Distribution of jack mackerel (Trachurus japonicus) larvae and juveniles in the East China Sea, with special reference to the larval transport by the Kuroshio Current

Horizontal distribution patterns of jack mackerel (Trachurus japonicus) larvae and juveniles were investigated in the East China Sea between 4 February and 30 April 2001. A total of 1549 larvae and juveniles were collected by bongo and neuston nets at 357 stations. The larvae were concentrated in the frontal area between the Kuroshio Current and shelf waters in the upstream region of the Kuroshio. The abundance of small larvae (<3 mm notochord length) was highest in the southern East China Sea (SECS) south of 28°N, suggesting that the principal spawning ground is formed in the SECS from late winter to spring. Jack mackerel also spawned in the northern and central East China Sea (NECS and CECS, respectively), as some small larvae were also collected in these areas. In the SECS, the abundance of small larvae was highest in February and gradually decreased from March to April. The habitat temperature of small larvae in the SECS and CECS (20–26°C) was higher than that in the NECS (15–21°C), suggesting higher growth rates in the SECS and CECS than in the NECS. The juveniles (10‐ to 30‐mm standard length) became abundant in the NECS off the west coast of Kyushu Island and CECS in April and were collected in association with scyphozoans typical of the Kuroshio waters. However, juveniles were rarely collected in the SECS, where the small larvae were concentrated. Considering the current systems in the study area, a large number of the eggs and larvae spawned and hatched in the SECS would be transported northeastward by the Kuroshio and its branches into the jack mackerels’ nursery grounds, such as the shallow waters off the west coast of Kyushu and the Pacific coast of southern Japan.     

亲鱼脂类营养对鱼类生殖性能的影响

亲鱼饲料的营养质量是影响生殖性能的主要因素之一,目前的研究大多集中在脂类营养方面。本文主要综述了饲料脂类成分对亲鱼的产卵量、卵和仔鱼质量、胚胎发育、精卵的脂肪酸构成的影响,以及营养成分影响生殖性能的机制。     

光裸方格星虫繁殖习性的初步观察

2011年6、7、8月每月10日,挑选♀∶♂为5∶1的性成熟光裸方格星虫(Sipunculus nudus)亲体,在水泥池中暂养20 d,观察其产卵习性、产卵量及其体腔中生殖细胞的变化。结果表明,光裸方格星虫雌雄异体、体外受精;卵母细胞分批成熟,分批产卵;产卵时间不固定,昼夜皆可产卵,但夜间产卵次数和产卵量均高于白天;大量产卵时集群游动;6、7、8月的雌光裸方格星虫平均产卵分别为:3.20×104、4.43×104、3.46×104cell,平均受精率达98.3%;6、7、8月日累计产卵量y与时间x的变化方程分别为:y=0.430 5x3-25.971x2+503.39x-582.56(R2=0.982 0)、y=0.583 3x3-33.942x2+659.04x-712.43(R2=0.984 7)、y=-0.31x3+1.4676x2+245.11x-278.22(R2=0.994 3)。6、7、8月成熟卵细胞相对百分含量分别降低4.8%、9.0%、26.0%(P<0.01);6、7月的光裸方格星虫产后具有较好的再繁殖能力。     

福建莆田近海鲻鱼渔业现状及秋冬季产卵群体特点

本文主要根据2010年11月—2011年2月福建莆田近海流刺网作业鲻鱼生产调查资料,分析秋冬季渔获鲻鱼产卵群体组成、性腺成熟度分布等生物学特点及鲻鱼生产基本情况。结果表明:秋冬季(11月至翌年1月)是鲻鱼产卵盛期,也是鲻鱼渔业生产旺季;鲻鱼产卵群体主要为流刺网作业所利用,渔获群体优势叉长450～550 mm;近岸众多的流刺网作业过度捕捞亲鱼是造成鲻鱼资源量不断减少的主要原因之一。为更好地保护和利用莆田近海鲻鱼资源,建议进一步开展流刺网及张网作业对鲻鱼资源合理开发利用的专项调查研究。     

金乌贼新型产卵附着基的实验研究

2015年6—7月和2016年6—7月在青岛金沙滩水产有限公司室内产卵池中开展了不同材料、不同颜色、不同水深金乌贼(Sepia esculenta)产卵附着基附卵效果对比实验,以及柽柳附卵器对附卵效果的影响实验。实验用产卵附着基为0.33 m×0.33 m×0.33 m的十字形可折叠钢丝框架,上覆黑白2种聚乙烯网衣材料;每个产卵池中金乌贼亲体数量约35只,雌雄比约为1∶1,胴长(139.2±1.1)mm,体重(435.9±8.5)g。同时选用等比例放大的1.0 m×1.0 m×1.0 m钢筋框架与不同颜色网衣制作的十字形可折叠附着基,于2015年6—7月在青岛斋堂岛附近海域(35?36?6?N,119?54?8?E)和杨家洼湾前附近海域(35?36'6?N,119?50'50?E),以及2016年6—7月在青岛薛家岛近海(35?57?24?N,120?16?22?E)和杨家洼湾前附近海域(35?35?45?N,119?50?38?E)开展了海区附卵验证实验。结果表明:室内同一水体环境中柽柳附卵效果最佳,其次是十字形附着基,海参框附卵效果最差;白色十字形附着基的附卵效果显著优于黑色(P0.05);柽柳附卵器对附卵效果有积极影响,加装柽柳附卵器的十字形附着基附卵效果明显提高;产卵池底层摆放的十字形附着基的附卵效果显著优于表层悬挂的十字形附着基(P0.01)。海区附卵验证结果表明:2015年和2016年海区投放的十字形附着基附卵效果良好,最高附卵率分别为82.14%和56.72%;海区投放的黑色和白色十字形附着基的附卵效果差异不显著(P0.05);海底悬挂的十字形附着基的附卵效果显著优于近底层悬挂的十字形附着基(P0.05)。综合分析认为,在金乌贼产卵繁殖季节,选择其重要产卵场和主要增殖放流海区水深15~20 m的缓流区,底层设置十字形可折叠产卵附着基,可有效进行资源增殖与产卵场修复。     

2004-2009年渤海湾(天津区域)鱼虾贝产卵场水质环境综合评价

2004-2009年对渤海湾鱼虾贝产卵场(天津区域)水体实施连续调查监测,对该水域水质的年代变化趋势和质量状况进行研究和综合评价.结果表明, 渤海湾鱼虾贝产卵场(天津区域)水质处于波动状态, 2004年、2006年、2008年水质质量相对较好,2005年、2007年、2009年水质污染较重;有机污染严重, 已达到高富营养化程度.水质中主要污染物为石油类、化学需氧量,无机氮、活性磷酸盐是造成水体富营养化的关键因子.     

Migration and spawning behavior of the greater amberjack Seriola dumerili in eastern Taiwan

Greater amberjack (Seriola dumerili) is an important fishery resource with a circumglobal distribution from tropical to temperate waters. Here, we investigated the spawning migration and habitat utilization of S. dumerili in the East China Sea (ECS). Archival tags were attached to 22 adult fish to examine their horizontal and vertical movements and estimate the spawning ground. S. dumerili were captured and released in the coastal waters of eastern Taiwan on November of 2016 and 2017. Information from seven pop-up satellite archival tags and seven depth–temperature recorders was recovered. Almost all of the fish stayed in the Taiwanese exclusive economic zone. Most individuals moved from released site to the southern edge of the ECS and showed behavior associated with the topographic features in winter (November to December). These phenomena may be related to foraging and be driven by oceanographic features such as the seasonal monsoon and the Kuroshio. The fish then migrated to the south offshore area of Taiwan in January and February. During their southward migration, the fish experienced a slowly elevated water temperature regime (SETR), which is one of the environmental factors that induce final oocyte maturation. In the spawning season (February to April), tagged females exhibited continuous diel vertical movements (DVMs) after experiencing the SETR. These continuous DVMs were observed over a wide geographic range from north to south in the Kuroshio off eastern Taiwan. Our study demonstrated that the putative spawning ground of S. dumerili must extend further in a north–south direction than predicted in a previous study.     

泥鳅雌雄性比对繁殖影响的试验

试验研究了不同雌雄比例对泥鳅产卵的影响。结果表明:7个组中产卵量随着雌性数目的增加而提高,但相对产卵量不同。在雄性为2条的情况下,相对产卵率随着雌性数目的增加相对产卵量逐渐降低。在雌性为2条的情况下,相对产卵量在2♀4♂组泥鳅的相对产卵量最高,为572.75颗/g。并不随着雄性的进一步增加而提高。这可能是由于雄性泥鳅在潜在竞争对手存在的情况下约束了自身的求偶行为,以避免精子的竞争。     

从连续到偶发：中华鲟在葛洲坝下发生小规模自然繁殖

中华鲟(Acipenser sinensis Gray)为国家一级重点保护野生动物,典型的溯河洄游产卵鱼类。历史上,中华鲟在长江上游及金沙江下游产卵,由于葛洲坝修建阻隔了其洄游通道,1981年以后在葛洲坝下形成了比较稳定的产卵场,1982―2013年,每年均有自然繁殖发生。由于其栖息生境退化,每年洄游进入长江的中华鲟繁殖亲本逐年减少,2013―2015年连续3年在已知葛洲坝下中华鲟产卵场未监测到中华鲟自然繁殖活动。2016年11―12月的野外监测发现,中华鲟在宜昌葛洲坝下已知产卵场发生了自然繁殖。其中底层网具采集到中华鲟鱼卵(卵膜)67粒、仔鱼22尾;解剖食卵鱼发现,10尾食卵鱼类共摄食中华鲟卵454粒;水下视频观测到5处中华鲟卵黏附底质位点。根据采集到的鱼卵发育期及采集位点推算,产卵时间为2016年11月24日凌晨,产卵场位于葛洲坝大江电厂以下约300 m的江段内,产卵日水温为19.7℃,流量为6610 m3/s,水位为39.7 m。     

中华乌塘鳢人工育苗技术研究

进行了中华乌塘鳢人工育苗试验，采用背鳍基部肌肉注射，多次注射激素促熟催产，控制水温，不断充气等措施，提前１个多月孵出苗，相对延长了养殖期，提高了经济效益，试验证明：培育亲鱼投喂活沙蚕好，雌雄比１：１，孵化水温２６～２８℃，盐度１６～１７注射ＬＲＨ－Ａ剂量１５０μｇ／尾，可提高催产率，受精率和出苗率。