Sebastian Menze, Gavin J. Macaulay, Guosong Zhang, Andrew D. Lowther, Bjørn A. Krafft
Krillscan software was developed to automatically process echosounder data and achieve an accelerated and transparent analysis of backscatter data that allows calculation of target biomass. Herein, the fishery for Antarctic krill (Euphausia superba, Henceforth Krill) was used as a case study to develop the approach. Implementation of a sustainable management strategy for the krill fishery is complicated by a lack of regularly updated krill abundance data on spatiotemporal scales of the fishery. To increase krill biomass data availability, automatic echosounder data processing and swarm detection software was tested against traditional manual scrutinization with LSSS software and agreed with only minor offsets in estimated nautical area scattering coefficients. In addition to automatic processing and data transfer, Krillscan also has a graphical user interface to supervise automatic krill swarm detection. Echogram size can be compressed up to 100 times and raw data are processed faster than generated, thereby enabling near‐real time analysis and data transfer. Compressed data can be transmitted online to allow fishing vessels to conduct surveys without having scientific personnel with special expertise on board.
{"title":"KRILLSCAN: An automated open‐source software for processing and analysis of echosounder data from the Antarctic krill fishery","authors":"Sebastian Menze, Gavin J. Macaulay, Guosong Zhang, Andrew D. Lowther, Bjørn A. Krafft","doi":"10.1111/fme.12739","DOIUrl":"https://doi.org/10.1111/fme.12739","url":null,"abstract":"Krillscan software was developed to automatically process echosounder data and achieve an accelerated and transparent analysis of backscatter data that allows calculation of target biomass. Herein, the fishery for Antarctic krill (<jats:italic>Euphausia superba</jats:italic>, Henceforth Krill) was used as a case study to develop the approach. Implementation of a sustainable management strategy for the krill fishery is complicated by a lack of regularly updated krill abundance data on spatiotemporal scales of the fishery. To increase krill biomass data availability, automatic echosounder data processing and swarm detection software was tested against traditional manual scrutinization with LSSS software and agreed with only minor offsets in estimated nautical area scattering coefficients. In addition to automatic processing and data transfer, Krillscan also has a graphical user interface to supervise automatic krill swarm detection. Echogram size can be compressed up to 100 times and raw data are processed faster than generated, thereby enabling near‐real time analysis and data transfer. Compressed data can be transmitted online to allow fishing vessels to conduct surveys without having scientific personnel with special expertise on board.","PeriodicalId":50444,"journal":{"name":"Fisheries Management and Ecology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Traditional methods for collecting robust samples of recreational effort and catch data from offsite mail or telephone surveys are becoming increasingly difficult to obtain. Smartphone applications (apps) that allow recreational fishers to report their effort and catch are a potentially viable data collection tool, but may be biased. We evaluated demographics, effort, and catch of freshwater anglers in south‐west Western Australia by comparing independent data from concurrent phone‐recall and app‐diary surveys for a 12‐month period in 2017–2018. Survey modes differed, with higher proportions of app respondents angling in freshwater and being avid anglers. For both survey modes, unweighted mean effort (days fished) was higher in dams than rivers, but was higher from the phone‐recall survey for dams and rivers. The unweighted distribution of kept and released catches (number of fish per angler) of rainbow trout (Oncorhynchus mykiss) and redfin (Perca fluviatilis) were similar between survey modes, with higher retention of redfin and higher release of rainbow trout. Kept and released rates of freshwater cobbler (Tandanus bostocki) and brown trout (Salmo trutta) were less common in both survey modes. Lower response rates and higher survey participation by avid anglers (≥20 days per year) from the app‐diary survey may bias survey data. Such bias needs to be addressed when using digital data collection methods, along with improving recruitment and retention of app participants.
{"title":"Differences in fisher demographics and fishing behaviour from concurrent phone‐recall and smartphone app surveys of recreational angling in south‐western Australia","authors":"Fabian I. Trinnie, Karina L. Ryan","doi":"10.1111/fme.12736","DOIUrl":"https://doi.org/10.1111/fme.12736","url":null,"abstract":"Traditional methods for collecting robust samples of recreational effort and catch data from offsite mail or telephone surveys are becoming increasingly difficult to obtain. Smartphone applications (apps) that allow recreational fishers to report their effort and catch are a potentially viable data collection tool, but may be biased. We evaluated demographics, effort, and catch of freshwater anglers in south‐west Western Australia by comparing independent data from concurrent phone‐recall and app‐diary surveys for a 12‐month period in 2017–2018. Survey modes differed, with higher proportions of app respondents angling in freshwater and being avid anglers. For both survey modes, unweighted mean effort (days fished) was higher in dams than rivers, but was higher from the phone‐recall survey for dams and rivers. The unweighted distribution of kept and released catches (number of fish per angler) of rainbow trout (<jats:italic>Oncorhynchus mykiss</jats:italic>) and redfin (<jats:italic>Perca fluviatilis</jats:italic>) were similar between survey modes, with higher retention of redfin and higher release of rainbow trout. Kept and released rates of freshwater cobbler (<jats:italic>Tandanus bostocki</jats:italic>) and brown trout (<jats:italic>Salmo trutta</jats:italic>) were less common in both survey modes. Lower response rates and higher survey participation by avid anglers (≥20 days per year) from the app‐diary survey may bias survey data. Such bias needs to be addressed when using digital data collection methods, along with improving recruitment and retention of app participants.","PeriodicalId":50444,"journal":{"name":"Fisheries Management and Ecology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Martin Šindler, Miloš Buřič, Martin Plesch, Pavel Franta, Bořek Drozd
Sterlet (Acipenser ruthenus), one of the last sturgeons in the Danube basin, is regularly stocked in national and international restoration programs, but the efficacy of stocking has not yet been evaluated. Effectiveness of stocking should involve marking and evaluating growth and survival of juveniles. Chemical marking with alizarin red S (ARS) was evaluated to establish optimal ARS staining approaches for juvenile sterlet. Bathing in a 100–200 mg l−1 ARS concentration for 12 h had no affect on fish mortality or growth. Use of a green laser on the upper five external structures (dorsal, lateral, and ventral scutes and rostral and anal plates) allowed easy detection for at least a year. Simultaneous use of multiple external structures was effective for distinguishing stocked from wild fish without harm or sacrifice. We conclude that ARS staining enabled a cost‐effective, quick, and labour‐nonintensive way to mark sterlet, with a high‐field detectability and minimal previous experience required.
鲟鱼（Acipenser ruthenus）是多瑙河流域最后的鲟鱼之一，在国家和国际恢复计划中被定期放养，但放养的效果尚未得到评估。放养效果应包括标记和评估幼鱼的生长和存活率。对茜素红 S（ARS）的化学标记进行了评估，以确定针对幼鱼的最佳 ARS 染色方法。在 100-200 mg l-1 浓度的 ARS 中浸浴 12 小时对鱼的死亡率和生长没有影响。使用绿色激光对上部五个外部结构（背鳞、侧鳞、腹鳞、喙板和肛板）进行染色，可轻松检测至少一年。同时使用多个外部结构可有效区分放养鱼和野生鱼，而不会造成伤害或牺牲。我们的结论是，ARS 染色是一种经济、快速、不需要大量劳动力的标记小尾寒羊的方法，具有很高的野外可探测性，而且只需要很少的经验。
{"title":"Effectiveness of mass marking of juvenile sterlet (Acipenser ruthenus) with alizarin red S stain on field detection","authors":"Martin Šindler, Miloš Buřič, Martin Plesch, Pavel Franta, Bořek Drozd","doi":"10.1111/fme.12737","DOIUrl":"https://doi.org/10.1111/fme.12737","url":null,"abstract":"Sterlet (<jats:italic>Acipenser ruthenus</jats:italic>), one of the last sturgeons in the Danube basin, is regularly stocked in national and international restoration programs, but the efficacy of stocking has not yet been evaluated. Effectiveness of stocking should involve marking and evaluating growth and survival of juveniles. Chemical marking with alizarin red S (ARS) was evaluated to establish optimal ARS staining approaches for juvenile sterlet. Bathing in a 100–200 mg l<jats:sup>−1</jats:sup> ARS concentration for 12 h had no affect on fish mortality or growth. Use of a green laser on the upper five external structures (dorsal, lateral, and ventral scutes and rostral and anal plates) allowed easy detection for at least a year. Simultaneous use of multiple external structures was effective for distinguishing stocked from wild fish without harm or sacrifice. We conclude that ARS staining enabled a cost‐effective, quick, and labour‐nonintensive way to mark sterlet, with a high‐field detectability and minimal previous experience required.","PeriodicalId":50444,"journal":{"name":"Fisheries Management and Ecology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stian Stensland, Christian Skov, Sveinn Agnarsson, Patrik Rönnbäck, Teppo Vehanen, Malgorzata Blicharska, Jon Olaf Olaussen, Anders Kagervall, Gustav Hellström, Samuel Blyth, Casper Gundelund, Øystein Aas
The Delphi method was used to gather assessments from 93 experts about drivers of future angling participation by locals and tourist anglers in Denmark, Finland, Iceland, Norway, and Sweden. The main drivers of future angling participation related to habitat and fish populations, and access to and information about fishing. For Norway and Finland, the predicted future decline in local angler numbers was consistent with a life‐cycle model of recreational fisheries, while the anticipated increase for the three other countries contradicted the model. For tourist anglers, growth was expected for both domestic and foreign tourists. Long‐term and societal drivers, such as urbanization, sociocultural changes, and climate change were not seen as strong drivers, and may be considered out of reach by managers, but should be included with information and conservation drivers in angler recruitment and retention strategies.
{"title":"A Delphi‐study to identify drivers of future angling participation in five Nordic countries","authors":"Stian Stensland, Christian Skov, Sveinn Agnarsson, Patrik Rönnbäck, Teppo Vehanen, Malgorzata Blicharska, Jon Olaf Olaussen, Anders Kagervall, Gustav Hellström, Samuel Blyth, Casper Gundelund, Øystein Aas","doi":"10.1111/fme.12735","DOIUrl":"https://doi.org/10.1111/fme.12735","url":null,"abstract":"The Delphi method was used to gather assessments from 93 experts about drivers of future angling participation by locals and tourist anglers in Denmark, Finland, Iceland, Norway, and Sweden. The main drivers of future angling participation related to habitat and fish populations, and access to and information about fishing. For Norway and Finland, the predicted future decline in local angler numbers was consistent with a life‐cycle model of recreational fisheries, while the anticipated increase for the three other countries contradicted the model. For tourist anglers, growth was expected for both domestic and foreign tourists. Long‐term and societal drivers, such as urbanization, sociocultural changes, and climate change were not seen as strong drivers, and may be considered out of reach by managers, but should be included with information and conservation drivers in angler recruitment and retention strategies.","PeriodicalId":50444,"journal":{"name":"Fisheries Management and Ecology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Mekong River is the most productive inland fishery in the world and identified as a valuable source of hydropower generation. Consequently, benefits of energy production must be traded off against impacts on other ecological and environmental services, especially on fisheries that have been largely downplayed. We surveyed fish markets in 12 provinces in the Lower Mekong River Basin (LMB) to quantify the diversity, abundance and prices of fish species and to account for potential impacts of water infrastructure and development projects. Of 116 species in nine major ecological guilds in markets, potamodromous main channel spawners were the most diverse guild that contributed 30% of species and were present in markets in all countries and sites, whereas anadromous species were the least diverse guild with two species in Vietnam only. More than 45% of fish recorded in local markets in Cambodia and more than 80% in Vietnam were small‐sized fish (<25 cm), whereas about 50% of fish marketed in Lao PDR and Thailand were large‐sized fish (>50 cm). Fish were sold by both size and species, with most species sold in only one size category. The first‐sale price was highest in Lao PDR, followed by Thailand, Vietnam and Cambodia. Our findings provide primary ecological and economic information that can be used to estimate potential economic losses of fisheries when considering trade‐offs between energy and the environment.
{"title":"Fish assemblages and first sale prices from local markets in the Lower Mekong River Basin","authors":"Quan T. Lai, Ian G. Cowx, Hoang Duc Huy, Nam So","doi":"10.1111/fme.12734","DOIUrl":"https://doi.org/10.1111/fme.12734","url":null,"abstract":"The Mekong River is the most productive inland fishery in the world and identified as a valuable source of hydropower generation. Consequently, benefits of energy production must be traded off against impacts on other ecological and environmental services, especially on fisheries that have been largely downplayed. We surveyed fish markets in 12 provinces in the Lower Mekong River Basin (LMB) to quantify the diversity, abundance and prices of fish species and to account for potential impacts of water infrastructure and development projects. Of 116 species in nine major ecological guilds in markets, potamodromous main channel spawners were the most diverse guild that contributed 30% of species and were present in markets in all countries and sites, whereas anadromous species were the least diverse guild with two species in Vietnam only. More than 45% of fish recorded in local markets in Cambodia and more than 80% in Vietnam were small‐sized fish (<25 cm), whereas about 50% of fish marketed in Lao PDR and Thailand were large‐sized fish (>50 cm). Fish were sold by both size and species, with most species sold in only one size category. The first‐sale price was highest in Lao PDR, followed by Thailand, Vietnam and Cambodia. Our findings provide primary ecological and economic information that can be used to estimate potential economic losses of fisheries when considering trade‐offs between energy and the environment.","PeriodicalId":50444,"journal":{"name":"Fisheries Management and Ecology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Theis, Angela Wallace, Brian Graham, Brynn Coey, Lyndsay Cartwright, M. Poesch, Rick Portiss, Jonathan L. W. Ruppert
To enhance management of aquatic systems, long‐term monitoring programs are crucial. However, managers often lack sufficient guidance in decision‐making. In this study, we analyzed nearshore electrofishing data from Lake Ontario spanning 18 years and over 100,000 caught fish to assess sampling designs for various coastal habitats. Using simulation, we evaluated precision of catch per unit effort (CPUE) for all species, piscivores, and specialist species, at different levels of electrofishing sampling effort. For overall CPUE in any habitat type, increased precision declined with additional electrofishing runs, particularly after reaching 30–40 runs. Adjustments in sampling effort, such as adding 10 runs per year for open‐coast sites, increased precision of overall CPUE by 10%. Adding 8 runs per year for wetlands increased precision of specialist‐species CPUE by 10%. However, additional runs in embayments did not increase precision for all species, piscivores, or specialist species. Our findings underscore the importance of considering community composition and abundance when evaluating CPUE precision and illustrates a flexible approach to optimize sampling effort in aquatic monitoring programs.
{"title":"Balancing boat‐electrofishing sampling effort against costs for nearshore fish communities in the Toronto waterfront, Lake Ontario","authors":"S. Theis, Angela Wallace, Brian Graham, Brynn Coey, Lyndsay Cartwright, M. Poesch, Rick Portiss, Jonathan L. W. Ruppert","doi":"10.1111/fme.12733","DOIUrl":"https://doi.org/10.1111/fme.12733","url":null,"abstract":"To enhance management of aquatic systems, long‐term monitoring programs are crucial. However, managers often lack sufficient guidance in decision‐making. In this study, we analyzed nearshore electrofishing data from Lake Ontario spanning 18 years and over 100,000 caught fish to assess sampling designs for various coastal habitats. Using simulation, we evaluated precision of catch per unit effort (CPUE) for all species, piscivores, and specialist species, at different levels of electrofishing sampling effort. For overall CPUE in any habitat type, increased precision declined with additional electrofishing runs, particularly after reaching 30–40 runs. Adjustments in sampling effort, such as adding 10 runs per year for open‐coast sites, increased precision of overall CPUE by 10%. Adding 8 runs per year for wetlands increased precision of specialist‐species CPUE by 10%. However, additional runs in embayments did not increase precision for all species, piscivores, or specialist species. Our findings underscore the importance of considering community composition and abundance when evaluating CPUE precision and illustrates a flexible approach to optimize sampling effort in aquatic monitoring programs.","PeriodicalId":50444,"journal":{"name":"Fisheries Management and Ecology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gear selectivity is crucial in fisheries management because it influences the size and species of fish caught, with traditional methods often basing optimal mesh size on the mature length of a target species. However, to ensure sustainable fisheries, both biological aspects of resource protection and fishing operation efficiency must be considered. This study aimed to determine the ideal mesh size for trap fishing of marbled flounder (Pseudopleuronectes yokohamae) in Gyeongsangnam‐do, South Korea, by using biological and economic factors for sustainable fisheries management. We sampled fish caught in traps of varying mesh sizes (35, 50, 65, 80, and 100 mm) and developed two models based on fish maturity, bycatch ratio, and CPUE. Model 1 used a maturity criterion of 17.8 cm, and Model 2 used the legal minimum length limit of 20 cm. Net selectivity curves indicated that the optimal mesh size ranged 50–65 mm based only on a minimum mature body length of 17.8 cm. In contrast, the optimal mesh size based on both biological and economic factors ranged 57.5–90 mm. Our findings could guide policymakers in enhancing marble flounder population management strategies through policy adjustments in mesh size and gear restrictions.
{"title":"Optimal mesh size of traps for marbled flounder (Pseudopleuronectes yokohamae) based on biological and economic factors","authors":"Myungsung Koo, Inyeong Kwon","doi":"10.1111/fme.12730","DOIUrl":"https://doi.org/10.1111/fme.12730","url":null,"abstract":"Gear selectivity is crucial in fisheries management because it influences the size and species of fish caught, with traditional methods often basing optimal mesh size on the mature length of a target species. However, to ensure sustainable fisheries, both biological aspects of resource protection and fishing operation efficiency must be considered. This study aimed to determine the ideal mesh size for trap fishing of marbled flounder (<jats:italic>Pseudopleuronectes yokohamae</jats:italic>) in Gyeongsangnam‐do, South Korea, by using biological and economic factors for sustainable fisheries management. We sampled fish caught in traps of varying mesh sizes (35, 50, 65, 80, and 100 mm) and developed two models based on fish maturity, bycatch ratio, and CPUE. Model 1 used a maturity criterion of 17.8 cm, and Model 2 used the legal minimum length limit of 20 cm. Net selectivity curves indicated that the optimal mesh size ranged 50–65 mm based only on a minimum mature body length of 17.8 cm. In contrast, the optimal mesh size based on both biological and economic factors ranged 57.5–90 mm. Our findings could guide policymakers in enhancing marble flounder population management strategies through policy adjustments in mesh size and gear restrictions.","PeriodicalId":50444,"journal":{"name":"Fisheries Management and Ecology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141881869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sustainability of natural stocks of crayfish is critical because of their economic and ecological importance. Crayfish (Pontastacus leptodactylus), one of the most important species in Turkish inland fisheries, has been facing serious threats recently. One threat the species faces is high landed bycatch of undersized crayfish because of selective fishing gear, such as fyke nets. We estimated size‐selectivity of sorting grids with various bar spacings for crayfish to reduce bycatch. Six bar spacings (15.0, 17.5, 20.0, 22.5, 25.0, and 30.0 mm) were tested alongside commercial crayfish fyke nets. Mean selectivity (L50) (±95% CI) was 6.90 (6.63–6.99) cm for 15.0 mm bar spacing, 7.52 (7.16–8.02) cm for 17.5 mm, 8.52 (8.32–8.71) cm for 20.0 mm, 9.70 (9.28–9.90) cm for 22.5, 10.75 (10.34–11.17) cm for 25.0 mm, 11.80 (11.31–12.24) cm for 30.0 mm, and 8.79 (8.05–9.29) cm for commercial fyke nets. The proportion of undersized specimens caught be reduced from 32.27% for commercial fyke nets to as low as 2.46% by using sorting grids. The codend of 22.5 mm bar spacing was more selective, with significantly lower discard rates, and more effective for individuals above the minimum conservation reference size than commercial fyke nets.
{"title":"Sorting grid usage to reduce the catch of undersized narrow‐clawed crayfish (Pontastacus leptodactylus Eschscholtz, 1823) in fyke net fisheries","authors":"Mehmet Cilbiz, Celalettin Aydın","doi":"10.1111/fme.12731","DOIUrl":"https://doi.org/10.1111/fme.12731","url":null,"abstract":"Sustainability of natural stocks of crayfish is critical because of their economic and ecological importance. Crayfish (<jats:italic>Pontastacus leptodactylus</jats:italic>), one of the most important species in Turkish inland fisheries, has been facing serious threats recently. One threat the species faces is high landed bycatch of undersized crayfish because of selective fishing gear, such as fyke nets. We estimated size‐selectivity of sorting grids with various bar spacings for crayfish to reduce bycatch. Six bar spacings (15.0, 17.5, 20.0, 22.5, 25.0, and 30.0 mm) were tested alongside commercial crayfish fyke nets. Mean selectivity (<jats:italic>L</jats:italic><jats:sub>50</jats:sub>) (±95% CI) was 6.90 (6.63–6.99) cm for 15.0 mm bar spacing, 7.52 (7.16–8.02) cm for 17.5 mm, 8.52 (8.32–8.71) cm for 20.0 mm, 9.70 (9.28–9.90) cm for 22.5, 10.75 (10.34–11.17) cm for 25.0 mm, 11.80 (11.31–12.24) cm for 30.0 mm, and 8.79 (8.05–9.29) cm for commercial fyke nets. The proportion of undersized specimens caught be reduced from 32.27% for commercial fyke nets to as low as 2.46% by using sorting grids. The codend of 22.5 mm bar spacing was more selective, with significantly lower discard rates, and more effective for individuals above the minimum conservation reference size than commercial fyke nets.","PeriodicalId":50444,"journal":{"name":"Fisheries Management and Ecology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141881871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Spatial and temporal distribution of European eel (Anguilla anguilla) during 1967–2020 was used to model European eel distribution in response to climate variability. Modeling integrated predictions from two distinct models for inferences. First, modeling of the relationship between temperature and precipitation and European eel catch values using multiple time‐series regression analyses showed that climate variables contributed to eel distribution in Türkiye. Eel catch became restricted to western and southern coasts of Türkiye and total catch decreased between 1967 and 2020. From 1967 to 2020, favorable climatic conditions for European eels in Türkiye were characterized by moderate temperatures. Furthermore, projections for 2050 and 2070 suggested that suitable habitat would be lost in Türkiye. Our findings underscore the urgent need for immediate and widespread implementation of effective conservation policies to mitigate threats to European eel in Türkiye and globally.
{"title":"Climate change effects on abundance and distribution of the European eel in Türkiye","authors":"Burcu Mestav, Şükran Yalçın Özdilek, Zahide Acar, Kemal Gökkaya, Nurbanu Partal","doi":"10.1111/fme.12732","DOIUrl":"https://doi.org/10.1111/fme.12732","url":null,"abstract":"Spatial and temporal distribution of European eel (<jats:italic>Anguilla anguilla</jats:italic>) during 1967–2020 was used to model European eel distribution in response to climate variability. Modeling integrated predictions from two distinct models for inferences. First, modeling of the relationship between temperature and precipitation and European eel catch values using multiple time‐series regression analyses showed that climate variables contributed to eel distribution in Türkiye. Eel catch became restricted to western and southern coasts of Türkiye and total catch decreased between 1967 and 2020. From 1967 to 2020, favorable climatic conditions for European eels in Türkiye were characterized by moderate temperatures. Furthermore, projections for 2050 and 2070 suggested that suitable habitat would be lost in Türkiye. Our findings underscore the urgent need for immediate and widespread implementation of effective conservation policies to mitigate threats to European eel in Türkiye and globally.","PeriodicalId":50444,"journal":{"name":"Fisheries Management and Ecology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141881870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Durante, Crystal Beckmann, Frédéric Bailleul, Greg Ferguson
Understanding drivers of effort and catch is important for sustainable management of recreational fisheries. For the Pipi (Latona deltoides) fishery in South Australia as a case study, publicly available datasets on fisher demography, market forces and internet connectivity improved understanding of fisher motivations and capabilities, identified different historical periods in the fishery and addressed temporal gaps in effort and catch estimates from on‐site surveys. Most variables were correlated with recreational effort and catch estimates from on‐site surveys and principal component analysis identified 2013–2014, 2015–2018 and 2019–2022 as distinct periods in the Pipi fishery. Results corroborated studies and anecdotal information that suggested declining availability and higher prices of local, commercially caught Pipi, and reduced imports of bivalves from Asia that previously supplied the South Australian bait market. Reduced availability and higher prices of Pipi likely motivated recreational fishers to gather their own bait to increase catch over the years. Similarly, increased internet and smartphone access and increased numbers of utility vehicles aided recreational catch efficiency of Pipi. Effective management of recreationally harvested resources requires understanding of external processes that drive fisher motivations and capabilities, particularly for stocks that are shared among fisheries. The need for improved data on fisher behaviour for management of recreational fisheries can be addressed by leveraging external information from available datasets. We recommend that the temporal gap between surveys should be less than 5 years, supplemented by analysing behavioural information collected from fishers during interviews.
{"title":"Existing datasets uncover complex interactions driving catches of a data‐poor recreational fishery in South Australia","authors":"L. Durante, Crystal Beckmann, Frédéric Bailleul, Greg Ferguson","doi":"10.1111/fme.12727","DOIUrl":"https://doi.org/10.1111/fme.12727","url":null,"abstract":"Understanding drivers of effort and catch is important for sustainable management of recreational fisheries. For the Pipi (Latona deltoides) fishery in South Australia as a case study, publicly available datasets on fisher demography, market forces and internet connectivity improved understanding of fisher motivations and capabilities, identified different historical periods in the fishery and addressed temporal gaps in effort and catch estimates from on‐site surveys. Most variables were correlated with recreational effort and catch estimates from on‐site surveys and principal component analysis identified 2013–2014, 2015–2018 and 2019–2022 as distinct periods in the Pipi fishery. Results corroborated studies and anecdotal information that suggested declining availability and higher prices of local, commercially caught Pipi, and reduced imports of bivalves from Asia that previously supplied the South Australian bait market. Reduced availability and higher prices of Pipi likely motivated recreational fishers to gather their own bait to increase catch over the years. Similarly, increased internet and smartphone access and increased numbers of utility vehicles aided recreational catch efficiency of Pipi. Effective management of recreationally harvested resources requires understanding of external processes that drive fisher motivations and capabilities, particularly for stocks that are shared among fisheries. The need for improved data on fisher behaviour for management of recreational fisheries can be addressed by leveraging external information from available datasets. We recommend that the temporal gap between surveys should be less than 5 years, supplemented by analysing behavioural information collected from fishers during interviews.","PeriodicalId":50444,"journal":{"name":"Fisheries Management and Ecology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141641854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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