Nirukshika D. F. Abeykoon , Hiroichi Kono , Keisuke Kato , Takahiro Sajiki , Jiffry Athambawa
Shrimp farming in Sri Lanka is economically advantageous but faces challenges like disease outbreaks and environmental issues. The government has introduced Best Management Practices (BMPs) to ensure sustainability. This study aimed to assess BMP knowledge and adoption among Sri Lankan shrimp farmers while identifying socio-demographic and behavioral factors influencing them, which have not been previously assessed. Data were gathered from 131 shrimp farmers in Puttalam district in Sri Lanka through a questionnaire survey and analyzed using descriptive statistics and ordered logistic regressions. The results showed that 26% of farmers had poor BMP knowledge, while 37% each had fair and good knowledge. Regarding adoption, 2% exhibited poor, 89% fair, and 9% good BMP adoption. According to the ordered logistic regression results, BMP training (p < 0.01), education (p < 0.05), and workforce (p < 0.05) significantly affect the knowledge level of BMPs. In contrast, age (p < 0.05), experience (p < 0.05), income share (p < 0.1), and risk preference (p < 0.1) significantly affect the adoption of BMPs. It is recommended to provide more BMP training to shrimp farmers, to improve their knowledge. Moreover, considering socioeconomic and behavioral factors is crucial when designing policies and interventions to promote BMP adoption.
{"title":"Knowledge and behavior: a study on adoption of best management practices among Sri Lankan shrimp farmers","authors":"Nirukshika D. F. Abeykoon , Hiroichi Kono , Keisuke Kato , Takahiro Sajiki , Jiffry Athambawa","doi":"10.1051/alr/2024017","DOIUrl":"10.1051/alr/2024017","url":null,"abstract":"<div><div>Shrimp farming in Sri Lanka is economically advantageous but faces challenges like disease outbreaks and environmental issues. The government has introduced Best Management Practices (BMPs) to ensure sustainability. This study aimed to assess BMP knowledge and adoption among Sri Lankan shrimp farmers while identifying socio-demographic and behavioral factors influencing them, which have not been previously assessed. Data were gathered from 131 shrimp farmers in Puttalam district in Sri Lanka through a questionnaire survey and analyzed using descriptive statistics and ordered logistic regressions. The results showed that 26% of farmers had poor BMP knowledge, while 37% each had fair and good knowledge. Regarding adoption, 2% exhibited poor, 89% fair, and 9% good BMP adoption. According to the ordered logistic regression results, BMP training (<em>p</em> < 0.01), education (<em>p <</em> 0.05), and workforce (<em>p <</em> 0.05) significantly affect the knowledge level of BMPs. In contrast, age (<em>p <</em> 0.05), experience (<em>p <</em> 0.05), income share (<em>p <</em> 0.1), and risk preference (<em>p <</em> 0.1) significantly affect the adoption of BMPs. It is recommended to provide more BMP training to shrimp farmers, to improve their knowledge. Moreover, considering socioeconomic and behavioral factors is crucial when designing policies and interventions to promote BMP adoption.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"38 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143548994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Arka Chowdhury , Tapas Kumar Ghosh , Sanjib Khatua , Sayani Hore , Palak Kumari , Kumari Kajal , Prasanta Jana
The experiment was intended to evaluate the competent restricted feeding strategy for amur common carp fingerlings reared under actual pond condition. Fingerlings (2.28 ± 0.27 g) were subjected to five different restricted feeding regimes; viz. TC (daily feeding), T1/1 (1-day feeding/ 1-day starvation), T2/1 (2-days feeding/ 1-day starvation), T2/2 (2-days feeding/ 2-days starvation), and T1/2 (1-day feeding/ 2-days starvation). The results indicated significantly similar (P > 0.05) growth pattern in T2/1, when compared to TC. But in other feed-deprived groups the fish growth was much poor. In T2/1, the feeding strategy had no significant adverse effect on SGR; rather it supported improved nutrient utilization indices. T2/1 asserted superior digestive capacity in the starved group, with elevated (P < 0.05) protease and amylase activity. Reduced (P < 0.05) hepatic lactate dehydrogenase and malate dehydrogenase activity in T2/1 group suggests reduced stress, which might strengthen compensatory growth. Feed deprivation increased (P < 0.05) both alanine aminotransferase and aspartate aminotransferase activity in blood. In the current study, elevated (P < 0.05) level of hepatic superoxide dismutase, catalase, glutathione peroxidase activity and Insulin like growth factor 1 and reduced (P < 0.05) blood glucose level, parallel to the degree of starvation was also evidenced. The present study suggests that 2-day feeding followed by 1-day feed restriction (T2/1) as the best feeding strategy for pond culture of amur common carp with the highest net return without compromising the growth, yield and antioxidative status.
{"title":"Effect of different feeding regimes in amur common carp fingerlings: compensatory growth, physio-metabolic responses, and expression of IGF-1 gene","authors":"Arka Chowdhury , Tapas Kumar Ghosh , Sanjib Khatua , Sayani Hore , Palak Kumari , Kumari Kajal , Prasanta Jana","doi":"10.1051/alr/2025001","DOIUrl":"10.1051/alr/2025001","url":null,"abstract":"<div><div>The experiment was intended to evaluate the competent restricted feeding strategy for amur common carp fingerlings reared under actual pond condition. Fingerlings (2.28 ± 0.27 g) were subjected to five different restricted feeding regimes; viz. TC (daily feeding), T1/1 (1-day feeding/ 1-day starvation), T2/1 (2-days feeding/ 1-day starvation), T2/2 (2-days feeding/ 2-days starvation), and T1/2 (1-day feeding/ 2-days starvation). The results indicated significantly similar (<em>P</em> > 0.05) growth pattern in T2/1, when compared to TC. But in other feed-deprived groups the fish growth was much poor. In T2/1, the feeding strategy had no significant adverse effect on SGR; rather it supported improved nutrient utilization indices. T2/1 asserted superior digestive capacity in the starved group, with elevated (<em>P</em> < 0.05) protease and amylase activity. Reduced (<em>P</em> < 0.05) hepatic lactate dehydrogenase and malate dehydrogenase activity in T2/1 group suggests reduced stress, which might strengthen compensatory growth. Feed deprivation increased (<em>P</em> < 0.05) both alanine aminotransferase and aspartate aminotransferase activity in blood. In the current study, elevated (<em>P</em> < 0.05) level of hepatic superoxide dismutase, catalase, glutathione peroxidase activity and Insulin like growth factor 1 and reduced (<em>P</em> < 0.05) blood glucose level, parallel to the degree of starvation was also evidenced. The present study suggests that 2-day feeding followed by 1-day feed restriction (T2/1) as the best feeding strategy for pond culture of amur common carp with the highest net return without compromising the growth, yield and antioxidative status.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"38 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143548996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 prevalence of sailfin catfishes (Pterygoplichthys spp.) in inland waters, including vast aquaculture systems of India is rising. This might be a serious threat to the country’s native freshwater biological resources and aquaculture production. Therefore, studies were carried out to evaluate the impact of Amazon sailfin catfish Pterygoplichthys pardalis on different life-stages of native fishes. First, we analyzed the impact of three different size classes (small: 9.95 ± 0.70 cm, medium: 21.74 ± 0.87 cm and large: 30.81 ± 1.59 cm total length) of Amazon sailfin catfish on the survival of early life-stages (eggs, hatchlings, first-feeding fry, and 10-day-old fry) of two native fishes; native carp Labeo rohita (rohu) and native catfish Ompok bimaculatus (butter catfish). All size classes of Amazon sailfin catfish showed preference towards fish eggs over aquatic macro-invertebrates (Tubifex worms) and ingested over 90% of the eggs of both the native species. However, their effects on native species’ mobile life stages (hatchlings forth) were found to be insignificant in terms of mortality. We then assessed the competition between advanced stages (fingerlings, advanced fingerlings, and sub-adult) of the Amazon sailfin catfish and the native fishes by evaluating growth and survival in three different experimental setups (indoor tanks with artificial feeds; outdoor tanks with natural food and artificial feed; and earthen pond with natural food) and in different combinations for a period of three to six months. In indoor experiment, no discernible impact of Amazon sailfin catfish on the growth of fingerlings of native species was found. But, in the outdoor experiment, growth of advanced fingerlings of rohu and butter catfish was decreased by 18.8–23.4% and 28.9–36.7%, respectively, in low- and high-biomass Amazon sailfin catfish treatments. The growth of rohu and butter catfish sub-adult was also reduced in the pond experiment, by 29.7% and 32.2%, respectively. However, impact of Amazon sailfin catfish on survival of native fish species at advanced stages was found minimal. Overall findings of this study indicate that sailfin catfish may have an adverse effect on the survival and growth of native fishes by either directly consuming or destroying native fish eggs or by competing with them for food and space.
{"title":"Invasive Amazon sailfin catfish (Pterygoplichthys pardalis) impacts the survivability and growth of native food fishes in India","authors":"Ajmal Hussan , AT Ramachandra Naik , Subhendu Adhikari , Arabinda Das , Farhana Hoque , Pramoda Kumar Sahoo , Jitendra Kumar Sundaray","doi":"10.1051/alr/2025002","DOIUrl":"10.1051/alr/2025002","url":null,"abstract":"<div><div>The prevalence of sailfin catfishes (<em>Pterygoplichthys</em> spp.) in inland waters, including vast aquaculture systems of India is rising. This might be a serious threat to the country’s native freshwater biological resources and aquaculture production. Therefore, studies were carried out to evaluate the impact of Amazon sailfin catfish <em>Pterygoplichthys pardalis</em> on different life-stages of native fishes. First, we analyzed the impact of three different size classes (small: 9.95 ± 0.70 cm, medium: 21.74 ± 0.87 cm and large: 30.81 ± 1.59 cm total length) of Amazon sailfin catfish on the survival of early life-stages (eggs, hatchlings, first-feeding fry, and 10-day-old fry) of two native fishes; native carp <em>Labeo rohita</em> (rohu) and native catfish <em>Ompok bimaculatus</em> (butter catfish). All size classes of Amazon sailfin catfish showed preference towards fish eggs over aquatic macro-invertebrates (<em>Tubifex</em> worms) and ingested over 90% of the eggs of both the native species. However, their effects on native species’ mobile life stages (hatchlings forth) were found to be insignificant in terms of mortality. We then assessed the competition between advanced stages (fingerlings, advanced fingerlings, and sub-adult) of the Amazon sailfin catfish and the native fishes by evaluating growth and survival in three different experimental setups (indoor tanks with artificial feeds; outdoor tanks with natural food and artificial feed; and earthen pond with natural food) and in different combinations for a period of three to six months. In indoor experiment, no discernible impact of Amazon sailfin catfish on the growth of fingerlings of native species was found. But, in the outdoor experiment, growth of advanced fingerlings of rohu and butter catfish was decreased by 18.8–23.4% and 28.9–36.7%, respectively, in low- and high-biomass Amazon sailfin catfish treatments. The growth of rohu and butter catfish sub-adult was also reduced in the pond experiment, by 29.7% and 32.2%, respectively. However, impact of Amazon sailfin catfish on survival of native fish species at advanced stages was found minimal. Overall findings of this study indicate that sailfin catfish may have an adverse effect on the survival and growth of native fishes by either directly consuming or destroying native fish eggs or by competing with them for food and space.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"38 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143548995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shah Mahmud Sumon , Mohammad Sabbir Hossain , Nezum Uddin , Professor Badiuzzaman
This study assessed the technical and scale efficiency of tilapia farmers in Bangladesh with a focus on identifying key factors influencing their efficiency levels. Data from 199 randomly selected tilapia farmers were analyzed using Data Envelopment Analysis (DEA), followed by a Tobit regression model to determine the key variables affecting efficiency. The results revealed a mean TE of 0.77 under CRS, 0.83 under VRS, and a mean SE of 0.92, indicating that most inefficiencies were technical rather than scale-related issues. The study also identified farming training, credit access, and years of experience had a positive effect on TE, while adverse climatic conditions negatively impacted efficiency. The findings emphasize the importance of mitigating climate impacts and improving resource management to enhance efficiency. Expanding credit access, improving training programs, and taking initiatives for mitigating climate impacts could significantly improve the efficiency and long-term viability of tilapia production in the region.
{"title":"Assessing technical and scale efficiencies in tilapia production: influential factors and insights","authors":"Shah Mahmud Sumon , Mohammad Sabbir Hossain , Nezum Uddin , Professor Badiuzzaman","doi":"10.1051/alr/2024016","DOIUrl":"10.1051/alr/2024016","url":null,"abstract":"<div><div>This study assessed the technical and scale efficiency of tilapia farmers in Bangladesh with a focus on identifying key factors influencing their efficiency levels. Data from 199 randomly selected tilapia farmers were analyzed using Data Envelopment Analysis (DEA), followed by a Tobit regression model to determine the key variables affecting efficiency. The results revealed a mean TE of 0.77 under CRS, 0.83 under VRS, and a mean SE of 0.92, indicating that most inefficiencies were technical rather than scale-related issues. The study also identified farming training, credit access, and years of experience had a positive effect on TE, while adverse climatic conditions negatively impacted efficiency. The findings emphasize the importance of mitigating climate impacts and improving resource management to enhance efficiency. Expanding credit access, improving training programs, and taking initiatives for mitigating climate impacts could significantly improve the efficiency and long-term viability of tilapia production in the region.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"38 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143172013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Temesgen Tola Geletu , Shoujie Tang , Jinliang Zhao
Sub-Saharan Africa, including Ethiopia, is a center of native Nile tilapia populations, which are important for conservation and aquaculture development. Nile tilapia aquaculture in Ethiopia is dominated by small-scale fish farming in ponds, with seeds from poorly managed hatcheries and wild sources. Hence, the development of aquaculture in Ethiopia faces a major hurdle owing to the absence of good-quality seeds, largely because of the lack of genetic management practices within hatchery centers. This study aimed to assess the genetic diversity and differentiation among farmed Nile tilapia populations to inform genetic management strategies and support the development of robust strains for aquaculture advancement. Using ddRAD-seq technology for SNP discovery, we assessed genetic diversity metrics across three farmed populations, Sebeta, Batu, and Aweday, comprising 20, 21, and 15 individuals, respectively. Expected heterozyosity (He), observed heterozygosity (Ho) and nucleotide diversity (π) estimates indicated moderate within-population genetic diversity (mean: He = 0.24, Ho = 0.25, π = 0.25). Pairwise FST values revealed the highest genetic distance (FST = 0.067) between Batu and Aweday populations, while the lowest genetic distance (FST = 0.027) was observed between Sebeta and Aweday populations. STRUCTURE analysis identified two genetic clusters, with the first cluster including Batu individuals and some from Sebeta and Aweday. Overall, our results show moderate within-population genetic variation and weak genetic differentiation among the populations. This study underscores the importance of documentation of broodstock backgrounds and formulation of reasonable hatchery practices to assist in aquaculture development and conservation of native genetic resources in Ethiopia.
{"title":"Genetic diversity and differentiation of cultured Nile tilapia populations from Ethiopia revealed by ddRAD-seq: implications for better hatchery management","authors":"Temesgen Tola Geletu , Shoujie Tang , Jinliang Zhao","doi":"10.1051/alr/2024018","DOIUrl":"10.1051/alr/2024018","url":null,"abstract":"<div><div>Sub-Saharan Africa, including Ethiopia, is a center of native Nile tilapia populations, which are important for conservation and aquaculture development. Nile tilapia aquaculture in Ethiopia is dominated by small-scale fish farming in ponds, with seeds from poorly managed hatcheries and wild sources. Hence, the development of aquaculture in Ethiopia faces a major hurdle owing to the absence of good-quality seeds, largely because of the lack of genetic management practices within hatchery centers. This study aimed to assess the genetic diversity and differentiation among farmed Nile tilapia populations to inform genetic management strategies and support the development of robust strains for aquaculture advancement. Using ddRAD-seq technology for SNP discovery, we assessed genetic diversity metrics across three farmed populations, Sebeta, Batu, and Aweday, comprising 20, 21, and 15 individuals, respectively. Expected heterozyosity (<em>H<sub>e</sub></em>), observed heterozygosity (<em>H<sub>o</sub></em>) and nucleotide diversity (<em>π</em>) estimates indicated moderate within-population genetic diversity (mean: <em>H<sub>e</sub></em> = 0.24, <em>H<sub>o</sub></em> = 0.25, <em>π</em> = 0.25). Pairwise F<sub>ST</sub> values revealed the highest genetic distance (<em>F</em><sub>ST</sub> = 0.067) between Batu and Aweday populations, while the lowest genetic distance (<em>F</em><sub>ST</sub> = 0.027) was observed between Sebeta and Aweday populations. STRUCTURE analysis identified two genetic clusters, with the first cluster including Batu individuals and some from Sebeta and Aweday. Overall, our results show moderate within-population genetic variation and weak genetic differentiation among the populations. This study underscores the importance of documentation of broodstock backgrounds and formulation of reasonable hatchery practices to assist in aquaculture development and conservation of native genetic resources in Ethiopia.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"38 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143172012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sarah Nahon , Christophe Jaeger , Christophe Menniti , Marc Roucaute , Philippe Kerhervé , Jean-Michel Mortillaro , Joël Aubin
Integrated multi-trophic aquaculture (IMTA) is a solution to biomitigate waste by rearing species from different trophic levels. In European freshwater fishponds, common carp is often produced along with secondary fish species. Developing recycling IMTA systems requires better understanding of the complexity of trophic interactions between fish. Analyses of fatty acid and stable isotopes of carbon and nitrogen are suitable tools for determining food preferences of fish species. Three IMTA systems, including carp, roach, rudd and perch, were investigated in ponds: a semi-intensive (SI) pond in which fish were fed pellets; a semi-intensive pond in which fish were fed pellets, coupled with a lagoon planted with macrophytes (SIC); and an extensive (E) pond in which fish were not fed pellets. In the SI and SIC ponds, fatty acid profiles of carp, roach and rudd were closed to those of pellets. The δ13C and δ15N values of fish confirmed that they mainly fed on pellets, but the diet of roach and rudd also contained natural food sources. In the E ponds, fatty acid profiles of carp, roach and rudd slightly differed but their δ13C and δ15N values were similar. Mixing model indicated that fish from E ponds mainly fed on zooplankton. Regardless of the IMTA systems, fatty acid and stable isotope analyses indicated that juveniles consumed mainly large zooplankton. In the three systems, the FA profile of perch was closed to that of juvenile fish. Mixing model estimated that perch supplemented their diet with large zooplankton and crayfish. In the SI and SIC ponds, the distribution of commercial pellets drove the trophic interactions among fish. In the E ponds, fish had significant feeding overlap due to the limited resources available.
{"title":"Food preferences of fish in integrated multi-trophic aquaculture freshwater ponds based on fatty acids and stable isotopes","authors":"Sarah Nahon , Christophe Jaeger , Christophe Menniti , Marc Roucaute , Philippe Kerhervé , Jean-Michel Mortillaro , Joël Aubin","doi":"10.1051/alr/2024015","DOIUrl":"10.1051/alr/2024015","url":null,"abstract":"<div><div>Integrated multi-trophic aquaculture (IMTA) is a solution to biomitigate waste by rearing species from different trophic levels. In European freshwater fishponds, common carp is often produced along with secondary fish species. Developing recycling IMTA systems requires better understanding of the complexity of trophic interactions between fish. Analyses of fatty acid and stable isotopes of carbon and nitrogen are suitable tools for determining food preferences of fish species. Three IMTA systems, including carp, roach, rudd and perch, were investigated in ponds: a semi-intensive (SI) pond in which fish were fed pellets; a semi-intensive pond in which fish were fed pellets, coupled with a lagoon planted with macrophytes (SIC); and an extensive (E) pond in which fish were not fed pellets. In the SI and SIC ponds, fatty acid profiles of carp, roach and rudd were closed to those of pellets. The δ<sup>13</sup>C and δ<sup>15</sup>N values of fish confirmed that they mainly fed on pellets, but the diet of roach and rudd also contained natural food sources. In the E ponds, fatty acid profiles of carp, roach and rudd slightly differed but their δ<sup>13</sup>C and δ<sup>15</sup>N values were similar. Mixing model indicated that fish from E ponds mainly fed on zooplankton. Regardless of the IMTA systems, fatty acid and stable isotope analyses indicated that juveniles consumed mainly large zooplankton. In the three systems, the FA profile of perch was closed to that of juvenile fish. Mixing model estimated that perch supplemented their diet with large zooplankton and crayfish. In the SI and SIC ponds, the distribution of commercial pellets drove the trophic interactions among fish. In the E ponds, fish had significant feeding overlap due to the limited resources available.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"37 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 reef octopus Octopus cyanea fishery is the most economically important fishery in southwest Madagascar. The substantial increase of octopus exploitation in the region has raised concerns over the sustainability of this fishery. While a growing number of measures have been implemented to sustainably manage the octopus stock, there is a lack of information on the status of this octopus stock. In this study, we analyse the status of octopus stock in southwest Madagascar by investigating the interannual and seasonal variability in recruitment and fishing mortality using virtual population analysis (VPA) performed on monthly basis from 2020 to 2022. Yield per recruit is also predicted using a Thomson and Bell model. Our results indicate that octopus fishery national closures (December 15 to January 31 each year) result overall in increase of catches and stock biomass, evidencing the positive impacts of the implemented fisheries regulations in the region. Recruitment exhibits high interannual and seasonal variability with a peak observed between October and December. The simulation model suggests that yield per recruit remains almost unchanged from one year to the next and not exceeding the maximum yield per recruit. Overall, this study shows the importance of understanding the status of octopus stock for sustainable octopus fisheries in southwest Madagascar.
{"title":"Assessing stock of reef octopus Octopus cyanea in southwest Madagascar using age-based population modelling","authors":"Daniel Raberinary , Aladin Andrisoa","doi":"10.1051/alr/2024011","DOIUrl":"10.1051/alr/2024011","url":null,"abstract":"<div><div>The reef octopus <em>Octopus cyanea</em> fishery is the most economically important fishery in southwest Madagascar. The substantial increase of octopus exploitation in the region has raised concerns over the sustainability of this fishery. While a growing number of measures have been implemented to sustainably manage the octopus stock, there is a lack of information on the status of this octopus stock. In this study, we analyse the status of octopus stock in southwest Madagascar by investigating the interannual and seasonal variability in recruitment and fishing mortality using virtual population analysis (VPA) performed on monthly basis from 2020 to 2022. Yield per recruit is also predicted using a Thomson and Bell model. Our results indicate that octopus fishery national closures (December 15 to January 31 each year) result overall in increase of catches and stock biomass, evidencing the positive impacts of the implemented fisheries regulations in the region. Recruitment exhibits high interannual and seasonal variability with a peak observed between October and December. The simulation model suggests that yield per recruit remains almost unchanged from one year to the next and not exceeding the maximum yield per recruit. Overall, this study shows the importance of understanding the status of octopus stock for sustainable octopus fisheries in southwest Madagascar.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"37 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An in-depth history of the European native oyster in Northern Irish waters has been absent from international and regional peer-reviewed publications. The knowledge of historical losses and a need to recover ecosystems for habitat and biodiversity purposes are primary drivers in an urgency to restore Ostrea edulis. However, a comprehensive record of O. edulis in Northern Ireland is required to assist with this work. The authors compiled a list of relevant references from grey material, rare historical archives, library collections, government reports and peer-reviewed publications. Archival reviews have been tabulated into a timeline, which documents site location, exploitation, sites of significant interest and socio-economic histories of the coastal communities who relied on the oyster. The reference material identified four distinctive phases of exploitation whereby harvesting transits from personal use to commercialization, collapse and then restoration. The study revealed that O. edulis harvests in the early 1800s in Northern Ireland were predominantly destined for export to supply collapsing stocks throughout Britain. Fishing was intense with the fishery closed by 1903. However, the species has proved to be extremely resilient with small artisanal fisheries still in existence today. This research will offer habitat managers guidance in relation to site selection and anthropogenic pressures when restoring the European flat oyster to the iconic historical beds of the Northern Irish Sea loughs.
{"title":"The history of the European native oyster Ostrea edulis in Northern Irish waters and the four phases of resource exploitation","authors":"Jade Kirkpatrick , Rachel Millar , David Smyth","doi":"10.1051/alr/2024012","DOIUrl":"10.1051/alr/2024012","url":null,"abstract":"<div><div>An in-depth history of the European native oyster in Northern Irish waters has been absent from international and regional peer-reviewed publications. The knowledge of historical losses and a need to recover ecosystems for habitat and biodiversity purposes are primary drivers in an urgency to restore <em>Ostrea edulis</em>. However, a comprehensive record of <em>O. edulis</em> in Northern Ireland is required to assist with this work. The authors compiled a list of relevant references from grey material, rare historical archives, library collections, government reports and peer-reviewed publications. Archival reviews have been tabulated into a timeline, which documents site location, exploitation, sites of significant interest and socio-economic histories of the coastal communities who relied on the oyster. The reference material identified four distinctive phases of exploitation whereby harvesting transits from personal use to commercialization, collapse and then restoration. The study revealed that <em>O. edulis</em> harvests in the early 1800s in Northern Ireland were predominantly destined for export to supply collapsing stocks throughout Britain. Fishing was intense with the fishery closed by 1903. However, the species has proved to be extremely resilient with small artisanal fisheries still in existence today. This research will offer habitat managers guidance in relation to site selection and anthropogenic pressures when restoring the European flat oyster to the iconic historical beds of the Northern Irish Sea loughs.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"37 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marc Roucaute , Joël Aubin , Sarah Nahon , Christophe Jaeger
The aim of this study was to compare the impact of three aquaculture production systems on the biodiversity and productivity of aquatic invertebrates. We compared two conventional fishpond designs (extensive and semi-intensive) with a new design combining a semi-intensive carp polyculture fishpond with a planted lagoon, called coupled semi-intensive design. All fishponds were stocked with the same proportions of common carp, roach, and Eurasian perch. Fish density was double in coupled semi-intensive and semi-intensive ponds compared to extensive ponds for which no formulated feed was provided. Benthic macroinvertebrates were sampled in May and September. Zooplankton was sampled monthly from May to November. For benthic macroinvertebrates, community taxonomic richness, biomass, production, and mean individual dry mass were higher in lagoons than in the coupled semi-intensive, semi-intensive and extensive fishponds. Zooplankton production was highest in extensive fishponds and lowest in coupled semi-intensive ponds. Zooplankton production peaked in summer and was lower than benthic macroinvertebrates production in May and September. Asellus aquaticus, whose production was higher in September than May, was the dominant macroinvertebrate in lagoons, but was almost absent from all fishponds. Bosmina longirostris, the most productive plankton taxon, especially in extensive fishponds, reached peak production in July and August. Our study highlighted the functional role of a shallow, fishless, planted lagoon linked to the fishpond for biodiversity and production of benthic macroinvertebrates and zooplankton.
{"title":"Influence of a new fishpond design on invertebrate community biodiversity and secondary production","authors":"Marc Roucaute , Joël Aubin , Sarah Nahon , Christophe Jaeger","doi":"10.1051/alr/2024013","DOIUrl":"10.1051/alr/2024013","url":null,"abstract":"<div><div>The aim of this study was to compare the impact of three aquaculture production systems on the biodiversity and productivity of aquatic invertebrates. We compared two conventional fishpond designs (extensive and semi-intensive) with a new design combining a semi-intensive carp polyculture fishpond with a planted lagoon, called coupled semi-intensive design. All fishponds were stocked with the same proportions of common carp, roach, and Eurasian perch. Fish density was double in coupled semi-intensive and semi-intensive ponds compared to extensive ponds for which no formulated feed was provided. Benthic macroinvertebrates were sampled in May and September. Zooplankton was sampled monthly from May to November. For benthic macroinvertebrates, community taxonomic richness, biomass, production, and mean individual dry mass were higher in lagoons than in the coupled semi-intensive, semi-intensive and extensive fishponds. Zooplankton production was highest in extensive fishponds and lowest in coupled semi-intensive ponds. Zooplankton production peaked in summer and was lower than benthic macroinvertebrates production in May and September. <em>Asellus aquaticus</em>, whose production was higher in September than May, was the dominant macroinvertebrate in lagoons, but was almost absent from all fishponds. <em>Bosmina longirostris</em>, the most productive plankton taxon, especially in extensive fishponds, reached peak production in July and August. Our study highlighted the functional role of a shallow, fishless, planted lagoon linked to the fishpond for biodiversity and production of benthic macroinvertebrates and zooplankton.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"37 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Northern Ireland went into COVID-19 enforced lockdown with the rest of the UK in March 2020. A stay-at-home order banned “non-essential” travel and contact with others, and closing schools and businesses. Such closures also impacted commercial fishing activities, including the Lough Neagh eel fishery. The eel fishery in Lough Neagh, Northern Ireland is the largest in Europe with an annual mean catch of around 330 t, valued at ∼£3 M. The effect of the Northern Ireland lockdown was the reduction of the Neagh fleet by 60% and delay to the start of the yellow eel fishing season by 2 months. The pandemic reduced the market demand for Lough Neagh yellow eel from ∼280,00 kg yr−1 to 100,000 kg yr−1. The objective of the study was to assess the impact of the regulations on silver eel output and the socio-economic effects on fishers and the fishery. The main impact of the market disruption was for an increase in silver eel escapement of about 15% and for those fishers who remained in the fishery, at least in the short term, a continuing livelihood. In contrast, there were direct socio-economic consequences; the fishery had to reduce in size with associated cultural and heritage loss. Upon the lifting of COVID-19 restrictions the former fleet size did not and has not returned highlighting the wide ranging socio-economic impacts from the pandemic. As of November 2023, the market demand for eel across Europe remains deflated.
{"title":"How COVID-19 changed the dynamics of a fishery","authors":"Derek W. Evans , Miran W. Aprahamian","doi":"10.1051/alr/2024007","DOIUrl":"10.1051/alr/2024007","url":null,"abstract":"<div><div>Northern Ireland went into COVID-19 enforced lockdown with the rest of the UK in March 2020. A stay-at-home order banned “non-essential” travel and contact with others, and closing schools and businesses. Such closures also impacted commercial fishing activities, including the Lough Neagh eel fishery. The eel fishery in Lough Neagh, Northern Ireland is the largest in Europe with an annual mean catch of around 330 t, valued at ∼£3 M. The effect of the Northern Ireland lockdown was the reduction of the Neagh fleet by 60% and delay to the start of the yellow eel fishing season by 2 months. The pandemic reduced the market demand for Lough Neagh yellow eel from ∼280,00 kg yr<sup>−1</sup> to 100,000 kg yr<sup>−1</sup>. The objective of the study was to assess the impact of the regulations on silver eel output and the socio-economic effects on fishers and the fishery. The main impact of the market disruption was for an increase in silver eel escapement of about 15% and for those fishers who remained in the fishery, at least in the short term, a continuing livelihood. In contrast, there were direct socio-economic consequences; the fishery had to reduce in size with associated cultural and heritage loss. Upon the lifting of COVID-19 restrictions the former fleet size did not and has not returned highlighting the wide ranging socio-economic impacts from the pandemic. As of November 2023, the market demand for eel across Europe remains deflated.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"37 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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