Pub Date : 2025-10-03DOI: 10.1016/j.fishres.2025.107546
Trevor Hutton, Sean Pascoe, Denham Parker
Most fisheries stock assessments rely on fishery dependent data to a large extent, with catch per unit effort a key indicator of changes in stock conditions. However, increases in fishing efficiency due to changes in technology and physical fleet attributes distort the relationship between observable effort (e.g., days or hours fished), catch and biomass. To compensate, a key component of fisheries stock assessment is the estimation of changes in fishing power over time to adjust catch rate information for this “effort creep”. Two approaches have developed in parallel for estimating changes in efficiency of fishing vessels over time. An approach commonly applied in stock assessment is engineering-based, focusing on changes in physical inputs. In contrast, economic based approaches have developed for assessing efficiency change that also capture non-physical inputs such as fisher skill, management changes and resulting behavioural change. We apply both of these approaches to the Australian Northern Prawn Fishery (NPF) and test the degree to which the derived efficiency time series agree. We find that the two series are highly correlated and cointegrated, suggesting that both provide a consistent measure of efficiency change over time. In the case of the NPF, this validates the current method used to adjust for effort creep in the stock assessments.
{"title":"Productivity versus engineering-based approaches to measure effort creep over time","authors":"Trevor Hutton, Sean Pascoe, Denham Parker","doi":"10.1016/j.fishres.2025.107546","DOIUrl":"10.1016/j.fishres.2025.107546","url":null,"abstract":"<div><div>Most fisheries stock assessments rely on fishery dependent data to a large extent, with catch per unit effort a key indicator of changes in stock conditions. However, increases in fishing efficiency due to changes in technology and physical fleet attributes distort the relationship between observable effort (e.g., days or hours fished), catch and biomass. To compensate, a key component of fisheries stock assessment is the estimation of changes in fishing power over time to adjust catch rate information for this “effort creep”. Two approaches have developed in parallel for estimating changes in efficiency of fishing vessels over time. An approach commonly applied in stock assessment is engineering-based, focusing on changes in physical inputs. In contrast, economic based approaches have developed for assessing efficiency change that also capture non-physical inputs such as fisher skill, management changes and resulting behavioural change. We apply both of these approaches to the Australian Northern Prawn Fishery (NPF) and test the degree to which the derived efficiency time series agree. We find that the two series are highly correlated and cointegrated, suggesting that both provide a consistent measure of efficiency change over time. In the case of the NPF, this validates the current method used to adjust for effort creep in the stock assessments.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"291 ","pages":"Article 107546"},"PeriodicalIF":2.3,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-03DOI: 10.1016/j.fishres.2025.107536
Jialu Wang, Shigeru Tabeta, Katsunori Mizuno
With the goal of achieving clean energy and green transition, offshore wind farms (OWFs) have been rapidly established worldwide. The underwater pile foundations in OWFs have shown potential to serve as artificial reefs. To explore the ecological benefits in subtropical ecosystems, fish distributions were investigated at selected sites: two OWFs, a nearby natural reef, and a shipwreck reef. A low-cost optical method was developed to collect fish data, followed by deep learning techniques to identify four target species from underwater videos. To reconstruct distribution patterns from the sea surface to the bottom, fish densities were calculated along the recording path based on the camera view. In the OWFs, fish aggregation was confirmed by the high densities of round scad (0.025–0.26 per m) and spinefoot (0.052–0.15 per m). The target fish groups were observed near the individual wind turbine foundations throughout the entire vertical water column, with higher aggregation in the mid-water layers. Black scrapers exhibited the highest density at the shipwreck reef (0.024 per m). Damselfish were dominant at the natural reef area (0.055–0.14 per m); however, they were rarely found at the nearby OWF or shipwreck reef, indicating that the ecological function of artificial reefs may not fully cover that of natural reefs. Multiple regression analysis showed that the fish may exhibit specific preferences for structural features and environmental variables. This study provides insights into potential fish distributions to inform local managers and fishing enthusiasts, while supporting sustainable OWF development and contributing to marine conservation efforts.
{"title":"Investigating potential fish distributions in artificial and natural reefs using an optical method: Insights from subtropical offshore wind farms","authors":"Jialu Wang, Shigeru Tabeta, Katsunori Mizuno","doi":"10.1016/j.fishres.2025.107536","DOIUrl":"10.1016/j.fishres.2025.107536","url":null,"abstract":"<div><div>With the goal of achieving clean energy and green transition, offshore wind farms (OWFs) have been rapidly established worldwide. The underwater pile foundations in OWFs have shown potential to serve as artificial reefs. To explore the ecological benefits in subtropical ecosystems, fish distributions were investigated at selected sites: two OWFs, a nearby natural reef, and a shipwreck reef. A low-cost optical method was developed to collect fish data, followed by deep learning techniques to identify four target species from underwater videos. To reconstruct distribution patterns from the sea surface to the bottom, fish densities were calculated along the recording path based on the camera view. In the OWFs, fish aggregation was confirmed by the high densities of round scad (0.025–0.26 per m<span><math><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span>) and spinefoot (0.052–0.15 per m<span><math><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span>). The target fish groups were observed near the individual wind turbine foundations throughout the entire vertical water column, with higher aggregation in the mid-water layers. Black scrapers exhibited the highest density at the shipwreck reef (0.024 per m<span><math><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span>). Damselfish were dominant at the natural reef area (0.055–0.14 per m<span><math><msup><mrow></mrow><mrow><mn>3</mn></mrow></msup></math></span>); however, they were rarely found at the nearby OWF or shipwreck reef, indicating that the ecological function of artificial reefs may not fully cover that of natural reefs. Multiple regression analysis showed that the fish may exhibit specific preferences for structural features and environmental variables. This study provides insights into potential fish distributions to inform local managers and fishing enthusiasts, while supporting sustainable OWF development and contributing to marine conservation efforts.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"291 ","pages":"Article 107536"},"PeriodicalIF":2.3,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-03DOI: 10.1016/j.fishres.2025.107542
Vinaya Kumar Vase, Rajan Kumar, Shikha Rahangdale, A. Azeez, G. Jaysree, S. Vipul, Jayasankar Jayaraman, P.U. Zacharia
The study offers a detailed assessment of the vulnerability of marine fishery resources along the Gujarat coast using the Productivity and Susceptibility Analysis (PSA) approach. A total of 37 species, including pelagic (9), demersal (12) finfish, elasmobranch (2), shrimp (6), crabs/lobsters (3), and cephalopods (5), were evaluated based on their productivity and susceptibility to fishing pressures. The modified PSA (m-PSA) method included 10 productivity and 12 susceptibility attributes, with species vulnerability scores calculated using Euclidean distance. Results show a broad range of Vulnerability Index (VI), with species like Sepia elliptica (1.03) and Sepia pharaonis (1.12) classified as low vulnerable, reflecting their resilience due to high productivity and lower susceptibility. Conversely, species such as Panulirus polyphagus (1.97) and Rhinobatos annandalei (2.2) are highly vulnerable, mainly because of their lower growth rates and increased fishing pressure. The study highlights a general trend of moderate to high susceptibility among many species, especially those with slower reproductive cycles or high commercial value. Cephalopods show higher resilience with their short life cycles, while long-lived species, particularly elasmobranchs, are more susceptible to overexploitation. The findings emphasize the importance of adaptive management strategies, including species-specific conservation measures, periodic stock assessments, and catch limits to mitigate risks. The analysis also underlines the importance of protecting critical habitats to sustain fishery resources and the marine ecosystem. Overall, this study provides valuable insights into the vulnerability of key marine species in Gujarat, stressing the urgent need for customized management approaches to ensure the long-term sustainability of the region’s fisheries and the livelihoods dependent on them.
{"title":"Evaluating the status of marine fishery resources along the Gujarat coast of India: A productivity and susceptibility analysis","authors":"Vinaya Kumar Vase, Rajan Kumar, Shikha Rahangdale, A. Azeez, G. Jaysree, S. Vipul, Jayasankar Jayaraman, P.U. Zacharia","doi":"10.1016/j.fishres.2025.107542","DOIUrl":"10.1016/j.fishres.2025.107542","url":null,"abstract":"<div><div>The study offers a detailed assessment of the vulnerability of marine fishery resources along the Gujarat coast using the Productivity and Susceptibility Analysis (PSA) approach. A total of 37 species, including pelagic (9), demersal (12) finfish, elasmobranch (2), shrimp (6), crabs/lobsters (3), and cephalopods (5), were evaluated based on their productivity and susceptibility to fishing pressures. The modified PSA (m-PSA) method included 10 productivity and 12 susceptibility attributes, with species vulnerability scores calculated using Euclidean distance. Results show a broad range of Vulnerability Index (VI), with species like <em>Sepia elliptica</em> (1.03) and <em>Sepia pharaonis</em> (1.12) classified as low vulnerable, reflecting their resilience due to high productivity and lower susceptibility. Conversely, species such as <em>Panulirus polyphagus</em> (1.97) and <em>Rhinobatos annandalei</em> (2.2) are highly vulnerable, mainly because of their lower growth rates and increased fishing pressure. The study highlights a general trend of moderate to high susceptibility among many species, especially those with slower reproductive cycles or high commercial value. Cephalopods show higher resilience with their short life cycles, while long-lived species, particularly elasmobranchs, are more susceptible to overexploitation. The findings emphasize the importance of adaptive management strategies, including species-specific conservation measures, periodic stock assessments, and catch limits to mitigate risks. The analysis also underlines the importance of protecting critical habitats to sustain fishery resources and the marine ecosystem. Overall, this study provides valuable insights into the vulnerability of key marine species in Gujarat, stressing the urgent need for customized management approaches to ensure the long-term sustainability of the region’s fisheries and the livelihoods dependent on them.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"291 ","pages":"Article 107542"},"PeriodicalIF":2.3,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-03DOI: 10.1016/j.fishres.2025.107548
Huihui Zhang , Chunde Zhao , Jintao Wang , Xinjun Chen , Lin Lei
Habitat Suitability Index (HSI) models are widely used in wildlife management to assess species-environment relationships and inform conservation strategies. However, traditional HSI models often rely on simplistic weighting schemes that may inadequately capture the complexities of species-habitat interactions, particularly under climate change. This study presents an enhanced HSI model that addresses these limitations by integrating multicollinearity analysis to exclude highly correlated variables and applying a Random Forest (RF) for variable selection and weighting. The model was validated using datasets from the Northwest Pacific Ommastrephes bartramii and Southwest Atlantic Illex argentinus fisheries. Results show the proposed model significantly outperforms conventional approaches in predicting species distribution, with improved precision and the identification of key environmental drivers. This refined HSI model would offer greater interpretability, supporting more informed decision-making in marine spatial planning and fisheries management.
{"title":"Designing of high-performance species habitat suitability index model","authors":"Huihui Zhang , Chunde Zhao , Jintao Wang , Xinjun Chen , Lin Lei","doi":"10.1016/j.fishres.2025.107548","DOIUrl":"10.1016/j.fishres.2025.107548","url":null,"abstract":"<div><div>Habitat Suitability Index (HSI) models are widely used in wildlife management to assess species-environment relationships and inform conservation strategies. However, traditional HSI models often rely on simplistic weighting schemes that may inadequately capture the complexities of species-habitat interactions, particularly under climate change. This study presents an enhanced HSI model that addresses these limitations by integrating multicollinearity analysis to exclude highly correlated variables and applying a Random Forest (RF) for variable selection and weighting. The model was validated using datasets from the Northwest Pacific <em>Ommastrephes bartramii</em> and Southwest Atlantic <em>Illex argentinus</em> fisheries. Results show the proposed model significantly outperforms conventional approaches in predicting species distribution, with improved precision and the identification of key environmental drivers. This refined HSI model would offer greater interpretability, supporting more informed decision-making in marine spatial planning and fisheries management.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"291 ","pages":"Article 107548"},"PeriodicalIF":2.3,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-02DOI: 10.1016/j.fishres.2025.107544
İdris TURNA , Orkun Burak ÖZTÜRK , Şaban Emre KARTAL , Ahmet Emre PİRİM , Zafer KURT , Murat YAYLACI
The growing popularity of recreational boating—fuelled by the promotion of boating and fishing experiences on social media - has led to a significant increase in boat purchases and maritime activities. However, many of these amateur fishers or boaters possess limited knowledge of the potential risks they may encounter while operating a boat. These risks must be addressed to ensure safe and sustainable boating activities. This study aims to evaluate and quantitatively assess the potential allision risks faced by sailors by integrating Fuzzy Bayesian Networks (FBN) with the Finite Element Method (FEM). The proposed approach is intended to identify the most influential risk factors, measure their relative impacts, and provide a systematic framework to support risk-informed decision-making in maritime safety management. The findings of the research conducted using the FBN method indicate that the two most significant root causes of accidents are sobriety and lack of experience. Furthermore, the FEM analysis demonstrated that fiberglass boats experienced higher stress and displacement under impact than oakwood boats. The implementation of these approaches facilitates enhanced risk management strategies for recreational boaters and operational guidelines for regulatory authorities and the fishing community. By promoting awareness and adherence to these guidelines, it is possible to significantly reduce the risks associated with recreational boating activities.
{"title":"Allision risk and impact analysis in recreational fishing boats using fuzzy bayesian networks and the finite element method","authors":"İdris TURNA , Orkun Burak ÖZTÜRK , Şaban Emre KARTAL , Ahmet Emre PİRİM , Zafer KURT , Murat YAYLACI","doi":"10.1016/j.fishres.2025.107544","DOIUrl":"10.1016/j.fishres.2025.107544","url":null,"abstract":"<div><div>The growing popularity of recreational boating—fuelled by the promotion of boating and fishing experiences on social media - has led to a significant increase in boat purchases and maritime activities. However, many of these amateur fishers or boaters possess limited knowledge of the potential risks they may encounter while operating a boat. These risks must be addressed to ensure safe and sustainable boating activities. This study aims to evaluate and quantitatively assess the potential allision risks faced by sailors by integrating Fuzzy Bayesian Networks (FBN) with the Finite Element Method (FEM). The proposed approach is intended to identify the most influential risk factors, measure their relative impacts, and provide a systematic framework to support risk-informed decision-making in maritime safety management. The findings of the research conducted using the FBN method indicate that the two most significant root causes of accidents are sobriety and lack of experience. Furthermore, the FEM analysis demonstrated that fiberglass boats experienced higher stress and displacement under impact than oakwood boats. The implementation of these approaches facilitates enhanced risk management strategies for recreational boaters and operational guidelines for regulatory authorities and the fishing community. By promoting awareness and adherence to these guidelines, it is possible to significantly reduce the risks associated with recreational boating activities.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"291 ","pages":"Article 107544"},"PeriodicalIF":2.3,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145226973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-27DOI: 10.1016/j.fishres.2025.107540
Ryan W. Schloesser, Nathan P. Brennan, Paula Caldentey, Kenneth M. Leber
Research on stock enhancement of Common Snook Centropomus undecimalis in southwest Florida has recently prioritized using passive integrated transponder (PIT) tags to monitor released fish. Autonomous antenna arrays deployed around release sites allowed for continuous sampling of PIT tagged fish, increasing post-release observations to estimate survival and establish best practices. A series of 25 iterative stocking experiments from 2015 to 2023 have generated data on 333 unique release groups (mean sizes = 112–287 mm FL) spanning a suite of stocking times, locations, and protocols. Stocking experiments were conducted with 45,958 juveniles, with ∼65 % being PIT tagged (100 % tagged for replicated studies and 10 % for larger, one-time releases). Mark-recapture models regularly indicated that survival is high and constant around 35 days post-release, providing a consistent point in time to assess experimental impacts. The diversity of stocking efforts resulted in survival rates to day 35 ranging from 0 % to 50.9 % of individuals. A step-wise modeling approach examined the spatial, temporal, and procedural factors for each unique release group to identify best practices with the goal of > 20 % survival to day 35, which occurred for 68 release groups. Although low-surviving groups (<10 %) can occur at any time, many were anecdotally associated with experimental designs with high-handling or stressful environmental times. We determined best practices for stocking Snook in southwest Florida to be releasing large juveniles into the mouth, lower, or middle reaches of tidal creeks in May, June, or September, using acclimation cages when stocking into locations considered to be high predation risk or environmentally stressful, and waiting an additional year between releases following a high-survival stocking event.
{"title":"Best practices for common snook stock enhancement identified through iterative release experiments","authors":"Ryan W. Schloesser, Nathan P. Brennan, Paula Caldentey, Kenneth M. Leber","doi":"10.1016/j.fishres.2025.107540","DOIUrl":"10.1016/j.fishres.2025.107540","url":null,"abstract":"<div><div>Research on stock enhancement of Common Snook <em>Centropomus undecimalis</em> in southwest Florida has recently prioritized using passive integrated transponder (PIT) tags to monitor released fish. Autonomous antenna arrays deployed around release sites allowed for continuous sampling of PIT tagged fish, increasing post-release observations to estimate survival and establish best practices. A series of 25 iterative stocking experiments from 2015 to 2023 have generated data on 333 unique release groups (mean sizes = 112–287 mm FL) spanning a suite of stocking times, locations, and protocols. Stocking experiments were conducted with 45,958 juveniles, with ∼65 % being PIT tagged (100 % tagged for replicated studies and 10 % for larger, one-time releases). Mark-recapture models regularly indicated that survival is high and constant around 35 days post-release, providing a consistent point in time to assess experimental impacts. The diversity of stocking efforts resulted in survival rates to day 35 ranging from 0 % to 50.9 % of individuals. A step-wise modeling approach examined the spatial, temporal, and procedural factors for each unique release group to identify best practices with the goal of > 20 % survival to day 35, which occurred for 68 release groups. Although low-surviving groups (<10 %) can occur at any time, many were anecdotally associated with experimental designs with high-handling or stressful environmental times. We determined best practices for stocking Snook in southwest Florida to be releasing large juveniles into the mouth, lower, or middle reaches of tidal creeks in May, June, or September, using acclimation cages when stocking into locations considered to be high predation risk or environmentally stressful, and waiting an additional year between releases following a high-survival stocking event.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"291 ","pages":"Article 107540"},"PeriodicalIF":2.3,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-26DOI: 10.1016/j.fishres.2025.107539
Steven W. Purcell , Lea A.F. Djenidi , Hugo Denis , Florian Baletaud , Antoine Gilbert
Growth rates and life-history parameters of marine animals underpin conservation planning and fishery harvest strategies yet are unknown for most sea cucumbers. The white teatfish Holothuria (Microthele) fuscogilva, a high-value species, is widely harvested and listed on CITES Appendix II. We used a photographic mark−recapture method to measure growth of wild white teatfish in New Caledonia. Ex situ measurements of the animals weakly corresponded with their in situ measurements. Bidimensional metrics of body size using ex situ measures provided the most reliable predictions of body weight. Length−weight relationships for H. fuscogilva varied greatly among data from New Caledonia, French Polynesia, Torres Strait (Australia) and the Coral Sea. Of 67 animals photographically marked, seven were recaptured 13 months later. Growth averaged 220 g (total whole weight) or 1.4 cm (total length) per individual. We modelled growth using the Electronic Length Frequency Analysis (ELEFAN) routine using data of all captured animals. The growth coefficient (K) was estimated at 0.082 y−1 and natural mortality rate (M) was approximated at 0.19 y−1. Age-at-first-sexual-maturity was estimated at 15−23 years and longevity at 57 years. While the modelling deserves caution, the data overall suggest that H. fuscogilva is a slow-growing species with a considerable lifespan. Management and conservation measures for teatfish sea cucumbers (subgenus Microthele) should be highly conservative in light of their vulnerable life-history traits.
{"title":"Growth and life-history parameters of the high-value sea cucumber, Holothuria fuscogilva","authors":"Steven W. Purcell , Lea A.F. Djenidi , Hugo Denis , Florian Baletaud , Antoine Gilbert","doi":"10.1016/j.fishres.2025.107539","DOIUrl":"10.1016/j.fishres.2025.107539","url":null,"abstract":"<div><div>Growth rates and life-history parameters of marine animals underpin conservation planning and fishery harvest strategies yet are unknown for most sea cucumbers. The white teatfish <em>Holothuria</em> (<em>Microthele</em>) <em>fuscogilva</em>, a high-value species, is widely harvested and listed on CITES Appendix II. We used a photographic mark−recapture method to measure growth of wild white teatfish in New Caledonia. <em>Ex situ</em> measurements of the animals weakly corresponded with their <em>in situ</em> measurements. Bidimensional metrics of body size using <em>ex situ</em> measures provided the most reliable predictions of body weight. Length−weight relationships for <em>H. fuscogilva</em> varied greatly among data from New Caledonia, French Polynesia, Torres Strait (Australia) and the Coral Sea. Of 67 animals photographically marked, seven were recaptured 13 months later. Growth averaged 220 g (total whole weight) or 1.4 cm (total length) per individual. We modelled growth using the Electronic Length Frequency Analysis (ELEFAN) routine using data of all captured animals. The growth coefficient (<em>K</em>) was estimated at 0.082 y<sup>−1</sup> and natural mortality rate (<em>M</em>) was approximated at 0.19 y<sup>−1</sup>. Age-at-first-sexual-maturity was estimated at 15−23 years and longevity at 57 years. While the modelling deserves caution, the data overall suggest that <em>H. fuscogilva</em> is a slow-growing species with a considerable lifespan. Management and conservation measures for teatfish sea cucumbers (subgenus <em>Microthele</em>) should be highly conservative in light of their vulnerable life-history traits.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"291 ","pages":"Article 107539"},"PeriodicalIF":2.3,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-26DOI: 10.1016/j.fishres.2025.107541
Nathan E. Hebert , Timothy J. Barrett , Julie R. Marentette , François Turcotte , Brad Hubley
Providing science advice for fisheries management generally involves estimating reference points, commonly defined in terms of a proportion of the biomass at maximum sustainable yield or unfished biomass. These reference points assume a population in equilibrium, a premise frequently challenged by the time-varying productivity observed in many fish stocks. Reference points can serve as control points in harvest control rules (HCRs) and as indicators of stock status that can trigger a rebuilding plan. The guidance for addressing time-varying productivity varies among jurisdictions (e.g., using mean productivity over a time series or recent productivity only). Fisheries and Oceans Canada (DFO) has recently identified a need for further research on time-varying reference points before providing policy guidance for use in fisheries management. In this study, we describe how individual components of productivity influence reference points using three generalized fish life-histories. We also assess the impact of alternative approaches (i.e., static vs. time-varying) to defining reference points on implied stock status (using the DFO status categories of critical, cautious, and healthy) and management advice using reference points as control points in HCRs. Using a static limit reference point (LRP) to operationalize DFO’s objective to avoid serious harm to stock productivity, we evaluate the performance of various HCRs under time-varying productivity, with control points defined via different productivity scenarios. We identify an HCR with a static biomass lower control point and a dynamic fishing mortality upper control point that has relatively high yields while maintaining a high probability of keeping the stock above the LRP. This HCR performs well across both increasing and decreasing productivity scenarios. An HCR with control points based only on recent productivity performed well under decreasing productivity only when stock biomass didn’t fall far below the LRP. We show that perceived stock status can vary from critical to healthy in a given year, depending on choice of productivity period used to define stock status reference points, implying that careful selection of such reference points is needed. There can be risks to using policy default approaches based solely on recent productivity when productivity is decreasing over time.
{"title":"Influence of time-varying productivity on fishery reference points and implications for conservation objectives and management advice","authors":"Nathan E. Hebert , Timothy J. Barrett , Julie R. Marentette , François Turcotte , Brad Hubley","doi":"10.1016/j.fishres.2025.107541","DOIUrl":"10.1016/j.fishres.2025.107541","url":null,"abstract":"<div><div>Providing science advice for fisheries management generally involves estimating reference points, commonly defined in terms of a proportion of the biomass at maximum sustainable yield or unfished biomass. These reference points assume a population in equilibrium, a premise frequently challenged by the time-varying productivity observed in many fish stocks. Reference points can serve as control points in harvest control rules (HCRs) and as indicators of stock status that can trigger a rebuilding plan. The guidance for addressing time-varying productivity varies among jurisdictions (e.g., using mean productivity over a time series or recent productivity only). Fisheries and Oceans Canada (DFO) has recently identified a need for further research on time-varying reference points before providing policy guidance for use in fisheries management. In this study, we describe how individual components of productivity influence reference points using three generalized fish life-histories. We also assess the impact of alternative approaches (i.e., static vs. time-varying) to defining reference points on implied stock status (using the DFO status categories of critical, cautious, and healthy) and management advice using reference points as control points in HCRs. Using a static limit reference point (LRP) to operationalize DFO’s objective to avoid serious harm to stock productivity, we evaluate the performance of various HCRs under time-varying productivity, with control points defined via different productivity scenarios. We identify an HCR with a static biomass lower control point and a dynamic fishing mortality upper control point that has relatively high yields while maintaining a high probability of keeping the stock above the LRP. This HCR performs well across both increasing and decreasing productivity scenarios. An HCR with control points based only on recent productivity performed well under decreasing productivity only when stock biomass didn’t fall far below the LRP. We show that perceived stock status can vary from critical to healthy in a given year, depending on choice of productivity period used to define stock status reference points, implying that careful selection of such reference points is needed. There can be risks to using policy default approaches based solely on recent productivity when productivity is decreasing over time.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"291 ","pages":"Article 107541"},"PeriodicalIF":2.3,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-23DOI: 10.1016/j.fishres.2025.107538
Yu-Ling Nien , Nan-Jay Su , Ching-Ping Lu , Hsueh-Jung Lu , Chia-Hui Wang
This study investigates the impact of ENSO on the species composition and growth during the early-life history of three cryptic mullet species (NWP1–3) in the estuaries around Taiwan. Juvenile mullets were identified using genetic method, and their growth rates were analyzed using generalized additive models (GAMs) based on biological and environmental variables. The results found that NWP2 was the most abundant species, dominating several months and estuaries. NWP1 had lower abundance than NWP2, but its proportion was relatively higher in La Niña and rarer in El Niño. NWP3 exhibited the lowest abundance, but expanded spatially during El Niño. Moreover, the growth of juvenile mullet was influenced by multiple factors annually, especially sea surface temperature (SST) and drifting growth rate (DGR). The environmental changes induced by ENSO and species-specific traits simultaneously impact both the distribution and growth patterns of cryptic mullet species. Both these factors directly influence species composition and indirectly affect species abundance by modifying growth and mortality rates. Consequently, lower SST during La Niña year benefited the abundance and growth of NWP1, while higher SST during El Niño year benefited NWP3 population. Although NWP2 maintained high abundance annually, rising SST may impact the growth of this species. These findings underscore the critical role of interannual environmental variability in regulating the distribution, abundance, and growth during the early life stages of cryptic mullet species in subtropical estuarine systems.
{"title":"The effects of ENSO on spatial-temporal distribution and growth rate of three cryptic mullet species in Taiwan","authors":"Yu-Ling Nien , Nan-Jay Su , Ching-Ping Lu , Hsueh-Jung Lu , Chia-Hui Wang","doi":"10.1016/j.fishres.2025.107538","DOIUrl":"10.1016/j.fishres.2025.107538","url":null,"abstract":"<div><div>This study investigates the impact of ENSO on the species composition and growth during the early-life history of three cryptic mullet species (NWP1–3) in the estuaries around Taiwan. Juvenile mullets were identified using genetic method, and their growth rates were analyzed using generalized additive models (GAMs) based on biological and environmental variables. The results found that NWP2 was the most abundant species, dominating several months and estuaries. NWP1 had lower abundance than NWP2, but its proportion was relatively higher in La Niña and rarer in El Niño. NWP3 exhibited the lowest abundance, but expanded spatially during El Niño. Moreover, the growth of juvenile mullet was influenced by multiple factors annually, especially sea surface temperature (SST) and drifting growth rate (DGR). The environmental changes induced by ENSO and species-specific traits simultaneously impact both the distribution and growth patterns of cryptic mullet species. Both these factors directly influence species composition and indirectly affect species abundance by modifying growth and mortality rates. Consequently, lower SST during La Niña year benefited the abundance and growth of NWP1, while higher SST during El Niño year benefited NWP3 population. Although NWP2 maintained high abundance annually, rising SST may impact the growth of this species. These findings underscore the critical role of interannual environmental variability in regulating the distribution, abundance, and growth during the early life stages of cryptic mullet species in subtropical estuarine systems.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"291 ","pages":"Article 107538"},"PeriodicalIF":2.3,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fatty acid compositions of chum salmon (Oncorhynchus keta) fry were examined to distinguish between hatchery and wild fish in natural environments. Levels (%) of 18:2n-6 (linoleic acid) were significantly higher in fry obtained from a hatchery (13.0 %) than in wild fry collected in a river (2.1 %). Conversely, levels of 20:5n-3 (eicosapentaenoic acid; EPA) were significantly lower in the former (4.2 %) than in the latter (11.4 %). Differences in the levels of the two fatty acids between artificial pellets and wild fry stomach contents suggest that dietary differences caused the observed differences in fry fatty acid composition. The levels of 18:2n-6 and 20:5n-3 in hatchery fry collected in coastal waters decreased and increased, respectively, within days after stocking in the river. Furthermore, the levels became similar to those of riverine wild fry by approximately 20 days after stocking. These results indicate that the two fatty acids can be used to distinguish between hatchery and wild chum salmon fry in the natural environment. However, the period during which the two can be distinguished is limited.
{"title":"The use of fatty acid markers to distinguish hatchery and wild chum salmon fry and a description of post-stocking changes in fatty acid levels","authors":"Yutaka Yano, Koh Hasegawa, Kentaro Honda, Yuhei Ogura","doi":"10.1016/j.fishres.2025.107537","DOIUrl":"10.1016/j.fishres.2025.107537","url":null,"abstract":"<div><div>Fatty acid compositions of chum salmon (<em>Oncorhynchus keta</em>) fry were examined to distinguish between hatchery and wild fish in natural environments. Levels (%) of 18:2n-6 (linoleic acid) were significantly higher in fry obtained from a hatchery (13.0 %) than in wild fry collected in a river (2.1 %). Conversely, levels of 20:5n-3 (eicosapentaenoic acid; EPA) were significantly lower in the former (4.2 %) than in the latter (11.4 %). Differences in the levels of the two fatty acids between artificial pellets and wild fry stomach contents suggest that dietary differences caused the observed differences in fry fatty acid composition. The levels of 18:2n-6 and 20:5n-3 in hatchery fry collected in coastal waters decreased and increased, respectively, within days after stocking in the river. Furthermore, the levels became similar to those of riverine wild fry by approximately 20 days after stocking. These results indicate that the two fatty acids can be used to distinguish between hatchery and wild chum salmon fry in the natural environment. However, the period during which the two can be distinguished is limited.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"291 ","pages":"Article 107537"},"PeriodicalIF":2.3,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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