台湾海峡南部灯光围网捕捞的水温选择及其季节变化

Selective water temperature and its seasonal variation for light-seine fishing in southern Taiwan Strait

对 1 98 9～ 1 998年台湾海峡南部渔场生产记录资料分析结果表明 :灯光围网捕捞主要捕捞年适宜水温 1 6 .1～ 30℃ ,年较佳水温 2 0 .1～ 30℃ ,年最佳选择水温 2 1 .1～ 2 9℃ .环境水温过高或过低 ,不利于灯光围网生产 .各季度的选择水温 ,冬季为 2 1 .1～ 2 4℃ ,春季为 2 1 .1～ 2 7℃ ,夏季为 2 6 .1～ 2 9℃ ,秋季为 2 5 .1～ 2 8℃ ;各月选择水温为该月环境水温的中间值至偏高 2℃ ,多数比中间值偏高 1～ 2℃ .选择水温范围的宽幅 3～ 5℃ ;随环境水温升高或降低 ,鱼类对水温选择发生同向、同步的变化 ,是一种渐进的过程 ;在环境水温上升或持续高温 ,温跃层存在、底层低温涌升水强盛的条件下 ,灯光围网的作业效率均受影响 .

According to the information of light seine fishing in the southern Taiwan Strait from 1989～1998, the result indicated that annual suitable temperature is 16.1～30℃ for light seine fishing, 20.1～30℃ for annual better temperature, 21.1～29℃ for annual better selective temperature. If water temperature is higher or lower, it is not advantageous to light seine fishing. The selective temperature for light seine is 21.1～24℃ in winter, 21.1～27℃ in spring, 26.1～29℃ in summer and 25.1～28℃ in autumn. In various months selective temperature for fishing is the median temperature in that month or is higher 2℃ than the median temperature, higher 1～2℃ mainly. Variable range of selective temperature is 3～5℃. Fish keep up same direction and range with temperature variety in temperature selection. It is affected by press of temperature and is a progressive process. Fishing efficiency of light seine is affected by water temperature rising, continue higher temperature, larger temperature gradient, thermocline or the strong upwelling with lower temperature in bottom.