinus confluentus</i>, but few examples of successful translocations (re-establishment or range expansion) have been documented. Here, we describe an example in which 63 Bull Trout were translocated in 1987 to establish a population in fishless Marie Lake, Alberta.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"122 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140587891","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}
Quinnlan C. Smith, Stephanie L. Shaw, Joshua K. Raabe, Greg G. Sass, Thomas R. Hrabik
Fish movements and distributions throughout an ecosystem are important for understanding ecological interactions, conservation, and management. Coarse woody habitat (CWH) additions are a popular habitat enhancement tool that can influence movements and distributions of fishes; however, behavioral responses in relation to CWH additions are understudied. The objectives of our study were to test for changes in habitat use and behavioral responses of Muskellunge Esox masquinongy, Smallmouth Bass Micropterus dolomieu, and Walleye Sander vitreus to CWH additions in a small inland northern lake over 3 years and to evaluate two common forms of fish tracking to estimate daily movement of these fishes.
{"title":"Sport fish movement responses to a littoral zone coarse woody habitat addition","authors":"Quinnlan C. Smith, Stephanie L. Shaw, Joshua K. Raabe, Greg G. Sass, Thomas R. Hrabik","doi":"10.1002/nafm.10995","DOIUrl":"https://doi.org/10.1002/nafm.10995","url":null,"abstract":"Fish movements and distributions throughout an ecosystem are important for understanding ecological interactions, conservation, and management. Coarse woody habitat (CWH) additions are a popular habitat enhancement tool that can influence movements and distributions of fishes; however, behavioral responses in relation to CWH additions are understudied. The objectives of our study were to test for changes in habitat use and behavioral responses of Muskellunge <i>Esox masquinongy</i>, Smallmouth Bass <i>Micropterus dolomieu</i>, and Walleye <i>Sander vitreus</i> to CWH additions in a small inland northern lake over 3 years and to evaluate two common forms of fish tracking to estimate daily movement of these fishes.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"17 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140587812","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}
Manuel E. Coffill-Rivera, J. Wesley Neal, Grisel Rodríguez-Ferrer, Craig G. Lilyestrom
Spearfishing is a common activity used to harvest coastal marine species worldwide and can be a significant contributor to landings of ecologically and economically relevant species. As such, it is important to monitor spearfishing catch and effort. Spearfishing is commonly practiced throughout the Caribbean, yet characteristics of this gear's fishery remain understudied in the region. Thus, the objectives of this study were to provide a description of the Puerto Rico spearfishing fishery utilizing a long-term MRIP APAIS data set, examine the data set quality of this survey, and provide suggestions to improve MRIP implementation in the U.S. Caribbean.
{"title":"Using lessons learned from a multidecadal intercept survey of Puerto Rico spear fishers to improve data collection in the U.S. Caribbean","authors":"Manuel E. Coffill-Rivera, J. Wesley Neal, Grisel Rodríguez-Ferrer, Craig G. Lilyestrom","doi":"10.1002/nafm.10987","DOIUrl":"https://doi.org/10.1002/nafm.10987","url":null,"abstract":"Spearfishing is a common activity used to harvest coastal marine species worldwide and can be a significant contributor to landings of ecologically and economically relevant species. As such, it is important to monitor spearfishing catch and effort. Spearfishing is commonly practiced throughout the Caribbean, yet characteristics of this gear's fishery remain understudied in the region. Thus, the objectives of this study were to provide a description of the Puerto Rico spearfishing fishery utilizing a long-term MRIP APAIS data set, examine the data set quality of this survey, and provide suggestions to improve MRIP implementation in the U.S. Caribbean.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140587914","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}
Jason T. Shaffer, Andrew P. Kinziger, Eric P. Bjorkstedt, Andre Buchheister
ObjectiveThis study compares the probability of detecting juvenile Coho Salmon Oncorhynchus kisutch using both environmental DNA (eDNA) techniques and underwater visual count (UVC) surveys in northern California rivers. Here, UVC surveys commonly have detection probabilities (p) surpassing 0.90, providing an ideal setting to examine the performance of newer eDNA methods. We also evaluate the potential for using eDNA concentrations to predict the count of Coho Salmon within pool habitats.MethodsWe conducted paired eDNA and UVC surveys in 96 pools across 25 stream reaches within the Smith River basin, California. Method‐specific p and the effect of environmental covariates were estimated using multiscale occupancy modeling. We used generalized linear models to evaluate the relationship of fish counts to eDNA concentrations and habitat covariates.ResultThe eDNA and UVC methods showed a high degree of agreement in detecting the presence of Coho Salmon within a pool (93% agreement) and survey reach (80% agreement). Detection probabilities for eDNA (peDNA) and for UVC (pUVC) were similar and high at median levels of pool residual depth and contributing basin area (peDNA = 91%, pUVC = 89%). Contributing basin area (a proxy for discharge) had a strong, negative effect that was more pronounced for peDNA than for pUVC (e.g., in the largest basins, peDNA = 34% whereas pUVC = 77%). We did not find eDNA concentrations to be a good predictor of Coho Salmon counts in small pools.ConclusionThis study demonstrates that eDNA methods yielded nearly identical results to UVC surveys in catchments <36 km2 and can provide a highly effective approach for determining the distribution of Coho Salmon. However, additional investigation is required before eDNA could be used to estimate relative abundance in small pools.
{"title":"Comparison of environmental DNA and underwater visual count surveys for detecting juvenile Coho Salmon in small rivers","authors":"Jason T. Shaffer, Andrew P. Kinziger, Eric P. Bjorkstedt, Andre Buchheister","doi":"10.1002/nafm.10993","DOIUrl":"https://doi.org/10.1002/nafm.10993","url":null,"abstract":"ObjectiveThis study compares the probability of detecting juvenile Coho Salmon <jats:italic>Oncorhynchus kisutch</jats:italic> using both environmental DNA (eDNA) techniques and underwater visual count (UVC) surveys in northern California rivers. Here, UVC surveys commonly have detection probabilities (<jats:italic>p</jats:italic>) surpassing 0.90, providing an ideal setting to examine the performance of newer eDNA methods. We also evaluate the potential for using eDNA concentrations to predict the count of Coho Salmon within pool habitats.MethodsWe conducted paired eDNA and UVC surveys in 96 pools across 25 stream reaches within the Smith River basin, California. Method‐specific <jats:italic>p</jats:italic> and the effect of environmental covariates were estimated using multiscale occupancy modeling. We used generalized linear models to evaluate the relationship of fish counts to eDNA concentrations and habitat covariates.ResultThe eDNA and UVC methods showed a high degree of agreement in detecting the presence of Coho Salmon within a pool (93% agreement) and survey reach (80% agreement). Detection probabilities for eDNA (<jats:italic>p</jats:italic><jats:sub>eDNA</jats:sub>) and for UVC (<jats:italic>p</jats:italic><jats:sub>UVC</jats:sub>) were similar and high at median levels of pool residual depth and contributing basin area (<jats:italic>p</jats:italic><jats:sub>eDNA</jats:sub> = 91%, <jats:italic>p</jats:italic><jats:sub>UVC</jats:sub> = 89%). Contributing basin area (a proxy for discharge) had a strong, negative effect that was more pronounced for <jats:italic>p</jats:italic><jats:sub>eDNA</jats:sub> than for <jats:italic>p</jats:italic><jats:sub>UVC</jats:sub> (e.g., in the largest basins, <jats:italic>p</jats:italic><jats:sub>eDNA</jats:sub> = 34% whereas <jats:italic>p</jats:italic><jats:sub>UVC</jats:sub> = 77%). We did not find eDNA concentrations to be a good predictor of Coho Salmon counts in small pools.ConclusionThis study demonstrates that eDNA methods yielded nearly identical results to UVC surveys in catchments <36 km<jats:sup>2</jats:sup> and can provide a highly effective approach for determining the distribution of Coho Salmon. However, additional investigation is required before eDNA could be used to estimate relative abundance in small pools.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"203 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140202897","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}
Joel W. Yeager, Timothy F. Bonvechio, Martin J. Hamel
ObjectiveSuwannee Bass Micropterus notius are a unique black bass that are endemic to riverine systems in Georgia and Florida, USA. Despite their “near threatened” status by the International Union for Conservation of Nature's Red List, Suwannee Bass are a popular sport fish that can be harvested throughout their range under a single harvest regulation with all black basses (genus Micropterus). However, a single harvest regulation may have disproportion effects on Suwannee Bass because of their rarity, limited distribution, and sex‐specific growth patterns.MethodsBoat electrofishing was used to collect Suwannee Bass and Largemouth Bass M. nigricans from both the Withlacoochee and Ochlockonee rivers to assess population demographics and angler exploitation. Common fisheries assessment metrics were calculated and annual exploitation rate was estimated from high reward (US$100) tags under simulated variability in tag loss and angler reporting rates.ResultWe observed different relative abundance and size structure among river systems. Electrofishing catch per unit effort of Suwannee Bass was higher in the Withlacoochee River (6.89 fish/h) than the Ochlockonee River (2.01 fish/h). Length‐frequency histograms suggested a wide breadth of lengths and presumed ages except for a lack of stock size Suwannee Bass in the Ochlockonee River. Eight percent of monetary reward tags were returned from anglers, yielding an overall exploitation estimate of 3.2%.ConclusionAnnual angler exploitation rates of Suwannee Bass and Largemouth Bass were low (<9.1%) in the Withlacoochee and Ochlockonee rivers of Georgia. Low exploitation coupled with a wide breadth of lengths and ages suggest these populations are currently not at risk of overexploitation.
{"title":"Population demographics and angler exploitation of Suwannee Bass in two Georgia rivers","authors":"Joel W. Yeager, Timothy F. Bonvechio, Martin J. Hamel","doi":"10.1002/nafm.10990","DOIUrl":"https://doi.org/10.1002/nafm.10990","url":null,"abstract":"ObjectiveSuwannee Bass <jats:italic>Micropterus notius</jats:italic> are a unique black bass that are endemic to riverine systems in Georgia and Florida, USA. Despite their “near threatened” status by the International Union for Conservation of Nature's Red List, Suwannee Bass are a popular sport fish that can be harvested throughout their range under a single harvest regulation with all black basses (genus <jats:italic>Micropterus</jats:italic>). However, a single harvest regulation may have disproportion effects on Suwannee Bass because of their rarity, limited distribution, and sex‐specific growth patterns.MethodsBoat electrofishing was used to collect Suwannee Bass and Largemouth Bass <jats:italic>M. nigricans</jats:italic> from both the Withlacoochee and Ochlockonee rivers to assess population demographics and angler exploitation. Common fisheries assessment metrics were calculated and annual exploitation rate was estimated from high reward (US$100) tags under simulated variability in tag loss and angler reporting rates.ResultWe observed different relative abundance and size structure among river systems. Electrofishing catch per unit effort of Suwannee Bass was higher in the Withlacoochee River (6.89 fish/h) than the Ochlockonee River (2.01 fish/h). Length‐frequency histograms suggested a wide breadth of lengths and presumed ages except for a lack of stock size Suwannee Bass in the Ochlockonee River. Eight percent of monetary reward tags were returned from anglers, yielding an overall exploitation estimate of 3.2%.ConclusionAnnual angler exploitation rates of Suwannee Bass and Largemouth Bass were low (<9.1%) in the Withlacoochee and Ochlockonee rivers of Georgia. Low exploitation coupled with a wide breadth of lengths and ages suggest these populations are currently not at risk of overexploitation.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"44 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140202895","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}
Travis C. Durhack, Holly A. Simpson, Douglas A. Watkinson, Mark A. Pegg, Eva C. Enders
ObjectiveDocumenting the movement of Channel Catfish Ictalurus punctatus through telemetry, where a transmitter tag is surgically implanted in the fish, can provide valuable insight into the species' spatial ecology and habitat use. However, since fish in the order Siluriformes can expel foreign objects such as tags from their body cavity, the utility of telemetry technology may be limited for Channel Catfish. This study aimed to determine (1) how quickly Channel Catfish reject tags that were surgically implanted into the body cavity, (2) if surgical implantation of transmitter tags causes mortality, and (3) what surgical method is best to minimize tag rejection and/or mortality.MethodsThree surgical trials were conducted on Channel Catfish (n = 24) using two tag implantation methods: a nontethered method, in which the tag was freely implanted into the body cavity, and a tethered method, where the tag was attached to the pectoral girdle. Fish were observed in the lab for 30 days for trials 1 and 2 and 225 days for trial 3 following tag implantation.ResultNo complete tag rejections occurred during any of the three experimental trials. However, all five tethered fish experienced mortality during trial 3 (58–221 days postsurgery). Necropsies indicated that the tethered tagging method led to septicaemia infections and internal lacerations from the tether, which were not observed in the nontethered fish. Tags in the nontethered fish were in the process of being absorbed into the intestinal tract, which over time might have led to tag rejection.ConclusionWhile rejection is possibly the end point of the nontethered tagging method, our results suggest it is nevertheless the better tagging method for Channel Catfish given higher survival.
{"title":"A comparison of tag retention and mortality from two tagging methods for internal tag placement in Channel Catfish","authors":"Travis C. Durhack, Holly A. Simpson, Douglas A. Watkinson, Mark A. Pegg, Eva C. Enders","doi":"10.1002/nafm.10991","DOIUrl":"https://doi.org/10.1002/nafm.10991","url":null,"abstract":"ObjectiveDocumenting the movement of Channel Catfish <jats:italic>Ictalurus punctatu</jats:italic>s through telemetry, where a transmitter tag is surgically implanted in the fish, can provide valuable insight into the species' spatial ecology and habitat use. However, since fish in the order Siluriformes can expel foreign objects such as tags from their body cavity, the utility of telemetry technology may be limited for Channel Catfish. This study aimed to determine (1) how quickly Channel Catfish reject tags that were surgically implanted into the body cavity, (2) if surgical implantation of transmitter tags causes mortality, and (3) what surgical method is best to minimize tag rejection and/or mortality.MethodsThree surgical trials were conducted on Channel Catfish (<jats:italic>n</jats:italic> = 24) using two tag implantation methods: a nontethered method, in which the tag was freely implanted into the body cavity, and a tethered method, where the tag was attached to the pectoral girdle. Fish were observed in the lab for 30 days for trials 1 and 2 and 225 days for trial 3 following tag implantation.ResultNo complete tag rejections occurred during any of the three experimental trials. However, all five tethered fish experienced mortality during trial 3 (58–221 days postsurgery). Necropsies indicated that the tethered tagging method led to septicaemia infections and internal lacerations from the tether, which were not observed in the nontethered fish. Tags in the nontethered fish were in the process of being absorbed into the intestinal tract, which over time might have led to tag rejection.ConclusionWhile rejection is possibly the end point of the nontethered tagging method, our results suggest it is nevertheless the better tagging method for Channel Catfish given higher survival.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"56 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140070578","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}
ObjectiveAltered flow regimes pose significant risks to the stability of populations of riverine Smallmouth Bass Micropterus dolomieu. Periods of poor recruitment, due to early life stage mortality resulting from high‐flow events, can cause size‐structure and density alterations of populations. The aim of this study was to opportunistically test for changes in dynamic rates of a riverine Smallmouth Bass population using a long‐term data set that spanned a period of poor recruitment.MethodsOur study evaluated size‐specific CPUE (fish/h), mortality, growth, and condition and tested for recruitment determinants of Smallmouth Bass through three consecutive years of poor age‐0 recruitment in the South Branch Potomac River, West Virginia. We used fall nighttime boat electrofishing surveys during 2009–2022 to monitor this population before and after the poor‐recruitment time frame (2016–2018).ResultAge‐0 CPUE was greater during the time frame prior to the poor‐recruitment time frame. However, there was no difference in the CPUE of quality‐length Smallmouth Bass between the two time frames and CPUE of preferred‐length fish was greater during the poor‐recruitment time frame. Growth and relative weight increased during the poor‐recruitment time frame. There was no significant difference detected in mortality between the recruitment time frames. Streamflow during the spawning period was a significant factor influencing fall recruitment of age‐0 Smallmouth Bass. A Ricker density‐dependent model with an added streamflow term performed as well as a basic, log‐linear streamflow model and a density‐independent model that also incorporated a streamflow term.ConclusionOur results provide evidence of density‐dependent structuring in this population. Decreases in population density increased population dynamic rates that maintained or improved size structure. High adult biomasses did not increase age‐0 recruitment. Many riverine Smallmouth Bass populations may display favorable density‐dependent responses to declines in juvenile recruitment. Thus, management agencies should better understand the resiliency of these populations prior to establishing expensive programs or regulations, which may be ineffective, to combat alterations in juvenile recruitment.
{"title":"Effects of poor recruitment on riverine Smallmouth Bass population dynamics","authors":"Brandon Keplinger, Christopher T. Rota","doi":"10.1002/nafm.10994","DOIUrl":"https://doi.org/10.1002/nafm.10994","url":null,"abstract":"ObjectiveAltered flow regimes pose significant risks to the stability of populations of riverine Smallmouth Bass <jats:italic>Micropterus dolomieu</jats:italic>. Periods of poor recruitment, due to early life stage mortality resulting from high‐flow events, can cause size‐structure and density alterations of populations. The aim of this study was to opportunistically test for changes in dynamic rates of a riverine Smallmouth Bass population using a long‐term data set that spanned a period of poor recruitment.MethodsOur study evaluated size‐specific CPUE (fish/h), mortality, growth, and condition and tested for recruitment determinants of Smallmouth Bass through three consecutive years of poor age‐0 recruitment in the South Branch Potomac River, West Virginia. We used fall nighttime boat electrofishing surveys during 2009–2022 to monitor this population before and after the poor‐recruitment time frame (2016–2018).ResultAge‐0 CPUE was greater during the time frame prior to the poor‐recruitment time frame. However, there was no difference in the CPUE of quality‐length Smallmouth Bass between the two time frames and CPUE of preferred‐length fish was greater during the poor‐recruitment time frame. Growth and relative weight increased during the poor‐recruitment time frame. There was no significant difference detected in mortality between the recruitment time frames. Streamflow during the spawning period was a significant factor influencing fall recruitment of age‐0 Smallmouth Bass. A Ricker density‐dependent model with an added streamflow term performed as well as a basic, log‐linear streamflow model and a density‐independent model that also incorporated a streamflow term.ConclusionOur results provide evidence of density‐dependent structuring in this population. Decreases in population density increased population dynamic rates that maintained or improved size structure. High adult biomasses did not increase age‐0 recruitment. Many riverine Smallmouth Bass populations may display favorable density‐dependent responses to declines in juvenile recruitment. Thus, management agencies should better understand the resiliency of these populations prior to establishing expensive programs or regulations, which may be ineffective, to combat alterations in juvenile recruitment.","PeriodicalId":19263,"journal":{"name":"North American Journal of Fisheries Management","volume":"74 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140046810","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：