南海外海鲹科鱼类资源量及其分布

Biomass and distribution of carangoid fish resources in the offshore South China Sea

为查明南海外海鲹科鱼类的资源量及其分布,利用科学探鱼仪(Simrad EY60)并结合灯光罩网采样方法,2012年秋季和2013年春季对南海中南部(6°N^17°N)及2015年春季和秋季对南海北部外海(17°N^22°N)鲹科鱼类资源进行了调查与评估。在确定该方法的有效性基础上,调查结果显示,2012年秋季和2013年春季南海中南部鲹科鱼类资源量分别是4.13×105t和3.49×105t,两季调查中鲹科鱼类分布的高值区均是15°N断面;2015年春季南海北部外海鲹科鱼类资源量是2.03×105t,高值区位于18.50°N^19.50°N、113.00°E^116.00°E海域,而2015年秋季该海域其资源量仅0.59×105t。研究表明,南海外海鲹科鱼类种类组成存在明显季节变化;细鳞圆鲹(Decapterus macarellus)和长体圆鲹(D.macrosoma)是最重要的经济鲹科种类;2012年秋季中南部鲹科鱼类资源量密度明显高于2015年秋季北部外海(P<0.01,t检验),但与2013年春季中南部无显著差异(P>0.05,t检验);2015年春季北部外海鲹科鱼类资源量密度与2013年春季中南部无显著差异(P>0.05,t检验),但明显大于2015年秋季(P<0.01,t检验)。

In order to identify the biomass and distribution of carangoid fish resources in the offshore South China Sea,four acoustical surveys were conducted using scientific echosounder（ Simrad EY60） with light falling-net fishing in the middle south area（ 6°N - 17°N） of the open South China Sea（ autumn 2012,spring 2013） and north area（ 17°N - 22°N） of the offshore South China Sea（ spring2015,autumn 2015）. On the basis of determining the effectiveness of the method,the survey results show that the biomass of carangoid fish resources was 4. 13 × 10^5 t and 3. 49 × 10^5 t in the south-central area in autumn 2012 and in spring 2013,and the high density area were both 15°N transect. In the north area,the biomass of carangoid fish resources was 2. 03 × 10^5 t in spring 2015 and the high density area was 18. 50°N - 19. 50° N,113. 00° E - 116. 00° E,but that biomass was only 0. 59 × 10^5 t in autumn 2015. The species composition of carangoid fish presented significant seasonal difference,and Decapterus macarellus and D. macrosoma were the most important economic carangoid species; the biomass density of carangoid fish resources in the south-central area in autumn 2012 was significantly higher than that in the north area in autumn 2015（ P 〈 0. 01,t-test）,but was not significantly different with that in spring 2013（ P 〈 0. 05,t-test）; the difference of the biomass density was not significant between the south-central area in spring 2013 and the north area in spring 2015（ P 〈0. 05,t-test）,but the biomass density in the north area in spring 2015 was significantly higher than that in autumn 2015（ P 〈0. 01,t-test）.