M. Harikrishnan, Deepak Jose, B. Nidhin, K.P. Anilkumar
Species specific identification of early larval stages of many decapod crustaceans sampled from plankton collections remains cumbersome owing to lack of distinguishable characteristics, where DNA based molecular methods provide accurate results without taxonomic ambiguities. In the present study, an attempt was made to detect temporal occurrence of early zoea of freshwater prawn Macrobrachium rosenbergii (de Man) using real-time PCR assays in polyhaline, mesohaline and oligohaline areas of a tropical positive estuary, the Vembanad lake (S. India). High caridean larval abundance could be recorded in polyhaline areas in all seasons while it could be recorded in monsoon season in mesohaline and oligohaline areas. 113 DNA isolations were successfully made from morphologically identified taxonomic units (MOTU) and SYBR Green based RT-PCR amplifications using designed primer for M. rosenbergii yielded positive detections in 38 samples (34%) representing all seasons in all three zones. Positive detections could be recorded in all months except May in mesohaline areas and differed significantly (F = 17.2 p < 0.01) with the same in polyhaline and oligohaline areas. The present results of molecular detection of M. rosenbergii larvae extend confirmation of its breeding ground in Vembanad lake where appropriate management strategies could be enforced for stock conservation of this species.
由于缺乏可区分的特征，从浮游生物收集的样本中对许多十足甲壳类动物的早期幼虫阶段进行物种特异性鉴定仍然很麻烦，其中基于DNA的分子方法提供了准确的结果而没有分类歧义。在本研究中，利用实时荧光定量PCR技术，在热带河口Vembanad湖的多盐、中盐和低盐区检测罗氏沼虾(de Man)早期藻的发生时间。多盐区四季均有较高的鲤鱼幼虫丰度，中盐区和低盐区在季风季节均有较高的鲤鱼幼虫丰度。从形态学鉴定的分类单位(MOTU)中成功分离出113个DNA，使用设计的引物对罗氏分枝杆菌进行基于SYBR Green的RT-PCR扩增，在38个样本(34%)中检测出阳性，代表了所有三个地区的所有季节。除5月份外，中盐区各月份均有阳性检测，多盐区和低盐区差异有统计学意义(F = 17.2 p < 0.01)。本文对罗氏沼虾幼虫的分子检测结果进一步证实了其在Vembanad湖的繁殖地，为该物种的种群保护提供了合理的管理策略。
{"title":"Real Time PCR detection of Macrobrachium rosenbergii (de Man, 1879) larvae with emphasis to their ecology","authors":"M. Harikrishnan, Deepak Jose, B. Nidhin, K.P. Anilkumar","doi":"10.1051/ALR/2021012","DOIUrl":"https://doi.org/10.1051/ALR/2021012","url":null,"abstract":"Species specific identification of early larval stages of many decapod crustaceans sampled from plankton collections remains cumbersome owing to lack of distinguishable characteristics, where DNA based molecular methods provide accurate results without taxonomic ambiguities. In the present study, an attempt was made to detect temporal occurrence of early zoea of freshwater prawn Macrobrachium rosenbergii (de Man) using real-time PCR assays in polyhaline, mesohaline and oligohaline areas of a tropical positive estuary, the Vembanad lake (S. India). High caridean larval abundance could be recorded in polyhaline areas in all seasons while it could be recorded in monsoon season in mesohaline and oligohaline areas. 113 DNA isolations were successfully made from morphologically identified taxonomic units (MOTU) and SYBR Green based RT-PCR amplifications using designed primer for M. rosenbergii yielded positive detections in 38 samples (34%) representing all seasons in all three zones. Positive detections could be recorded in all months except May in mesohaline areas and differed significantly (F = 17.2 p < 0.01) with the same in polyhaline and oligohaline areas. The present results of molecular detection of M. rosenbergii larvae extend confirmation of its breeding ground in Vembanad lake where appropriate management strategies could be enforced for stock conservation of this species.","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":"57824244","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}
L. Veneranta, I. Kallio‐Nyberg, I. Saloniemi, E. Jokikokko
The maturation of anadromous whitefish (Coregonus lavaretus) was analysed from samples taken from commercial coastal fishing in 1998–2014 in the Gulf of Bothnia. Whitefish matured at a younger age from year to year. The proportion of older (5–12 sea years) mature males decreased from 79% to 39% in the northern Gulf of Bothnia (66°N–64°N) and from 76% to 14% in southern (64°N–60°30'N) during the study period. At the same time, the proportion of young males (2–4 sea years) increased. Whitefish matured younger: the proportion of mature fish at age four increased in both the north and south among females (13% → 98%; 6% → 85%) and males (68% → 99%; 29% → 89%). The catch length of four-year-old fish increased during the study period in both sexes. In contrast, the length of six-year-old females decreased from year to year. Sea surface temperatures increased during the study period, and were possibly associated with a decrease in the age of maturation and faster growth.
{"title":"Changes in age and maturity of anadromous whitefish (Coregonus lavaretus) in the northern Baltic Sea from 1998 to 2014","authors":"L. Veneranta, I. Kallio‐Nyberg, I. Saloniemi, E. Jokikokko","doi":"10.1051/ALR/2021007","DOIUrl":"https://doi.org/10.1051/ALR/2021007","url":null,"abstract":"The maturation of anadromous whitefish (Coregonus lavaretus) was analysed from samples taken from commercial coastal fishing in 1998–2014 in the Gulf of Bothnia. Whitefish matured at a younger age from year to year. The proportion of older (5–12 sea years) mature males decreased from 79% to 39% in the northern Gulf of Bothnia (66°N–64°N) and from 76% to 14% in southern (64°N–60°30'N) during the study period. At the same time, the proportion of young males (2–4 sea years) increased. Whitefish matured younger: the proportion of mature fish at age four increased in both the north and south among females (13% → 98%; 6% → 85%) and males (68% → 99%; 29% → 89%). The catch length of four-year-old fish increased during the study period in both sexes. In contrast, the length of six-year-old females decreased from year to year. Sea surface temperatures increased during the study period, and were possibly associated with a decrease in the age of maturation and faster growth.","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":"57824045","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 potential of biofloc media in in-situ environmental amelioration mediated through the removal of nitrogenous metabolites, reduce the dominance of disease-causing Vibrio to beneficial Bacillus community and reduction of costly commercial feed was investigated in white leg shellfish (Litopenaeus vannamei) farming. Three treatments viz. biofloc without neem + commercial feed (B), biofloc with neem +commercial feed (NB), only commercial feed without biofloc (F)and, one control (C) withno biofloc and no feed in triplicate was applied with a stocking density of 60 PL-20 m−3 in outdoor earthen ponds (1000 m3). Two biofloc media (C:N = 15–10:1) with and without neem leave extract were applied with reduction of feed supplement from 50% to 100%. The significant difference was observed in final body weight (33.82 ± 0.18 g) in neem based biofloc media than the other tested shrimp with the survival percentage above 87%. Superiority of biofloc based rearing system over the traditional feed based one was established as live weight gain was 28.48–137% more with a reduction of feed conversion ratio by 7.60% to 8.18% in the former. Moreover, feed cost was reduced both in B (8.1%) and NB (8.77%) compared to conventional feed −based culture system (F). The nutrient profile of floc and shrimp also improved as higher protein content was recorded in floc (18.65–19.63%) and shrimp (24.58–26.29%). The development of biofloc within the culture system resulted in cumulative increase of Bacillus population with concomitant decrease of luminous Vibrio population. The findings of the study strongly indicated that biofloc technology could be a potential tool of ecosystem approach towards in-situ environmental amelioration in shrimp farming ponds with substantial reduction of cost towards feed, aqua chemicals used for disease and environmental health management and other operational cost like water exchange.
{"title":"Environmental amelioration in biofloc based rearing system of white leg shrimp (Litopenaeus vannamei) in West Bengal, India","authors":"S. Das, A. Mandal","doi":"10.1051/ALR/2021016","DOIUrl":"https://doi.org/10.1051/ALR/2021016","url":null,"abstract":"The potential of biofloc media in in-situ environmental amelioration mediated through the removal of nitrogenous metabolites, reduce the dominance of disease-causing Vibrio to beneficial Bacillus community and reduction of costly commercial feed was investigated in white leg shellfish (Litopenaeus vannamei) farming. Three treatments viz. biofloc without neem + commercial feed (B), biofloc with neem +commercial feed (NB), only commercial feed without biofloc (F)and, one control (C) withno biofloc and no feed in triplicate was applied with a stocking density of 60 PL-20 m−3 in outdoor earthen ponds (1000 m3). Two biofloc media (C:N = 15–10:1) with and without neem leave extract were applied with reduction of feed supplement from 50% to 100%. The significant difference was observed in final body weight (33.82 ± 0.18 g) in neem based biofloc media than the other tested shrimp with the survival percentage above 87%. Superiority of biofloc based rearing system over the traditional feed based one was established as live weight gain was 28.48–137% more with a reduction of feed conversion ratio by 7.60% to 8.18% in the former. Moreover, feed cost was reduced both in B (8.1%) and NB (8.77%) compared to conventional feed −based culture system (F). The nutrient profile of floc and shrimp also improved as higher protein content was recorded in floc (18.65–19.63%) and shrimp (24.58–26.29%). The development of biofloc within the culture system resulted in cumulative increase of Bacillus population with concomitant decrease of luminous Vibrio population. The findings of the study strongly indicated that biofloc technology could be a potential tool of ecosystem approach towards in-situ environmental amelioration in shrimp farming ponds with substantial reduction of cost towards feed, aqua chemicals used for disease and environmental health management and other operational cost like water exchange.","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":"57824383","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}
Siniperca chuatsiandSiniperca kneriare two economically important freshwater fishes endemic to East Asia. Recently, someSinipercaspecimens collected from Lake Poyang and Lake Dongting in the middle reaches of the Yangtze River couldn't be clearly identified as they showed intermediate morphological characteristics betweenS. chuatsiandS. kneri,and some inter-species hybrids were detected by microsatellite loci. To further verify genetic composition of these intermediate individuals, and determine the prevalence and degree of introgression between the twoSinipercaspecies, a large set of high-quality, independent, diagnostic genetic markers were necessarily required. Based on enrichment and sequencing of target genes in sinipercid fishes, 463 loci (FST = 1) betweenS. chuatsiandS. kneriwere selected and verified for species diagnosis. A total of 349 loci with 458 diagnostic SNPs were identified for discriminatingS. chuatsiandS. kneri. From those markers, 224 diagnostic SNPs (only one SNP per locus) were selected to identify and categorize 48 specimens with intermediate morphological characters. The results showed that there were 8 specimens identified as hybrids, 8 specimens asS. chuatsiand 32 specimens asS. kneri.NEWHYBRIDS analysis showed that the hybrid offsprings were composed of the first-generation hybrid (2 individuals), first-generation backcross (1 individual), second-generation backcross (1 individual) and fourth-generation backcross (4 individuals), and the backcrossing could happen to bothS. chuatsiandS. kneri. These hybrids could occur naturally, or escaped from farmed fish, due to extensive artificial breeding practice in these regions. However, the origin of the introgressive hybridization can't be easily traced. Therefore, some measures for protecting genetic resource ofSinipercaspeies in the Yangtze River should be enforced, such as assessing genetic background of the cultured stocks, reducing the escapement from farmed fish, and monitoring the trend of introgressive hybridization betweenSinipercaspecies in the future.
{"title":"Introgressive hybridization between two close speciesSiniperca chuatsiandSiniperca kneri(Percomorpharia: Sinipercidae) in the Middle Reaches of the Yangtze River","authors":"Shuqin Zhu, Chenhong Li, Jinliang Zhao","doi":"10.1051/ALR/2021001","DOIUrl":"https://doi.org/10.1051/ALR/2021001","url":null,"abstract":"Siniperca chuatsiandSiniperca kneriare two economically important freshwater fishes endemic to East Asia. Recently, someSinipercaspecimens collected from Lake Poyang and Lake Dongting in the middle reaches of the Yangtze River couldn't be clearly identified as they showed intermediate morphological characteristics betweenS. chuatsiandS. kneri,and some inter-species hybrids were detected by microsatellite loci. To further verify genetic composition of these intermediate individuals, and determine the prevalence and degree of introgression between the twoSinipercaspecies, a large set of high-quality, independent, diagnostic genetic markers were necessarily required. Based on enrichment and sequencing of target genes in sinipercid fishes, 463 loci (FST = 1) betweenS. chuatsiandS. kneriwere selected and verified for species diagnosis. A total of 349 loci with 458 diagnostic SNPs were identified for discriminatingS. chuatsiandS. kneri. From those markers, 224 diagnostic SNPs (only one SNP per locus) were selected to identify and categorize 48 specimens with intermediate morphological characters. The results showed that there were 8 specimens identified as hybrids, 8 specimens asS. chuatsiand 32 specimens asS. kneri.NEWHYBRIDS analysis showed that the hybrid offsprings were composed of the first-generation hybrid (2 individuals), first-generation backcross (1 individual), second-generation backcross (1 individual) and fourth-generation backcross (4 individuals), and the backcrossing could happen to bothS. chuatsiandS. kneri. These hybrids could occur naturally, or escaped from farmed fish, due to extensive artificial breeding practice in these regions. However, the origin of the introgressive hybridization can't be easily traced. Therefore, some measures for protecting genetic resource ofSinipercaspeies in the Yangtze River should be enforced, such as assessing genetic background of the cultured stocks, reducing the escapement from farmed fish, and monitoring the trend of introgressive hybridization betweenSinipercaspecies in the future.","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":"57824071","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}
Lestari L. Widowati, S. Budi Prayitno, S. Rejeki, T. Elfitasari, P. W. Purnomo, R. Ariyati, R. Bosma
The high organic waste content of river water in Demak, north coast of Java, has caused traditional small-scale pond farmers to stop stocking shrimp. This paper examines whether seaweed and mussel will improve the quality of water these farmers use. The effect of Gracilaria verucosa and Perna viridis on the water quality was assessed by measuring the removal rates (RRs) of total organic material (TOM), total ammonia nitrogen (TAN), nitrite, and nitrate. The specific growth rates (SGRs) of seaweed and mussel were also measured. Thirty-six semi-outdoor tanks containing 800 L of brackish water and 7 cm substrate were randomly assigned to four replications of four densities of G. verucosa: 50 (S50), 100 (S100), 150 (S150), and 200 (S200) g m−2, and of P. viridis: 60 (M60), 90 (M90), 120 (M120), and 150 (M150) g m−2. Weekly, the TOM, TAN, nitrite, and nitrate contents were measured, seaweed and mussel weighted; RRs and SGRs were calculated at the end of the study. The effect of densities on the RRs was significant for both seaweed and mussel. P. viridis was more effective in reducing TOM (by 38%) than G. verucosa (7%); G. verucosa achieved higher RRs for TAN, nitrite, and nitrate. At S200, TOM and TAN decreased by 7.4% and 67%, respectively. At M90, TOM and TAN, decreased by 38% and 49%, respectively. However, nitrite increased significantly at S200 and M150. The SGR of seaweed was significantly lower at S200 than that at S150, S100, and S50. The best performing densities were S100 and M90.
爪哇北部海岸德马克的河水中有机废物含量高，导致传统的小规模池塘养殖户停止放养虾。本文考察了海藻和贻贝是否会改善这些农民使用的水质。通过测定对总有机物(TOM)、总氨氮(TAN)、亚硝酸盐和硝酸盐的去除率，评价江蓠和绿滨草对水质的影响。测定了海藻和贻贝的特定生长率(sgr)。36个半室外水箱，装800 L苦盐水和7 cm底物，随机分为4个重复，分别为4种密度:50 (S50)、100 (S100)、150 (S150)和200 (S200) g m - 2，以及60 (M60)、90 (M90)、120 (M120)和150 (M150) g m - 2。每周测定水体中TOM、TAN、亚硝酸盐和硝酸盐的含量，对海藻和贻贝进行称重;在研究结束时计算rrr和sgr。密度对海藻和贻贝的比摄比均有显著影响。绿假单胞菌(P. viridis)对TOM的降低率为38%，高于绿假单胞菌(G. verucosa)的7%;verucosa对TAN、亚硝酸盐和硝酸盐具有较高的rr。在S200时，TOM和TAN分别下降了7.4%和67%。在M90时，TOM和TAN分别下降38%和49%。而亚硝酸盐在S200和M150处理显著增加。S200处理的海藻SGR显著低于S150、S100和S50处理。表现最佳的密度为S100和M90。
{"title":"Organic matter reduction using four densities of seaweed (Gracilaria verucosa) and green mussel (Perna viridis) to improve water quality for aquaculture in Java, Indonesia","authors":"Lestari L. Widowati, S. Budi Prayitno, S. Rejeki, T. Elfitasari, P. W. Purnomo, R. Ariyati, R. Bosma","doi":"10.1051/ALR/2021002","DOIUrl":"https://doi.org/10.1051/ALR/2021002","url":null,"abstract":"The high organic waste content of river water in Demak, north coast of Java, has caused traditional small-scale pond farmers to stop stocking shrimp. This paper examines whether seaweed and mussel will improve the quality of water these farmers use. The effect of Gracilaria verucosa and Perna viridis on the water quality was assessed by measuring the removal rates (RRs) of total organic material (TOM), total ammonia nitrogen (TAN), nitrite, and nitrate. The specific growth rates (SGRs) of seaweed and mussel were also measured. Thirty-six semi-outdoor tanks containing 800 L of brackish water and 7 cm substrate were randomly assigned to four replications of four densities of G. verucosa: 50 (S50), 100 (S100), 150 (S150), and 200 (S200) g m−2, and of P. viridis: 60 (M60), 90 (M90), 120 (M120), and 150 (M150) g m−2. Weekly, the TOM, TAN, nitrite, and nitrate contents were measured, seaweed and mussel weighted; RRs and SGRs were calculated at the end of the study. The effect of densities on the RRs was significant for both seaweed and mussel. P. viridis was more effective in reducing TOM (by 38%) than G. verucosa (7%); G. verucosa achieved higher RRs for TAN, nitrite, and nitrate. At S200, TOM and TAN decreased by 7.4% and 67%, respectively. At M90, TOM and TAN, decreased by 38% and 49%, respectively. However, nitrite increased significantly at S200 and M150. The SGR of seaweed was significantly lower at S200 than that at S150, S100, and S50. The best performing densities were S100 and M90.","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":"57824084","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 movement of fish eggs and larvae in bay and estuarine systems is affected by freshwater discharge. In this study, the assemblage structures of ichthyoplankton eggs and larvae were assessed for the first time in Jinju Bay, South Korea, to identify the spawning and nursery functions of the bay. Fish eggs and larvae and several environmental parameters were sampled monthly from April 2015 to March 2016 inside and outside of the bay. Within the bay we collected eggs and larvae from 25 and 35 species, respectively, indicating greater diversity than outside the bay, where we collected eggs and larvae of 20 and 28 species, respectively. Fluctuations in water temperature and salinity were larger inside than outside of the bay, and chlorophyll-a concentration was higher within the bay, likely due to discharge from the Namgang Dam, which causes water to flow from the inside to the outside of the bay. This process influences fish larva abundance, such that more larvae are found outside than inside the bay. We also found that 28 fish species use Jinju Bay as a spawning ground. For some species, the timing of egg and larva appearance differed inside and outside of the bay, suggesting that the timing of spawning may differ between the two environments.
{"title":"Effect of freshwater discharge from Namgang Dam on ichthyoplankton assemblage structure in Jinju Bay, Korea","authors":"S. Myoung, S. Kwak, Jin-Koo Kim, J. Williamson","doi":"10.1051/alr/2021017","DOIUrl":"https://doi.org/10.1051/alr/2021017","url":null,"abstract":"The movement of fish eggs and larvae in bay and estuarine systems is affected by freshwater discharge. In this study, the assemblage structures of ichthyoplankton eggs and larvae were assessed for the first time in Jinju Bay, South Korea, to identify the spawning and nursery functions of the bay. Fish eggs and larvae and several environmental parameters were sampled monthly from April 2015 to March 2016 inside and outside of the bay. Within the bay we collected eggs and larvae from 25 and 35 species, respectively, indicating greater diversity than outside the bay, where we collected eggs and larvae of 20 and 28 species, respectively. Fluctuations in water temperature and salinity were larger inside than outside of the bay, and chlorophyll-a concentration was higher within the bay, likely due to discharge from the Namgang Dam, which causes water to flow from the inside to the outside of the bay. This process influences fish larva abundance, such that more larvae are found outside than inside the bay. We also found that 28 fish species use Jinju Bay as a spawning ground. For some species, the timing of egg and larva appearance differed inside and outside of the bay, suggesting that the timing of spawning may differ between the two environments.","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":"57824440","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}
François Martignac, J. Baglinière, D. Ombredane, J. Guillard
The acoustic camera is a non-intrusive method increasingly used to monitor fish populations. Acoustic camera data are video-like, providing information on fish behaviour and morphology helpful to discriminate fish species. However, acoustic cameras used in long-term monitoring studies generate a large amount of data, making one of the technical limitations the time spent analysing data, especially for multi-species fish communities. The specific analysis software provided for DIDSON acoustic cameras is problematic to use for large datasets. Sonar5-Pro, a popular software in freshwater studies offers several advantages due to its automatic tracking tool that follows targets moving into the detection beam and distinguishes fish from other targets. This study aims to assess the effectiveness of Sonar5-Pro for detecting and describing fish passages in a high fish diversity river in low flow conditions. The tool's accuracy was assessed by comparing Sonar5-Pro outputs with a complete manual analysis using morphological and behavioural descriptors. Ninety-eight percent of the fish moving into the detection beam were successfully detected by the software. The fish swimming direction estimation was 90% efficient. Sonar5-Pro and its automatic tracking tool have great potential as a database pre-filtering process and decrease the overall time spent on data analysis but some limits were also identified. Multi-counting issues almost doubled the true fish abundance, requiring manual operator validation. Furthermore, fish length of each tracked fish needed to be manually measured with another software (SMC). In conclusion, a combination of Sonar5-Pro and SMC software can provide reliable results with a significant reduction of manpower needed for the analysis of a long-term monitoring DIDSON dataset.
{"title":"Efficiency of automatic analyses of fish passages detected by an acoustic camera using Sonar5-Pro","authors":"François Martignac, J. Baglinière, D. Ombredane, J. Guillard","doi":"10.1051/alr/2021020","DOIUrl":"https://doi.org/10.1051/alr/2021020","url":null,"abstract":"The acoustic camera is a non-intrusive method increasingly used to monitor fish populations. Acoustic camera data are video-like, providing information on fish behaviour and morphology helpful to discriminate fish species. However, acoustic cameras used in long-term monitoring studies generate a large amount of data, making one of the technical limitations the time spent analysing data, especially for multi-species fish communities. The specific analysis software provided for DIDSON acoustic cameras is problematic to use for large datasets. Sonar5-Pro, a popular software in freshwater studies offers several advantages due to its automatic tracking tool that follows targets moving into the detection beam and distinguishes fish from other targets. This study aims to assess the effectiveness of Sonar5-Pro for detecting and describing fish passages in a high fish diversity river in low flow conditions. The tool's accuracy was assessed by comparing Sonar5-Pro outputs with a complete manual analysis using morphological and behavioural descriptors. Ninety-eight percent of the fish moving into the detection beam were successfully detected by the software. The fish swimming direction estimation was 90% efficient. Sonar5-Pro and its automatic tracking tool have great potential as a database pre-filtering process and decrease the overall time spent on data analysis but some limits were also identified. Multi-counting issues almost doubled the true fish abundance, requiring manual operator validation. Furthermore, fish length of each tracked fish needed to be manually measured with another software (SMC). In conclusion, a combination of Sonar5-Pro and SMC software can provide reliable results with a significant reduction of manpower needed for the analysis of a long-term monitoring DIDSON dataset.","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":"57824783","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 the Archipelago Sea, pikeperch (Sander lucioperca) is an important species in both commercial and recreational fisheries. Pikeperch is caught mainly with small mesh size gillnets, and annual fishing mortality is high. The possible effects of such fisheries, as well as temperature or density on pikeperch growth have not been studied earlier. The first hypothesis of this study was that the effect of temperature on growth is positive and that of density is negative. The second hypothesis was that size-selectivity of gillnets causes the fast-growing individuals to be caught at younger ages than the slow-growing ones. The results showed that temperature had a significant positive effect on growth, and this was greater than the negative effect of year-class density, which was also significant. The gillnet selectivity caused a difference of up to 60 mm in back-calculated lengths in the fully recruited age groups within the same year class, between pikeperch caught at age 6+ and age 9+. Thus, the Rosa Lee phenomenon caused by gillnet size-selectivity led to the removal of faster growing specimens from the population at younger ages. This can potentially cause underestimation of real growth, and thus, poor fishery management.
{"title":"Density and temperature dependent growth of pikeperch (Sander lucioperca) in the Archipelago Sea","authors":"K. Saulamo, O. Heikinheimo, J. Lappalainen","doi":"10.1051/alr/2020020","DOIUrl":"https://doi.org/10.1051/alr/2020020","url":null,"abstract":"In the Archipelago Sea, pikeperch (Sander lucioperca) is an important species in both commercial and recreational fisheries. Pikeperch is caught mainly with small mesh size gillnets, and annual fishing mortality is high. The possible effects of such fisheries, as well as temperature or density on pikeperch growth have not been studied earlier. The first hypothesis of this study was that the effect of temperature on growth is positive and that of density is negative. The second hypothesis was that size-selectivity of gillnets causes the fast-growing individuals to be caught at younger ages than the slow-growing ones. The results showed that temperature had a significant positive effect on growth, and this was greater than the negative effect of year-class density, which was also significant. The gillnet selectivity caused a difference of up to 60 mm in back-calculated lengths in the fully recruited age groups within the same year class, between pikeperch caught at age 6+ and age 9+. Thus, the Rosa Lee phenomenon caused by gillnet size-selectivity led to the removal of faster growing specimens from the population at younger ages. This can potentially cause underestimation of real growth, and thus, poor fishery management.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2020-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46555081","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}
Eirini-Slavka Polovina, Evelina Kourkouni, C. Tsigenopoulos, P. Sanchez‐Jerez, E. Ladoukakis
Microsatellite markers were used to investigate the genetic structure of the two most important cultured fish in the Mediterranean Sea, the gilthead seabream (Sparus aurata) and the European seabass (Dicentrarchus labrax), from two (one wild and one farmed) populations in Western Mediterranean (Spain) and from two (one wild and one farmed) populations Eastern Mediterranean (Greece). All populations were in Hardy-Weinberg disequilibrium. Interestingly, wild and farmed populations for both species from Greece were genetically differentiated and could be distinguished from each other. We used Bayesian methods for cluster analysis of farmed and wild populations. Our analysis has implications for the identification of escapees from fish farms to the wild.
{"title":"Genetic structuring in farmed and wild Gilthead seabream and European seabass in the Mediterranean Sea: implementations for detection of escapees","authors":"Eirini-Slavka Polovina, Evelina Kourkouni, C. Tsigenopoulos, P. Sanchez‐Jerez, E. Ladoukakis","doi":"10.1051/alr/2020007","DOIUrl":"https://doi.org/10.1051/alr/2020007","url":null,"abstract":"Microsatellite markers were used to investigate the genetic structure of the two most important cultured fish in the Mediterranean Sea, the gilthead seabream (Sparus aurata) and the European seabass (Dicentrarchus labrax), from two (one wild and one farmed) populations in Western Mediterranean (Spain) and from two (one wild and one farmed) populations Eastern Mediterranean (Greece). All populations were in Hardy-Weinberg disequilibrium. Interestingly, wild and farmed populations for both species from Greece were genetically differentiated and could be distinguished from each other. We used Bayesian methods for cluster analysis of farmed and wild populations. Our analysis has implications for the identification of escapees from fish farms to the wild.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2020-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47517955","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}
Miguel Ángel Mejía-Ramírez, Verónica Valadez Rocha, C. I. Pérez‐Rostro
The snail Pomacea patula catemacensis is an endemic mollusk from the southeast Gulf of Mexico, which is commercially exploited and in decline since 2010. This decline is associated with an increasing market demand and illegal capture. We designed a small-scale production system for P. p. catemacensis and determined its financial feasibility for a base scenario. We used information gathered from stakeholders and stochastic modeling to predict the impact of uncertain variables on the economic indicators to assess the financial viability under varying conditions. The small-scale intensive production system, designed to yield 3.9 tons/year of unshelled product, requires an investment of about US $65,000. The production unit was financially assessed using the Modified Internal Return Rate and The Net Present Value of cash flow, considering a 14% discount rate and a 7% reinvestment rate. We obtained a Net Present Value of $67,000 and a Modified Internal Return Rate of 20% for the base scenario, which indicates the viability of the project. A Monte Carlo simulation was run to assess the robustness of the project to variability of three parameters: labor cost, energy cost, and market price; with random and simultaneous variation, resulting in 95% probability of getting a Modified Internal Return Rate larger than the current interest rate (8%) and a low probability (2.8%) to be financially unviable. This production system is worthy of consideration as an option to reduce the fishing pressure on the tegogolo natural populations of the Catemaco Lake while satisfying the market demand.
{"title":"Economic feasibility analysis of small-scale aquaculture of the endemic snail Pomacea patula catemacensis (Baker 1922) from southeast Mexico","authors":"Miguel Ángel Mejía-Ramírez, Verónica Valadez Rocha, C. I. Pérez‐Rostro","doi":"10.1051/alr/2020001","DOIUrl":"https://doi.org/10.1051/alr/2020001","url":null,"abstract":"The snail Pomacea patula catemacensis is an endemic mollusk from the southeast Gulf of Mexico, which is commercially exploited and in decline since 2010. This decline is associated with an increasing market demand and illegal capture. We designed a small-scale production system for P. p. catemacensis and determined its financial feasibility for a base scenario. We used information gathered from stakeholders and stochastic modeling to predict the impact of uncertain variables on the economic indicators to assess the financial viability under varying conditions. The small-scale intensive production system, designed to yield 3.9 tons/year of unshelled product, requires an investment of about US $65,000. The production unit was financially assessed using the Modified Internal Return Rate and The Net Present Value of cash flow, considering a 14% discount rate and a 7% reinvestment rate. We obtained a Net Present Value of $67,000 and a Modified Internal Return Rate of 20% for the base scenario, which indicates the viability of the project. A Monte Carlo simulation was run to assess the robustness of the project to variability of three parameters: labor cost, energy cost, and market price; with random and simultaneous variation, resulting in 95% probability of getting a Modified Internal Return Rate larger than the current interest rate (8%) and a low probability (2.8%) to be financially unviable. This production system is worthy of consideration as an option to reduce the fishing pressure on the tegogolo natural populations of the Catemaco Lake while satisfying the market demand.","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1051/alr/2020001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57823836","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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