涉海建设项目中深水海域渔业资源调查问题的研究

为解决涉海工程深水渔业资源评估的问题,于2014~2015年在南海北部局部海域开展底拖网与灯光罩网联合调查渔业资源活动。结果表明:在深水区底拖网渔获组成与灯光罩网有明显的不同,并受到季节与海域的影响(P0.05)。拖网渔获物中鱼类平均占渔获总尾数的93.36%,头足类占3.53%,甲壳类占3.11%;灯光罩网渔获物中鱼类平均占渔获总尾数的63.33%,头足类占36.65%,甲壳类占0.02%。两种调查的相同渔获物1~6种,主要为鱼类和头足类,在拖网中所占比值较低,平均占渔获总尾数的2.07%,而在灯光罩网中比值极高,平均占渔获总尾数的67.03%。灯光罩网与底拖网调查的渔业资源密度直接比值平均为0.06,灯光罩网与底拖网扣除相同渔获种类后的资源密度比值平均为0.06,相应的质量密度直接比值平均为0.62,扣除相同渔获种类后的比值平均为0.67。研究认为,深水海域的渔业资源量应该是两种渔具调查结果之和,对两种渔具调查中出现的相同渔获物,宜取其评估数据的平均值。由于各站点调查结果差异较大,采用所有站点的平均值来计算评估海域的损害赔偿较为合适。建议对SC/T9110-2007技术规程修订,规范中上层渔业资源调查方法。

On fishery resources survey in deepwater areain the sea with construction project

For there is no explanation on the deepwater fishery resources survey in the current technical specification (SC/T9110-2007) for the impact assessment of construction projects on the marine biological resources, a joint fishery resources survey by bottom trawl and light falling net in partial sea area in the northern South China Sea during 2014-2015 was done.The results showed that the composition of catch species in the bottom trawl was greatly different from light falling net in deepwater area.The quantity and weight of fishes and cephalopods changed greatly among seasons and sea areas.As for the total catch, in bottom trawl, fishes, cephalopods and crustaceans accounted for 93.36%, 3.53% and 3.11%, respectively.In contrast, in light falling net, fishes, cephalopods and crustaceans accounted for 63.33%, 36.65% and 0.02%,respectively. As for total catch weight, in bottom trawl, fishes, cephalopods and crustaceans accounted for 85.19, 12.68% and 2.13%, respectively. In contrast, in light falling net, fishes, cephalopods and crustaceans accounted for 89.59%, 10.36% and 0.05%, respectively. There were 1-6 same species in the two fishing gear catch, which were mainly fishes and cephalopods. They accounted for 2.07% and 67.03% of total catch in bottom trawl and light falling net, respectively. The ratio of same catch by two fishing gear in quantity and weight were 2.17 and 2.80, respectively. The species and weight of fishes in the same catch changed greatly among sea areas. And species, quantity and weight of cephalopods in the same catch changed greatly among sea areas and seasons. The gross abundance ratio of two fishing gears was 0.06 for pelagic and demersal fishery resource, and the net abundance ratio of two fishing gears was 0.06 without repeating parts in bottom trawl. Correspondingly, the gross biomass ratio of two fishing gears was 0.62 for pelagic and demersal fishery resource, and net abundance ratio of two fishing gears was 0.67 without repeating parts in bottom trawl. There was no great difference among sea areas and seasons for gross and net abundance ratio. However, there were great differences among sea areas and seasons for gross and net biomass ratio. Therefore, it can be concluded that the biomass should be the sum of the catch from two fishing gears. As for the same catch part, it is recommended to take the average of assessment data from two fishing gears into account. For the survey results are highly variant among different station locations, it should be appropriate to calculate the compensation from the average of different location surveys. In summary, it is suggested that the criteria in the technical regulation SC/T9110-2007 should be revised and supplemented for the pelagic fishery resources survey.