The physiological response of two species of mussels (Mytilus edulis and M. galloprovincialis) and two species of oysters (Crassostrea gigas and Ostrea edulis) to temperature, oxygen levels and food concentration, factors likely to vary as a result of climate change, was determined experimentally. Bivalves of similar size from different origins were exposed to six temperatures (3, 8, 15, 20, 25 and 30 °C) at two food regimes (2 and 10 μg Chl a L−1) for 6 weeks. In a parallel running experiment M. edulis from the same batches were exposed to three different temperatures (15, 20 and 25 °C) and three different oxygen levels (30, 50 and 100%) at two food regimes (2 and >8 μg Chl a L−1) for 3–4 weeks. Survival during the experiment ranged from 93% to 100% except for the mussels exposed to 30 °C which showed 100% mortality after three to 32 days. Higher food conditions showed higher optimal temperatures for growth of mussels and oysters. In addition, at the high food treatment, reduced O2 saturation resulted in lower growth of mussels. At the low food treatment there were no differences in growth among the different O2 levels at the same temperature. At high food concentration treatment, M. edulis growth was higher with low temperature and high oxygen level. Condition index was higher at higher food concentrations and decreased with increasing temperature. In addition, condition was lower at low oxygen saturation. Lower clearance rates were observed at high food concentrations. At 100% saturation of oxygen, mussel clearance rate increased with temperature at High food regime, but not at Low food regime. Mussel clearance rates were significantly reduced with low oxygen concentrations together with high temperature. Oxygen consumption significantly increased with temperature. Oxygen saturation was the main factor affecting mussel clearance rate. High temperature and low oxygen concentration combined significantly reduced clearance rate and increased oxygen consumption. These response curves can be used to improve parameterisation of individual shellfish growth models taking into consideration factors in the context of climate change: temperature, food concentration, oxygen concentration and their interactions. The observation that abiotic factors interact in affecting mussels and oysters is an important result to take into account.
实验研究了两种贻贝(Mytilus edulis和M. galloprovincialis)和两种牡蛎(Crassostrea gigas和Ostrea edulis)对温度、氧气水平和食物浓度等可能因气候变化而变化的因素的生理反应。研究人员将来自不同来源的大小相似的双壳贝在6个温度(3、8、15、20、25和30°C)和两种食物体系(2和10 μg Chl a L−1)下暴露6周。在平行运行的实验中，将同一批次的毛竹芽孢杆菌暴露在三种不同温度(15、20和25°C)和三种不同氧气水平(30、50和100%)下，在两种食物体系(2和bbb80 μg Chl a L−1)下，持续3-4周。实验期间的存活率为93%至100%，但暴露于30°C的贻贝在3至32天后死亡率为100%。较高的食物条件表明贻贝和牡蛎生长的最佳温度较高。此外，在高食物处理下，氧饱和度降低导致贻贝生长减慢。在低食处理下，相同温度下不同氧含量的植株生长无差异。在高食物浓度处理下，毛竹芽孢杆菌在低温和高氧条件下生长更快。条件指数随食物浓度的升高而升高，随温度的升高而降低。此外，低氧饱和度条件较低。在高浓度食物中观察到较低的清除率。在100%氧饱和度下，高摄食条件下贻贝清除率随温度升高而升高，而低摄食条件下则不升高。低氧和高温条件下贻贝清除率显著降低。耗氧量随温度的升高而显著增加。氧饱和度是影响贻贝清除率的主要因素。高温和低氧浓度的结合显著降低了清除率，增加了耗氧量。这些响应曲线可用于改善单个贝类生长模型的参数化，考虑气候变化背景下的因素:温度、食物浓度、氧气浓度及其相互作用。观察到非生物因素在影响贻贝和牡蛎时相互作用，这是一个值得考虑的重要结果。
{"title":"Interacting climate change effects on mussels (Mytilus edulis and M. galloprovincialis) and oysters (Crassostrea gigas and Ostrea edulis): experiments for bivalve individual growth models","authors":"P. Kamermans, C. Saurel","doi":"10.1051/alr/2022001","DOIUrl":"https://doi.org/10.1051/alr/2022001","url":null,"abstract":"The physiological response of two species of mussels (Mytilus edulis and M. galloprovincialis) and two species of oysters (Crassostrea gigas and Ostrea edulis) to temperature, oxygen levels and food concentration, factors likely to vary as a result of climate change, was determined experimentally. Bivalves of similar size from different origins were exposed to six temperatures (3, 8, 15, 20, 25 and 30 °C) at two food regimes (2 and 10 μg Chl a L−1) for 6 weeks. In a parallel running experiment M. edulis from the same batches were exposed to three different temperatures (15, 20 and 25 °C) and three different oxygen levels (30, 50 and 100%) at two food regimes (2 and >8 μg Chl a L−1) for 3–4 weeks. Survival during the experiment ranged from 93% to 100% except for the mussels exposed to 30 °C which showed 100% mortality after three to 32 days. Higher food conditions showed higher optimal temperatures for growth of mussels and oysters. In addition, at the high food treatment, reduced O2 saturation resulted in lower growth of mussels. At the low food treatment there were no differences in growth among the different O2 levels at the same temperature. At high food concentration treatment, M. edulis growth was higher with low temperature and high oxygen level. Condition index was higher at higher food concentrations and decreased with increasing temperature. In addition, condition was lower at low oxygen saturation. Lower clearance rates were observed at high food concentrations. At 100% saturation of oxygen, mussel clearance rate increased with temperature at High food regime, but not at Low food regime. Mussel clearance rates were significantly reduced with low oxygen concentrations together with high temperature. Oxygen consumption significantly increased with temperature. Oxygen saturation was the main factor affecting mussel clearance rate. High temperature and low oxygen concentration combined significantly reduced clearance rate and increased oxygen consumption. These response curves can be used to improve parameterisation of individual shellfish growth models taking into consideration factors in the context of climate change: temperature, food concentration, oxygen concentration and their interactions. The observation that abiotic factors interact in affecting mussels and oysters is an important result to take into account.","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":"57824892","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}
C. Gérard, M. Hervé, Héloïse Hamel, M. Gay, Michel Barbier, T. Barreau
The starry smooth-hound Mustelus asterias is a near-threatened coastal shark in Europe, whose parasitofauna is largely unknown. We studied metazoan parasites of 20 immature sharks (13 males and seven females) from the English Channel and we examined their relationships with host condition and their use as host bioindicators. All the sharks were parasitized by one to six metazoan taxa among the twelve recorded in the whole sampling (one trematode, six cestodes and two nematodes trophically-transmitted; one monogenean, one copepod and one myxosporean on gills), with a mean abundance of 30.5 ± 21.4 parasites per fish (myxosporeans not included). The three major taxa were in decreasing order: the nematode Acanthocheilus rotundatus (prevalence: 75%, Confidence Interval 53–89%), the cestode Eutetrarhynchus sp. (70%, CI 48–85%), and the monogenean Erpocotyle laevis (60%, CI 39–78%). The gill copepod Kroyeria lineata and the gut nematode Proleptus obtusus were identified as significant pathogens. Parasite community differed between males and females despite their immature stage, suggesting early spatial sex-segregation, with E. laevis, Eutetrarhynchus sp. and Anthobothrium sp. proposed as tags. We discuss results in terms of host fitness loss and information given by parasites on diet ecology and stock discrimination. We recommend incorporating parasitology in further research to improve shark conservation and management.
{"title":"Metazoan parasite community as a potential biological indicator in juveniles of the starry smooth-hound Mustelus asterias Cloquet, 1819 (Carcharhiniformes Triakidae)","authors":"C. Gérard, M. Hervé, Héloïse Hamel, M. Gay, Michel Barbier, T. Barreau","doi":"10.1051/alr/2022002","DOIUrl":"https://doi.org/10.1051/alr/2022002","url":null,"abstract":"The starry smooth-hound Mustelus asterias is a near-threatened coastal shark in Europe, whose parasitofauna is largely unknown. We studied metazoan parasites of 20 immature sharks (13 males and seven females) from the English Channel and we examined their relationships with host condition and their use as host bioindicators. All the sharks were parasitized by one to six metazoan taxa among the twelve recorded in the whole sampling (one trematode, six cestodes and two nematodes trophically-transmitted; one monogenean, one copepod and one myxosporean on gills), with a mean abundance of 30.5 ± 21.4 parasites per fish (myxosporeans not included). The three major taxa were in decreasing order: the nematode Acanthocheilus rotundatus (prevalence: 75%, Confidence Interval 53–89%), the cestode Eutetrarhynchus sp. (70%, CI 48–85%), and the monogenean Erpocotyle laevis (60%, CI 39–78%). The gill copepod Kroyeria lineata and the gut nematode Proleptus obtusus were identified as significant pathogens. Parasite community differed between males and females despite their immature stage, suggesting early spatial sex-segregation, with E. laevis, Eutetrarhynchus sp. and Anthobothrium sp. proposed as tags. We discuss results in terms of host fitness loss and information given by parasites on diet ecology and stock discrimination. We recommend incorporating parasitology in further research to improve shark conservation and management.","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":"57824903","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}
Juliana Monteiro da Silva Vieira, P. Costa, A. C. Braga, R. R. São-Clemente, C. Ferreira, Jodir P. Silva
Age, growth and maturity of frigate tuna (Auxis thazard) were studied for the first time in Southeast Brazil. A total of 650 fish (265–494 mm Fork Length) were sampled from beach-seine landings between March 2018 and February 2019. Sectioned fin spines from 548 specimens were processed and age was determined by counting and measuring of increments. Growth parameters were fitted to length-at-age data using the von Bertalanffy growth function and were compared to the literature using the growth performance index (Phi). Macro and microscopic characterization of gonads and physiological indexes were used for the analysis of the reproductive cycle. The length distribution did not differ by sex. Assigned ages were between 0+ and 4 years, with annual increments formed during winter. Coefficient of variation between readings was 11%. Growth differed by sex, and the von Bertalanffy growth parameters were L∞ = 471 mm; k = 0.47 year−1; and t0 = –1.46 year−1 for females; L∞ = 498 mm; k = 0.35 year−1; and t0 = –2.01 year−1 for males. Phi was 5.0 for both sexes. Estimated growth rate is among the lowest recorded for the species, possibly related to the method used for age and growth assessment. Gonadosomatic index peaked in December, associated with the upwelling of the South Atlantic Central Waters, at a temperature of approximately 16 °C. Spawning activity in colder waters has never been reported for this species and may be influenced by a richer habitat caused by the intrusion of more nutritive rich waters during spring-summer, which allows larval development. Length-at-first-maturity (L50) was 345.4 mm for females and 329.8 mm for males.
{"title":"Age, growth and maturity of frigate tuna (Auxis thazard Lacepède, 1800) in the Southeastern Brazilian coast","authors":"Juliana Monteiro da Silva Vieira, P. Costa, A. C. Braga, R. R. São-Clemente, C. Ferreira, Jodir P. Silva","doi":"10.1051/alr/2022010","DOIUrl":"https://doi.org/10.1051/alr/2022010","url":null,"abstract":"Age, growth and maturity of frigate tuna (Auxis thazard) were studied for the first time in Southeast Brazil. A total of 650 fish (265–494 mm Fork Length) were sampled from beach-seine landings between March 2018 and February 2019. Sectioned fin spines from 548 specimens were processed and age was determined by counting and measuring of increments. Growth parameters were fitted to length-at-age data using the von Bertalanffy growth function and were compared to the literature using the growth performance index (Phi). Macro and microscopic characterization of gonads and physiological indexes were used for the analysis of the reproductive cycle. The length distribution did not differ by sex. Assigned ages were between 0+ and 4 years, with annual increments formed during winter. Coefficient of variation between readings was 11%. Growth differed by sex, and the von Bertalanffy growth parameters were L∞ = 471 mm; k = 0.47 year−1; and t0 = –1.46 year−1 for females; L∞ = 498 mm; k = 0.35 year−1; and t0 = –2.01 year−1 for males. Phi was 5.0 for both sexes. Estimated growth rate is among the lowest recorded for the species, possibly related to the method used for age and growth assessment. Gonadosomatic index peaked in December, associated with the upwelling of the South Atlantic Central Waters, at a temperature of approximately 16 °C. Spawning activity in colder waters has never been reported for this species and may be influenced by a richer habitat caused by the intrusion of more nutritive rich waters during spring-summer, which allows larval development. Length-at-first-maturity (L50) was 345.4 mm for females and 329.8 mm for males.","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":"57824634","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}
A. Chizhayeva, A. Amangeldi, Y. Oleinikova, A. Alybaeva, A. Sadanov
Industrial aquaculture is a dynamic area capable of solving problems of healthy nutrition and food security. Increase of organic pollution, number of opportunistic microorganisms in the aquatic environment of fish farms and the global contamination of feed by mycotoxigenic fungi are serious problems of industrial fish cultivation. The results are weakening of the general condition of fish, immunosuppression, the occurrence of various diseases complicated by drug resistance, the accumulation of antibiotics and chemical compounds in tissues. Probiotics can be an alternative to antibiotics. The use of probiotics is also one of the biological methods for maintaining and restoring the normal physiological state of fish and increasing their productivity. The aim of this review is the scientific justification of the use of lactic acid bacteria as the safest microorganisms in the development of probiotics for aquaculture. The review presented provides criteria for selecting candidate strains for effective probiotics development. The advantages of lactic acid bacteria for the prevention or control of infectious diseases in cultured fish are considered. Lactic acid bacteria are representatives of the fish microbiota, they have antagonistic activity against opportunistic pathogens, fungi and viruses that cause microbiological spoilage of feed, pollute water bodies, and cause diseases of aquatic animals. The review provides information on various researches in which lactic acid bacteria or products derived from them have been used to assess their potential in aquaculture. Numerous scientific studies prove the value of this vast group of microorganisms for the prevention and treatment of fish diseases, for increasing the resistance of aquatic animals to infectious diseases and various stresses, for improving their survival and productivity, and for improving water sanitation in fish reservoirs. Increased use of effective probiotic lactic acid bacteria in aquaculture can make the fish sector safer, more productive and friendly to the environment and human well-being, and will contribute to the sustainable development of aquaculture.
{"title":"Lactic acid bacteria as probiotics in sustainable development of aquaculture","authors":"A. Chizhayeva, A. Amangeldi, Y. Oleinikova, A. Alybaeva, A. Sadanov","doi":"10.1051/alr/2022011","DOIUrl":"https://doi.org/10.1051/alr/2022011","url":null,"abstract":"Industrial aquaculture is a dynamic area capable of solving problems of healthy nutrition and food security. Increase of organic pollution, number of opportunistic microorganisms in the aquatic environment of fish farms and the global contamination of feed by mycotoxigenic fungi are serious problems of industrial fish cultivation. The results are weakening of the general condition of fish, immunosuppression, the occurrence of various diseases complicated by drug resistance, the accumulation of antibiotics and chemical compounds in tissues. Probiotics can be an alternative to antibiotics. The use of probiotics is also one of the biological methods for maintaining and restoring the normal physiological state of fish and increasing their productivity. The aim of this review is the scientific justification of the use of lactic acid bacteria as the safest microorganisms in the development of probiotics for aquaculture. The review presented provides criteria for selecting candidate strains for effective probiotics development. The advantages of lactic acid bacteria for the prevention or control of infectious diseases in cultured fish are considered. Lactic acid bacteria are representatives of the fish microbiota, they have antagonistic activity against opportunistic pathogens, fungi and viruses that cause microbiological spoilage of feed, pollute water bodies, and cause diseases of aquatic animals. The review provides information on various researches in which lactic acid bacteria or products derived from them have been used to assess their potential in aquaculture. Numerous scientific studies prove the value of this vast group of microorganisms for the prevention and treatment of fish diseases, for increasing the resistance of aquatic animals to infectious diseases and various stresses, for improving their survival and productivity, and for improving water sanitation in fish reservoirs. Increased use of effective probiotic lactic acid bacteria in aquaculture can make the fish sector safer, more productive and friendly to the environment and human well-being, and will contribute to the sustainable development of aquaculture.","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":"57824644","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}
Alicia Mallet, J. Jouvenel, Morgane Broyon, N. Pirot, B. Geffroy
The mutable nassa, Tritia mutabilis, a marine gastropod that is widely exploited on the Adriatic coast is an important source of income for small-scale fishermen in the Mediterranean Sea, particularly in the Gulf of Lion. However, the lack of knowledge on the ecology and biology of this species limits our capacities to propose and produce an effective management plan. As a result, stocks are currently declining, especially in Italy. In order to optimize a management plan for this fishery, we designed a study to better characterize the reproductive biology of T. mutabilis, using gonad histology and performing a regular monitoring of population size frequency. The average shell height of individuals during the breeding period was 24 ± 2.7 mm for males and 30 ± 3.7 mm for females. The presence of small females (10 mm) and large males (32 mm) in the whole sample challenged previous assumptions regarding protandry (sex change from male to female). The size at first maturity was estimated for males and females at 17.5 mm and 24.4 mm shell height, respectively. In Italy, current management measures include a minimum conservation reference size of 20 mm in shell height. Therefore, it is likely that many individuals that did not reproduce are being caught, which could partly explain the decline observed, despite conservation measures introduced more than ten years ago. Overall, our study provides some baseline information to establish, in consultation with fishermen, management measures for this small-scale fishery in France.
{"title":"Histology of Tritia mutabilis gonads: using reproductive biology to support sustainable fishery management","authors":"Alicia Mallet, J. Jouvenel, Morgane Broyon, N. Pirot, B. Geffroy","doi":"10.1051/ALR/2021006","DOIUrl":"https://doi.org/10.1051/ALR/2021006","url":null,"abstract":"The mutable nassa, Tritia mutabilis, a marine gastropod that is widely exploited on the Adriatic coast is an important source of income for small-scale fishermen in the Mediterranean Sea, particularly in the Gulf of Lion. However, the lack of knowledge on the ecology and biology of this species limits our capacities to propose and produce an effective management plan. As a result, stocks are currently declining, especially in Italy. In order to optimize a management plan for this fishery, we designed a study to better characterize the reproductive biology of T. mutabilis, using gonad histology and performing a regular monitoring of population size frequency. The average shell height of individuals during the breeding period was 24 ± 2.7 mm for males and 30 ± 3.7 mm for females. The presence of small females (10 mm) and large males (32 mm) in the whole sample challenged previous assumptions regarding protandry (sex change from male to female). The size at first maturity was estimated for males and females at 17.5 mm and 24.4 mm shell height, respectively. In Italy, current management measures include a minimum conservation reference size of 20 mm in shell height. Therefore, it is likely that many individuals that did not reproduce are being caught, which could partly explain the decline observed, despite conservation measures introduced more than ten years ago. Overall, our study provides some baseline information to establish, in consultation with fishermen, management measures for this small-scale fishery in France.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824000","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. Vandeputte, A. Bestin, Louarn Fauchet, J. Allamellou, S. Bosc, O. Menchi, P. Haffray
Parentage assignment with genomic markers provides an opportunity to monitor salmon restocking programs. Most of the time, it is used to study the fate of hatchery-born fish in those programs, as well as the genetic impacts of restocking. In such analyses, only fish that are assigned to their parents are considered. In the Garonne-Dordogne river basin in France, native salmon have disappeared, and supportive breeding is being used to try to reinstate a self-sustained population. It is therefore of primary importance to assess the numbers of wild-born returning salmon, which could appear as wrongly assigned or not assigned, depending on the power of the marker set and on the size of the mating plan. We used the genotypes at nine microsatellites of the 5800 hatchery broodstock which were used from 2008 to 2014, and of 884 upstream migrating fish collected from 2008 to 2016, to assess our ability to identify wild-born salmon. We simulated genotypes of hatchery fish and wild-born fish and assessed how they were identified by the parentage assignment software Accurassign. We showed that 98.7% of the fish assigned within the recorded mating plan could be considered hatchery fish, while 93.3% of the fish in other assignment categories (assigned out of the mating plan, assigned to several parent pairs, not assigned) could be considered wild-born. Using a Bayesian approach, we showed that 31.3% of the 457 upstream migrating fish sampled from 2014 to 2016 were wild-born. This approach is thus efficient to identify wild-born fish in a restoration program. It remains dependent on the quality of the recording of the mating plan, which we showed was rather good (<5% mistakes) in this program. To limit this potential dependence, an increase in the number of markers genotyped (17 instead of 9) is now being implemented.
{"title":"Can we identify wild-born salmon from parentage assignment data? A case study in the Garonne-Dordogne rivers salmon restoration programme in France","authors":"M. Vandeputte, A. Bestin, Louarn Fauchet, J. Allamellou, S. Bosc, O. Menchi, P. Haffray","doi":"10.1051/ALR/2021008","DOIUrl":"https://doi.org/10.1051/ALR/2021008","url":null,"abstract":"Parentage assignment with genomic markers provides an opportunity to monitor salmon restocking programs. Most of the time, it is used to study the fate of hatchery-born fish in those programs, as well as the genetic impacts of restocking. In such analyses, only fish that are assigned to their parents are considered. In the Garonne-Dordogne river basin in France, native salmon have disappeared, and supportive breeding is being used to try to reinstate a self-sustained population. It is therefore of primary importance to assess the numbers of wild-born returning salmon, which could appear as wrongly assigned or not assigned, depending on the power of the marker set and on the size of the mating plan. We used the genotypes at nine microsatellites of the 5800 hatchery broodstock which were used from 2008 to 2014, and of 884 upstream migrating fish collected from 2008 to 2016, to assess our ability to identify wild-born salmon. We simulated genotypes of hatchery fish and wild-born fish and assessed how they were identified by the parentage assignment software Accurassign. We showed that 98.7% of the fish assigned within the recorded mating plan could be considered hatchery fish, while 93.3% of the fish in other assignment categories (assigned out of the mating plan, assigned to several parent pairs, not assigned) could be considered wild-born. Using a Bayesian approach, we showed that 31.3% of the 457 upstream migrating fish sampled from 2014 to 2016 were wild-born. This approach is thus efficient to identify wild-born fish in a restoration program. It remains dependent on the quality of the recording of the mating plan, which we showed was rather good (<5% mistakes) in this program. To limit this potential dependence, an increase in the number of markers genotyped (17 instead of 9) is now being implemented.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824098","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}
In-situ identification of fish species using acoustic methods is a key issue for fisheries research and ecological applications. We propose a novel approach to fish discrimination based on the relationship between target strength frequency response (TS(f)) and vertical swim velocity (VSV), as a proxy of fish body orientation. The measurements were carried out with a wideband echosounder on live fish of five species confined in a net cage. The data show a large dependence of TS(f) on VSV. To compare the variability of frequency responses of different fishes, we calculated ΔTS(f, VSV) as the difference between the TS(f) at given VSV and the TS(f) at VSV = 0, i.e. when the fish was swimming horizontally. We demonstrated that the relationships between ΔTS and VSV were similar for fish of the same species but dissimilar for different species. This implies that the acoustic fish discrimination in nature might be performed when the variations of the VSV can be measured from acoustically tracked fish. This can be a promising method for remote fish discrimination, for instance, for fish with diurnal vertical migrations. Further validation of this approach for fish recognition is required.
{"title":"The relationship between target strength frequency response and vertical swim velocity: a new approach for fish discrimination","authors":"H. Homma, I. Ostrovsky","doi":"10.1051/ALR/2021011","DOIUrl":"https://doi.org/10.1051/ALR/2021011","url":null,"abstract":"In-situ identification of fish species using acoustic methods is a key issue for fisheries research and ecological applications. We propose a novel approach to fish discrimination based on the relationship between target strength frequency response (TS(f)) and vertical swim velocity (VSV), as a proxy of fish body orientation. The measurements were carried out with a wideband echosounder on live fish of five species confined in a net cage. The data show a large dependence of TS(f) on VSV. To compare the variability of frequency responses of different fishes, we calculated ΔTS(f, VSV) as the difference between the TS(f) at given VSV and the TS(f) at VSV = 0, i.e. when the fish was swimming horizontally. We demonstrated that the relationships between ΔTS and VSV were similar for fish of the same species but dissimilar for different species. This implies that the acoustic fish discrimination in nature might be performed when the variations of the VSV can be measured from acoustically tracked fish. This can be a promising method for remote fish discrimination, for instance, for fish with diurnal vertical migrations. Further validation of this approach for fish recognition is required.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824229","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}
Theory suggests the use of individual transferable quotas (ITQs) as a solution to overcapacity and to keep efficient fishers active. While the reduction of overcapacity under ITQ implementation is well documented, empirical evidence on the role of capacity utilisation in adjusting the labour force is scarce. This article analyses whether the capacity utilisation of the vessels that fishers own/work on influences their probability of continuing fishing or whether factors such as fishing income and pension are more important. Danish small-scale fisheries with vessels less than 17 m in length, in which ITQs were introduced in 2007, are studied using a multinomial logit regression based on a unique dataset of individual income and socioeconomic characteristics of Danish fishers in the period 2002-2012 as well as individual vessel data. Together with other relevant socioeconomic variables, vessel capacity utilisation is included in the regression. The latter is identified in a productivity analysis of all commercial active vessels using Data Envelopment Analysis. It is found that increasing vessel capacity utilisation both significantly and positively influences the decision to stay in a small-scale fishery. Increasing income from fisheries also significantly influences the probability of staying in the fishery business. The Danish results provide evidence that the most efficient fishers are those who remain active when ITQs are implemented.
{"title":"Do efficient small-scale fishers stay active in eras of introducing individual transferable quotas? Evidence from Denmark","authors":"Ayoe Hoff, M. Nielsen, R. Nielsen","doi":"10.1051/alr/2021014","DOIUrl":"https://doi.org/10.1051/alr/2021014","url":null,"abstract":"Theory suggests the use of individual transferable quotas (ITQs) as a solution to overcapacity and to keep efficient fishers active. While the reduction of overcapacity under ITQ implementation is well documented, empirical evidence on the role of capacity utilisation in adjusting the labour force is scarce. This article analyses whether the capacity utilisation of the vessels that fishers own/work on influences their probability of continuing fishing or whether factors such as fishing income and pension are more important. Danish small-scale fisheries with vessels less than 17 m in length, in which ITQs were introduced in 2007, are studied using a multinomial logit regression based on a unique dataset of individual income and socioeconomic characteristics of Danish fishers in the period 2002-2012 as well as individual vessel data. Together with other relevant socioeconomic variables, vessel capacity utilisation is included in the regression. The latter is identified in a productivity analysis of all commercial active vessels using Data Envelopment Analysis. It is found that increasing vessel capacity utilisation both significantly and positively influences the decision to stay in a small-scale fishery. Increasing income from fisheries also significantly influences the probability of staying in the fishery business. The Danish results provide evidence that the most efficient fishers are those who remain active when ITQs are implemented.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824319","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. Çi̇ftçi, O. Eroğlu, Ş. Firidin, Hacı Savaş, Yusuf Bektaş
In this study, the genetic relationships of 804 tarek (Alburnus tarichi) samples from a total of 18 populations, including the potamodromus and resident individuals from Lake Van basin in eastern Turkey, were studied by using nine microsatellite loci. A total of 93 alleles was detected, and the average number of alleles per locus was 10.3 ± 3.39. The mean estimated observed and expected heterozygosity were 0.340 ± 0.016 and 0.362 ± 0.015, respectively, which indicated a low level of polymorphism. After Bonferroni correction (P< 0.0027), the multi-locus test applied to each population revealed that 12 out of 18 populations were in Hardy-Weinberg equilibrium (HWE) (P = 0.0120–0.9981). Analysis of molecular variance (AMOVA) showed more than 76% genetic variability within individuals and 19% among populations, which was significantly higher than zero (FST = 0.19), and furthermore, a low level of genetic variation was observed among individuals within populations (4.84%: FIS = 0.06). Bayesian clustering analysis indicated that the total genetic variation grouped into 3 clusters. Additionally, the significance test results revealed that 11 of the 18 populations are threatened with extinction due to recent bottleneck events.We conclude that the tarek populations from the Lake Van basin can be classified into distinct genetic groups, based on microsatellite information. In addition, our results provide essential information for the development of a management plan that conserves the tarek's genetic diversity and achieves a sustainable fishery.
{"title":"Genetic diversity and population structure of Tarek (Alburnus tarichi), an endemic species to the Lake Van basin, Turkey","authors":"Y. Çi̇ftçi, O. Eroğlu, Ş. Firidin, Hacı Savaş, Yusuf Bektaş","doi":"10.1051/ALR/2021005","DOIUrl":"https://doi.org/10.1051/ALR/2021005","url":null,"abstract":"In this study, the genetic relationships of 804 tarek (Alburnus tarichi) samples from a total of 18 populations, including the potamodromus and resident individuals from Lake Van basin in eastern Turkey, were studied by using nine microsatellite loci. A total of 93 alleles was detected, and the average number of alleles per locus was 10.3 ± 3.39. The mean estimated observed and expected heterozygosity were 0.340 ± 0.016 and 0.362 ± 0.015, respectively, which indicated a low level of polymorphism. After Bonferroni correction (P< 0.0027), the multi-locus test applied to each population revealed that 12 out of 18 populations were in Hardy-Weinberg equilibrium (HWE) (P = 0.0120–0.9981). Analysis of molecular variance (AMOVA) showed more than 76% genetic variability within individuals and 19% among populations, which was significantly higher than zero (FST = 0.19), and furthermore, a low level of genetic variation was observed among individuals within populations (4.84%: FIS = 0.06). Bayesian clustering analysis indicated that the total genetic variation grouped into 3 clusters. Additionally, the significance test results revealed that 11 of the 18 populations are threatened with extinction due to recent bottleneck events.We conclude that the tarek populations from the Lake Van basin can be classified into distinct genetic groups, based on microsatellite information. In addition, our results provide essential information for the development of a management plan that conserves the tarek's genetic diversity and achieves a sustainable fishery.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824343","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}
Unreliable information on harvest potential is a persistent challenge for the Indonesian government and industry alike to manage an efficient supply chain of seaweed raw material. The use of remote sensing technology to assess seaweed harvest potential has been scarcely available in the literature. This current research aimed at estimating the harvest potential of seaweed Kappaphycus alvarezii through remote sensing using supervised classification with maximum likelihood (MLC) and contextual editing (CE) methods. This research evaluated the capabilities of different band combinations along with depth invariant index (DII) to enhance the remote sensing accuracy in estimating seaweed harvest potential. The seaweed classification using Worldview-2 imagery was compared with the in-situ references (ground-truthing). The potential data bias resulted from different imagery acquisition timestamps with the in-situ measurement was kept minimal as both data time stamps were ten days apart and within the same seaweed culture cycle. The average dry weight of all seaweed samples collected during the research was 924 ± 278.91 g/m2 with culture ages between 1 and 40 days. The classification results based on MLC+CE with a 5-band combination method without DII showed a better correlation and closer fit with the in-situ references compared to the other methods, with an overall accuracy of 79.05% and Tau coefficient value of 0.75. The estimated total harvest potential based on the combined seaweed classes was 531.26 ± 250.29 tons dry weight.
{"title":"Mapping and estimating harvest potential of seaweed culture using Worldview-2 Satellite images: a case study in Nusa Lembongan, Bali − Indonesia","authors":"I. Pratama, H. Albasri","doi":"10.1051/ALR/2021015","DOIUrl":"https://doi.org/10.1051/ALR/2021015","url":null,"abstract":"Unreliable information on harvest potential is a persistent challenge for the Indonesian government and industry alike to manage an efficient supply chain of seaweed raw material. The use of remote sensing technology to assess seaweed harvest potential has been scarcely available in the literature. This current research aimed at estimating the harvest potential of seaweed Kappaphycus alvarezii through remote sensing using supervised classification with maximum likelihood (MLC) and contextual editing (CE) methods. This research evaluated the capabilities of different band combinations along with depth invariant index (DII) to enhance the remote sensing accuracy in estimating seaweed harvest potential. The seaweed classification using Worldview-2 imagery was compared with the in-situ references (ground-truthing). The potential data bias resulted from different imagery acquisition timestamps with the in-situ measurement was kept minimal as both data time stamps were ten days apart and within the same seaweed culture cycle. The average dry weight of all seaweed samples collected during the research was 924 ± 278.91 g/m2 with culture ages between 1 and 40 days. The classification results based on MLC+CE with a 5-band combination method without DII showed a better correlation and closer fit with the in-situ references compared to the other methods, with an overall accuracy of 79.05% and Tau coefficient value of 0.75. The estimated total harvest potential based on the combined seaweed classes was 531.26 ± 250.29 tons dry weight.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824371","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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