基于JABBA-Select模型对不同时间序列渔获量和渔船效应的印度洋长鳍金枪鱼资源评估

Stock assessment for albacore tuna(Thunnus alalunga)in the Indian Ocean based on JABBA-Select model under different time series of catch and fishing vessel effects

为了解印度洋长鳍金枪鱼(Thunnus alalunga)种群动态及资源开发利用状况,采用结合了种群生物学参数和渔业选择性的JABBA-Select模型,分别从渔获量的不同时间序列、单位捕捞努力量渔获量(CPUE)标准化过程是否考虑渔船效应两个方面,考察对印度洋长鳍金枪鱼资源量评估结果的影响。结果表明:当模型选取1979-2020年短时间序列渔获量数据时,CPUE的拟合效果更好;而当模型选取长时间序列渔获量数据时,CPUE对数残差较大,拟合效果较差;同时考虑渔船效应的CPUE数据对模型拟合效果表现更佳;2020年印度洋长鳍金枪鱼未发生资源型过度捕捞(B_(SB)/B_(SB),MSY>1),也未发生捕捞型过度捕捞(F/F_(MSY)<1);模型重要参数的敏感性分析显示,种群评估结果对陡度(steepness,h)较稳健,但对自然死亡率(natural mortality,M)较敏感。研究表明,不同时间序列的渔获量对资源评估结果存在较大差异,考虑渔船效应的标准化CPUE可以更好地反映种群资源变动趋势,减少种群评估结果的不确定性。

In order to understand population dynamics and resource exploitation status of albacore tuna(Thunnus alalunga)in the Indian Ocean and to promote the sustainable exploitation of the fishery resources,the JABBA-Select model combining the biological parameters of the stock and fishery selectivity was used to assess albacore tuna,focusing on the impact of different time series of catch and with or without considering the fishing vessel effects in standardized CPUE on the stock assessment.The results showed that the model with short time series of catch from 1979 to 2020 and longline CPUE with vessel effect fitted better than the model with time series from 1950 to 2020,resulting in the estimated stock neither to be overfished(B_(SB)/B_(SB),MSY>1)nor subject to overfishing(F/F_(MSY)<1)in 2020.The sensitivity analysis indicated that the stock assessment results were robust to steepness(h),but sensitive to natural mortality(M).The finding showed that the stock assessment results varied with different time series of catch data,and the standardized CPUE considering the fishing vessel effect better reflected the dynamics of stock,with decrease in the uncertainty of assessment.