Pub Date : 2025-12-13DOI: 10.1016/j.fishres.2025.107631
Andre E. Punt , Paul Burch , Kristin M. Privitera-Johnson , Pia Bessell-Browne , Geoffrey N. Tuck
Natural mortality (M) is a key parameter in age- and size-structured methods of fish stock assessment because estimates of biomass in absolute terms and relative to reference points are sensitive to its value. M can be pre-specified based on “indirect” methods, estimated with a prior, or estimated without a prior. However, there is an absence of best practice guidelines for how to treat M within stock assessments. Five alternative broad categories of methods for treating M in stock assessments (unconstrained estimation, estimation with a prior, the “lowest plausible” and “highest plausible” values based on indirect methods, and the results of the Hamel-Amax indirect method) are compared for ten stocks in Australia’s Southern and Eastern Scalefish and Shark Fishery using likelihood profiles, retrospective analyses and hindcast skill. There is no method that performs best in all cases. However, the results support a proposed best practice where estimation with a prior should be the default unless evidence such as diagnostics suggests that the population dynamics or the observation model is clearly and substantially mis-specified (e.g., an estimate of M that differs markedly from the mean of a prior based on longevity information) such that estimates of management-related quantities will likely be appreciably in error. It is also appropriate to conduct sensitivity analyses and use decision tables to highlight the effects of incorrectly assumed values of M when substantial mis-specification appears to be present and M is pre-specified using a longevity-based method.
{"title":"Comparison of treatments of natural mortality in integrated assessment models, with reference to fish stocks off southeast Australia: Towards best practices for estimation","authors":"Andre E. Punt , Paul Burch , Kristin M. Privitera-Johnson , Pia Bessell-Browne , Geoffrey N. Tuck","doi":"10.1016/j.fishres.2025.107631","DOIUrl":"10.1016/j.fishres.2025.107631","url":null,"abstract":"<div><div>Natural mortality (<em>M</em>) is a key parameter in age- and size-structured methods of fish stock assessment because estimates of biomass in absolute terms and relative to reference points are sensitive to its value. <em>M</em> can be pre-specified based on “indirect” methods, estimated with a prior, or estimated without a prior. However, there is an absence of best practice guidelines for how to treat <em>M</em> within stock assessments. Five alternative broad categories of methods for treating <em>M</em> in stock assessments (unconstrained estimation, estimation with a prior, the “lowest plausible” and “highest plausible” values based on indirect methods, and the results of the Hamel-Amax indirect method) are compared for ten stocks in Australia’s Southern and Eastern Scalefish and Shark Fishery using likelihood profiles, retrospective analyses and hindcast skill. There is no method that performs best in all cases. However, the results support a proposed best practice where estimation with a prior should be the default unless evidence such as diagnostics suggests that the population dynamics or the observation model is clearly and substantially mis-specified (e.g., an estimate of <em>M</em> that differs markedly from the mean of a prior based on longevity information) such that estimates of management-related quantities will likely be appreciably in error. It is also appropriate to conduct sensitivity analyses and use decision tables to highlight the effects of incorrectly assumed values of <em>M</em> when substantial mis-specification appears to be present and <em>M</em> is pre-specified using a longevity-based method.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107631"},"PeriodicalIF":2.3,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790732","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 : 2025-12-12DOI: 10.1016/j.fishres.2025.107626
Michael A. Spence, Thomas I.J. Bartos, Michael J. Thomson, Robert B. Thorpe
Many jurisdictions have a legal requirement to manage fish stocks at maximum sustainable yield (MSY), while following the precautionary approach (PA). Generally, MSY is calculated on a single-species basis; however, due to species interactions, there is no guarantee that fishing multiple stocks at their precautionary single-species MSY level will lead to all stocks being precautionary or even at fished MSY. This suggests the necessity of a multispecies MSY (MMSY). Although there are several definitions of MMSY, there is no agreed best definition. At least two approaches have been suggested, firstly a community maximum yield, either with or without integrated risk measures designed to prevent stock-depletion, and secondly, defining MMSY in terms of a set of simultaneous single-species MSYs. Here we adopt the second interpretation which allows for the implementation of MMSY without requiring new concepts when combined with multispecies PA to safeguard stock structure. We extend single-species definitions of MSY and PA to give two potential definitions of precautionary MMSY. In the first we constrain the search for MMSY to fishing mortalities that follow the multispecies PA and in the second we find the closest fishing mortality that follows the multispecies PA to the unconstrained MMSY. We demonstrate these definitions using a case study of 9 stocks in the North Sea and compare them with single-species and non-precautionary equivalents. We propose that the second definition be precautionary MMSY as it is more robust than the first.
{"title":"Extending single-species maximum sustainable yield and precautionary approaches to account for species interactions","authors":"Michael A. Spence, Thomas I.J. Bartos, Michael J. Thomson, Robert B. Thorpe","doi":"10.1016/j.fishres.2025.107626","DOIUrl":"10.1016/j.fishres.2025.107626","url":null,"abstract":"<div><div>Many jurisdictions have a legal requirement to manage fish stocks at maximum sustainable yield (MSY), while following the precautionary approach (PA). Generally, MSY is calculated on a single-species basis; however, due to species interactions, there is no guarantee that fishing multiple stocks at their precautionary single-species MSY level will lead to all stocks being precautionary or even at fished MSY. This suggests the necessity of a multispecies MSY (MMSY). Although there are several definitions of MMSY, there is no agreed best definition. At least two approaches have been suggested, firstly a community maximum yield, either with or without integrated risk measures designed to prevent stock-depletion, and secondly, defining MMSY in terms of a set of simultaneous single-species MSYs. Here we adopt the second interpretation which allows for the implementation of MMSY without requiring new concepts when combined with multispecies PA to safeguard stock structure. We extend single-species definitions of MSY and PA to give two potential definitions of precautionary MMSY. In the first we constrain the search for MMSY to fishing mortalities that follow the multispecies PA and in the second we find the closest fishing mortality that follows the multispecies PA to the unconstrained MMSY. We demonstrate these definitions using a case study of 9 stocks in the North Sea and compare them with single-species and non-precautionary equivalents. We propose that the second definition be precautionary MMSY as it is more robust than the first.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107626"},"PeriodicalIF":2.3,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737712","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 : 2025-12-12DOI: 10.1016/j.fishres.2025.107629
Rachel L. Dixon, Mary C. Fabrizio, Piero L.F. Mazzini, Robert J. Latour
Contemporary fishery management approaches do not fully account for the spatial structuring evident in many populations. Yet, synchrony in recruitment among intrapopulation components may afford insights on population productivity and inform future management efforts. The coastal population of Atlantic striped bass (Morone saxatilis) is comprised of individuals from multiple distinct estuarine nurseries along the east coast of the United States, including Chesapeake Bay, Delaware River, and the Hudson River. The relative contribution of each producing area to the coastal population fluctuates annually, but the link between variable regional recruitment and the dynamics of the coastal population remains unexplored. Fishery-independent catch data of age-0 striped bass were used to generate time series of recruitment from each producing area from 1983 to 2021. Dynamic factor analysis was applied to identify common trends and the level of synchrony in recruitments, and investigate biotic and abiotic factors hypothesized to impact year-class strength and production in this species. Time series of recruitments were best represented by multiple common trends, highlighting asynchronous patterns in recruitment from individual producing areas. Two climate signals, the winter index of the North Atlantic Oscillation and marine heatwaves in the coastal ocean, had the largest impact on the observed patterns in recruitment. Differential production among individual producing areas may have conferred historical stability to the coastal population, but shared responses to broad scale stressors may indicate reduced resilience to climate impacts.
{"title":"Climate change threatens stability conferred by asynchronous coastwide recruitment of Atlantic striped bass, Morone saxatilis","authors":"Rachel L. Dixon, Mary C. Fabrizio, Piero L.F. Mazzini, Robert J. Latour","doi":"10.1016/j.fishres.2025.107629","DOIUrl":"10.1016/j.fishres.2025.107629","url":null,"abstract":"<div><div>Contemporary fishery management approaches do not fully account for the spatial structuring evident in many populations. Yet, synchrony in recruitment among intrapopulation components may afford insights on population productivity and inform future management efforts. The coastal population of Atlantic striped bass (<em>Morone saxatilis</em>) is comprised of individuals from multiple distinct estuarine nurseries along the east coast of the United States, including Chesapeake Bay, Delaware River, and the Hudson River. The relative contribution of each producing area to the coastal population fluctuates annually, but the link between variable regional recruitment and the dynamics of the coastal population remains unexplored. Fishery-independent catch data of age-0 striped bass were used to generate time series of recruitment from each producing area from 1983 to 2021. Dynamic factor analysis was applied to identify common trends and the level of synchrony in recruitments, and investigate biotic and abiotic factors hypothesized to impact year-class strength and production in this species. Time series of recruitments were best represented by multiple common trends, highlighting asynchronous patterns in recruitment from individual producing areas. Two climate signals, the winter index of the North Atlantic Oscillation and marine heatwaves in the coastal ocean, had the largest impact on the observed patterns in recruitment. Differential production among individual producing areas may have conferred historical stability to the coastal population, but shared responses to broad scale stressors may indicate reduced resilience to climate impacts.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107629"},"PeriodicalIF":2.3,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737710","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 : 2025-12-11DOI: 10.1016/j.fishres.2025.107630
Antoni Quetglas, Aina de Mesa, Beatriz Guijarro, Enric Massutí, Francesc Ordinas, Núria Zaragoza, Maria Valls
In the Mediterranean, the squids Loligo vulgaris (LV) and L. forbesii (LF) are important fishing resources with high economic value, especially for the bottom trawl fishery. LV also constitutes an important target species for recreational and small-scale fisheries. In this work, several life-history traits (population structure, reproduction, condition), the bathymetric distribution and the fishery of these two squids were analysed using data collected during the last 20 years in the Western Mediterranean. The highest frequency of appearance was at 50–100 m depth for LV and at 200–350 m for LF. The overlap between the two squids was low, since they only co-occurred in 5 % of the sampling stations performed at their shared strata (50–200 m). The mean squid size and the percentage of mature individuals increased with depth in both species, pointing to an ontogenetic migration related to reproduction. In LF, females outnumbered males at 300–400 m, which might indicate that these are preferential spawning grounds. While reproduction of LV occurs all year round, it is mainly concentrated in a semester in LF. In the study area, where both species are sold together in a single commercial category, landings come from bottom trawl (66 %), small-scale (20 %), and purse-seine (14 %) fisheries. The catch per unit effort during the last 55 years showed a decreasing trend (1975–1998) followed by an increasing trend (1998–2023) as a result of important fishing effort variations. Squid landings were separated by species using fleet segmentation tools, which showed that the bulk of landings (84 %) belonged to LV.
{"title":"Life history and fishery of two sympatric squid species (Loligo vulgaris and L. forbesii) from the Western Mediterranean","authors":"Antoni Quetglas, Aina de Mesa, Beatriz Guijarro, Enric Massutí, Francesc Ordinas, Núria Zaragoza, Maria Valls","doi":"10.1016/j.fishres.2025.107630","DOIUrl":"10.1016/j.fishres.2025.107630","url":null,"abstract":"<div><div>In the Mediterranean, the squids <em>Loligo vulgaris</em> (LV) and <em>L. forbesii</em> (LF) are important fishing resources with high economic value, especially for the bottom trawl fishery. LV also constitutes an important target species for recreational and small-scale fisheries. In this work, several life-history traits (population structure, reproduction, condition), the bathymetric distribution and the fishery of these two squids were analysed using data collected during the last 20 years in the Western Mediterranean. The highest frequency of appearance was at 50–100 m depth for LV and at 200–350 m for LF. The overlap between the two squids was low, since they only co-occurred in 5 % of the sampling stations performed at their shared strata (50–200 m). The mean squid size and the percentage of mature individuals increased with depth in both species, pointing to an ontogenetic migration related to reproduction. In LF, females outnumbered males at 300–400 m, which might indicate that these are preferential spawning grounds. While reproduction of LV occurs all year round, it is mainly concentrated in a semester in LF. In the study area, where both species are sold together in a single commercial category, landings come from bottom trawl (66 %), small-scale (20 %), and purse-seine (14 %) fisheries. The catch per unit effort during the last 55 years showed a decreasing trend (1975–1998) followed by an increasing trend (1998–2023) as a result of important fishing effort variations. Squid landings were separated by species using fleet segmentation tools, which showed that the bulk of landings (84 %) belonged to LV.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107630"},"PeriodicalIF":2.3,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737711","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 : 2025-12-09DOI: 10.1016/j.fishres.2025.107622
Víctor Sanz-Fernández , Ivone A. Czerwinski , Remedios Cabrera-Castro , Rubén Muñoz-Lechuga , Juan Carlos Gutiérrez-Estrada , Inmaculada Pulido-Calvo , Dante Queirolo
In the Gulf of Cádiz and the Alboran Sea, the common octopus (Octopus vulgaris Cuvier, 1797) represents a key economic resource for the Andalusian artisanal fleet, which employs both small-scale fishing gear and bottom trawling techniques. Due to the biological characteristics of this species, its high environmental sensitivity, and its economic importance, it is essential to implement management strategies based on accurate projections and robust models. This study analyzes monthly commercial landing data from the Andalusian Fisheries Marketing and Production Information System (IDAPES) from 2000 to 2022, combining traditional time series models (ARIMA and ETS) with machine learning algorithms (NNAR, MLP and ELM) and a deep learning architecture (LSTM) to characterize and project the fishery’s dynamics from a univariate perspective. Historically, landings have increased in both areas, with 57 % originating from the Gulf of Cádiz, where the strength of seasonality was moderate (0.4), and 43 % from the Alboran Sea, where the strength of seasonality was strong (0.7). Wavelet analysis identified variability cycles of 6 years in the Gulf of Cádiz and 7 years in the Alboran Sea. Traditional models detected trends and autoregressive patterns, while machine learning algorithms captured complex and nonlinear patterns. Regarding deep learning, the LSTM showed strong but context-dependent performance, competitive under the Alboran Sea’s stable seasonality, but not superior under the Gulf of Cádiz’s pulse-driven dynamics. One- and two-year projection scenarios revealed different dynamics. In the Gulf of Cádiz, ARIMA and ELM forecasted peak landings between November and January, whereas MLP indicated a progressive increase until November, the LSTM aligned with a moderate November–December peak. Consequently, the ensemble approach showed a pattern of higher landings from November to January, accompanied by a minor rise between June and August, followed by a gradual decline throughout the rest of the year. In the Alboran Sea, all models, along with their ensemble projection, indicated peak landings in June, followed by a decline towards the end of the year. This study highlights the effectiveness of combined approaches that integrate traditional statistical techniques with machine learning and deep learning to enhance fishery landing projections. These tools provide valuable insights for fishery strategic planning and contribute to the sustainability of one of the most economically significant marine resources in southern Spain.
{"title":"Univariate approaches for forecasting of commercial octopus (Octopus vulgaris Cuvier, 1797) landings: A comprehensive analysis of traditional time series models, machine learning algorithms and a deep learning algorithm","authors":"Víctor Sanz-Fernández , Ivone A. Czerwinski , Remedios Cabrera-Castro , Rubén Muñoz-Lechuga , Juan Carlos Gutiérrez-Estrada , Inmaculada Pulido-Calvo , Dante Queirolo","doi":"10.1016/j.fishres.2025.107622","DOIUrl":"10.1016/j.fishres.2025.107622","url":null,"abstract":"<div><div>In the Gulf of Cádiz and the Alboran Sea, the common octopus (<em>Octopus vulgaris</em> Cuvier, 1797) represents a key economic resource for the Andalusian artisanal fleet, which employs both small-scale fishing gear and bottom trawling techniques. Due to the biological characteristics of this species, its high environmental sensitivity, and its economic importance, it is essential to implement management strategies based on accurate projections and robust models. This study analyzes monthly commercial landing data from the Andalusian Fisheries Marketing and Production Information System (IDAPES) from 2000 to 2022, combining traditional time series models (ARIMA and ETS) with machine learning algorithms (NNAR, MLP and ELM) and a deep learning architecture (LSTM) to characterize and project the fishery’s dynamics from a univariate perspective. Historically, landings have increased in both areas, with 57 % originating from the Gulf of Cádiz, where the strength of seasonality was moderate (0.4), and 43 % from the Alboran Sea, where the strength of seasonality was strong (0.7). Wavelet analysis identified variability cycles of 6 years in the Gulf of Cádiz and 7 years in the Alboran Sea. Traditional models detected trends and autoregressive patterns, while machine learning algorithms captured complex and nonlinear patterns. Regarding deep learning, the LSTM showed strong but context-dependent performance, competitive under the Alboran Sea’s stable seasonality, but not superior under the Gulf of Cádiz’s pulse-driven dynamics. One- and two-year projection scenarios revealed different dynamics. In the Gulf of Cádiz, ARIMA and ELM forecasted peak landings between November and January, whereas MLP indicated a progressive increase until November, the LSTM aligned with a moderate November–December peak. Consequently, the ensemble approach showed a pattern of higher landings from November to January, accompanied by a minor rise between June and August, followed by a gradual decline throughout the rest of the year. In the Alboran Sea, all models, along with their ensemble projection, indicated peak landings in June, followed by a decline towards the end of the year. This study highlights the effectiveness of combined approaches that integrate traditional statistical techniques with machine learning and deep learning to enhance fishery landing projections. These tools provide valuable insights for fishery strategic planning and contribute to the sustainability of one of the most economically significant marine resources in southern Spain.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107622"},"PeriodicalIF":2.3,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737709","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 : 2025-12-08DOI: 10.1016/j.fishres.2025.107625
Martin H. Larsen , Kim Birnie-Gauvin , Henrik Baktoft , Søren T. Thomassen , Kim Aarestrup
Stocked Atlantic salmon (Salmo salar) used to supplement wild populations often exhibit lower survival than their wild counterparts. The causes of their reduced survival in nature are multifaceted and likely include morphological deformities that can arise in the rearing environment. Opercular shortening, characterized by a partially or completely missing gill cover, is a common deformity in hatchery-reared salmon. However, although the opercula are important for respiration and protecting the gills, the causes and consequences of opercular shortening are not well known. Here, we assessed whether shortened opercula influenced the seaward migration success of stocked salmon smolts using passive integrated transponder (PIT) telemetry. One-year-old smolts with intact opercula and varying degrees of opercular shortening were PIT-tagged and released into Gudsø stream in 2017 and River Omme in 2018, Denmark. Their downstream spring migration was subsequently tracked using stationary PIT antenna stations. The overall migration success was higher in Gudsø stream, where 61.9 % of smolts were classified as successful migrants, compared to 31.1 % in River Omme. However, the degree of opercular shortening did not influence the likelihood of successful seaward migration in either study system. Similarly, opercular shortening had no detectable effect on migration timing or bird predation risk of smolts. Despite these findings, it remains important for hatcheries to minimise the occurrence of opercular deformities to promote fish welfare during rearing. As the salmon must still undertake an extensive marine migration to reach their feeding areas, further studies are needed to assess marine survival before robust conclusions can be drawn about the long-term effects of opercular shortening.
{"title":"Does opercular shortening influence seaward migration success of stocked Atlantic salmon (Salmo salar) smolts?","authors":"Martin H. Larsen , Kim Birnie-Gauvin , Henrik Baktoft , Søren T. Thomassen , Kim Aarestrup","doi":"10.1016/j.fishres.2025.107625","DOIUrl":"10.1016/j.fishres.2025.107625","url":null,"abstract":"<div><div>Stocked Atlantic salmon (<em>Salmo salar</em>) used to supplement wild populations often exhibit lower survival than their wild counterparts. The causes of their reduced survival in nature are multifaceted and likely include morphological deformities that can arise in the rearing environment. Opercular shortening, characterized by a partially or completely missing gill cover, is a common deformity in hatchery-reared salmon. However, although the opercula are important for respiration and protecting the gills, the causes and consequences of opercular shortening are not well known. Here, we assessed whether shortened opercula influenced the seaward migration success of stocked salmon smolts using passive integrated transponder (PIT) telemetry. One-year-old smolts with intact opercula and varying degrees of opercular shortening were PIT-tagged and released into Gudsø stream in 2017 and River Omme in 2018, Denmark. Their downstream spring migration was subsequently tracked using stationary PIT antenna stations. The overall migration success was higher in Gudsø stream, where 61.9 % of smolts were classified as successful migrants, compared to 31.1 % in River Omme. However, the degree of opercular shortening did not influence the likelihood of successful seaward migration in either study system. Similarly, opercular shortening had no detectable effect on migration timing or bird predation risk of smolts. Despite these findings, it remains important for hatcheries to minimise the occurrence of opercular deformities to promote fish welfare during rearing. As the salmon must still undertake an extensive marine migration to reach their feeding areas, further studies are needed to assess marine survival before robust conclusions can be drawn about the long-term effects of opercular shortening.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107625"},"PeriodicalIF":2.3,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737726","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 : 2025-12-05DOI: 10.1016/j.fishres.2025.107621
Wessley Merten
The combination of age-at-length and tag-recapture data allowed for an integrated growth model to be explored for dolphinfish. Dolphinfish tag-recapture events (n = 266) were distributed throughout the Western Central Atlantic and Eastern Tropical Pacific Ocean and otolith data (n = 124) were obtained from a study conducted in Puerto Rico. Age-at-length and length-increment data, when integrated, led to lower growth parameters for the Gompertz and Richards growth models. The estimated asymptotic size (L∞) for the different models varied between 130 and 136 cm (fork length (FL)) fit to only the otolith data and 128–147 cm FL when integrated with tag-recapture data. Maximum estimated age obtained through the length-increment model was 2.28 years. Predicted maximum longevity was 4 years. Nominal daily growth rates versus size at release and sex indicated a two-stage growth process up to 67 cm FL when growth rates steadily declined from peaks (female: 0.30 cm FL/day; male: 0.37 cm FL/d). When gender specific growth estimates were combined with tag-recapture events with indeterminate sex, nominal growth rates smoothed but still indicated a two-stage growth process for young fish. Overall, integrated nominal daily growth rate was 0.368 cm FL/day. For a species that has yet to have a stock assessment in the Atlantic Ocean, and routine assessments in the Pacific Ocean, this work can be used to contribute to better management advice for this important resource as growth assumptions have a great impact on stock assessment results and derived management quantities.
结合体龄和标签重新捕获数据，可以探索海豚的综合生长模型。海豚标签重新捕获事件（n = 266）分布在大西洋中西部和热带太平洋东部，耳石数据（n = 124）来自波多黎各进行的一项研究。当将年龄长度和长度增量数据整合在一起时，Gompertz和Richards增长模型的增长参数较低。不同模型的估计渐近大小（L∞）在130 ~ 136 cm（分叉长度（FL））之间变化，仅适用于耳石数据，与标签重新捕获数据相结合时，估计的长度为128 ~ 147 cm。通过长度增量模型得到的最大估计年龄为2.28岁。预计最长寿命为4年。名义日生长率与释放时大小和性别的关系表明，生长过程分为两个阶段，最高可达67 cm FL，然后生长速率从峰值稳步下降（雌性：0.30 cm FL/d；雄性：0.37 cm FL/d）。当性别特异性生长估计值与性别不确定的标签重新捕获事件相结合时，名义增长率趋于平缓，但仍然表明幼鱼的生长过程分为两个阶段。总体而言，综合名义日增长率为0.368 cm FL/day。对于尚未在大西洋进行种群评估和在太平洋进行常规评估的物种，由于生长假设对种群评估结果和导出的管理数量有很大影响，因此这项工作可用于为这一重要资源提供更好的管理建议。
{"title":"Growth estimates from integrated analysis of tag-recapture and direct aging data for dolphinfish (Coryphaena hippurus)","authors":"Wessley Merten","doi":"10.1016/j.fishres.2025.107621","DOIUrl":"10.1016/j.fishres.2025.107621","url":null,"abstract":"<div><div>The combination of age-at-length and tag-recapture data allowed for an integrated growth model to be explored for dolphinfish. Dolphinfish tag-recapture events (n = 266) were distributed throughout the Western Central Atlantic and Eastern Tropical Pacific Ocean and otolith data (n = 124) were obtained from a study conducted in Puerto Rico. Age-at-length and length-increment data, when integrated, led to lower growth parameters for the Gompertz and Richards growth models. The estimated asymptotic size (<em>L</em>∞) for the different models varied between 130 and 136 cm (fork length (FL)) fit to only the otolith data and 128–147 cm FL when integrated with tag-recapture data. Maximum estimated age obtained through the length-increment model was 2.28 years. Predicted maximum longevity was 4 years. Nominal daily growth rates versus size at release and sex indicated a two-stage growth process up to 67 cm FL when growth rates steadily declined from peaks (female: 0.30 cm FL/day; male: 0.37 cm FL/d). When gender specific growth estimates were combined with tag-recapture events with indeterminate sex, nominal growth rates smoothed but still indicated a two-stage growth process for young fish. Overall, integrated nominal daily growth rate was 0.368 cm FL/day. For a species that has yet to have a stock assessment in the Atlantic Ocean, and routine assessments in the Pacific Ocean, this work can be used to contribute to better management advice for this important resource as growth assumptions have a great impact on stock assessment results and derived management quantities.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107621"},"PeriodicalIF":2.3,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145684881","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 : 2025-12-01DOI: 10.1016/j.fishres.2025.107612
Brett Wilson , Joseph Facendola , Amanda Southwood Williard
The commercial blue crab (Callinectes sapidus) harvest represents one of the most valuable fisheries in North Carolina and is a significant economic driver for coastal communities. The diamond-backed terrapin (Malaclemys terrapin), an estuarine Emydid turtle, is listed as a Species of Special Concern in North Carolina, where incidental bycatch in crab pots is a prominent threat. Efforts to reduce bycatch by installing bycatch reduction devices (BRDs) to funnel openings on crab pots have been met with resistance due to perceived negative impacts to blue crab catch. In 2020, the North Carolina Marine Fisheries Commission (NCMFC) designated Diamond-backed Terrapin Management Areas (DTMAs) in two waterbodies in North Carolina, within which North Carolina Division of Marine Fisheries (NCDMF) approved BRDs must be incorporated into all crab pots. While this regulatory measure was taken to mitigate fisheries impacts on diamond-backed terrapins, the NCDMF acknowledged the need to explore alternative gear modifications that exclude diamond-backed terrapins while minimizing impacts to target species catch. The primary goal of our study was to test the efficacy of industry-sourced gear modifications to crab pot funnel entries for diamond-backed terrapin exclusion and assess impacts of these modifications on blue crab catch. Results from fisheries-independent and fisheries-dependent testing show that narrow funnel designs (NFD) effectively exclude diamond-backed terrapins without significant reductions in catch or size of blue crabs. Our results highlight the effectiveness of collaboration between management agencies, researchers, and industry stakeholders to achieve broadly acceptable solutions to reduce diamond-backed terrapin bycatch in the commercial blue crab fishery.
{"title":"Industry-sourced approaches to diamond-backed terrapin bycatch reduction in the North Carolina commercial blue crab fishery","authors":"Brett Wilson , Joseph Facendola , Amanda Southwood Williard","doi":"10.1016/j.fishres.2025.107612","DOIUrl":"10.1016/j.fishres.2025.107612","url":null,"abstract":"<div><div>The commercial blue crab (<em>Callinectes sapidus</em>) harvest represents one of the most valuable fisheries in North Carolina and is a significant economic driver for coastal communities. The diamond-backed terrapin (<em>Malaclemys terrapin</em>), an estuarine Emydid turtle, is listed as a Species of Special Concern in North Carolina, where incidental bycatch in crab pots is a prominent threat. Efforts to reduce bycatch by installing bycatch reduction devices (BRDs) to funnel openings on crab pots have been met with resistance due to perceived negative impacts to blue crab catch. In 2020, the North Carolina Marine Fisheries Commission (NCMFC) designated Diamond-backed Terrapin Management Areas (DTMAs) in two waterbodies in North Carolina, within which North Carolina Division of Marine Fisheries (NCDMF) approved BRDs must be incorporated into all crab pots. While this regulatory measure was taken to mitigate fisheries impacts on diamond-backed terrapins, the NCDMF acknowledged the need to explore alternative gear modifications that exclude diamond-backed terrapins while minimizing impacts to target species catch. The primary goal of our study was to test the efficacy of industry-sourced gear modifications to crab pot funnel entries for diamond-backed terrapin exclusion and assess impacts of these modifications on blue crab catch. Results from fisheries-independent and fisheries-dependent testing show that narrow funnel designs (NFD) effectively exclude diamond-backed terrapins without significant reductions in catch or size of blue crabs. Our results highlight the effectiveness of collaboration between management agencies, researchers, and industry stakeholders to achieve broadly acceptable solutions to reduce diamond-backed terrapin bycatch in the commercial blue crab fishery.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"293 ","pages":"Article 107612"},"PeriodicalIF":2.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145684884","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 : 2025-12-01DOI: 10.1016/j.fishres.2025.107576
Russell B. Millar, Matt K. Broadhurst
{"title":"Response by Millar and Broadhurst to the letter to the editor by Herrmann et al.","authors":"Russell B. Millar, Matt K. Broadhurst","doi":"10.1016/j.fishres.2025.107576","DOIUrl":"10.1016/j.fishres.2025.107576","url":null,"abstract":"","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"292 ","pages":"Article 107576"},"PeriodicalIF":2.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145624185","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 : 2025-12-01DOI: 10.1016/j.fishres.2025.107608
K.C. Hall , D.D. Johnson , J.A. Smith
Catch allocation models can split aggregated mixed-species catches into individual species for stock assessments and fisheries management. In this paper, we evaluate a suite of these models for splitting mixed ‘trawl whiting’ catches into eastern school whiting (Sillago flindersi) and stout whiting (S. robusta) allocations for a commercial ocean prawn trawl fishery in New South Wales (NSW), Australia. Accuracy of the models was evaluated against a scientific observer survey which accurately recorded species catches, and we compared the modelled allocations to an existing coarse ‘rule-based’ allocation. There was no single best structure for the allocation model, but the most successful models included depth as a covariate because this helped split species along habitat preferences. The model-based allocations reduced trip-level error by around 40 % compared to the existing rules, and removed an existing bias in total catch estimates. This led to altered time series of catches and catch-per-unit-effort, especially for northern zones. When data were analysed for the entire NSW region, the catch allocation process (existing or modelled) had little impact on resulting indices of relative abundance for each whiting species, even when using a spatio-temporal standardization model. This was likely due to changes affecting scale rather than trend and our indices being rescaled to better compare time periods. Therefore, past stock assessments relying on statewide indices derived from existing rule-based allocations are likely reliable. Nevertheless, the modelled allocations were more accurate at a local and zonal scale, which will enable analyses with a finer spatial resolution in future stock assessments. Additional observer surveys are an important tool for ongoing improvement and validation of our allocation models.
{"title":"Modelling approaches to distinguish whiting species in mixed-species commercial catches, and the impact on stock status metrics","authors":"K.C. Hall , D.D. Johnson , J.A. Smith","doi":"10.1016/j.fishres.2025.107608","DOIUrl":"10.1016/j.fishres.2025.107608","url":null,"abstract":"<div><div>Catch allocation models can split aggregated mixed-species catches into individual species for stock assessments and fisheries management. In this paper, we evaluate a suite of these models for splitting mixed ‘trawl whiting’ catches into eastern school whiting (<em>Sillago flindersi</em>) and stout whiting (<em>S. robusta</em>) allocations for a commercial ocean prawn trawl fishery in New South Wales (NSW), Australia. Accuracy of the models was evaluated against a scientific observer survey which accurately recorded species catches, and we compared the modelled allocations to an existing coarse ‘rule-based’ allocation. There was no single best structure for the allocation model, but the most successful models included depth as a covariate because this helped split species along habitat preferences. The model-based allocations reduced trip-level error by around 40 % compared to the existing rules, and removed an existing bias in total catch estimates. This led to altered time series of catches and catch-per-unit-effort, especially for northern zones. When data were analysed for the entire NSW region, the catch allocation process (existing or modelled) had little impact on resulting indices of relative abundance for each whiting species, even when using a spatio-temporal standardization model. This was likely due to changes affecting scale rather than trend and our indices being rescaled to better compare time periods. Therefore, past stock assessments relying on statewide indices derived from existing rule-based allocations are likely reliable. Nevertheless, the modelled allocations were more accurate at a local and zonal scale, which will enable analyses with a finer spatial resolution in future stock assessments. Additional observer surveys are an important tool for ongoing improvement and validation of our allocation models.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"292 ","pages":"Article 107608"},"PeriodicalIF":2.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145624187","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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