秘鲁沿岸秘鲁鳀渔场及渔汛分析

秘鲁鳀(Engraulis ringens)是栖息于东南太平洋沿岸的小型中上层鱼类,了解秘鲁鳀渔场和渔汛的状况有助于渔情预报工作的开展进而实现资源的合理利用。利用2005~2014年秘鲁各港口的上岸量数据,以上岸量(landings)、总捕捞努力量(fishing effort)和单位捕捞努力量渔获量(CPUE)为指标分析秘鲁鳀渔场分布及渔汛;结合二因素方差分析(two-factor analysis of variance)探究渔场月份和纬度上的显著性差异;利用分位数的方法,找出各年的旺汛时间。研究表明,每年的4~6月和11~12月为秘鲁鳀的主汛期;主要的捕捞区域分布在7°S~13°S;渔汛的前中期,上岸量和捕捞努力量有着明显的年间差异,而CPUE在渔汛后期年间差异明显。方差分析表明,不同月份和不同纬度对捕捞努力量ln(effort+1)]有极显著的影响(P0.01);5月为一年中最主要的捕捞阶段。旺汛期分析表明,第一渔汛阶段的旺汛一般在5月出现,而第二渔汛阶段的旺汛一般在11月出现。研究结果有助于对秘鲁沿岸秘鲁鳀渔场及渔汛的认识。

Analysis on fishing season and fishing ground of Engraulis ringens in the coastal waters of Peru

Anchoveta (Engraulis ringens)is a kind of small pelagic fish living in the Southeast Pacific.This fish forms the largest single-fish fishery in the world.However,its’yield has huge yearly difference. Understanding its fishing season and fishing ground is essential in developing fishery forecast and sustainable utilization of this resource.Therefore,based on the Peru ports’anchoveta fishery data from 2005 to 2014, landings,fishing effort and catch per unit effort (CPUE)were used as fishery indices to analyze the changes of fishing conditions and fishing seasons.The means and standard deviation of fishery indices were calculated to study the changes in month and latitude.Significant differences of fishing grounds in different months and latitudes were explored by two-factor analysis of variance.And the method of quantile was used to search the main fishing season in each year where the third quantile (Q3)of CPUEday was scheduled to be the high yield CPUE.Results indicated that the primary period in the first and second fishing season was from April to June and November to December,respectively.7°S -13°S was the main fishing area.The standard deviation of fishery indices suggested that there were obvious yearly differences of landings and fishing effort in the early and middle period while the large yearly difference of CPUE appeared at the end of fishing season.Two-factor analysis of variance showed that there were significant differences in effort In(effort +1)]between the first and second fishing season while the most primary fishing period was in May.By using the method of quantile, high yield CPUEday was scheduled to be 210.71 t·vessel -1 ·d -1 .The main fishing season was usually in May at the first fishing season and in November at the second fishing season.The start time,length and time of the main fishing season showed differences by year.The first fishing season might have more than one time of the main fishing season but the second might be only once.It suggested that landings and fishing effort could indicate the spatial change of fishing ground,but the CPUE indicated characteristics of the fishing season.The oceanic environment,climate and politics variations all have influences on the changes of Anchoveta’s fishing ground.In future research,the annual variations of fishing ground should be focused on. The distribution of anchoveta stock and the water mass in its habitat affect the fishing ground spatial difference.This study can help us understand the changes of anchoveta’s fishing season and fishing ground.