南澳白沙湾海藻养殖区内外渔业资源声学评估

Acoustic estimation of fishery resources inside and outside the algae breeding zone of Baishawan in Nan'ao

摘要:

为初步了解南澳岛白沙湾海藻养殖区鱼类资源状况，利用便捷式分裂波束式Simrad EY60科学探鱼仪，于2015年4月28日、12月2日与2016年4月19日对该海域进行3次声学调查，结果显示，3次调查中藻区内、外鱼类资源丰度密度分别为3.45/1.38×10⁵、0.63/1.45×10⁵、3.67/2.98×10⁵尾/n mile²。藻区内春季鱼类资源量显著高于冬季，资源丰度密度随季节变化显著；藻区外资源丰度密度变化较小且均匀；藻区内、外鱼类资源丰度密度最高值出现于2~6 m水层，6~8 m次之，表、底层最小,资源丰度密度受深度影响显著。在海藻养殖期间，藻区内鱼类资源丰度密度较藻区外大且年变化明显，表明海藻生物量对鱼类资源量及其分布变化具有一定影响。本次调查通过声学评估技术对海藻养殖区鱼类资源进行初步评价，为其具有改善水质环境、恢复渔业资源的作用提供理论依据。

关键词:鱼类资源;丰度密度;空间分布;声学评估;南澳岛

Abstract:

In order to know the fish resource distribution and the variation of the biomass density, three acoustic surveys were conducted with a split-beam echo sounder (EY60 model, 200 kHz, Simrad) inside and outside the algae breeding zone of Baishawan in Nan'ao on Apr. 28, Dec. 2, 2015, and Apr. 19, 2016. The acoustic assessment results showed that the resource abundance density of three times inside and outside the algae breeding zone were 3.45/1.38×10⁵, 0.63/1.45×10⁵ and 3.67/2.98×10⁵ inds/n mile². Obviously, the biomass was higher in spring than in winter inside the algae breeding zone and the resource abundance density changed evidently as the seasons than outside the algae breeding zone. The highest resource abundance density was mainly in 2–6 m depth layer, 6–8 m depth layer took second place, and the upper and the bottom had the least. The biomass was affected by the depth of significant resources abundance density. Our research confirmed that during the period of algae breeding, the resource abundance density was higher inside than outside the algae breeding zone and changed evidently. It was important for the algal biology to change the biomass and distribution inside the algae breeding zone.

Key words:fish resources;abundance density;spatial distribution;acoustic surveys;Nan'ao Island