Many fishing fleets operate in mixed fisheries where several target species are caught together along with other bycatch species unintentionally caught. In some cases, fleets operate in multiple mixed fisheries depending on various factors such as time of year or current market conditions, among other factors. Data collection in the European Union (EU) involves various levels of detailed data. Economic data is generally collected on an annual time-step whereas other sources provide information at much higher resolution such as the fishing trip (landings declarations), fish day (logbook) or even in real-time (electronic logbook). In this paper a methodology is described to disaggregate the annual cost of a fleet segment into a cost per fishery and per species within the fishery. This information is of interest as it permits incorporation of the economic implications of fishery dynamics into fisheries management. Assessment of these unit costs on a fishery basis also allows accurate input into value chain analysis which is carried out on a species basis.
{"title":"Disaggregating species unit costs in mixed fisheries: the case of the Irish whitefish fleet","authors":"Richard Curtin , Olivier Thebaud","doi":"10.1051/alr/2021013","DOIUrl":"10.1051/alr/2021013","url":null,"abstract":"<div><div>Many fishing fleets operate in mixed fisheries where several target species are caught together along with other bycatch species unintentionally caught. In some cases, fleets operate in multiple mixed fisheries depending on various factors such as time of year or current market conditions, among other factors. Data collection in the European Union (EU) involves various levels of detailed data. Economic data is generally collected on an annual time-step whereas other sources provide information at much higher resolution such as the fishing trip (landings declarations), fish day (logbook) or even in real-time (electronic logbook). In this paper a methodology is described to disaggregate the annual cost of a fleet segment into a cost per fishery and per species within the fishery. This information is of interest as it permits incorporation of the economic implications of fishery dynamics into fisheries management. Assessment of these unit costs on a fishery basis also allows accurate input into value chain analysis which is carried out on a species basis.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"34 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824259","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}
Supplementation of biofloc in rearing of common carp (Cyprinus carpio var. Communis (0.84 ± 0.003 g) was tested in replacing costly feed and environmental amelioration. Neem (Azadirachta indica) leave extract in biofloc media has beenknown to be beneficial in controlling pathogenic Vibrio sp. in brackish water shrimp. Two studies were conducted for 120 days in outdoor experimental cisterns with reduction of feed from 50% to 100%, with two biofloc media; without (Experiment 1; E1) and with neem extract (Experiment 2; E2). The experimental groups were: biofloc with feeding at 6% body weight (T1E1 and T1E2), biofloc with feeding at 3% body weight (T2E1 and T2E2), biofloc without feeding (T3E1 and T3E2), feeding at 6% body weight (C1) and only biofloc (C2E1 and C2E2). Absolute weight gain in T2E1 (9.96 g) was 8.23% and in T2E2 (9.56 g) was 4.39% higher than C1 (9.14). In spite of 5.04% and 13.98% higher growth respectively in T1E1 (10.50 g) and T1E2 (11.66 g) than C1 (9.97 g), BFT could not compensate the total withdrawal of feed (T3E1 and T3E2) and resulted in 22.22% to 33.33% mortality in T3E2 and T3E1 respectively. Under identical feeding regime, FCR was improved by 52.57% to 53.76% in T2E1 (1.84) and 48.71% to 51.23% in T2E2 (1.99) compared to T1E1 (3.98) and T1E2 (4.08). Absolute weight gain in T2E1 was 8.97 times and in T2E2 was 4.63 times higher than C1. In spite of 18.54% and 7.26% higher growth respectively in T1E1 and T1E2 than C1, BFT could not compensate the total withdrawal of feed (T3E1 and T3E2) and resulted in 22.22% to 33.33% mortality in T3E2 and T3E1 respectively. Under identical feeding regime, FCR was improved by 52.57% to 53.76% in T2E1 and 48.71% to 51.23% in T2E2 compared to T1E1 and T1E2 respectively. Increased N: P ratio of water and soil in E2 favoured fish growth. Neem leave extract in biofloc media should be judicious as it may cause nitrification inhibition.
{"title":"Supplementation of biofloc in carp (Cyprinus carpio var. Communis) culture as a potential tool of resource management in aquaculture","authors":"Shib Kinkar Das , Amit Mandal , Joel Aubin","doi":"10.1051/alr/2021019","DOIUrl":"10.1051/alr/2021019","url":null,"abstract":"<div><div>Supplementation of biofloc in rearing of common carp (<em>Cyprinus carpio</em> var. <em>Communis</em> (0.84 ± 0.003 g) was tested in replacing costly feed and environmental amelioration. Neem (<em>Azadirachta indica</em>) leave extract in biofloc media has beenknown to be beneficial in controlling pathogenic <em>Vibrio</em> sp. in brackish water shrimp. Two studies were conducted for 120 days in outdoor experimental cisterns with reduction of feed from 50% to 100%, with two biofloc media; without (Experiment 1; E1) and with neem extract (Experiment 2; E2). The experimental groups were: biofloc with feeding at 6% body weight (T1E1 and T1E2), biofloc with feeding at 3% body weight (T2E1 and T2E2), biofloc without feeding (T3E1 and T3E2), feeding at 6% body weight (C1) and only biofloc (C2E1 and C2E2). Absolute weight gain in T2E1 (9.96 g) was 8.23% and in T2E2 (9.56 g) was 4.39% higher than C1 (9.14). In spite of 5.04% and 13.98% higher growth respectively in T1E1 (10.50 g) and T1E2 (11.66 g) than C1 (9.97 g), BFT could not compensate the total withdrawal of feed (T3E1 and T3E2) and resulted in 22.22% to 33.33% mortality in T3E2 and T3E1 respectively. Under identical feeding regime, FCR was improved by 52.57% to 53.76% in T2E1 (1.84) and 48.71% to 51.23% in T2E2 (1.99) compared to T1E1 (3.98) and T1E2 (4.08). Absolute weight gain in T2E1 was 8.97 times and in T2E2 was 4.63 times higher than C1. In spite of 18.54% and 7.26% higher growth respectively in T1E1 and T1E2 than C1, BFT could not compensate the total withdrawal of feed (T3E1 and T3E2) and resulted in 22.22% to 33.33% mortality in T3E2 and T3E1 respectively. Under identical feeding regime, FCR was improved by 52.57% to 53.76% in T2E1 and 48.71% to 51.23% in T2E2 compared to T1E1 and T1E2 respectively. Increased N: P ratio of water and soil in E2 favoured fish growth. Neem leave extract in biofloc media should be judicious as it may cause nitrification inhibition.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"34 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824734","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. M. Mahbub Alam , Snæbjörn Pálsson , Carlos Saavedra
The genus Parapenaeopsis is an important group of marine shrimps for wild capture in the Indo-West Pacific region. Phylogenetics of penaeid shrimps is still a debatable issue. This study focuses on the phylogenetic relationships among seven species within the genus Parapenaeupsis, the population genetic variation of Parapenaeupsis sculptilis along Bangladesh coastline of the Bay of Bengal and the phylogeography of P. sculptilis in the Indian Ocean region by analysing cytochrome oxidase subunit 1 barcode (CO1) sequence. No population structure was detected in P. sculptilis collected from two sampling sites along the Bangladesh coastline (AMOVA and ΦST = ‑0.014, p > 0.05; FST = 0.061, p = 0.04), which expanded first around 73 (CI: 36‑119) kyr ago. The genealogical relationships in Bangladesh P. sculptilis population are shallow with haplotype diversity (h) of 0.58 and nucleotide diversity (π) of 0.0014. The different P. sculptilis samples from Bangladesh, India and Mozambique of the Indian Ocean revealed connectivity between western Indian Ocean and the Bay of Bengal. The phylogeny within the genus Parapenaeupsis showed a polyphyletic relationships for P. hardickwii and its taxonomy needs to be reevaluated. The study will help for genetic upgradation in aquaculture and monitoring of the population genetic diversity of P. sculptilis.
副虾属（Parapenaeopsis）是印度-西太平洋地区重要的野生捕获海虾群。对虾的系统发育仍然是一个有争议的问题。本研究通过细胞色素氧化酶亚基1条形码（CO1）序列分析，探讨了副虾蛄属（Parapenaeupsis） 7种间的系统发育关系、孟加拉湾孟加拉国沿岸雕刻副虾蛄（Parapenaeupsis sculptilis）种群遗传变异以及印度洋地区雕刻副虾蛄（P. sculptilis）的系统地理特征。在孟加拉国海岸线的两个采样点(AMOVA和Φ ST =‑0.014,p >；0.05;F ST = 0.061, p = 0.04)，该指数在73年前（CI: 36 - 119）左右首次扩张。孟加拉石竹种群的亲缘关系较浅，单倍型多样性(h)为0.58，核苷酸多样性（π）为0.0014。从印度洋的孟加拉国、印度和莫桑比克采集的不同的雕刻假单脚虫样本揭示了西印度洋和孟加拉湾之间的联系。副带绦虫属的系统发育表明其与哈迪克氏带绦虫属存在多系关系，其分类有待重新评估。该研究将有助于水产养殖的遗传升级和石斑鱼种群遗传多样性的监测。
{"title":"Genetic variation of Parapenaeopsis sculptilis (Decapoda, Penaeidae) and reassessment of the phylogenetic relationships within the genus Parapenaeopsis based on mitochondrial DNA variation","authors":"M. M. Mahbub Alam , Snæbjörn Pálsson , Carlos Saavedra","doi":"10.1051/alr/2020027","DOIUrl":"10.1051/alr/2020027","url":null,"abstract":"<div><div>The genus <em>Parapenaeopsis</em> is an important group of marine shrimps for wild capture in the Indo-West Pacific region. Phylogenetics of penaeid shrimps is still a debatable issue. This study focuses on the phylogenetic relationships among seven species within the genus <em>Parapenaeupsis</em>, the population genetic variation of <em>Parapenaeupsis sculptilis</em> along Bangladesh coastline of the Bay of Bengal and the phylogeography of <em>P. sculptilis</em> in the Indian Ocean region by analysing cytochrome oxidase subunit 1 barcode (CO1) sequence. No population structure was detected in <em>P. sculptilis</em> collected from two sampling sites along the Bangladesh coastline (AMOVA and <em>Φ</em> <sub>ST</sub> = ‑0.014, <em>p</em> > 0.05; <em>F</em> <sub>ST</sub> = 0.061, <em>p</em> = 0.04), which expanded first around 73 (CI: 36‑119) kyr ago. The genealogical relationships in Bangladesh <em>P. sculptilis</em> population are shallow with haplotype diversity (<em>h</em>) of 0.58 and nucleotide diversity (<em>π</em>) of 0.0014. The different <em>P. sculptilis</em> samples from Bangladesh, India and Mozambique of the Indian Ocean revealed connectivity between western Indian Ocean and the Bay of Bengal. The phylogeny within the genus <em>Parapenaeupsis</em> showed a polyphyletic relationships for <em>P. hardickwii</em> and its taxonomy needs to be reevaluated. The study will help for genetic upgradation in aquaculture and monitoring of the population genetic diversity of <em>P. sculptilis</em>.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"34 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824031","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}
Parapenaeopsis stylifera, a major commercial penaeid shrimp fishery resource in the Indian Ocean, has lacked adequate information on life history parameters for nearly two decades. In this study, growth and mortality parameters of P. stylifera from the southwest coast of India were estimated using length data and used to derive biological reference points for the species. The asymptotic length for females was L∞ = 131 mm; k = 1.1 y−1 and for males L∞ = 117 mm; k = 1.25 y−1. Mortality parameter estimates were Z = 4.42, M = 1.24, F = 3.18 y−1 and exploitation rate E = 0.72 for females; Z = 5.76, M = 1.39, F = 4.37 y−1 and E = 0.76 for males. Thomson and Bell yield biomass, Beverton and Holt yield per recruit, and relative yield per recruit models were applied to predict the stock status and length cohort analysis for estimating the stock size. The Beverton and Holt analysis gave Emax = 0.69 in females and 0.75 for males, which is below the Ecurrent values obtained for the sexes. The Thomson and Bell analysis indicated that if Fcurrent at which the yield is 121 460 t in females and in males 128 064 t is further increased, rise in yield will be modest. B/B0 and SB/SB0 at Fcurrent were 24% and 18% for females and 21% and 16% for males, respectively. Target reference point F0.1 and F0.5 at different levels of age at capture tc (0.5, 0.6, 0.7 and 0.8 yrs) was estimated by Beverton and Holt yield per recruit model. The outcome from these models forms integral inputs for multispecies/multigear tropical fisheries management. Parapenaeopsis stylifera is one of the inshore penaeid shrimp identified by the Marine Stewardship Council for certification from the region and, moreover, biological reference points are a prerequisite to assessment and management of tropical multispecies fisheries for ecosystem-based fisheries management.
style Parapenaeopsis stylifera是印度洋上一种主要的商业对虾渔业资源，近20年来一直缺乏足够的生活史参数信息。本研究利用长度数据估算了印度西南海岸style style style的生长和死亡参数，并以此为基础推导了该物种的生物学参考点。女性的渐近长度为L∞= 131 mm；k = 1.1 y−1，男性L∞= 117 mm；K = 1.25 y−1。雌虫死亡率参数估计Z = 4.42, M = 1.24, F = 3.18 y - 1，剥削率E = 0.72；Z = 5.76 M = 1.39, F = 4.37 y−1和E = 0.76为男性。采用Thomson和Bell产量、Beverton和Holt单产和相对单产模型预测种群状态，采用长度队列分析估计种群大小。贝弗顿和霍尔特的分析给出了女性的Emax = 0.69，男性的Emax = 0.75，这低于目前获得的性别值。汤姆森和贝尔的分析表明，如果进一步增加雌株产量为121 460吨、雄株产量为128 064吨的产量，产量的增加将是适度的。B/B0和SB/SB0分别为雌虫的24%和18%，雄虫的21%和16%。在捕获tc（0.5, 0.6, 0.7和0.8岁）的不同年龄水平上，目标参考点F0.1和F0.5通过Beverton和Holt每招募产量模型估计。这些模式的结果构成了多物种/多年轮热带渔业管理的整体投入。style Parapenaeopsis stylifera是该地区海洋管理委员会认定的近岸对虾之一，生物参考点是基于生态系统的渔业管理对热带多物种渔业进行评估和管理的先决条件。
{"title":"Using length data to derive biological reference points for kiddi shrimp Parapenaeopsis stylifera (Milne Edwards, 1837) from the south-eastern Arabian Sea, India","authors":"Saraswathy Lakshmi Pillai , Gidda Maheswarudu , Ponnathara Kandankoran Baby , Madavan Radhakrishnan , Nadakkal Ragesh , Lakshmanan Sreesanth , AE David Kaplan","doi":"10.1051/alr/2021003","DOIUrl":"10.1051/alr/2021003","url":null,"abstract":"<div><div><em>Parapenaeopsis stylifera</em>, a major commercial penaeid shrimp fishery resource in the Indian Ocean, has lacked adequate information on life history parameters for nearly two decades. In this study, growth and mortality parameters of <em>P. stylifera</em> from the southwest coast of India were estimated using length data and used to derive biological reference points for the species. The asymptotic length for females was L<sub>∞</sub> = 131 mm; k = 1.1 y<sup>−1</sup> and for males L<sub>∞</sub> = 117 mm; k = 1.25 y<sup>−1</sup>. Mortality parameter estimates were Z = 4.42, M = 1.24, F = 3.18 y<sup>−1</sup> and exploitation rate E = 0.72 for females; Z = 5.76, M = 1.39, F = 4.37 y<sup>−1</sup> and E = 0.76 for males. Thomson and Bell yield biomass, Beverton and Holt yield per recruit, and relative yield per recruit models were applied to predict the stock status and length cohort analysis for estimating the stock size. The Beverton and Holt analysis gave E<sub>max</sub> = 0.69 in females and 0.75 for males, which is below the E<sub>current</sub> values obtained for the sexes. The Thomson and Bell analysis indicated that if F<sub>current</sub> at which the yield is 121 460 t in females and in males 128 064 t is further increased, rise in yield will be modest. B/B<sub>0</sub> and SB/SB<sub>0</sub> at F<sub>current</sub> were 24% and 18% for females and 21% and 16% for males, respectively. Target reference point F<sub>0.1</sub> and F<sub>0.5</sub> at different levels of age at capture t<sub>c</sub> (0.5, 0.6, 0.7 and 0.8 yrs) was estimated by Beverton and Holt yield per recruit model. The outcome from these models forms integral inputs for multispecies/multigear tropical fisheries management. <em>Parapenaeopsis stylifera</em> is one of the inshore penaeid shrimp identified by the Marine Stewardship Council for certification from the region and, moreover, biological reference points are a prerequisite to assessment and management of tropical multispecies fisheries for ecosystem-based fisheries management.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"34 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57824120","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}
Mahadevan Harikrishnan , Deepak Jose , B. Nidhin , K.P. Anilkumar , Antonio Figueras
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。中盐区除5月份外，其余月份均有阳性检测，差异有统计学意义(F = 17.2 p <；0.01)，多卤区和低卤区差异无统计学意义。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":"Mahadevan Harikrishnan , Deepak Jose , B. Nidhin , K.P. Anilkumar , Antonio Figueras","doi":"10.1051/alr/2021012","DOIUrl":"10.1051/alr/2021012","url":null,"abstract":"<div><div>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 <em>Macrobrachium rosenbergii</em> (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 <em>M. rosenbergii</em> 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 <em>M. rosenbergii</em> larvae extend confirmation of its breeding ground in Vembanad lake where appropriate management strategies could be enforced for stock conservation of this species.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"34 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-04-29","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}
Lari Veneranta , Irma Kallio-Nyberg , Irma Saloniemi , Erkki Jokikokko , AE Richard Nash
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":"Lari Veneranta , Irma Kallio-Nyberg , Irma Saloniemi , Erkki Jokikokko , AE Richard Nash","doi":"10.1051/alr/2021007","DOIUrl":"10.1051/alr/2021007","url":null,"abstract":"<div><div>The maturation of anadromous whitefish (<em>Coregonus lavaretus</em>) 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.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"34 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-04-29","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":"Shib Kinkar Das , Amit Mandal , Domenico Caruso","doi":"10.1051/alr/2021016","DOIUrl":"10.1051/alr/2021016","url":null,"abstract":"<div><div>The potential of biofloc media in <em>in-situ</em> environmental amelioration mediated through the removal of nitrogenous metabolites, reduce the dominance of disease-causing <em>Vibrio</em> to beneficial <em>Bacillus</em> community and reduction of costly commercial feed was investigated in white leg shellfish (<em>Litopenaeus vannamei</em>) 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<sup>−3</sup> in outdoor earthen ponds (1000 m<sup>3</sup>). 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 <em>Bacillus</em> population with concomitant decrease of luminous <em>Vibrio</em> population. The findings of the study strongly indicated that biofloc technology could be a potential tool of ecosystem approach towards <em>in-situ</em> 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.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"34 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-04-29","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}
Shuqin Zhu , Chenhong Li , Jinliang Zhao , Roman Wenne
Siniperca chuatsi and Siniperca kneri are two economically important freshwater fishes endemic to East Asia. Recently, some Siniperca specimens 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 between S. chuatsi and S. 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 two Siniperca species, 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) between S. chuatsi and S. kneri were selected and verified for species diagnosis. A total of 349 loci with 458 diagnostic SNPs were identified for discriminating S. chuatsi and S. 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 as S. chuatsi and 32 specimens as S. 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 both S. chuatsi and S. 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 of Siniperca speies 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 between Siniperca species in the future.
{"title":"Introgressive hybridization between two close species Siniperca chuatsi and Siniperca kneri (Percomorpharia: Sinipercidae) in the Middle Reaches of the Yangtze River","authors":"Shuqin Zhu , Chenhong Li , Jinliang Zhao , Roman Wenne","doi":"10.1051/alr/2021001","DOIUrl":"10.1051/alr/2021001","url":null,"abstract":"<div><div><em>Siniperca chuatsi</em> and <em>Siniperca kneri</em> are two economically important freshwater fishes endemic to East Asia. Recently, some <em>Siniperca</em> specimens 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 between <em>S. chuatsi</em> and <em>S. kneri,</em> 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 two <em>Siniperca</em> species, 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 (F<sub>ST</sub> = 1) between <em>S. chuatsi</em> and <em>S. kneri</em> were selected and verified for species diagnosis. A total of 349 loci with 458 diagnostic SNPs were identified for discriminating <em>S. chuatsi</em> and <em>S. kneri</em>. 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 as <em>S. chuatsi</em> and 32 specimens as <em>S. kneri.</em> 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 both <em>S. chuatsi</em> and <em>S. kneri</em>. 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 of <em>Siniperca</em> speies 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 between <em>Siniperca</em> species in the future.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"34 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-04-29","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 , Sri Rejeki , Tita Elfitasari , Pujiono W. Purnomo , Restiana W. Ariyati , Roel H. Bosma , Joel Aubin
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 , Sri Rejeki , Tita Elfitasari , Pujiono W. Purnomo , Restiana W. Ariyati , Roel H. Bosma , Joel Aubin","doi":"10.1051/alr/2021002","DOIUrl":"10.1051/alr/2021002","url":null,"abstract":"<div><div>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 <em>Gracilaria verucosa</em> and <em>Perna viridis</em> 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 <em>G. verucosa</em>: 50 (S50), 100 (S100), 150 (S150), and 200 (S200) g m<sup>−2</sup>, and of <em>P. viridis</em>: 60 (M60), 90 (M90), 120 (M120), and 150 (M150) g m<sup>−2</sup>. 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. <em>P. viridis</em> was more effective in reducing TOM (by 38%) than <em>G. verucosa</em> (7%); <em>G. verucosa</em> 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.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"34 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-04-29","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}
Se Hun Myoung , Seok Nam Kwak , Jin-Koo Kim , Jane E. Williamson , Nicole Richoux
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":"Se Hun Myoung , Seok Nam Kwak , Jin-Koo Kim , Jane E. Williamson , Nicole Richoux","doi":"10.1051/alr/2021017","DOIUrl":"10.1051/alr/2021017","url":null,"abstract":"<div><div>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-<em>a</em> 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.</div></div>","PeriodicalId":55491,"journal":{"name":"Aquatic Living Resources","volume":"34 ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-04-29","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}
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