中西太平洋长鳍金枪鱼(Thunnus alalunga)延绳钓渔场分布的时空变化

The Spatio-Temporal Changes in the Long-Line Fishing Grounds of Albacore (Thunnus alalunga) in Western and Central Pacific Ocean

关键词:  中西太平洋  长鳍金枪鱼  延绳钓  CPUE  SST

Key words:  Western and Central Pacific Ocean  Thunnus alalunga  Long-line  CPUE  SST

摘要:

为提高中西太平洋金枪鱼延绳钓渔业作业效率和应对多变的渔业政策等提供参考，本研究根据2011年2月2012年1月间中水集团远洋渔业股份有限公司的10艘延绳钓渔船的作业数据，结合海洋表层水温(SST)等环境因子，统计分析了单位努力量渔获量(CPUE)、渔获量和SST之间的关系并利用频度累加法分析了该海域长鳍金枪鱼渔场分布的时空变化。结果显示，中西太平洋海域，深度为200 m和150 m的水温全年基本维持不变，但SST变动较大并对渔场分布和CPUE有较大影响。渔场的周年变动是由14S左右向26S转移再回归14 °S的一个往复过程；20°S以北的渔场全年连续存在，高渔获量和高产CPUE主要分布于SST为2829℃的水域；23°S以南的渔场，因为受到复杂天气状况的限制，只有58月适合生产作业，高渔获量和高产CPUE主要分布于SST为2224℃的水域，被调查船只在南部渔场，在此期间，被调查作业船只以全年14.4%的作业天数，捕获了占全年总渔获量27.6%的长鳍金枪鱼渔获物。若加强作业船只和渔具的抗风浪性，则可以在25°S以南的海域探索新的全年稳定存在的长鳍金枪鱼渔场。

Abstract:

Albacore (Thunnus alalunga) is an important economic fish species in the long-line tuna fisheries in western and central Pacific Ocean, and it is also one of the major species that the Chinese long-line fleets target in this area. To explore the spatio–temporal changes in the fishing grounds of albacore and provide guidance to the long-line fishery practice, we studied the relationship between the catch per unit effort (CPUE), the monthly catch and the sea surface temperature (SST), and analyzed the geographical changes in the fishing grounds using the frequentness accumulation method. The statistical analysis was based on the data collected from 10 albacore long-line fishing vessels of China National Fisheries Corporation (CNFC) from Feb. 2011 to Jan. 2012, combined with the environmental factors such as the SST. The results showed that in western and central Pacific Ocean, the temperature at the depth of 200 m and 150 m remained stable in a year but SST fluctuated dramatically and thus had great effects on the distribution of fishing grounds and CPUE. In a year (Feb. 2011 to Jan. 2012) the fishing ground moved periodically from 14S to 26S then back to 14S. To the north of 20S the fishing ground existed all year long, and the high catch and high CPUE were present in the area where SST was 28–29℃. To the south of 23S the fishing ground only existed from May to August because the adverse weather conditions in other months imperiled the fishing vessels, and the high catch and high CPUE were present in the area where SST was 22–24℃. In this time window the catch accounted for 27.6% of the yearly total catch while the fishing vessels worked for only 14.4% of the yearly total fishing days. Given the enhanced anti-wind and anti-wave features of fishing vessels and gears, a new sustainable fishing ground of albacore could be explored and exploited to the south of 25S.