基于鱼卵仔鱼数据的东海中南部日本鲭产卵场分析

利用2016年4—5月在东海中南部海域的调查数据,对该海域日本鲭(Scomber japonicus)鱼卵仔鱼的分布特征进行了研究,并对产卵场的划分展开讨论及提出保护措施和管理建议。结果显示:4月,日本鲭鱼卵仔鱼主要出现在台湾海峡和东海南部海域,出现率均大于25%,但仔鱼在东海南部外海的出现率和丰度均较低,分别为5.00%和0.01个·100m-3。5月,日本鲭鱼卵仔鱼在台湾海峡的出现率和丰度均显著降低,分别下降至5.88%和0.22个·100m^-3;东海南部外海日本鲭鱼卵仔鱼的出现率和丰度则均显著升高,分别升至50%和36.48个·100m^-3,其中鱼卵集中出现在南部外海,出现率和丰度分别达到了40%和36.46个·100m^-3;东海中部外海从5月开始出现日本鲭鱼卵和仔鱼。结合历史资料,可以判断东海中南部日本鲭产卵场主要有台湾海峡、东海中南部近海、东海南部外海、东海中部外海等4个。日本鲭鱼卵丰度与表层水温呈显著相关关系(R=0.37,P<0.05),与表层盐度无显著相关关系(P>0.05);仔鱼丰度与表层水温及表层盐度均无显著相关关系(P>0.05)。结果表明,水温对日本鲭的产卵活动影响较大,随着水温的逐步升高,性腺发育速度加快,开始产卵的亲体数量也大量增加,这从鱼卵仔鱼的数量大量增加得以体现;而盐度变化对日本鲭的产卵活动影响相对较小。针对日本鲭不同的产卵场,建议制定差异化的繁殖亲体和幼鱼保护措施。

Analysis of Scomber japonicus spawning grounds based on fish eggs and larvae data in the Central and Southern East China Sea

Based on data obtained in the Central and Southern East China Sea from April to May 2016,the distribution characteristics of Scomber japonicus eggs and larvae in this area were studied,and the division of spawning grounds was discussed and protective measures and management suggestions were put forward.The results showed that in April,the eggs and larvae mainly appeared in the Taiwan Strait and the southern waters of the East China Sea.The occurrence rate was more than 25%.But the occurrence rate and abundance of larvae were both low in the southern open waters of the East China Sea.They were 5.00%and 0.01 ind·100m^-3,respectively.In May,the occurrence rate and abundance of eggs and larvae in the Taiwan Strait both decreased significantly,falling to 5.88%and 0.22 ind·100m^-3,respectively.But those of the southern open waters of the East China Sea increased significantly,reaching 50%and 36.48 ind·100m^-3,respectively.Fish eggs were concentrated in the open waters of the Southern East China Sea.Its occurrence rate and abundance reached 40%and 36.46 ind·100m^-3,respectively.The fish eggs and larvae began to appear in the open waters of the Central East China Sea.Combined with historical data,it can be judged that there are spawning grounds of the Taiwan Strait,offshore of the Central and Southern East China Sea,open waters of the Southern East China Sea and open waters of the Central East China Sea.There was a significant correlation between egg abundance and sea surface temperature(R=0.37,P<0.05),no significant correlation with the sea surface salinity(P>0.05).There was no significant correlation between larvae abundance and surface water temperature and salinity(P>0.05).The water temperature had a greater impact on the spawning activities of S.japonicus.The rate of gonad development has accelerated and the number of spawning fish parents has also increased significantly with the gradual increase of water temperature.This is reflected in the large increase in the number of fish eggs.The change in salinity has a relatively small impact on the spawning activities of S.japonicus.In view of different spawning grounds of S.japonicus,it is proposed to develop differentiated protection measures for reproductive parents and juveniles.