摘 要：
以2009年至2010年在东海中部采集的鲐鱼(Scomber japonicus)样本叉长数据为基础,结合历史数据,开展叉长数据误差对资源评估结果影响的研究。评估考虑2种情况:1)使用完整采样数据和历史数据建立Von Bertalanffy生长方程,并将鲐鱼的叉长转换为年龄。其生长参数为:K=0.49,L∞=404.6,t0=-0.9;2)删除部分大个体鲐鱼,使用剩余叉长数据建立有误差的Von Bertalanffy生长方程,同样将叉长转换为年龄。其生长参数为:K=0.4,L∞=372.5,t0=-0.34。根据以上2个转换结果,基于2006年至2012年鲐鱼产量和捕捞努力量等数据,分别进行资源评估。2组数据得出的剩余产量曲线基本吻合,最大可持续产量(MSY)和捕捞努力量(EMSY)分别约为18.8万t和72艘标准机轮围网渔船。而亲体补充量曲线则相去甚远,含有误差的年龄分组得出的亲体量范围在3000×106到5000×106之间,呈现出亲体量过高,需要增加捕捞努力量来提高补充量的状态,这与现实情况的400×106到500×106不相符。含误差的分组预测出的近几十年亲体量和渔获量是大幅度周期性剧烈变化的,生物量将在1年内达到高峰值约135.5万t,而随后2年内降至约40万t,之后又将在2年内升至高峰值,以此周期循环。亲体量的高峰值与低谷值与渔获量十分接近,渔获量的高峰值与低谷值维持在约60万t和15万t左右。与无误差分组得出的生物量将在6年内减少至约32.3万t,随后保持稳定,亲体量与年渔获量分别将稳定在15.8万t和10.5万t的评估结果相比存在很大差异。
译 名：
Influence of Fork Length Frequency Data Error on Stock Assessment Result of Chub Mackerel in Middle East China Sea
作 者：
ZHOU Congyu;WANG Yingbin;ZHENG Ji;School of Fisheries,Zhejiang Ocean University;
关键词：
chub mackerel;;fork length;;error;;stock assessment
摘 要：
In this report,we researched the effect of fork length data error on the results of the stock assessment.The data is based on the fork lengths of 5,386 chub mackerel(Scomber japonicus)samples collected from 2009 to 2010in combination with the historical data.Two cases of assessment were considered:in the first case,complete data are used to establish the Von Bertalanffy growth function and convert fork length to age with the parameters K = 0.49,L∞= 404.6,t0=-0.9.In the second case,some large individual samples are deleted and the remaining sample data is used to establish the Von Bertalanffy growth function and convert fork length to age with the parameters K = 0.4,L∞= 372.5,t0=-0.34.The stock assessment was carried out through above two conversion results and the data of production and fishing efforts from 2006 to 2012.The results showed that the complete fork length data were applicable to getting the first Von Bertalanffy growth function.It divided the chub mackerel into three age groups.Without the fork length data of large individuals,the second Von Bertalanffy growth function was obtained.Corresponding Chub Mackerel was divided into five age groups.Surplus production curves derived from the two sets of data were consistent.MSY(Maximum Sustainable Yield)and EMSY(Effort of Maximum Sustainable Yield)were approximately 188,000 tand 72.However,the stockrecruitment curves are very different from each other.The inclusions of stock derived from age groups with errors was between 3,000*106 and 5,000*106,which was too high and will facilitate overfishing in an attempt to improve the state of the stock by increasing fishing efforts.Including groups containing errors suggests that stock and catches in recent decades have shown dramatic cyclical changes.The error-free group,which predicts biomass,stock and catches,will stabilize respectively at 323,000 tons,158,000 tons and 105,000 tons in the last.The results showed that body length data containing errors of assessment will result in a significant impact.Groups with errors showed that the biomass will reach apeak value of about 1.35 million tons in a year,but fall to about 400,000 tons two years later.And it will rise to the peak again in 2years,as this cycle was significantly different compared to the error-free group.In the future enough attention should be given to the risk of data error when carrying out stock assessment based on length data.
