影响鸢乌贼手钓上钩率的因子探讨

Elementary Analysis on the Factors Affecting Hand-Jigging Efficiency of Symplectoteuthis oualaniensis

根据印度洋西北部鸢乌贼(Symplectoteuthis oualaniensis)作业渔场的现场调查数据,分析了作业水深、作业时段、摄食等级和月相等因子对手钓上钩率的影响。统计表明,晚上、午夜和凌晨3个不同时段和不同作业水深对手钓上钩率均有显著性影响。3个时段中,其摄食等级呈先低后高再低的现象。午夜和凌晨,上钩率的变化趋势与摄食等级的变化趋势呈显著的负相关。在月相的影响下,离朔日三四天之前,手钓产量呈上升趋势;离望日五六天之前,手钓产量呈明显的下降趋势。

The effects of four factors on jigging efficiency, fishing water depth, period of fishing time, degree of stomach fullness （DSF） and phase of the moon, were analyzed according to the cruising data from Northwest Indian Ocean Symplectoteuthis oualaniensis fishing ground. Statistics shows that hand-jigging efficiency under different fishing water depth and three different periods during one fishing night, i.e. evening, midnight and dawn, has great difference. DSF of these three periods indicate a trend from low to high and then low again. During midnight and dawn time, the changing tendencies of DSF and numbers of jigged-on show a negative correlation. Under the influence of the phase of the moon, hand-jigging yield has ascended 3 or 4 days before the first day of the lunar month, and it has descended obviously 5 or 6 days before the 15^th day of the lunar month.