鱼类早期生活史研究与其进展

鱼类早期生活史的研究,主要涉及卵和仔鱼发育,仔鱼最佳饲养条件、饵料密度、营养、生长、临界期、饥饿、捕食、环境耐力和毒性反应等和渔业密切相关的诸因子,是鱼类自然资源繁殖保护和养殖业苗种培育的基础。近二、三十年来,鱼类早期生活史研究已成为水产科学的一个崭新领域,在国际上受到广泛重视并迅速发展。国际海洋开发理事会(ICES)曾三次举行鱼类早期生活史学术讨论会,     

Survival and growth of selected marine fish larvae first fed with eggs and endotrophic larvae of the sea urchin Paracentrotus lividus

Two sets of experiments were carried out to evaluate the potential of eggs and endotrophic larvae of captive Paracentrotus lividus as alternative live prey for marine fish larvae first feeding. The first consisted in rearing sparids, Diplodus sargus and Sparus aurata, larvae until 15 days after hatching in a recirculation system. Compared with the commonly used live prey – rotifer Brachionus spp. – general lower values of survival and growth were obtained when fish larvae were fed with the alternative live prey. Among these, eggs showed to be the preferred feeding. Broodstock feed showed to play a fundamental role on prey quality and consequent fish larvae survival. In the second set of experiments, the 24‐h ingestions of the first feeding larvae in static water were determined for five currently cultured fish larvae species. Except for larger and more predatory Dicentrarchus labrax larvae, there was a trend for higher P. lividus egg ingestion, followed by pre‐plutei and prisms. Prey size, colour and movement affected food selection by fish larvae. It is concluded that, in spite of the alternative live prey being readily consumed by all tested fish larvae, they cannot however presently compete with rotifers in marine fish larvae first feeding.     

Surface disinfection of Pacific threadfin, Polydactylus sexfilis, and amberjack, Seriola rivoliana, eggs

The effects of exposing the eggs of Pacific threadfin and amberjack eggs (AEs) to different concentrations of hydrogen peroxide for 5 min on hatch rate and survival were assessed in a series of experiments using a petri dish model rearing system. Despite significant inter‐batch variation in hatch rate, it was shown that eggs of both species could be safely exposed to up to 11 340 mg L⁻¹ H₂O₂ for 5 min. Exposure to 34 230 mg L⁻¹ H₂O₂ for 5 min was shown to be lethal to AEs at a late stage of development. In two further experiments, it was demonstrated that Pacific threadfin eggs were resistant to all tested concentrations of a range of polyvinylpyrrolidone iodine (PVP‐I) concentrations and contact times (up to 1000 mg L⁻¹ PVP‐I for 10 min). The level of bacteria adhering to the eggs of both species was highly variable. Where eggs were heavily colonized (>10⁴ cfu egg⁻¹), hydrogen peroxide concentrations of at least 11 340 mg L⁻¹, or PVP‐I concentrations higher than 500 mg L⁻¹ for 10 min, were required for effective sterilization. In less colonized batches, rinsing in sterile seawater or exposure to lower (550 mg L⁻¹) concentrations of H₂O₂ was sufficient to result in high apparent levels of surface sterility (<1 cfu egg⁻¹).     

养殖鱼类同类残食现象研究进展及其预防措施

残食行为被定义为同物种间相互杀戮与掠食的现象。在鱼类人工育苗阶段,同类残食行为普遍存在,是制约育苗阶段苗种存活率的主要因素之一。本文针对海水鱼类育苗期间出现的残食行为问题,结合笔者的前期研究发现,对鱼类残食行为的发生、形态学制约、摄食规格、生长优势和影响因子进行了概述。根据残食方式,鱼类的自残现象主要分为Ⅰ型残食现象和Ⅱ型残食现象。Ⅰ型残食中,残食者首先咬住被残食者的尾部,逐渐吞食至头部后将剩余部分丢弃,被残食个体通常会被部分吞食、消化;Ⅱ型残食中,残食者自被残食者的头部开始将其完全吞食,被残食个体通常会被完全吞食、消化。残食者口裂大小是自残行为发生的主要限制因子,而且越是在鱼类的早期阶段,口裂大小差异越明显。在鱼类残食行为中,残食者倾向于由小到大的顺序选择被残食者。残食现象对群体的影响取决于残食者的相对生长速度。本文还探讨了减少鱼类自残行为发生的措施,以期丰富海水仔稚鱼行为学理论,为建立优质苗种繁育技术提供理论依据。     

Fatty acid nutritional quality of sea urchin Paracentrotus lividus (Lamarck 1816) eggs and endotrophic larvae: relevance for feeding of marine larval fish

Sea urchin eggs and larvae have been suggested as potential live prey for marine fish larval feeding. This study evaluated the fatty acid composition of Paracentrotus lividus eggs, prisms and four-armed plutei, obtained from wild and captive broodstocks fed on raw diets: maize, seaweed and a combination of maize and seaweed. Amounts of essential fatty acids (EFA) for marine fish larvae [arachidonic acid (ARA), eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA)] were determined in eggs and endotrophic larvae. ARA ranged from 3.93% in eggs from combination to 18.7% in plutei from maize diets. In any developmental stage, EPA amounts were always lower than 5% for the raw diets, and DHA showed null or trace amounts including the wild diet. Thus, broodstock-prepared diets had to be formulated based on different lipid sources (Algamac, linseed oil, cod liver oil and olive oil) in order to test eggs and larvae EFA enhancement. EFA improvement was possible for all tested prepared diets. Algamac diet lead to superior EFA enhancement mainly in DHA (7.24%, 4.92% and 6.09% for eggs, prisms and plutei, respectively) followed by cod liver oil diet. Only these two lipid sources should be considered for prepared broodstock diets in order to obtain suitable live prey for fish larval feeding.     

马鞍列岛人工鱼礁区鱼卵与仔稚鱼的群落结构

为了解人工鱼礁投放对鱼卵和仔稚鱼分布的影响,于2018年1月(冬季)、4月(春季)、7月(夏季)和10月(秋季)利用大型浮游生物网在马鞍列岛海洋牧场开展了4个航次的水平拖网调查。根据鱼卵、仔稚鱼的种类组成、数量分布等群落结构特征,对投礁区和未投礁区鱼卵、仔稚鱼的资源分布进行研究。结果显示,2018年在马鞍列岛海洋牧场共采集鱼卵5 642粒、仔稚鱼1 013尾,隶属于10目21科49种。鱼卵优势种为龙头鱼、短吻红舌鳎和小黄鱼;仔稚鱼的优势种为褐菖鲉、花鲈和小公鱼属未定种。投礁区和未投礁区鱼卵仔稚鱼的优势种种类组成基本一致,但是群落结构差异显著,投礁区各个季节的多样性指数、丰富度指数及均匀度指数均高于未投礁区,与未投礁区差异显著,且春季投礁区的生物多样性最高。聚类分析显示,春季鱼卵、仔稚鱼群落结构最为稳定,冬季群落结构最简单,夏、秋两季相似度较高,群落结构更复杂。研究表明,马鞍列岛海洋牧场人工鱼礁的投放对鱼卵、仔稚鱼具有一定的聚集和庇护作用,温度(T)、盐度(S)、水体浑浊度(Turb.)等海洋物理环境因子对鱼卵、仔稚鱼分布影响显著。     

Behavioural determinants of distribution and survival in early stages of walleye pollock, Theragra chalcogrammai a synthesis of experimental studies

This review summarizes results of an extensive series of laboratory studies on the behavioural responses of early life stages of walleye pollock, Theragra chakogramma to key environmental factors including light, temperature, gravity, turbulence, food availability and predator presence. Experiments focused on vertical distribution of egg through 0-age stages, and social interactions of age-0 juveniles. Key factors were modified either singly or in concert to determine their direct and indirect influence on fish behaviour. The observed results suggest that the behaviour of individual fish depends on the integration of a continually changing hierarchy of both intrinsic and extrinsic factors, with the relative importance of a specific factor varying with ontogeny and over time and space. The broad range of responses displayed by early life stages suggests that behaviour plays an important role in determining the consequences of environmental variability on walleye pollock populations. In general, results from our laboratory experiments are consistent with patterns observed in field studies, supporting the efficacy of using experimental behavioural research to define some of the underlying mechanisms controlling distribution and survival in the field, and eventual recruitment to adult populations.     

岱衢洋产卵场鱼卵、仔稚鱼群落结构及其与环境因子的关系

为了解岱衢洋海域鱼卵、仔稚鱼的群落结构及其与环境因子的关系,本团队分别在2010年5月—2012年2月春、夏、秋和冬季,利用大型浮游生物网在此海域开展了8个航次调查。共采集到鱼卵1 042粒,仔稚鱼2 055尾,隶属于10目19科37种。鱼卵优势种为扁舵鲣和小带鱼等;仔稚鱼的优势种为鰉、鳀和中华小公鱼等。调查海域鱼卵的平均密度是8.40粒/100 m3,仔稚鱼的平均密度是14.85尾/100 m3。单因素方差分析结果显示,2010年和2011年春、夏季4个季节之间丰富度指数(D)、均匀度指数(J′)和多样性指数(H′)均存在极显著差异。鱼卵、仔稚鱼资源密度分布不均匀,春、夏季较高,冬季最低,大体呈现南高北低的趋势。Pearson相关性结果分析得出,与鱼卵、仔稚鱼关系最密切的环境因子为温度、盐度和海水悬浮物。研究表明,春、夏季是岱衢洋海域鱼类产卵的重要时期,该海域是鳀、扁舵鲣、中华小公鱼等中上层鱼类的重要产卵场和育幼场。     

大亚湾鱼卵、仔稚鱼种群特征与环境因子的相关关系

为了解大亚湾鱼卵、稚仔鱼种群动态变化及其与环境因子的关系, 2015年采用浅水I型浮游生物拖网对大亚湾鱼卵、仔稚鱼进行了4个季度的调查,结果表明,4个季度共采获鱼卵31361粒,仔稚鱼244尾。经鉴定分析共有27种,其中鱼卵19种,隶属于6目16科18属;仔稚鱼18种,隶属于5目15科16属;鱼卵、仔稚鱼共有种11个。鱼卵平均丰度为614.55 ind/1000 m^3,稚仔鱼的平均丰度为3.69 ind/1000 m^3。鱼卵丰度季节变化由高到低依次为夏季、春季、冬季、秋季;空间分布显示,丰度由高到低依次为中央列岛、人工鱼礁区、湾口东岸。鱼卵多样性指数(H￠)范围为0.05～2.26,平均值为0.86,稚仔鱼多样性指数(H?)范围为0～2.53,平均值丰度0.82;鱼卵均匀度指数(J)范围为0.02～0.99,平均值为0.50;稚仔鱼均匀度指数(J)范围为0～1.00,平均值为0.52。根据Pearson相关性结果分析表明,与种群关系最密切的环境因子为温度和溶解氧(P<0.01)。研究结果显示,春夏季是大亚湾海域鱼类产卵的重要时期,中央列岛海域是大亚湾鱼类繁殖的关键区域。     

七星列岛产卵场保护区鱼卵、仔稚鱼种类组成及其与环境因子的关系

为了解七星列岛产卵场保护区鱼卵、仔稚鱼种类组成及其与环境因子的关系, 于 2018 年 4 月、5 月、11 月和 2019 年 4 月、5 月、11 月使用大型浮游生物网采集 6 个航次的样品, 分析该海域鱼卵和仔稚鱼种类组成、时空分布、群聚结构以及其与环境因子的关系。结果显示, 6 个航次共采集到鱼卵 1490 粒, 仔稚鱼 278 尾, 隶属于 9 目 26 科 60 种。鱼卵优势种为龙头鱼(Harpodon nehereus)、斑鰶(Konosirus punctatus)等, 仔稚鱼优势种为鳀(Engraulis japonicus)、康氏侧带小公鱼(Stolephorus commersonnii)。鱼卵、仔稚鱼资源密度时空分布不均, 主要集中于调查海域的东部, 2019 年较 2018 年增多。聚类分析和非参数多维标度分析(NMDS)排序结果显示, 鱼卵和仔稚鱼群聚组成呈极显著差异(P=0.001), 群落结构具有明显的区域划分特征。曼特尔检验(Mantel test)相关性分析和冗余分析 (redundancy analysis, RDA)结果显示, 温度、盐度、溶解氧等环境因子与鱼卵和仔稚鱼的分布密切相关。研究表明, 保护区在建立初期对鱼类早期资源的补充和修复起到了积极作用,但该海域以小型鱼类和低经济价值鱼类为主, 在现有渔业资源恢复措施的基础上, 应进一步加强重要经济种类的资源保护以及合理开发与利用。     

北部湾西北部饵料浮游动物季节变化及其与鱼卵、仔稚鱼的关系

根据2012年在北部湾西北部广西近海冬、春、夏和秋4个季节的调查资料,探讨了该海域浮游动物总丰度的平面分布、季节变化及鱼卵仔稚鱼的丰度的季节变化,结果表明,调查水域浮游动物的丰度在春夏、秋冬季变化较大,而在冬春与夏秋季变化较小,浮游动物在冬、春、夏、秋四季的平均丰度分别为337.35 ind/m3、280.01 ind/m3、4.32ind/m3和14.78 ind/m3,冬春季明显高于夏秋季,浮游动物数量高峰季比东海提前了一个季节。冬春两季,浮游动物的数量分布特征相近,在湾内和沿岸水域数量高于近海水域。相反,在夏秋季,丰度在近海水域明显高于沿岸及湾内水域。浮游动物在各季节不同的分布特征与该海域沿岸水、外海水和混合水的季节性变化有关,优势种经历了由春季的沿岸暖温种到夏季和秋季的外海暖水种到冬季的沿岸暖水种更替的过程。该海域的主要优势种,冬季为鸟喙尖头溞(Penilia avirostris),春季为中华哲水蚤(Calanus sinicus),夏季和秋季同为肥胖软箭虫(Flaccisagitta enflata),主要优势种类的生态适应性决定了浮游动物总数量的分布特征。鱼卵、仔稚鱼在冬、春、夏、秋季的丰度为6.83 ind/m3、3.09 ind/m3、0.05 ind/m3、0.20 ind/m3,季节变化趋势与浮游动物一致,由高到低依次为冬季、春季、秋季、夏季,两者较强的正相关关系表明,食物饵料充足对鱼卵仔鱼的发育具有促进作用。     

泉州湾浮性鱼卵和仔、稚鱼的种类和数量分布

根据2001-2002年在泉州湾海域分别进行4个季度月的调查资料,研究分析泉州湾鱼卵和仔、稚鱼的种类组成,数量和主要种类的分布。结果表明,本海区共出现鱼卵和仔、稚鱼34种,分别隶属于14科21属。在数量上,鱼卵和仔稚鱼最高值均出现在春季(5月),其中鱼卵数量最大的种类是鳀科鱼类,约占总卵量34．2％。仔稚鱼则以鱚科鱼类最为丰富,占61．8％。在数量分布上,不论鱼卵或是仔、稚鱼均以9号站最为密集。这表明该区鱼类主要产卵期在春季。