产卵深度变动对东海日本鲭鱼卵仔幼鱼输运和存活率的影响

日本鲭(Scomber japonicus)是我国近海重要经济鱼种,海洋环境变动对鱼类生命周期中最为脆弱的鱼卵和仔幼鱼的生长、存活直至种群补充产生重大的影响,其中产卵深度变动对其是否会产生影响,目前尚不清楚。为此,本文拟采用FVCOM(Finite-Volume Coastal Ocean Model)物理模型来模拟三维物理场,使用基于个体模型IBM(individual-based model)参数化并模拟日本鲭的早期生活史,从而建立起基于物理-生物个体的东海日本鲭初期生态耦合模型,使用该耦合模型模拟了日本鲭产卵水深不同导致鱼卵仔幼鱼从产卵场向育肥场的输运过程中经历物理环境的差异对鱼卵仔幼鱼的输运分布以及存活率的影响。研究发现,产卵深度的变动,未对鱼卵仔幼鱼的输运分布产生明显影响,但在输运过程中所处水深和水温的微小差异却导致了变浅(5 m)和加深(15 m)产卵深度鱼卵仔幼鱼的存活率降低,正常产卵深度(10 m)是最佳的产卵水深。因此,研究认为产卵深度的细微变动将会对东海日本鲭鱼卵仔幼鱼的存活率产生影响,但对鱼卵仔幼鱼输运则影响不大。     

东海中南部日本鲭种群分析

东海中南部日本鲭(Scomber japonicus)为中国和日本共同利用的商业性种类,是中日渔业协定暂定措施水域内的主要洄游分布种。为科学评估与管理该区域的日本鲭资源群体,对其种群属性进行了判别。本文以东海中南部海域(26°15'~29°15'N、122°45'~126°45'E)的日本鲭繁殖群体为研究样本,分别采用外部形态判别和分子遗传鉴定的方法,判别日本鲭种群属性。结果显示,研究区域采样点间日本鲭群体的形态特征显示分散状态,外部形态判别方法无法判断种群属性,而利用分子遗传方法可判别研究区域的日本鲭属于同一种群。研究认为,东海分布的日本鲭群体的发育初期可能处于不同生境,而源于不同产卵场的混合群体是导致无法利用外部形态判别种群属性的原因。东海中南部的日本鲭应视为同一资源评估单元。该研究提供了东海海域的日本鲭是一个种群的新证据。     

金线鱼仔稚鱼形态和在南海北部的产卵场和产卵期

本文是根据1973和1974年在南海北部拖网鱼类资源调查中,采到的鱼卵和仔鱼标本研究的结果,着重描述了仔稚鱼各发育阶段的形态特征和鱼卵仔鱼的分布。金线鱼仔稚鱼在发育过程中的主要特征,其头部及前鳃盖骨后缘,始终没出现刺,尾部下缘的黑色素胞一直保留到稚鱼阶段。根据鱼卵和仔鱼稚鱼出现的海区和时问,结合鱼类生物学的测定,观察性腺成熟系数,研究了其产卵场和产卵期。产卵场较分散,从海南岛至甲子、汕头外海,水深40～100米的广大海区有多个产卵场。在南海北部的产卵期为4～6月,产卵水温18.79～25.98℃,盐度33.94～34.92‰。     

东海北部和黄海南部Ti鱼卵和仔稚幼鱼数量、分布及其与环境条件的关系

1999年夏季鳀鱼卵和仔稚幼鱼主要分布于黄海南部,122°00′～123°45′E、34°00′～35°15′N与122°15′E以西海域分别为鳀鱼卵与鳀鱼仔稚幼鱼的密集分布中心,其表层水温和盐度分别为25.5～26.9℃和27.11～31.81与26.4～27.0℃和31.31～32.05。鳀鱼卵和仔稚幼鱼分布的最适表层水温分别为25.5～26.4℃和25.9～27.0℃;全长为20mm以上的鳀鱼稚鱼已初步形成广盐性分布的习性,鳀鱼卵和仔稚幼鱼的分布对盐度的要求并不非常严格,水温是影响鱼卵和仔稚幼鱼分布的主要原因之一。鳀鱼卵和仔稚幼鱼的分布与叶绿素a的分布也有密切的关系,鳀鱼卵和仔稚幼鱼的密集分布中心正是叶绿素a的高值区。随着季节的变化,黄海南部鳀鱼产卵场由青岛外海逐渐向深水区转移。黄海南部鳀鱼活卵所占的比例为45.76％,胚胎发育状况良好。     

东海太平洋褶柔鱼的数量分布及其与环境的关系

利用1997～2000年在东海4个季节的拖网以及温盐度调查资料，分析了东海太平洋褶柔鱼的数量分布及其与环境条件的关系。结果表明：东海太平洋褶柔鱼分布水深在40～175m，集中分布水深范围在80～150m。春、夏、秋三个季节的平均资源密度最高值都出现在北部外海，冬季的平均资源密度最高值转移到南部外海。四季都有生殖群体的存在，从春季到冬季，生殖群体的重心位置由北部外海向南部外海转移。四季生活海域的表层水温为13．63～28．38℃，生物量高区的表层水温为22～26℃；表层盐度为27．72～34．72，集中分布海域的盐度为32．5～34．7。因此，东海太平洋褶柔鱼属于暖水性外海高温高盐种。     

烟威近岸海域鲐产卵场时空分布及其与环境因子的关系

利用 2020 年 4?9 月在该海域开展逐月调查获取的鲐(Scomber japonicus)卵、0 龄幼鱼及环境数据, 建立基于 Tweedie 类分布的广义加性模型(Tweedie-GAM, generalized additive models), 分析鲐卵丰度与主要环境因子的关系, 并采用克里金插值绘制的鲐卵与主要生境因子时空分布图, 阐释该海域鲐产卵适宜生境; 同时分析了该海域鲐 0 龄幼鱼分布及其生物学特性, 获取了该海域鲐早期生活史参数。结果显示, 烟威近岸鲐产卵期为 4?7 月, 主要产卵期为 5 月下旬?6 月下旬; 主要产卵场分布在 121°30′~122°15′ E、37°30′~38°00′ N 的烟台牟平–威海刘公岛北部海域; 产卵场海表水温、鳀(Engraulis japonicus)卵丰度、海水流速和海表层盐度对鲐卵丰度有显著影响, 其偏差解释率分别为 54.6%、17.8%、4.0%和 1.7%; 烟威近岸鲐更适宜在海表水温 16.3~21.8 ℃、海表盐度 32.1~32.9、低海水流速和高鳀卵丰度的海水中产卵。当前烟威近岸海域仍然是我国黄、东海鲐种群重要的产卵场之一, 其时空分布与环境因子密切相关。     

象山港蓝点马鲛鱼卵、仔稚鱼的时空分布特征及其与环境因子关系

为了研究象山港蓝点马鲛(Scomberomorus niphonius)鱼卵和仔稚鱼的时空分布特征及其与环境因子的相关关系,在象山港港湾内设置14个站,于2015年4月3日至6月10日期间按周采样,共调查10个航次(Ⅰ~Ⅹ),以方形网(网口为1 m×2 m,网目1.0 mm)采集象山港水域蓝点马鲛鱼卵、仔稚鱼,同时利用CTD采集表层水温、表层盐度和水深等数据。结果表明,象山港蓝点马鲛鱼卵出现时间为4月初至6月初,鱼卵的丰度随时间呈先升后降趋势,4月中旬至5月初为高峰期。仔稚鱼出现时间相对滞后且提前结束,持续时间短,集中在5月初至5月中旬。鱼卵和仔稚鱼主要分布于港口和港中部水域,其中鱼卵、卵黄囊期和前弯曲期仔鱼空间分布相似,主要分布在较深水域,而后弯曲期仔鱼和稚鱼主要分布在较浅的近岸水域。鱼卵丰度与表层水温、表层盐度和水深均呈显著性相关(P0.05),最适表层水温范围为15~19℃,最适表层盐度范围为25.5~26.0,分布水深为15~30 m。仔稚鱼仅与表层水温呈显著性相关(P0.05),最适表层水温范围为18~19℃。     

气候变化对黄海中南部斑鰶产卵场适宜性的影响

为全面了解气候变化下黄海中南部近海海域斑鰶的产卵场适宜性变动规律,为黄海中南部产卵场的保护提供科学依据,实验根据2014—2018年5—7月黄海中南部产卵场调查数据,并结合FVCOM (Finite-Volume Community Ocean Model)模型提取的表层水温、表层盐度、水深、离岸距离、海表流速以及NOAA数据中心的叶绿素a浓度等6种环境因子,基于随机森林(Random Forest,RF)模型构建黄海中南部斑鰶产卵场适宜性的分布模型,根据未来气候变化的情景,预测该鱼种产卵场在未来的潜在分布。结果显示,不同月份中影响斑鰶鱼卵分布的主要环境因素不同,主要因子在5—7月分别为水深、叶绿素a和表层水温,其偏差贡献率分别为24.49%、28.08%、26.26%。研究表明,在未来气候变化的情景下,斑鰶的适宜产卵场将向北迁移。此外,黄海中南部北部沿岸海域及南部远岸深水区的栖息地适宜性明显增加。因此,未来在产卵场保护以及资源开发利用等方面,应当充分考虑这一变动趋势。     

春、夏季浙江南部近海日本鲭资源分布特征及其环境影响因子

为探明海洋环境因子对日本鲭资源分布的影响,基于2016、2019、2020年5月和8月浙江南部近海海域渔业资源和水文环境调查数据以及卫星遥感数据,利用两阶段广义加性模型研究春、夏季日本鲭资源分布与海洋环境因子之间的关系。结果显示,日本鲭资源密度的年际变化较大且存在明显的季节分布规律,春季近岸水域的资源密度大于外海水域,夏季与之相反。海水温度和盐度是影响日本鲭分布的重要因素,春季资源密度和水温呈线性正相关关系,与盐度存在非线性负相关关系;夏季,资源密度随着水温的增加呈先增后减的趋势,在29.3℃时达到最大值。研究结果表明,环境因子对春、夏季浙江南部近海海域日本鲭的出现概率以及资源密度具有重要影响。     

东海生态系统中鱼卵、仔稚鱼种类组成、数量分布及其与环境因素的关系

为了解当前东海生态系统中鱼卵、仔稚鱼种类组成和数量分布的现状及其变化与物理环境因素的关系,根据2006年11月—2008年6月5个航次的鱼卵、仔稚鱼和物理环境调查资料,对鱼卵、仔稚鱼种类组成、数量分布与产卵场物理环境进行分析,探讨不同季节、不同年份鱼卵、仔稚鱼种类组成和数量分布的变化及其与物理环境的关系。结果显示,5个航次采集到74 813粒鱼卵、16 826尾仔稚鱼,共有135个种类。其中,鉴定到种的有109种,隶属于15目67科99属,还有17个种类仅能鉴定到属、6个种类仅能鉴定到科和3个种类仅能鉴定到目。2006年—2007年秋季、冬季和春季鱼卵、仔稚鱼的种类和数量随着季节变化逐渐增多;2008年春季的种类和数量较2007年春季明显偏少;2008年初夏种类的数量与2008年春季基本相近,但鱼卵的数量明显增多,仔稚鱼的数量基本相近。42种优势种类、重要种类和主要种类构成当前东海生态系统中鱼卵、仔稚鱼种类组成的主要成分。东海表层水温和盐度分布有显著的季节变化。秋、冬季表层水温锋面强度最强,春季次之,初夏最弱;锋面的位置秋季离岸最近,冬季次之,春季和初夏离岸最远,冬季偏南,初夏季节北移。表层盐度锋面主要分布在近岸区域,与岸线大致平行,其强度冬季最强,春、秋季次之,初夏季节最弱。秋、冬季节陆架深水海域的水温较沿岸海域高,鱼类生殖群体在陆架深水高温区产卵;春季和初夏季节沿岸海域明显升温,鱼类生殖群体由深水区向近岸海域进行生殖洄游,产卵场分布由陆架中部向近岸海域扩展,并在近岸海域形成了中心产卵场。鱼卵和仔稚鱼的分布与温、盐锋面和种类的温、盐属性的关系密切,主要分布在温度锋面暖水一侧,并有各自最适宜的温度和盐度范围。水温、盐度与种类的繁殖生物学特性是导致鱼卵和仔稚鱼种类组成与数量发生变化的主要因素;适宜的温度和盐度范围、锋区的辐聚和卷夹作用以及种类的生物学属性是影响鱼卵和仔稚鱼数量分布以及密集分布区形成的主要因素。     

Transport and survival processes of eggs and larvae of jack mackerel <Emphasis Type="Italic">Trachurus japonicus</Emphasis> in the East China Sea

ABSTRACT:   Recent surveys showed substantial aggregation of larvae of jack mackerel in the southern East China Sea, indicating intensive spawning grounds near Taiwan. A numerical model was applied to investigate transport and survival processes of eggs and larvae of jack mackerel from the spawning area to the nurseries. The results show that: (i) the distributions of larvae simulated by the model agreed well with those obtained by field survey; (ii) the stock of jack mackerel in the Sea of Japan is composed of both groups from north of Taiwan and from the western coast of Kyushu. It takes more than two months for the former to reach the Sea of Japan, while it is within 40 days for the latter; and (iii) large proportions of the eggs and larvae spawned off the north of Taiwan are transported rapidly to the Pacific side of Kyushu by the Kuroshio Current, and the rest slowly to the east or north-east along the continental slope in the East China Sea. In contrast to the larval flux, survivors are more abundant in the northern East China Sea than in the Pacific Ocean, indicating that survival in the northern East China Sea would determine the jack mackerel stock in Japan.     

东海有尾类数量分布

根据1997~2000年东海23°30′~33°N、118°30′~128°E海域4个季节海洋调查资料,探讨了东海有尾类数量分布和季节变化。结果表明:秋季有尾类丰度最高,均值为149 ind/100m3,夏季38 ind/100m3,冬季20 ind/100m3,春季9 ind/100m3;有尾类数量在冬春夏季与水温和盐度相关关系不显著,秋季与表温有显著的正相关关系。有尾类数量季节变化机制具有暖水种的特征,这些特征形成与其优势种适温适盐特性有密切的关系。东海有尾类的数量波动,与东海暖流势力消长有密切的联系,也同暖流势力从夏到秋季维持一段时间有密切的关系。在东海,暖流势力较强的海域往往可以成为有尾类高丰度分布区域。秋季有尾类高分布区出现,对东海北部外海绿鳍马面鲀(Navodon septentrionalis)渔场和东海南部的带鱼(Trichiurus lepturus)和日本鲭(Scom ber japonicus)等多种经济鱼类渔场的形成有重要意义。     

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.     

海州湾及邻近海域春夏季典型断面鱼类浮游生物群落的结构特征

根据2015年5―7月在海州湾及邻近海域存在空间异质性的南北两个典型断面进行的鱼卵、仔稚鱼水平拖网调查数据,采用多元统计分析等方法研究了该海域春、夏季鱼类浮游生物群落的空间变化。结果表明,本次调查共获得鱼卵33587粒,仔稚鱼713尾。出现鱼卵25种(未定种1种),隶属于14科25属,仔稚鱼13种(未定种1种),隶属于13科13属。鱼卵优势种主要是鳀(Engraulis japonicus)、多鳞鱚(Sillago sihama)、(魚銜)属(Callionymus spp.)、皮氏叫姑鱼(Johnius belengerii)、江口小公鱼(Stolephorus commersonni)和短吻红舌鳎(Cynoglossus joyneri);仔稚鱼优势种主要是(魚銜)属和斑鰶(Konosirus punctatus)。鱼类浮游生物种类组成年代际变化明显,目前以生命周期短、个体小、资源更新节律快的小型鱼种为主;研究表明,鱼类浮游生物的优势种在不同月份和断面之间存在一定变化,5、6月南北两断面优势种组成不同,7月开始出现共同优势种。从鱼类浮游生物的空间分布来看,近岸海域的丰度较高,5、6月鱼类浮游生物的平均丰度均为北面断面1高于南面断面2,7月反之。鱼类浮游生物群落在两个典型断面随月份呈现出不同特征,水深、温度和盐等海洋环境因子综合影响着春、夏季海州湾及邻近海域鱼类浮游生物群落结构。     

东海中部日本鲭(Scomber japonicus)产卵群体繁殖力特征

利用2010–2012年春季在东海中部获得的日本鲭产卵群体样品的生物学及繁殖力测定数据,对其群体结构、性腺指数GSI和繁殖力特征进行了研究。结果显示,目前东海中部日本鲭产卵群体年龄结构由1–5龄组成,以2–4龄占优势。日本鲭的个体绝对繁殖力为24770–734684粒,平均为(145575±10067)粒;纯体重相对繁殖力为175–1404 grain/g,平均为(524±24)grain/g;叉长相对繁殖力为102–2070 grain/mm,平均为(483±29)grain/mm。ANOVA分析结果显示,不同叉长组间的性腺指数GSI(F=2.34,P0.05)、绝对繁殖力(F=8.57,P0.01)和叉长相对繁殖力(F=5.59,P0.05)均有显著性差异,但体重相对繁殖力差异不明显(F=2.03,P0.05)。多元逐步线性回归和非线性回归分析显示,绝对繁殖力与体高、肝重关系密切。为了应对高强度的捕捞压力,日本鲭主要采用降低性成熟年龄,减小最小性成熟叉长和卵径、增加繁殖力等策略来维持种群的延续。     

Larval Japanese eel (Anguilla japonica) as sub‐surface current bio‐tracers on the East Asia continental shelf

Larval Japanese eel (leptocephali) are passively transported from their spawning sites of the North Equatorial Current to the Kuroshio and its branch waters for 4–6 months before reaching the East Asian coasts. The larvae mainly stay within water depths between 50–150 m. The dispersal dynamics of larvae thus should reflect the sub‐surface oceanic currents on the East Asia continental shelf. An analysis of Japanese glass eel catch data in East Asian countries during 1985 to 2009, and for Taiwan from 1968 to 2008, indicates that the overall annual catch is generally correlated across countries of East Asia, and between north and west areas of Taiwan. The Kuroshio and its branch waters disperse glass eels throughout East Asian habitats, and the glass eel distribution matches the flow directionality of oceanic currents. Recruitment in western Taiwan occurs with a sequential southwestern to northwestern direction, suggesting that the Taiwan Strait Current penetrates the western coast of Taiwan in the sub‐surface layer in winter. The monthly averaged sub‐surface 50 m circulation pattern in the vicinity of Taiwan and modeled tracer experiments also support the northward winter sub‐surface current in Taiwan Strait. These results suggest that the larval Japanese eel could serve as a valuable bio‐tracer of sub‐surface currents, and the earlier recruitment dynamics of Japanese glass eels in Taiwan could be a good predictor for the subsequent catch in other East Asia areas.     

Using coupled fish behavior–hydrodynamic model to investigate spawning migration of Japanese anchovy,Engraulis japonicus,from the East China Sea to Taiwan

Adult Japanese anchovies (Engraulis japonicus) migrate from the East China Sea to the coastal region of Taiwan to spawn around late winter and early spring and, later, their larvae constitute important fisheries in Taiwan. However, their migration route and its mechanism remain unclear. To investigate their spawning migration, we used a coupled fish behavior–hydrodynamic modeling approach. The physical field is simulated by the Pacific Ocean adaptation of the TaIwan Multi‐scale Community Ocean Model (TIMCOM) and the fish migration by Lagrangian tracer tracking with the aid of approximation of fish swimming behavior. We investigated three fish behavioral scenarios: (i) passive tracking of the current, (ii) swimming along with the current, and (iii) swimming along with the current and then changing to swimming toward the optimal spawning temperature. The comparison with and without Changjiang discharge is used to investigate the impacts of discharge reduction due to the Three Gorges Dam. Our results suggest that spawning migration of Japanese anchovy from the East China Sea to Taiwan may be aided by the China Coastal Current and that adult anchovies cannot reach the spawning site by passive advection alone. Thus, the swimming behavior of anchovies is crucial during the spawning migration, as it provides extra velocity and the orientation to the favorable spawning grounds. In addition, the adult anchovy is unlikely to reach the coastal area of Taiwan without Changjiang discharge. Our findings indicate that a coupled fish behavior–hydrodynamic model can help understand the influences of physical environment on the migration of Japanese anchovies.     

东、黄渤海带鱼的洄游路线

为了研究带鱼的洄游路线,根据我国10余个主要渔业公司1971、1972、1981和1982年带鱼捕捞统计资料,先绘制带鱼鱼群移动影像图,据此进一步研究东、黄渤海近海带鱼的洄游路线图。结果显示,带鱼越冬场、产卵场和索饵场范围广阔,在空间上具有一定的重叠性。带鱼还有分批越冬、产卵和索饵洄游的特性,不同群体越冬、产卵和索饵洄游在时间上也有一定的重叠性。北方带鱼群体的越冬场主要在32°00'～36°00'N,124°00'～126°00'E黄海暖流水域。3—7月北上进入海州湾、乳山湾、海洋岛和渤海各湾产卵场;8—9月在产卵场外围宽阔水域索饵;9—11月游出渤海,绕过成山头南下,沿禁渔线外侧,沿途分别汇合海州湾、乳山湾及海洋岛的越冬鱼群,到了34°00'N后折向东南,分批于12月到达越冬场。南方带鱼群体越冬场主要位于浙江中南部禁渔线外侧,其次是济州岛西南海域。每年3—4月起,南部越冬的带鱼鱼群大致以每2个月1个纬度的速度向东北方向移动;5—7月,产卵洄游的鱼群到达舟山渔场和长江口渔场产卵;7—8月,产卵后的索饵群体北上黄海南部大沙渔场索饵;9月,索饵群体前锋到达35°00'N禁渔线外侧。10月以后,随着冷空气南下,南部群体带鱼向南越冬洄游,并且在10月回到长江口海域。其中小部分群体游向外海越冬场,大部分群体继续南下回到东海中南部近海的越冬场。台湾暖流和黄海暖流的进退和消长是影响带鱼越冬洄游路线空间和时间变化的主要环境因素。     

Stock identification of sword prawn Parapenaeopsis hardwickii in the East China Sea and Taiwan Strait inferred by morphometric variation

ABSTRACT:   Morphometric differences were used to elucidate the stock structure of sword prawn Parapenaeopsis hardwickii in the East China Sea and Taiwan Strait. Six samples were collected separately from the north of the East China Sea (NECS-02) and waters off Tamsui (Tamsui-10), Taichung (Taichung-11 and Taichung-02), Putai (Putai-02) and Cheding (Cheding-02). Eleven measurements made for each individual were size-standardized by allometric methods and the resulting measurements were analyzed by cluster analysis and canonical variate analysis (CVA). Randomization tests were used to test the morphometric variation between groups derived from cluster analysis and CVA. The results of cluster analysis and CVA indicated that the six samples were clustered into three groups: the first group included the NECS-02 sample; the second included the Tamsui-10 and Taichung-11 samples; and the third included the Taichung-02, Putai-02 and Cheding-02 samples. Randomization tests showed that morphometric differences among the three groups were significant. Animals with the same morphometric measurements are often assumed to constitute a stock, so there appear to be at least three morphologically distinguishable stocks of this species in the East China Sea and Taiwan Strait. The first stock is in the north of the East China Sea, the second is in the waters adjacent to Tamsui and Taichung, and the third is in the waters adjacent to Cheding, Putai and Taichung.