生物学特性
北太平洋公海日本鲭
基础生物学特征及其渔场时空动态
戴澍蔚
北太平洋公海日本鲭基础生物学特征及其渔场时空动态
摘 要
随着中国近海鱼类资源的的过度捕捞,近海资源的供应量已经达不到广大消费者日益增长的需求,在保护近海鱼类资源的同时,在世界各大洋公海海域捕捞经济鱼类是满足国内市场的重要解决路径。日本鲭(Scomber japonicus)是北太平洋公海灯光敷网及灯光围网渔业的重要捕捞鱼种之一,是一种暖水性中上层长距离洄游鱼类,广泛分布于西北太平洋沿海海域,资源数量庞大,其洄游路线受海洋环境影响较大,探索北太平洋日本鲭的基础生物学特征及渔场时空分布与海洋环境的关系,对更加合理利用该海域的日本鲭资源具有重要的意义。本研究根据2016年8~11月及2017年4~11月在北太平洋公海海域取样测定的日本鲭基础生物学数据,对其群体组成、性比、摄食等生物学特征进行了研究;根据2014~2016年三年收集的北太平洋公海围拖网作业的日本鲭生产月度数据,结合同期卫星遥感反演技术获取的海表温度(SST)、海水叶绿素a(Chl-a)浓度、海流等环境数据,运用渔获量重心法,地统计插值等方法,分析了北太平洋公海日本鲭的渔场分布情况与渔获量重心的时空变化及其与主要环境因子之间的关系。本研究结果如下:
(1)对北太平洋公海日本鲭的基础生物学特征进行研究,其结果表明:北太平洋日本鲭的叉长范围是130~378mm,平均叉长226.08mm,优势叉长组为161~210mm、271~300mm;雌性日本鲭体重范围是23.7~837.2g,平均体重144.59g,优势体重组为50~100g、200~300g;雄性日本鲭体重范围是22.5~740.6g,平均体重148.36g,优势体重组为0~150g、200~250g。在不同季节,不同叉长组日本鲭的雌雄性比基本符合1:1关系(p<0.5);体质量在200~300g范围的日本鲭,雌性显著多于雄性(p>0.5)。
(2)对其摄食习性研究结果表明:日本鲭主要摄食虾类、鱼类和桡足类等9大类16小类饵料生物,其中,虾类是最最要的饵料种类,以磷虾目为主;鱼类以未定种鱼类和远东拟沙丁鱼(Sardinops sagax)为主,鱼类饵料的质量百分比W(%)比虾类高,但数量比例N(%)不及虾类一半。叉长小于300mm或体重小于300g的日本鲭摄食强度与胃饱满指数P(%)没有明显变化,叉长大于300mm或体重大于300g时,摄食强度与胃饱满指数均出现增大趋势,叉长大于300mm的日本鲭由于摄食更多大型饵料,生态为宽度比叉长小于300mm的日本鲭普遍低。
(3)对北太平洋公海日本鲭渔场分布与海洋环境的研究认为:日本鲭渔场季节性差异明显,渔场重心集中分布在39°N~43°N、147°E~154°E范围内。三年渔场重心均呈现先向东北方向移动,自9月开始再向西南方向移动的趋势。GAM模型显示,北太平洋日本鲭渔场的最适海表温度范围是14~17℃,最适叶绿素a浓度范围是0.3~0.5mg·m-3,空间上集中分布在40°N~41°N、148°E~151°E,海流对日本鲭渔场形成尤为重要。
本研究的创新成果主要体现在:
(1)运用两年同期采样的日本鲭生物学数据得出该海域日本鲭群体生长特征,为今后更加合理利用其资源提供参考;
(2)用捕捞数据来反映日本鲭渔场情况;
(3)详细探讨了北太平洋公海日本鲭渔场分布与海洋环境的关系,得出日本鲭最适环境因子范围。
关键词:北太平洋,日本鲭,群体组成,性比,食性特征,海洋环境,GAM模型
Basic biological property and
spatiotemporal dynamics in fishing ground
of Scomber japonicas in North Pacific high seas
ABSTRACT
With the overfishing of fish resources in China’s offshore,the supply of the offshore resources can not meet the growing demand of the consumers. It is an important solution to supply the domestic market by catching economic fish species from the high seas around the world while protecting the fish resources offshore. Chub mackerel is one of the most important fishing species of light-purse seine and light lift net fishery in North Pacific high seas. It is a warm-water, middle upper and long-range migratory fish, widely distributed in the coastal waters of the Northwest Pacific Ocean and has a large number of resources and which migratory is greatly affected by the marine environment. It will make sense for us to take advantage of the resource if we explore its basic biological features and the relationship between its spatiotemporal and the marine environment. According to the basic biological data of chub mackerel collected from North Pacific high seas in Oct. to Nov. 2016 and Apr. to Nov. 2017, biological characteristics such as the stock composition, female to male ratio and feeding intensity were studied. Resource abundance, change of time and space of fishing ground centroids and the relationship with influential environmental factors of chub mackerel were analyzed with the method of production gravity center, statistical interpolation, Through environmental data like the sea surface temperature(SST), sea chlorophyll-a(Chl-a) concentration and ocean current got by satellite remote sensing inversion technology and monthly trawling and purse seine product data of chub mackerel in North Pacific high seas in 2014~2016.
The main results can be summarized as follows:
(1) Basic biological characteristics of chub mackerel in North Pacific high seas was analyzed. The results show that the fork length of the stock ranged from 130mm to 378mm with an average value of 226.08mm, and the dominant group ranged from 161mm to 210mm and 271mm to 300mm. The weight of the female stock ranged from 23.7g to 837.2g with an average value of 144.59g, and the dominant group of which ranged from 50g to 100g and 200g to 300g. The weight of the male stock ranged from 22.5g to 740.6g with an average value of 148.36g, and the dominant group of which ranged from 0 to 150g and 200g to 250g. Females to males conformed to a ratio of 1:1 in different fork length and different seasons, while female fish out-numbered male ones significantly in the weight range from 200~300g.
(2) The result of its feeding habits turns out that diet of chub mackerel in North Pacific Ocean included 9 taxa and 16 prey species, and was dominated by shrimps. In the taxonomic level of species, the dominant preys were the Euhausiacea sp. For shrimp’s items, the unidentified fish and Sardinops sagax for fish’s items. The fish prey had relatively higher weight percentage W(%)and lower numeric percentage value compared with the shrimps. There is no significant change in feeding intensity and stomach fullness index P(%)when the fork length less than 300mm or the weight less than 300g, on the other hand, feeding intensity and stomach fullness index P(%)tends to increase when the fork length greater than 300mm or the weight greater than 300g. Universally, the chub mackerel feeding more large bait and have lower trophic niche when its fork length greater than 300mm.
(3) The study of the distribution and the relationship with marine environment indicated that the fishing ground of chub mackerel have significant seasonal differences, and the gravity center of fishing ground distributed in the range of 39°N~43°N、147°E~154°E, which moved from northeast to southwest at September. Generalized additive models (GAM) indicates that optimal sea surface temperature of chub mackerel is 14~17℃, optimal chlorophyll-a concentration is 0.3~0.5mg·m-3, and the space distribution is centralized in 40°N~41°N、148°E~151°E in North Pacific Ocean. Sea current is important for the formation of chub mackerel fishing ground.
The innovation of this research is mainly reflected as followed:
(1) Using the biological data sampled in the same period of two years of chub mackerel to obtain the characteristics of the growth in the sea area, and provide a reference for more rational use of its resources in the future.
(2) Using the product data to reflect the fishing ground of chub mackerel.
(3) The relationship between the distribution of fishing ground of chub mackerel and the marine environment is discussed in detail, and the best environmental factors for chub mackerel is obtained.
KEY WORDS: North Pacific Ocean, chub mackerel, stock composition, female to male ratio, feeding characteristics , marine environment, GAM model