F. Asche, Hans‐Martin Straume, T. Garlock, Ulf Johansen, S. Kvamsdal, Rune Nygaard, R. Pincinato, Ragnar Tveterås
A rapidly growing literature shows that COVID-19 and the measures to contain the spread of the virus can have significant market impacts for seafood. These can be interruptions of production, or reductions in demand directly or indirectly due to supply chain challenges. In this paper we investigate the potential impacts of COVID-19 on seafood exports from Norway, the world's second largest seafood exporter, using highly detailed data from 2016 through May 2021. These data allow us to assess upstream impacts in the seafood supply chain close to the producer level in aggregate and by main sector, impacts on the largest products, and the extent to which export firm structure and export markets served have changed. We find very few impacts in aggregate as well as for individual products, suggesting that the markets and supply chains used by Norwegian seafood exports were sufficiently robust and flexible to accommodate the shocks created by COVID-19. Given Norway's size as a seafood exporter, the impact of COVID-19 has likely been moderate upstreams for a number of seafood sectors around the world, especially those in wealthy nations, with opportunities balancing out challenges, and that the supply chains have been highly resilient.
{"title":"Challenges and opportunities: impacts of COVID-19 on Norwegian seafood exports","authors":"F. Asche, Hans‐Martin Straume, T. Garlock, Ulf Johansen, S. Kvamsdal, Rune Nygaard, R. Pincinato, Ragnar Tveterås","doi":"10.1051/alr/2022017","DOIUrl":"https://doi.org/10.1051/alr/2022017","url":null,"abstract":"A rapidly growing literature shows that COVID-19 and the measures to contain the spread of the virus can have significant market impacts for seafood. These can be interruptions of production, or reductions in demand directly or indirectly due to supply chain challenges. In this paper we investigate the potential impacts of COVID-19 on seafood exports from Norway, the world's second largest seafood exporter, using highly detailed data from 2016 through May 2021. These data allow us to assess upstream impacts in the seafood supply chain close to the producer level in aggregate and by main sector, impacts on the largest products, and the extent to which export firm structure and export markets served have changed. We find very few impacts in aggregate as well as for individual products, suggesting that the markets and supply chains used by Norwegian seafood exports were sufficiently robust and flexible to accommodate the shocks created by COVID-19. Given Norway's size as a seafood exporter, the impact of COVID-19 has likely been moderate upstreams for a number of seafood sectors around the world, especially those in wealthy nations, with opportunities balancing out challenges, and that the supply chains have been highly resilient.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Farm escapees and their offspring impose a significant impact on the environment and may therefore alter the future evolutionary trajectories of wild populations. To date, there is no management plan in place in Mediterranean countries to prevent fish escapes. Here, we investigate microsatellite length variations in three candidate genes, including prolactin (PRL), growth hormone (GH), and the receptor activity modifying protein 3 gene (RAMP3), to study the genetic structure of the main fish species farmed in the Mediterranean, gilthead seabream (Sparus aurata). We also evaluate the performance of microsatellites in discriminating fish origin (wild or farmed). Results from 298 individuals, including farmed, wild adult and juvenile fish were compared with results from 19 neutral markers used in a previous study. All loci were polymorphic, selectively neutral, and had the statistical power to detect significant population differentiation. Global FST was similar to that estimated using 19 loci (0.019 and 0.023, respectively), while pairwise comparisons identified farmed populations as the main drivers of genetic divergence, with a much higher magnitude of overall genetic differentiation within farmed populations (0.076) than that estimated using the 19 neutral microsatellite loci (0.041). Bayesian structural analysis showed that the PRL, GH, and RAMP3 markers were able to distinguish farmed from wild populations, but were not able to distinguish different wild groups as 19 neutral microsatellite markers did. Farmed populations of different origins were assigned to a separate cluster with a high individual assignment score (>88%). It appears that the candidate markers are more influenced by artificial selection compared to neutral markers. Further validation of their efficiency in discriminating wild, farmed, and mixed fish origins using a more robust sample size is needed to ensure their potential use in an escaped fish monitoring programme.
{"title":"Genetic discrimination of wild versus farmed gilthead sea bream Sparus aurata using microsatellite markers associated with candidate genes","authors":"Iva Žužul, L. Grubišić, T. Šegvić-Bubić","doi":"10.1051/alr/2022009","DOIUrl":"https://doi.org/10.1051/alr/2022009","url":null,"abstract":"Farm escapees and their offspring impose a significant impact on the environment and may therefore alter the future evolutionary trajectories of wild populations. To date, there is no management plan in place in Mediterranean countries to prevent fish escapes. Here, we investigate microsatellite length variations in three candidate genes, including prolactin (PRL), growth hormone (GH), and the receptor activity modifying protein 3 gene (RAMP3), to study the genetic structure of the main fish species farmed in the Mediterranean, gilthead seabream (Sparus aurata). We also evaluate the performance of microsatellites in discriminating fish origin (wild or farmed). Results from 298 individuals, including farmed, wild adult and juvenile fish were compared with results from 19 neutral markers used in a previous study. All loci were polymorphic, selectively neutral, and had the statistical power to detect significant population differentiation. Global FST was similar to that estimated using 19 loci (0.019 and 0.023, respectively), while pairwise comparisons identified farmed populations as the main drivers of genetic divergence, with a much higher magnitude of overall genetic differentiation within farmed populations (0.076) than that estimated using the 19 neutral microsatellite loci (0.041). Bayesian structural analysis showed that the PRL, GH, and RAMP3 markers were able to distinguish farmed from wild populations, but were not able to distinguish different wild groups as 19 neutral microsatellite markers did. Farmed populations of different origins were assigned to a separate cluster with a high individual assignment score (>88%). It appears that the candidate markers are more influenced by artificial selection compared to neutral markers. Further validation of their efficiency in discriminating wild, farmed, and mixed fish origins using a more robust sample size is needed to ensure their potential use in an escaped fish monitoring programme.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Baidai, J. Uranga, M. Grande, H. Murua, J. Santiago, I. Quincoces, G. Boyra, B. Orue, L. Floch, M. Capello
Satellite-linked buoys used by tropical tuna purse-seine vessels on drifting fish aggregating devices (DFADs) provide a continuous stream of information on both the ocean characteristics and the presence and size of fish aggregations associated with DFADs, enabling the study of pelagic communities. This unprecedented amount of data is characterized by ocean-scale coverage with high spatial and temporal resolutions, but also by different data formats and specifications depending on buoy model and brand, as well as on the type of data exchange agreements into play. Their use for scientific and management purposes is therefore critically dependent on the abilities of algorithms to process heterogeneous data formats and resolutions. This paper proposes a unified set of algorithms for processing the buoys location data used by the two major purse seine fleets operating in the Atlantic and Indian oceans. Three main issues that need to be addressed prior to the exploitation of the data are identified (structural errors, data records on land and on-board vessels) and five specific filtering criteria are proposed to improve the data cleaning process and, hence, quality. Different filtering procedures are also compared, and their advantages and limitations are discussed.
{"title":"A standard processing framework for the location data of satellite-linked buoys on drifting fish aggregating devices","authors":"Y. Baidai, J. Uranga, M. Grande, H. Murua, J. Santiago, I. Quincoces, G. Boyra, B. Orue, L. Floch, M. Capello","doi":"10.1051/alr/2022013","DOIUrl":"https://doi.org/10.1051/alr/2022013","url":null,"abstract":"Satellite-linked buoys used by tropical tuna purse-seine vessels on drifting fish aggregating devices (DFADs) provide a continuous stream of information on both the ocean characteristics and the presence and size of fish aggregations associated with DFADs, enabling the study of pelagic communities. This unprecedented amount of data is characterized by ocean-scale coverage with high spatial and temporal resolutions, but also by different data formats and specifications depending on buoy model and brand, as well as on the type of data exchange agreements into play. Their use for scientific and management purposes is therefore critically dependent on the abilities of algorithms to process heterogeneous data formats and resolutions. This paper proposes a unified set of algorithms for processing the buoys location data used by the two major purse seine fleets operating in the Atlantic and Indian oceans. Three main issues that need to be addressed prior to the exploitation of the data are identified (structural errors, data records on land and on-board vessels) and five specific filtering criteria are proposed to improve the data cleaning process and, hence, quality. Different filtering procedures are also compared, and their advantages and limitations are discussed.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Identifying changes in the population structure and dynamics for fish stocks is important to support its management. Data obtained from 1976 to 2019 allowed to follow up long more than four decades the changes in the population structure and life-history of Umbrina canosai, an intensely exploited demersal sciaenid fish in southern Brazil. Intense fishing caused the truncation of the length/age structure with the loss of most of the bigger/older fishes and the sex ratio change, with increasing frequencies of males. A considerable increase in individual growth was observed and attributed to the lower competition for food due to the reduction in the density of the overall coastal benthic-feeding fish community caused by intense fishing. The large increase in the mortality and the exploitation rate resulted in a drastic decrease in the reproductive potential despite some anticipation in the sexual maturation. Despite the adaptative response to intense fishing, the high exploitation rates and the drastic reduction of the spawning potential ratio in recent years, are clear evidences that U. canosai could be reaching its adaptive capacity for resilience. Therefore, an urgent necessity for a drastic reduction of the fishing mortality to avoid the economic collapse of the fishery is required.
{"title":"Changes in the population structure and life history associated with long-term intense fishing of the Argentinian croaker Umbrina canosai in southern Brazil","authors":"M. Haimovici, E. Kikuchi, L. Cardoso","doi":"10.1051/alr/2022012","DOIUrl":"https://doi.org/10.1051/alr/2022012","url":null,"abstract":"Identifying changes in the population structure and dynamics for fish stocks is important to support its management. Data obtained from 1976 to 2019 allowed to follow up long more than four decades the changes in the population structure and life-history of Umbrina canosai, an intensely exploited demersal sciaenid fish in southern Brazil. Intense fishing caused the truncation of the length/age structure with the loss of most of the bigger/older fishes and the sex ratio change, with increasing frequencies of males. A considerable increase in individual growth was observed and attributed to the lower competition for food due to the reduction in the density of the overall coastal benthic-feeding fish community caused by intense fishing. The large increase in the mortality and the exploitation rate resulted in a drastic decrease in the reproductive potential despite some anticipation in the sexual maturation. Despite the adaptative response to intense fishing, the high exploitation rates and the drastic reduction of the spawning potential ratio in recent years, are clear evidences that U. canosai could be reaching its adaptive capacity for resilience. Therefore, an urgent necessity for a drastic reduction of the fishing mortality to avoid the economic collapse of the fishery is required.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anakhy Mondal, P. Sardar, Manish Jayant, S. N, G. Radhakrishnan, P. Jana, N. P. Sahu
Various single leaf meal can substitute costly de-oiled rice bran (DORB) in farm made feed for carps. However, the use of mixed leaf meal (LM) in fish feed is not reported yet. Therefore, Vigna mungo, Ipomoea aquatica and Hygrophila spinosa leaf meals were blended in an equal proportion to prepare LM. DORB was the major energy source in control diet (C) and LM substituted 50% and 100% of DORB in LM20 and LM40 experimental diets, respectively. In addition, control diet (C), LM20 and LM40 diets were supplemented with limiting amino acids and exogenous carbohydrases and denoted as CE, LM20E and LM40E, respectively. Labeo rohita fingerlings were fed till satiation for 60 days. Fish fed with LM20E diet exhibited maximum growth rates and feed conversion (p <0.05) however these were similar in C and LM40 (p > 0.05). Amylase and aminotransferase activities were positively related with growth indices (p < 0.05). Difference in hematological indices was negligible (except total leukocyte count), and lactate dehydrogenase activities in DORB and LM-based fed groups (p > 0.05) while lower superoxide dismutase activities was observed in LM fed groups (p < 0.05). The present study concluded that LM up to 400 g kg–1 could be incorporated as complete DORB replacer in L. rohita diet, however, 200 g kg–1 LM supplemented with 0.98 g L-lysine kg–1 and 1 g exogenous enzyme kg–1 registered the best growth, nutrient utilization, feed conversion ratio, physio-metabolic responses and hematological status.
各种单叶粕可以代替昂贵的去油米糠(DORB)作为鲤鱼饲料。然而，混合叶粕在鱼类饲料中的应用尚未见报道。因此，将芒藤叶粕、水木叶粕和刺湿菇叶粕按等比例混合制备LM。在对照饲粮(C)中，DORB是主要能量来源，LM20和LM40试验饲粮中，LM分别替代了50%和100%的DORB。在对照饲粮(C)、LM20和LM40中分别添加限制性氨基酸和外源糖酶，分别记为CE、LM20E和LM40E。饲养60 d至饱腹。饲喂LM20E饲料的鱼的生长率和饲料系数最高(p 0.05)。淀粉酶和转氨酶活性与生长指标呈正相关(p < 0.05)。血液学指标(白细胞总数除外)和乳酸脱氢酶活性差异可忽略不计(p < 0.05)，而超氧化物歧化酶活性低于LM饲喂组(p < 0.05)。综上所述，400 g kg-1的LM可作为罗氏乳鼠饲料中完全的DORB替代品，但在200 g kg-1的LM中，添加0.98 g l -赖氨酸kg-1和1 g外源酶kg-1时，生长、养分利用率、饲料转化率、生理代谢反应和血液学状况最佳。
{"title":"Mixed leaf meal supplemented with exogenous enzyme and limiting amino acids can completely replace DORB (de-oiled rice bran) in the diet of Labeo rohita","authors":"Anakhy Mondal, P. Sardar, Manish Jayant, S. N, G. Radhakrishnan, P. Jana, N. P. Sahu","doi":"10.1051/alr/2022007","DOIUrl":"https://doi.org/10.1051/alr/2022007","url":null,"abstract":"Various single leaf meal can substitute costly de-oiled rice bran (DORB) in farm made feed for carps. However, the use of mixed leaf meal (LM) in fish feed is not reported yet. Therefore, Vigna mungo, Ipomoea aquatica and Hygrophila spinosa leaf meals were blended in an equal proportion to prepare LM. DORB was the major energy source in control diet (C) and LM substituted 50% and 100% of DORB in LM20 and LM40 experimental diets, respectively. In addition, control diet (C), LM20 and LM40 diets were supplemented with limiting amino acids and exogenous carbohydrases and denoted as CE, LM20E and LM40E, respectively. Labeo rohita fingerlings were fed till satiation for 60 days. Fish fed with LM20E diet exhibited maximum growth rates and feed conversion (p <0.05) however these were similar in C and LM40 (p > 0.05). Amylase and aminotransferase activities were positively related with growth indices (p < 0.05). Difference in hematological indices was negligible (except total leukocyte count), and lactate dehydrogenase activities in DORB and LM-based fed groups (p > 0.05) while lower superoxide dismutase activities was observed in LM fed groups (p < 0.05). The present study concluded that LM up to 400 g kg–1 could be incorporated as complete DORB replacer in L. rohita diet, however, 200 g kg–1 LM supplemented with 0.98 g L-lysine kg–1 and 1 g exogenous enzyme kg–1 registered the best growth, nutrient utilization, feed conversion ratio, physio-metabolic responses and hematological status.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Naiel, H. M. Abdel‐Latif, M. A. Abd El-Hack, A. Khafaga, S. Elnesr, M. Dawood, L. Alkazmi, Hany Abdelfatah Elhady, G. Batiha, M. Alagawany, C. Conte‐Junior
The widespread usage of nanotechnology in many essential products has raised concerns about the possible release of nanoparticles (NPs) into aquatic habitats. Cerium dioxide (CeO2) has gained the most interest in the worldwide nanotechnology industry of all types of Ce minerals owing to its beneficial uses in a wide range of industry practices such as catalysts, sunscreens, fuel additives, fuel cells, and biomedicine. Besides, it was realized that CeO2 nanoparticles (n-CeO2) have multi-enzyme synthesized properties that create various biological impacts, such as effectively antioxidant towards almost all irritant intracellular reactive oxygen species. Lately, it was discovered that a large amount of n-CeO2 from untreated industrial waste could be released into the aquatic environment and affect all living organisms. In addition, the physical/chemical characteristics, fate, and bioavailability of nanomaterials in the aquatic environment were discovered to be related to the synthesis technique. Thus, there are intended needs in identifying the optimal technique of synthesized CeO2 nanoparticles in order to assess their beneficial use or their potential ecotoxicological impacts on aquatic organisms and humans. Therefore, this review sheds light on the possible threats of n-CeO2 to aquatic creatures as well as its synthesized techniques. Also, it discusses the possible mechanism of n-CeO2 toxicity as well as their potential benefits in the aquaculture industry.
{"title":"The applications of cerium oxide nanoform and its ecotoxicity in the aquatic environment: an updated insight","authors":"M. Naiel, H. M. Abdel‐Latif, M. A. Abd El-Hack, A. Khafaga, S. Elnesr, M. Dawood, L. Alkazmi, Hany Abdelfatah Elhady, G. Batiha, M. Alagawany, C. Conte‐Junior","doi":"10.1051/alr/2022008","DOIUrl":"https://doi.org/10.1051/alr/2022008","url":null,"abstract":"The widespread usage of nanotechnology in many essential products has raised concerns about the possible release of nanoparticles (NPs) into aquatic habitats. Cerium dioxide (CeO2) has gained the most interest in the worldwide nanotechnology industry of all types of Ce minerals owing to its beneficial uses in a wide range of industry practices such as catalysts, sunscreens, fuel additives, fuel cells, and biomedicine. Besides, it was realized that CeO2 nanoparticles (n-CeO2) have multi-enzyme synthesized properties that create various biological impacts, such as effectively antioxidant towards almost all irritant intracellular reactive oxygen species. Lately, it was discovered that a large amount of n-CeO2 from untreated industrial waste could be released into the aquatic environment and affect all living organisms. In addition, the physical/chemical characteristics, fate, and bioavailability of nanomaterials in the aquatic environment were discovered to be related to the synthesis technique. Thus, there are intended needs in identifying the optimal technique of synthesized CeO2 nanoparticles in order to assess their beneficial use or their potential ecotoxicological impacts on aquatic organisms and humans. Therefore, this review sheds light on the possible threats of n-CeO2 to aquatic creatures as well as its synthesized techniques. Also, it discusses the possible mechanism of n-CeO2 toxicity as well as their potential benefits in the aquaculture industry.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The durability of animal parts that are collected and traded as trophies has an impact on species sustainability, especially when animals are slow-growing, have low fecundity, or are particularly vulnerable to capture. CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora), aims to control the trade of wild fauna and flora specifically by using trade restrictions as a policy option. However, specialists in international trade have advised against using trade restrictions to correct social cost issues. The reasons for this advice have to do with the unintended economic consequences of animals being placed on an endangered species list, coupled with the trade restrictions themselves. We focused on Pristis spp. (sawfish), a species in danger of extinction found in Appendix I of the CITES convention. An extensive search of sawfish saws for sale on the internet was performed during 2016 and 2017. A total of 174 observations of market prices were collected. We estimated several models linking prices to the size of the saw with other variables that might explain price variability using OLS regression, and which included data from both the original internet searches and additional variables, including a dummy variable which indicated the year in which the species group was placed in Appendix I. These models show that rather than slow down the extinction pathway for this species, CITES may have sped it up, as well as driving the sawfish trophy markets underground.
{"title":"Do CITES trade restrictions work? Some evidence from the markets for sawfish trophies","authors":"Santiago Gómez-Rodríguez, James R. Wilson","doi":"10.1051/alr/2022003","DOIUrl":"https://doi.org/10.1051/alr/2022003","url":null,"abstract":"The durability of animal parts that are collected and traded as trophies has an impact on species sustainability, especially when animals are slow-growing, have low fecundity, or are particularly vulnerable to capture. CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora), aims to control the trade of wild fauna and flora specifically by using trade restrictions as a policy option. However, specialists in international trade have advised against using trade restrictions to correct social cost issues. The reasons for this advice have to do with the unintended economic consequences of animals being placed on an endangered species list, coupled with the trade restrictions themselves. We focused on Pristis spp. (sawfish), a species in danger of extinction found in Appendix I of the CITES convention. An extensive search of sawfish saws for sale on the internet was performed during 2016 and 2017. A total of 174 observations of market prices were collected. We estimated several models linking prices to the size of the saw with other variables that might explain price variability using OLS regression, and which included data from both the original internet searches and additional variables, including a dummy variable which indicated the year in which the species group was placed in Appendix I. These models show that rather than slow down the extinction pathway for this species, CITES may have sped it up, as well as driving the sawfish trophy markets underground.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Homère J. Alves Monteiro, C. Saurel, Maj-Britt Jacobsen, Jakob Hemmer-Hansen, D. Bekkevold
Preserving and maximizing genetic diversity in conservation programs, including for restocking, are of high importance. The threatened European flat oyster (Ostrea edulis) is currently the subject of several applied conservation and restocking programs, but concerns have been raised over potential negative side effects of these programs, for example due to our limited knowledge about the genetic effects in natural populations of releasing offspring of hatchery origin. Here, we developed an effective, easily applicable and highly reliable method to assess the genetic diversity and parental contributions in flat oyster hatchery production based on analyses of 17 microsatellite loci. We analysed four broodstocks and their hatchery-reared spat (total n = 354) and compared diversity to that in wild samples of adults and spat from the broodstock source in the Limfjorden (total n = 138). Based on four hatchery tank experiments with fully resolved parentage assignments, we found that five swarming events (larval releases) were characterized by a single maternal and multiple paternal contributions, and that the number of contributing parents varied greatly both among individual tanks, and between swarming events within tank. On average, the effective number of breeders was only one third of the actual broodstock size. Although the broodstock exhibited high genetic variation, the high reproductive skew resulted in produced offspring representing only a relatively small subset of this variation. The work demonstrates potential impact of hatchery reared offspring on decreasing genetic diversity in wild populations, but also that genetic monitoring can be integrated in conservation programs to minimize negative effects on restoration and supplementary restocking programs that utilize hatchery reared spats to support natural populations.
{"title":"Genetic parentage reconstruction as a practical tool applied to aquaculture and restoration programs for the European flat oyster, Ostrea edulis","authors":"Homère J. Alves Monteiro, C. Saurel, Maj-Britt Jacobsen, Jakob Hemmer-Hansen, D. Bekkevold","doi":"10.1051/alr/2022018","DOIUrl":"https://doi.org/10.1051/alr/2022018","url":null,"abstract":"Preserving and maximizing genetic diversity in conservation programs, including for restocking, are of high importance. The threatened European flat oyster (Ostrea edulis) is currently the subject of several applied conservation and restocking programs, but concerns have been raised over potential negative side effects of these programs, for example due to our limited knowledge about the genetic effects in natural populations of releasing offspring of hatchery origin. Here, we developed an effective, easily applicable and highly reliable method to assess the genetic diversity and parental contributions in flat oyster hatchery production based on analyses of 17 microsatellite loci. We analysed four broodstocks and their hatchery-reared spat (total n = 354) and compared diversity to that in wild samples of adults and spat from the broodstock source in the Limfjorden (total n = 138). Based on four hatchery tank experiments with fully resolved parentage assignments, we found that five swarming events (larval releases) were characterized by a single maternal and multiple paternal contributions, and that the number of contributing parents varied greatly both among individual tanks, and between swarming events within tank. On average, the effective number of breeders was only one third of the actual broodstock size. Although the broodstock exhibited high genetic variation, the high reproductive skew resulted in produced offspring representing only a relatively small subset of this variation. The work demonstrates potential impact of hatchery reared offspring on decreasing genetic diversity in wild populations, but also that genetic monitoring can be integrated in conservation programs to minimize negative effects on restoration and supplementary restocking programs that utilize hatchery reared spats to support natural populations.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study sheds light on challenges and possibilities for the German aquaculture sector resulting from the restrictions imposed by the German government to contain the Coronavirus SARS-CoV-2. By presenting results of expert interviews, stakeholder statements and a survey among German fish farmers, we provide insights into distribution, cost and turnover developments trigged by the restrictions in 2020. The survey shows that the pandemic had an impact on the business of a large group of producers: 44% of the fish farmers reported disturbed production processes, 46% experienced a decline in sales and the restricted gastronomy sector impacted negatively on the sales of 79%. On the other hand, 15% of the respondents were able to sell more than in 2019, 27% expanded their sales directly to the consumers. Nevertheless, a great majority (78%) did not perceive the impact of the Covid-19 pandemic as the main challenge of German aquaculture. Based on the gained insights, we estimated the economic impacts of the Covid-19 restrictions on typical German fish farms under three scenarios with EBIT changes ranging from −10% to +8% compared to 2019. In that way, the gained insights teach valuable lessons on the sector's resilience to external shocks. During the scenarios a lack of vertical integration and a dependency on wholesale led to financial challenges. On the other hand, the scenarios attest fish farms with direct marketing structures and diversified distribution channels a higher resilience to external shocks: the small-scale structure of the German aquaculture that was often seen as a weakness on a globalised market proved to be an advantage.
{"title":"German aquaculture under Covid-19 – impacts of the pandemic on the sector during 2020","authors":"Lina-Marie Huber, T. Lasner","doi":"10.1051/alr/2022019","DOIUrl":"https://doi.org/10.1051/alr/2022019","url":null,"abstract":"This study sheds light on challenges and possibilities for the German aquaculture sector resulting from the restrictions imposed by the German government to contain the Coronavirus SARS-CoV-2. By presenting results of expert interviews, stakeholder statements and a survey among German fish farmers, we provide insights into distribution, cost and turnover developments trigged by the restrictions in 2020. The survey shows that the pandemic had an impact on the business of a large group of producers: 44% of the fish farmers reported disturbed production processes, 46% experienced a decline in sales and the restricted gastronomy sector impacted negatively on the sales of 79%. On the other hand, 15% of the respondents were able to sell more than in 2019, 27% expanded their sales directly to the consumers. Nevertheless, a great majority (78%) did not perceive the impact of the Covid-19 pandemic as the main challenge of German aquaculture. Based on the gained insights, we estimated the economic impacts of the Covid-19 restrictions on typical German fish farms under three scenarios with EBIT changes ranging from −10% to +8% compared to 2019. In that way, the gained insights teach valuable lessons on the sector's resilience to external shocks. During the scenarios a lack of vertical integration and a dependency on wholesale led to financial challenges. On the other hand, the scenarios attest fish farms with direct marketing structures and diversified distribution channels a higher resilience to external shocks: the small-scale structure of the German aquaculture that was often seen as a weakness on a globalised market proved to be an advantage.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The narrow-clawed crayfish (Pontastacus leptodactylus) is one of the most ecologically and economically important freshwater species in Turkey. However, the harvest of this species has declined from 7937 t in 1984 to 696 t in 2019. One of primary reasons for this decrease in stock is the use of fishing gears with poor size selectivity. In this study, new codend designs were investigated to improve the size selectivity of fyke nets for P. leptodactylus. Seven codends of three different designs were tested: (1) a commercially used standard codend with 34 mm mesh size (Com34); (2) sorting grids with 20 (SG20), 25 (SG25) and 30 mm (SG30) bar spacing attached to the last circle of the net; and (3) a stiff rigged net, the last part of the fyke nets (codend) with 34 (SRN34), 42 (SRN42) and 50 mm (SRN50) mesh size. The average length at 50% retention probability (L50) and selection range (SR) (L75–L25) values of Com34 were 9.4 cm and 3.1 cm, respectively. For the SG20, SG25 and SG30 grids, the L50 values were 11.3 cm, 11.6 cm and 12.0 cm, while the SR values were 1.4 cm, 1.3 cm and 0.6 cm, respectively. For the SRN34, SRN42 and SRN50 codends, the L50 values were 10.9 cm, 11.6 cm and 11.6 cm, while the SR values were 2.1 cm, 2.1cm and 1.1 cm, respectively. Overall, the commercial codend resulted in lower L50 values when the minimum conservation reference length of 10 cm was considered. However, all tested new codend designs showed improved selectivity compared with the standard, with optimum results obtained with SG20. SG20 grid decreased discarding by 15.7% compared to the classic commercial fyke net; thus, this is a very important result for the sustainability of natural P. leptodactylus stocks.
窄爪小龙虾(Pontastacus leptodactylus)是土耳其最重要的生态和经济淡水物种之一。然而，该物种的收获量从1984年的7937吨下降到2019年的696吨。鱼类数量减少的主要原因之一是使用了尺寸选择性差的渔具。本研究探讨了新的码尾设计，以提高对细趾假单足虫网具的大小选择性。测试了三种不同设计的七种码头:(1)商用标准码头，网目尺寸为34 mm (Com34);(2)在网的最后一圈附着20 (SG20)、25 (SG25)和30 mm (SG30)棒距的分选网格;(3)硬式吊网，最后一部分的网目尺寸分别为34 (SRN34)、42 (SRN42)和50 mm (SRN50)。Com34在50%保留概率下的平均长度(L50)和选择范围(SR) (l75 ~ l25)分别为9.4 cm和3.1 cm。对于SG20、SG25和SG30栅格，L50值分别为11.3、11.6和12.0 cm, SR值分别为1.4、1.3和0.6 cm。SRN34、SRN42和SRN50的L50值分别为10.9 cm、11.6 cm和11.6 cm, SR值分别为2.1cm、2.1cm和1.1 cm。总体而言，当考虑最小保护参考长度为10 cm时，商业规范导致L50值较低。然而，与标准相比，所有测试的新编码端设计都显示出更高的选择性，其中SG20获得了最佳结果。与传统的商业电网相比，SG20电网的丢弃量减少了15.7%;因此，这是一个非常重要的结果，对自然的纤毛霉种群的可持续性。
{"title":"New codend designs to improve the size selectivity of fyke net for narrow-clawed crayfish (Pontastacus leptodactylus)","authors":"Mehmet Cìlbìz, Celalettin Aydın, B. Herrmann","doi":"10.1051/alr/2022014","DOIUrl":"https://doi.org/10.1051/alr/2022014","url":null,"abstract":"The narrow-clawed crayfish (Pontastacus leptodactylus) is one of the most ecologically and economically important freshwater species in Turkey. However, the harvest of this species has declined from 7937 t in 1984 to 696 t in 2019. One of primary reasons for this decrease in stock is the use of fishing gears with poor size selectivity. In this study, new codend designs were investigated to improve the size selectivity of fyke nets for P. leptodactylus. Seven codends of three different designs were tested: (1) a commercially used standard codend with 34 mm mesh size (Com34); (2) sorting grids with 20 (SG20), 25 (SG25) and 30 mm (SG30) bar spacing attached to the last circle of the net; and (3) a stiff rigged net, the last part of the fyke nets (codend) with 34 (SRN34), 42 (SRN42) and 50 mm (SRN50) mesh size. The average length at 50% retention probability (L50) and selection range (SR) (L75–L25) values of Com34 were 9.4 cm and 3.1 cm, respectively. For the SG20, SG25 and SG30 grids, the L50 values were 11.3 cm, 11.6 cm and 12.0 cm, while the SR values were 1.4 cm, 1.3 cm and 0.6 cm, respectively. For the SRN34, SRN42 and SRN50 codends, the L50 values were 10.9 cm, 11.6 cm and 11.6 cm, while the SR values were 2.1 cm, 2.1cm and 1.1 cm, respectively. Overall, the commercial codend resulted in lower L50 values when the minimum conservation reference length of 10 cm was considered. However, all tested new codend designs showed improved selectivity compared with the standard, with optimum results obtained with SG20. SG20 grid decreased discarding by 15.7% compared to the classic commercial fyke net; thus, this is a very important result for the sustainability of natural P. leptodactylus stocks.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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