Pub Date : 2024-10-10DOI: 10.1016/j.fishres.2024.107201
Danie van Zyl , Grant van der Heever , Andrew Cockcroft , Lutz Auerswald
Seasonal movement patterns of a sub-population of the West Coast rock lobster (WCRL), Jasus lalandii, in a fisheries-relevant area of South Africa were investigated from 2010 to 2018 by abundance and tag/recapture surveys. A small sub-population (3144 out of 152 914 WCRL analysed) of large male WCRL (carapace length ≥ 75 mm) gathered in a deep (± 200 m) commercial fishing area in January – May, whereas they are rare or absent in the periods between. This distribution was consistent with tagging information from 502 recaptured WCRL (from 15 211 tagged) which revealed an inshore movement (mainly in a NE direction) of a male sub-population (carapace length ≥ 75 mm = legal size) starting in austral autumn. The mean straight-line movement was 30.4 ± 0.6 km (maximum 75 km) and a mean time at large of 301 ± 15 days (maximum 3000 days) were recorded. The study revealed therefore the destination of the lobsters’ migration but not its origin.
{"title":"Seasonal migration of a male Jasus lalandii sub-population","authors":"Danie van Zyl , Grant van der Heever , Andrew Cockcroft , Lutz Auerswald","doi":"10.1016/j.fishres.2024.107201","DOIUrl":"10.1016/j.fishres.2024.107201","url":null,"abstract":"<div><div>Seasonal movement patterns of a sub-population of the West Coast rock lobster (WCRL), <em>Jasus lalandii</em>, in a fisheries-relevant area of South Africa were investigated from 2010 to 2018 by abundance and tag/recapture surveys. A small sub-population (3144 out of 152 914 WCRL analysed) of large male WCRL (carapace length ≥ 75 mm) gathered in a deep (± 200 m) commercial fishing area in January – May, whereas they are rare or absent in the periods between. This distribution was consistent with tagging information from 502 recaptured WCRL (from 15 211 tagged) which revealed an inshore movement (mainly in a NE direction) of a male sub-population (carapace length ≥ 75 mm = legal size) starting in austral autumn. The mean straight-line movement was 30.4 ± 0.6 km (maximum 75 km) and a mean time at large of 301 ± 15 days (maximum 3000 days) were recorded. The study revealed therefore the destination of the lobsters’ migration but not its origin.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"281 ","pages":"Article 107201"},"PeriodicalIF":2.2,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422066","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 : 2024-10-08DOI: 10.1016/j.fishres.2024.107194
Julian J. Hwang , Jacquelyn Strager , Matthew Walker
Lionfish (Pterois miles and P. volitans) is a highly invasive species originally from the South Pacific and Indian Oceans. As an effort to control its exponentially growing population, the Florida Fish and Wildlife Conservation Commission has launched a program called “Lionfish Challenge” to promote harvesting of lionfish from Florida waters. The program provides anglers with a unique recreational opportunity because they would need to dive and spearfish to harvest lionfish. Furthermore, participants in the program not only gain utility from spearfishing as a private good but also as a public good, knowing that they are contributing to the ecosystem in Florida waters. This paper contributes to the literature by measuring the economic benefit for participants from spearfishing as an impure public good. Using data provided by the Florida Fish and Wildlife Conservation Commission, a travel cost method was applied to model the demand for lionfish fishing trips. Data included information about counties where lionfish were harvested at the trip-level, but only if participants took a trip and harvested lionfish. Therefore, those who are good at catching lionfish had a higher probability of being included in the data. To account for potential sample selection bias, a probability weight was applied, using the average number of lionfish harvested as a proxy. Results indicate that the per-trip consumer surplus per participant was between $965.89 and $1,597.36, depending on model specifications, with the preferred specification indicating a mean CS of $1,117.72 per trip. The seasonal consumer surplus per participant was indicated to be between $4,550.45 and $3487.91, again, depending on model specification.
狮子鱼（Pterois miles 和 P. volitans）是一种高度入侵物种，原产于南太平洋和印度洋。为了控制其急剧增长的数量，佛罗里达鱼类和野生动物保护委员会发起了一项名为 "狮鱼挑战 "的计划，以促进在佛罗里达水域捕捞狮鱼。该计划为垂钓者提供了一个独特的娱乐机会，因为他们需要潜水和用鱼叉捕鱼才能收获狮子鱼。此外，该计划的参与者不仅能从鱼叉捕鱼中获得私人利益，还能获得公共利益，因为他们知道自己为佛罗里达水域的生态系统做出了贡献。本文将鱼叉捕鱼作为一种不纯粹的公共产品来衡量参与者的经济收益，从而为相关文献做出贡献。利用佛罗里达鱼类和野生动物保护委员会提供的数据，采用旅行成本法对钓狮鱼旅行的需求进行建模。数据包括在旅行层面收获蓑鲉的县的信息，但仅限于参与者参加旅行并收获蓑鲉的情况。因此，善于捕获蓑鲉的人被纳入数据的概率较高。为了考虑潜在的样本选择偏差，采用了概率加权法，以收获的蓑鲉平均数量作为替代。结果表明，每位参与者每次旅行的消费者剩余在 965.89 美元到 1,597.36 美元之间，具体取决于模型规格，首选规格表明每次旅行的平均 CS 为 1,117.72 美元。每位参与者的季节性消费者盈余在 4550.45 美元到 3487.91 美元之间，同样取决于模型规格。
{"title":"The economic benefit of spearfishing as an impure public good: A case study of invasive Lionfish in Florida","authors":"Julian J. Hwang , Jacquelyn Strager , Matthew Walker","doi":"10.1016/j.fishres.2024.107194","DOIUrl":"10.1016/j.fishres.2024.107194","url":null,"abstract":"<div><div>Lionfish (<em>Pterois miles and P. volitans</em>) is a highly invasive species originally from the South Pacific and Indian Oceans. As an effort to control its exponentially growing population, the Florida Fish and Wildlife Conservation Commission has launched a program called “Lionfish Challenge” to promote harvesting of lionfish from Florida waters. The program provides anglers with a unique recreational opportunity because they would need to dive and spearfish to harvest lionfish. Furthermore, participants in the program not only gain utility from spearfishing as a private good but also as a public good, knowing that they are contributing to the ecosystem in Florida waters. This paper contributes to the literature by measuring the economic benefit for participants from spearfishing as an impure public good. Using data provided by the Florida Fish and Wildlife Conservation Commission, a travel cost method was applied to model the demand for lionfish fishing trips. Data included information about counties where lionfish were harvested at the trip-level, but only if participants took a trip and harvested lionfish. Therefore, those who are good at catching lionfish had a higher probability of being included in the data. To account for potential sample selection bias, a probability weight was applied, using the average number of lionfish harvested as a proxy. Results indicate that the per-trip consumer surplus per participant was between $965.89 and $1,597.36, depending on model specifications, with the preferred specification indicating a mean CS of $1,117.72 per trip. The seasonal consumer surplus per participant was indicated to be between $4,550.45 and $3487.91, again, depending on model specification.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"281 ","pages":"Article 107194"},"PeriodicalIF":2.2,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422064","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}
Understanding the deployment ranges and behavior of fishing gear in relation to fishery efficiency will help us grasp the potential impact of future shifts in the fishery on resources and fishing activities. Fisheries for Greenland halibut are conducted by boat in open water during the summer. However, in winter, fishermen travel to fishing grounds on the sea ice using dog sleds, drill holes in the ice, and deploy longlines using metal plate kites. While the scale of deployment varies between boat and ice longlining, the movement of kites used in ice longlining and their effect on the deployment range of the line is not well understood. We conducted experiments using an accelerometer to determine the underwater movement of kites and their effect on the horizontal range of longline deployment. This is the first report describing specific operational information on longline fishing under sea ice, specifically on the effects of the kite on longline deployment. The kite is attached to the leading end of the mainline and deploys the longlines horizontally as it moves downward towards the sea floor. When the kite and mainline are dropped into the sea, the kite extends the line horizontally while shifting forward-facing long side, and forward-aligned short side. The motion resembles a fluttering action primarily influenced by the Reynolds number and moment of inertia. When the mainline is held, the kite descends in a circular motion. With repeated fishing operations and the passage of time, the kite's movement is expected to decrease in both range and speed due to the buoyancy and tension of the mainline. These kite movements suggest that the deployment range of longlines could extend several hundred meters. Therefore, it can be inferred that the impact of winter ice fishing on the Greenland halibut stock is relatively low due to the limited deployment range of the longline when using the kite.
{"title":"Artisanal longline fishing for Greenland halibut (Reinhardtius hippoglossoides) operated under sea ice using a metal plate kite in northwest Greenland","authors":"Kenzo Tanaka , Makoto Tomiyasu , Ryo Kusaka , Shin Sugiyama , Evgeny A. Podolskiy , Yasuzumi Fujimori","doi":"10.1016/j.fishres.2024.107203","DOIUrl":"10.1016/j.fishres.2024.107203","url":null,"abstract":"<div><div>Understanding the deployment ranges and behavior of fishing gear in relation to fishery efficiency will help us grasp the potential impact of future shifts in the fishery on resources and fishing activities. Fisheries for Greenland halibut are conducted by boat in open water during the summer. However, in winter, fishermen travel to fishing grounds on the sea ice using dog sleds, drill holes in the ice, and deploy longlines using metal plate kites. While the scale of deployment varies between boat and ice longlining, the movement of kites used in ice longlining and their effect on the deployment range of the line is not well understood. We conducted experiments using an accelerometer to determine the underwater movement of kites and their effect on the horizontal range of longline deployment. This is the first report describing specific operational information on longline fishing under sea ice, specifically on the effects of the kite on longline deployment. The kite is attached to the leading end of the mainline and deploys the longlines horizontally as it moves downward towards the sea floor. When the kite and mainline are dropped into the sea, the kite extends the line horizontally while shifting forward-facing long side, and forward-aligned short side. The motion resembles a fluttering action primarily influenced by the Reynolds number and moment of inertia. When the mainline is held, the kite descends in a circular motion. With repeated fishing operations and the passage of time, the kite's movement is expected to decrease in both range and speed due to the buoyancy and tension of the mainline. These kite movements suggest that the deployment range of longlines could extend several hundred meters. Therefore, it can be inferred that the impact of winter ice fishing on the Greenland halibut stock is relatively low due to the limited deployment range of the longline when using the kite.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"281 ","pages":"Article 107203"},"PeriodicalIF":2.2,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.fishres.2024.107193
Patricia Briones-Fourzán
Spiny lobsters are one of the most valuable fishing resources worldwide. These lobsters have a complex life cycle with a lengthy pelagic phase followed by a lengthier benthic phase, with several habitat shifts in some species. Finding adequate habitats is complicated for these lobsters, as they interact with different prey, predators, and competitors in subsequent habitats. This paper provides an overview of the characteristics of spiny lobster benthic habitats, focusing on two species from the wider Caribbean region, Panulirus argus and P. guttatus. Tropical spiny lobsters are omnivorous; therefore, food is not as limiting a component of habitat as is shelter, on which their survival greatly depends. Indeed, lack of appropriate shelter may result in population bottlenecks. This observation underlies the use of artificial structures (such as “casitas”) to enhance lobster habitats for fisheries and conservation purposes. Pros and potential cons of habitat enhancement are also reviewed. The other side of the coin is habitat degradation. Throughout the wider Caribbean and elsewhere, climate change –mostly resulting from anthropogenic stressors– and coastal development are increasing coastal pollution and eutrophication, seagrass loss, algal blooms, habitat fragmentation, coral reef degradation, and marine diseases, changing the habitat landscapes with potentially dire effects for spiny lobster populations. Because of the different habitats used by these two species throughout their benthic lives, P. guttatus is likely to be more vulnerable to coral reef degradation and the settling postlarvae and early juveniles of P. argus to degradation of seagrass and shallow hard bottom communities. Conservation of appropriate habitats for target species should be considered an important aim of ecosystem-based fisheries management.
{"title":"Influence of habitat enhancement and habitat degradation on spiny lobster populations in the Caribbean: An overview","authors":"Patricia Briones-Fourzán","doi":"10.1016/j.fishres.2024.107193","DOIUrl":"10.1016/j.fishres.2024.107193","url":null,"abstract":"<div><div>Spiny lobsters are one of the most valuable fishing resources worldwide. These lobsters have a complex life cycle with a lengthy pelagic phase followed by a lengthier benthic phase, with several habitat shifts in some species. Finding adequate habitats is complicated for these lobsters, as they interact with different prey, predators, and competitors in subsequent habitats. This paper provides an overview of the characteristics of spiny lobster benthic habitats, focusing on two species from the wider Caribbean region, <em>Panulirus argus</em> and <em>P. guttatus</em>. Tropical spiny lobsters are omnivorous; therefore, food is not as limiting a component of habitat as is shelter, on which their survival greatly depends. Indeed, lack of appropriate shelter may result in population bottlenecks. This observation underlies the use of artificial structures (such as “casitas”) to enhance lobster habitats for fisheries and conservation purposes. Pros and potential cons of habitat enhancement are also reviewed. The other side of the coin is habitat degradation. Throughout the wider Caribbean and elsewhere, climate change –mostly resulting from anthropogenic stressors– and coastal development are increasing coastal pollution and eutrophication, seagrass loss, algal blooms, habitat fragmentation, coral reef degradation, and marine diseases, changing the habitat landscapes with potentially dire effects for spiny lobster populations. Because of the different habitats used by these two species throughout their benthic lives, <em>P. guttatus</em> is likely to be more vulnerable to coral reef degradation and the settling postlarvae and early juveniles of <em>P. argus</em> to degradation of seagrass and shallow hard bottom communities. Conservation of appropriate habitats for target species should be considered an important aim of ecosystem-based fisheries management.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"281 ","pages":"Article 107193"},"PeriodicalIF":2.2,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-04DOI: 10.1016/j.fishres.2024.107179
Evelyn M. Layland , Emily Patrick , Molly Spencer , Rachel Lasley-Rasher , David M. Fields , Richard A. Wahle
The American lobster (Homarus americanus) plays an integral role in the coastal Northwest Atlantic as a benthic consumer and the target of the most valuable single-species fishery in North America. In the past decade, benthic recruitment of juvenile lobster has declined, even as egg production has increased, suggesting heightening levels of larval mortality. Recent correlative studies in the Gulf of Maine further suggest early-stage larval survival may be related to the supply and composition of planktonic foods. Despite these correlative studies and the economic importance of the species, relatively little is known about how larval lobster interacts with its prey in the pelagic environment. During these early developmental stages, lobster larvae undergo significant morphological changes which influence their ability to capture and handle prey. This study used a combination of laboratory-based feeding experiments and video recordings to examine changes in feeding behavior and ingestion rates between larval stages. Calculated Ivlev-type functional response curves were used to evaluate how larval ingestion rates vary with prey density and by larval stage on a suite of prey species. We observed dramatic stage-to-stage improvements in the capacity to pursue, capture, handle, and ingest specific prey, especially after the metamorphosis to the postlarval stage. The results highlight the vulnerability of the early life stages to low food densities. They also elucidate differences in the ability of specific prey taxa to evade predation by larval lobster. Quantifying the interactions between larval lobsters and their prey enhances our understanding of how this economically important species interacts with the pelagic food web, which fraction of available zooplankton represent viable food sources, and how lobster larvae may be impacted by altered prey availability associated with climate change.
{"title":"Larval ontogeny enhances resilience to a patchy planktonic food supply in the American lobster (Homarus americanus)","authors":"Evelyn M. Layland , Emily Patrick , Molly Spencer , Rachel Lasley-Rasher , David M. Fields , Richard A. Wahle","doi":"10.1016/j.fishres.2024.107179","DOIUrl":"10.1016/j.fishres.2024.107179","url":null,"abstract":"<div><div>The American lobster (<em>Homarus americanus</em>) plays an integral role in the coastal Northwest Atlantic as a benthic consumer and the target of the most valuable single-species fishery in North America. In the past decade, benthic recruitment of juvenile lobster has declined, even as egg production has increased, suggesting heightening levels of larval mortality. Recent correlative studies in the Gulf of Maine further suggest early-stage larval survival may be related to the supply and composition of planktonic foods. Despite these correlative studies and the economic importance of the species, relatively little is known about how larval lobster interacts with its prey in the pelagic environment. During these early developmental stages, lobster larvae undergo significant morphological changes which influence their ability to capture and handle prey. This study used a combination of laboratory-based feeding experiments and video recordings to examine changes in feeding behavior and ingestion rates between larval stages. Calculated Ivlev-type functional response curves were used to evaluate how larval ingestion rates vary with prey density and by larval stage on a suite of prey species. We observed dramatic stage-to-stage improvements in the capacity to pursue, capture, handle, and ingest specific prey, especially after the metamorphosis to the postlarval stage. The results highlight the vulnerability of the early life stages to low food densities. They also elucidate differences in the ability of specific prey taxa to evade predation by larval lobster. Quantifying the interactions between larval lobsters and their prey enhances our understanding of how this economically important species interacts with the pelagic food web, which fraction of available zooplankton represent viable food sources, and how lobster larvae may be impacted by altered prey availability associated with climate change.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"281 ","pages":"Article 107179"},"PeriodicalIF":2.2,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The marine fishing industry is considered as one of Bangladesh's most important contributors to the nation's economy. The post-harvest losses of marine fish have a substantial impact on the contribution of the industry. Therefore, the aim of this study was to assess post-harvest losses of marine fish at fishermen level and to identify the factors that influence post-harvest losses. In-person interviews were conducted in two coastal divisions of Bangladesh to collect data from 643 fishermen, which was then analyzed using multiple regression models. Results showed that the total post-harvest losses of marine fish in Bangladesh were 17.75 % of total caught, with physical and market losses accounting for 9.86 % and 90.14 %, respectively. The use of inadequate ice and uninsulated containers was estimated to increase post-harvest losses of marine fish by 40 %, all else being equal. Earning members, inadequate storage, longer time attached to the net, delayed marketing, and tide pressure were statistically significant and positively correlated with post-harvest losses, whereas family members and fish finder were negatively associated with post-harvest losses. This study thus recommends that those who harvest marine fish should be aware of the parameters they choose that affect post-harvest losses.
{"title":"Post-harvest losses of marine fish at fishers in Bangladesh","authors":"Anup Kumar Mandal , Md. Mamun Or Rashid , Md. Sujahangir Kabir Sarkar , Badiuzzaman , Md. Sazedul Hoque , Afjal Hossain","doi":"10.1016/j.fishres.2024.107198","DOIUrl":"10.1016/j.fishres.2024.107198","url":null,"abstract":"<div><div>The marine fishing industry is considered as one of Bangladesh's most important contributors to the nation's economy. The post-harvest losses of marine fish have a substantial impact on the contribution of the industry. Therefore, the aim of this study was to assess post-harvest losses of marine fish at fishermen level and to identify the factors that influence post-harvest losses. In-person interviews were conducted in two coastal divisions of Bangladesh to collect data from 643 fishermen, which was then analyzed using multiple regression models. Results showed that the total post-harvest losses of marine fish in Bangladesh were 17.75 % of total caught, with physical and market losses accounting for 9.86 % and 90.14 %, respectively. The use of inadequate ice and uninsulated containers was estimated to increase post-harvest losses of marine fish by 40 %, all else being equal. Earning members, inadequate storage, longer time attached to the net, delayed marketing, and tide pressure were statistically significant and positively correlated with post-harvest losses, whereas family members and fish finder were negatively associated with post-harvest losses. This study thus recommends that those who harvest marine fish should be aware of the parameters they choose that affect post-harvest losses.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"281 ","pages":"Article 107198"},"PeriodicalIF":2.2,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421613","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}
Fishers and fishing vessels are not homogeneous, with their level of catch affected by the choice of physical inputs such as engine size, boat size and the type of fishing technology employed, as well as less tangible factors such as skipper skill and experience. Economic output also vitally depends upon the value of the product in the market and the cost of inputs. These differences in the ability of individual fishers to catch fish, and create economic returns, can be assessed through the application of efficiency analysis. This paper provides an empirical examination of efficiency indicators in the South Australian Spencer Gulf and West Coast Prawn Fisheries. Applying data envelopment analysis (DEA) to a unique vessel-level dataset that includes both quantity and value information, we estimate measures of efficiency in these input-controlled fisheries where effort decisions are made in real-time using a participative management approach. We find that quantity and value-based efficiency measures are relatively high but that the variability of value-based measures is increasing. This increasing heterogeneity in value, despite the homogeneity in quantities, has potential implications for pressures on cooperative management going forwards as fishers pursue different business strategies. Comparing the measures of efficiency to direct measures of individual profit, we find a divergence: technical and cost measures of efficiency are more strongly positively related to short-run economic performance while revenue-efficiency is more strongly positively correlated with long-run economic performance, suggesting that different efficiency metrics may be required for short- and long-run monitoring.
{"title":"Measuring, interpreting and monitoring economic efficiency in South Australia’s Spencer Gulf and West Coast Prawn Fisheries","authors":"Stephanie McWhinnie , Sean Pascoe , Peggy Schrobback , Eriko Hoshino","doi":"10.1016/j.fishres.2024.107191","DOIUrl":"10.1016/j.fishres.2024.107191","url":null,"abstract":"<div><div>Fishers and fishing vessels are not homogeneous, with their level of catch affected by the choice of physical inputs such as engine size, boat size and the type of fishing technology employed, as well as less tangible factors such as skipper skill and experience. Economic output also vitally depends upon the value of the product in the market and the cost of inputs. These differences in the ability of individual fishers to catch fish, and create economic returns, can be assessed through the application of efficiency analysis. This paper provides an empirical examination of efficiency indicators in the South Australian Spencer Gulf and West Coast Prawn Fisheries. Applying data envelopment analysis (DEA) to a unique vessel-level dataset that includes both quantity and value information, we estimate measures of efficiency in these input-controlled fisheries where effort decisions are made in real-time using a participative management approach. We find that quantity and value-based efficiency measures are relatively high but that the variability of value-based measures is increasing. This increasing heterogeneity in value, despite the homogeneity in quantities, has potential implications for pressures on cooperative management going forwards as fishers pursue different business strategies. Comparing the measures of efficiency to direct measures of individual profit, we find a divergence: technical and cost measures of efficiency are more strongly positively related to short-run economic performance while revenue-efficiency is more strongly positively correlated with long-run economic performance, suggesting that different efficiency metrics may be required for short- and long-run monitoring.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"281 ","pages":"Article 107191"},"PeriodicalIF":2.2,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.fishres.2024.107189
Todd T. TenBrink , Jane Y. Sullivan , Christopher M. Gburski
Dusky rockfish (Sebastes variabilis) is a commercially valuable groundfish species in Alaska waters, with its highest abundance and fishery catch occurring in the Gulf of Alaska (GOA), and lesser abundance and catch occurring throughout the Aleutian Islands and southeastern Bering Sea. Despite its commercial importance, information regarding stock structure of dusky rockfish has been data-limited. In this study, otolith shape analysis was used to evaluate the stock structure of dusky rockfish across five geographical subareas exhibiting ecological differences in the GOA and Bering Sea and Aleutian Islands (BSAI), where dusky rockfish are managed as two separate stocks. A combination of size and shape indices, wavelet, and elliptic Fourier descriptors were examined from left and right-side otoliths collected from these regions (n = 522). Individual variation existed across subareas. Wavelet and elliptic Fourier descriptors indicated that mean otolith shapes were partitioned between the two management regions but also showed a high degree of overlap among subareas. Classification accuracies of otoliths to their subarea of origin through linear discriminant analysis (LDA) were variable (6.3–73.5 % and 15.4–65.8 % correctly classified for the elliptic Fourier and wavelet analyses, respectively). The highest classification rates were found between the western GOA and eastern Aleutian Islands, contributing to the observed differences between management regions and providing some support for current management paradigms. Dusky rockfish exhibited low to moderate overall classification rates (43.9–52.2 %), suggesting minimal stock structure within Alaska waters. This study highlights the utility of otolith shape analysis as a stock discrimination tool, and results will help refine further investigations and support fishery management in Alaska.
{"title":"Exploring the use of otolith shape analysis to identify the stock spatial structure of dusky rockfish (Sebastes variabilis)","authors":"Todd T. TenBrink , Jane Y. Sullivan , Christopher M. Gburski","doi":"10.1016/j.fishres.2024.107189","DOIUrl":"10.1016/j.fishres.2024.107189","url":null,"abstract":"<div><div>Dusky rockfish (<em>Sebastes variabilis</em>) is a commercially valuable groundfish species in Alaska waters, with its highest abundance and fishery catch occurring in the Gulf of Alaska (GOA), and lesser abundance and catch occurring throughout the Aleutian Islands and southeastern Bering Sea. Despite its commercial importance, information regarding stock structure of dusky rockfish has been data-limited. In this study, otolith shape analysis was used to evaluate the stock structure of dusky rockfish across five geographical subareas exhibiting ecological differences in the GOA and Bering Sea and Aleutian Islands (BSAI), where dusky rockfish are managed as two separate stocks. A combination of size and shape indices, wavelet, and elliptic Fourier descriptors were examined from left and right-side otoliths collected from these regions (<em>n</em> = 522). Individual variation existed across subareas. Wavelet and elliptic Fourier descriptors indicated that mean otolith shapes were partitioned between the two management regions but also showed a high degree of overlap among subareas. Classification accuracies of otoliths to their subarea of origin through linear discriminant analysis (LDA) were variable (6.3–73.5 % and 15.4–65.8 % correctly classified for the elliptic Fourier and wavelet analyses, respectively). The highest classification rates were found between the western GOA and eastern Aleutian Islands, contributing to the observed differences between management regions and providing some support for current management paradigms. Dusky rockfish exhibited low to moderate overall classification rates (43.9–52.2 %), suggesting minimal stock structure within Alaska waters. This study highlights the utility of otolith shape analysis as a stock discrimination tool, and results will help refine further investigations and support fishery management in Alaska.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"281 ","pages":"Article 107189"},"PeriodicalIF":2.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421547","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 : 2024-09-28DOI: 10.1016/j.fishres.2024.107188
Reana May Yen Ng , Adam Chee Ooi Lim , Chin Nurhiqwanalina Binti Henry Chin Siew Lee , Norazliana Binti Abdul Majib , Muhammad Ali Syed Hussein , Amy Yee-Hui Then
Seahorses (Hippocampus spp.) are sold primarily for traditional medicine (TM) uses in Southeast Asia. Although Malaysia is reportedly an important global seahorse exporter, documentation on the current extent of seahorse catch and trade of seahorse-based TM within the country is limited. This study aimed to quantify patterns of seahorse bycatch, gear-specific biological parameters of caught seahorses, and trade characteristics in Malaysia. Questionnaire-based fisher and TM surveys were administered nationwide from March 2021 to March 2023. Seventy-one percent of fisher respondents (612 out of 860) reported catching seahorses, with gill or drift net fishers (73 %) more likely to have caught seahorses than trawlers (12 %). Significant spatial differences in species composition was observed between Peninsular Malaysia and Malaysian Borneo (Sabah state). The total estimated annual seahorse catch within Malaysia was approximately 3376 kg per year, with 77 % of the catch attributed to gill or drift nets and 23 % to trawling operations. Almost half (40 %) of traditional Chinese medicine (TCM) practitioners/ traders (n = 138), 3 % of Malay TM practitioners (n = 3), and 88 % of other TM traders (n = 7) reported selling seahorse species. This study is one of the first to quantify the often overlooked but critical contribution of small-scale fisheries, especially gill and drift nets, towards seahorse bycatch. The current supply volume and selling price of seahorses were observed to be relatively high, while the present-day demand was reportedly low. Almost half of TCM practitioners/ traders interviewed were still actively selling seahorses, indicating that there is still considerable demand. To ensure the sustainability of seahorse populations in Malaysia, efforts in both small-scale and trawl fisheries must be reduced while strictly enforcing seahorse trade regulations.
{"title":"Quantifying non-target seahorse fisheries and domestic traditional medicine-based trade in Malaysia","authors":"Reana May Yen Ng , Adam Chee Ooi Lim , Chin Nurhiqwanalina Binti Henry Chin Siew Lee , Norazliana Binti Abdul Majib , Muhammad Ali Syed Hussein , Amy Yee-Hui Then","doi":"10.1016/j.fishres.2024.107188","DOIUrl":"10.1016/j.fishres.2024.107188","url":null,"abstract":"<div><div>Seahorses (<em>Hippocampus</em> spp.) are sold primarily for traditional medicine (TM) uses in Southeast Asia. Although Malaysia is reportedly an important global seahorse exporter, documentation on the current extent of seahorse catch and trade of seahorse-based TM within the country is limited. This study aimed to quantify patterns of seahorse bycatch, gear-specific biological parameters of caught seahorses, and trade characteristics in Malaysia. Questionnaire-based fisher and TM surveys were administered nationwide from March 2021 to March 2023. Seventy-one percent of fisher respondents (612 out of 860) reported catching seahorses, with gill or drift net fishers (73 %) more likely to have caught seahorses than trawlers (12 %). Significant spatial differences in species composition was observed between Peninsular Malaysia and Malaysian Borneo (Sabah state). The total estimated annual seahorse catch within Malaysia was approximately 3376 kg per year, with 77 % of the catch attributed to gill or drift nets and 23 % to trawling operations. Almost half (40 %) of traditional Chinese medicine (TCM) practitioners/ traders (<em>n</em> = 138), 3 % of Malay TM practitioners (<em>n</em> = 3), and 88 % of other TM traders (<em>n</em> = 7) reported selling seahorse species. This study is one of the first to quantify the often overlooked but critical contribution of small-scale fisheries, especially gill and drift nets, towards seahorse bycatch. The current supply volume and selling price of seahorses were observed to be relatively high, while the present-day demand was reportedly low. Almost half of TCM practitioners/ traders interviewed were still actively selling seahorses, indicating that there is still considerable demand. To ensure the sustainability of seahorse populations in Malaysia, efforts in both small-scale and trawl fisheries must be reduced while strictly enforcing seahorse trade regulations.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"281 ","pages":"Article 107188"},"PeriodicalIF":2.2,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328280","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}
The need for an ecosystem-based approach to fisheries management is widely recognized. Designing ecosystem models for management purposes requires the identification of key interactions and environmental forcing that drive the dynamics of fish stocks. This can be a very challenging task given the complexity of interactions, which determine the evolution of marine ecosystems. To overcome this difficulty, this study proposes a statistical approach based on multivariate time series analysis to identify the main biotic and abiotic interactions using as a case study of a complex and exploited marine ecosystem, the Gulf of Lions (GOL) in the Mediterranean Sea. To do so, first, pairwise Granger causality tests were performed to detect and select the strongest interactions and drivers, then followed by Multivariate Auto-Regressive (MAR) modelling techniques to evaluate the relevance of the selected causal relationships in a multivariate system. The results led to the identification of three statistical interaction networks (SINs) of moderated complexity. The first showed statistical interactions between blackbellied angler (Lophius budegassa), hake (Merluccius merluccius), grey gurnard (Eutrigla gurnardus), and John dory (Zeus faber), as well as the influence of phosphate concentration. The second focused on blackbellied angler, red mullet (Mullus barbatus), anchovy (Engraulis encrasicolus), under the combined influence of demersal trawlers, Sea Surface Temperature (SST) and nitrate concentration. Horned octopus (Eledone cirrhosa), capelan (Trisopterus capelanus), and sardine (Sardina pilchardus) were also investigated under the influence of nitrate concentration. These SINs can serve as a basis to build models of intermediate complexities to describe the dynamics of the main fish stocks of the GOL.
{"title":"Identifying statistical interaction networks in marine communities using multivariate time series analysis: An application in the Gulf of Lions","authors":"Cyria Meriem Bensebaini , Grégoire Certain , Sophie Gourguet , Olivier Thébaud , Tarek Hattab , Norbert Billet , Angélique Jadaud , Jean-Marc Fromentin","doi":"10.1016/j.fishres.2024.107177","DOIUrl":"10.1016/j.fishres.2024.107177","url":null,"abstract":"<div><div>The need for an ecosystem-based approach to fisheries management is widely recognized. Designing ecosystem models for management purposes requires the identification of key interactions and environmental forcing that drive the dynamics of fish stocks. This can be a very challenging task given the complexity of interactions, which determine the evolution of marine ecosystems. To overcome this difficulty, this study proposes a statistical approach based on multivariate time series analysis to identify the main biotic and abiotic interactions using as a case study of a complex and exploited marine ecosystem, the Gulf of Lions (GOL) in the Mediterranean Sea. To do so, first, pairwise Granger causality tests were performed to detect and select the strongest interactions and drivers, then followed by Multivariate Auto-Regressive (MAR) modelling techniques to evaluate the relevance of the selected causal relationships in a multivariate system. The results led to the identification of three statistical interaction networks (SINs) of moderated complexity. The first showed statistical interactions between blackbellied angler (<em>Lophius budegassa</em>), hake (<em>Merluccius merluccius</em>), grey gurnard (<em>Eutrigla gurnardus</em>), and John dory (<em>Zeus faber</em>), as well as the influence of phosphate concentration. The second focused on blackbellied angler, red mullet (<em>Mullus barbatus</em>), anchovy (<em>Engraulis encrasicolus</em>), under the combined influence of demersal trawlers, Sea Surface Temperature (SST) and nitrate concentration. Horned octopus (<em>Eledone cirrhosa</em>), capelan (<em>Trisopterus capelanus</em>), and sardine (<em>Sardina pilchardus</em>) were also investigated under the influence of nitrate concentration. These SINs can serve as a basis to build models of intermediate complexities to describe the dynamics of the main fish stocks of the GOL.</div></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"281 ","pages":"Article 107177"},"PeriodicalIF":2.2,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358693","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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