秘鲁外海茎柔鱼渔场分布和水温结构的关系

Distribution of fishing ground of jumbo flying squid(Dosidicus gigas) and its relationship with structure of sea water temperature in the waters off Peru

分布在东南太平洋海域的茎柔鱼是重要的经济性头足类，是我国鱿钓船队的主要捕捞对象之一。研究茎柔鱼渔场分布及其与水温的水平、垂直结构等关系，是探索渔场形成机制及其规律的重要内容。本文根据2006年1—12月我国鱿钓船在秘鲁外海的渔捞记录、表温（SST）和5～180m垂直水温等资料，用3种方法计算SST的水平梯度（Dmax，Dsquare和Dmean），用ArcGIS9．0和Sufer8．0软件分析绘制单船平均日产量（CPUE）和SST、SST水平梯度关系的分布图、水温垂直结构分布图，分析茎柔鱼渔场分布及其与水温结构的关系。结果表明，全年中心渔场分布在80～85°W、10～17°S，SST为18～28℃，产量分布呈现明显的空间变化。其中，6—8月为全年最高产时期，其中心渔场分布在81～83°W、12～13°S，相应的SST为18～23℃。SST水平梯度与渔场分布关系密切，水平梯度Dsquare和产量的拟合度为最优（P〈0．001），中心渔场相应的Dsquare为0．6～1．7℃。水温垂直结构分析认为，6-8月通常在81°W、12～13°S附近形成上升流中心，中心渔场基本位于上升流冷水团边缘81°30′～02°30′W。研究认为，该渔场因上升流而形成，主要分布在上升流引起冷水与外洋暖水的交汇区，与SST、SST水平结构、水温垂直结构关系极为密切。

Jumbo flying squid （Dosidicus gigas ） distributed in the southeastern Pacific is not only an important economic oceanic squid, but also one of the important fishing targets for Chinese jigging fleets. The researches on distribution of this squid and its relationship with environmental conditions such as water temperature and its structure are the key content in searching for the mechanism of fishing ground and inherent laws. In this study, based on the fishing data from Chinese squid jigging fleets in the waters off Peru from January to December 2006, and the environmental data including sea surface temperature （SST）, the water temperatures between 5 and 180 m, and the horizontal gradient of temperature （D） calculated by three different methods （Dmax Dsquare and Dmean ）, the spatial plots of CPUE, SST, D and the vertical temperature structure are drawn respectively by use of software ArcGIS 9.0 and Sufer 8.0 to analyze the distribution of fishing ground and its relationship with structure of sea water temperature. The result indicated that the main fishing ground was around 80 -85°W and 10 -17°S with the range of 18 -28℃ SST, and the spatial variations in the catch distribution were evident. From June to August, the monthly catch was relativly high in the waters of 81 -83°W and 12 -13°S with the range of 18 -23 ℃. The distribution of fishing ground was closely related to the D, the indicator Dsquare （P 〈 0. 001 ） was better than the two others, and the range of Dsquare was 0. 6 -1. 7℃ in the main fishing ground. The results also showed that the upwelling was centralized around 12 -13°S and 81°W during June to August, and the fishing ground was mainly distributed at the edge of upwelling between 81°30′ -82°30′W. Therefore, it could be concluded that the fishing ground was formed by the upwelling, which was distributed at the mixed region between oceanic warm water and cool water caused by upwelling, and was closely related with the optimum SST, D and vertical temperature structure.