夏秋季东海中部和南部海域澳洲鲐渔汛和渔场的年际变化

以2003-2008年夏秋季大型机轮围网在东海南部和中部外海的生产数据为基础,对澳洲鲐(Scomber australasicus)的集群开始时间、渔汛持续时间、渔场和渔获产量的年际变化进行了研究,并进一步探讨了渔汛开始和持续时间的影响因素以及渔场和渔获产量的年际变化因为.结果表明,夏秋季东海中南部澳洲鲐的平均渔汛开始时间平均为7月12日,即7月中旬开始;渔汛持续时间近2个月,一般在9月上中旬结束,个别年份可延迟到9月下旬;渔获产量的高峰期主要在7月下旬和8月份.渔场范围以2005、2006和2008年较大,而其余3年相对较小;中心渔场集中程度以2003、2004和2008年较高.年产量具有较大的波动性,最高产年份(2005年)的渔获量是最低产年份(2007年)的近5倍;而在高产渔区的产量方面,年间差异则更加突出.夏季澳洲鲐渔汛开始的时间和水温的上升速度有关,升温速度快的年份渔汛开始的时间也较早;渔汛持续时间和海水的高温持续时间基本一致.中心渔场的年间变动除了和等温线的年间变动有关外,也可能与黑潮在东海的流向有密切的关系.年产量的剧烈波动除了与澳洲鲐本身的资源量有关外,也与海洋环境的变化和捕捞因素有密切的关系.

Annual change of spotted mackerel Scomber australasicus fishing season and fishing grounds in central and southern East China Sea in summer and autumn

cluster starting time, duration of fishing season, fishing grounds and catch yield were studies and the related impact factors were further explored based on the production data by state-owned large purse-seine in central and southern East China Sea in summer and autumn of 20032008. The results showed that: the spotted mackerel average starting colony date of fishing season were July 12 in the central and southern East China Sea in summer and autumn. The fishing season usually started in the mid of July and ended by early September, lasting two months, though sometimes it was postponed until late September. The peak of catch mainly occurred in late July and August. cope of fishing ground varied in the six years with larger fishing grounds in 2005, 2006 and 2008, and smaller ones in the remaining three years. Concentrative degree of central fishing ground was higher in 2003, 2004 and 2008. atches for the most productive year (2005) was nearly five times that of the least productive year (2007), while the annual difference is more prominent in high-yield fishing areas. The time of spotted mackerel clustering in summer was closely related with the warming speed of water temperature. When temperature increased fast, the fishing season may start earlier. The fishing season duration was in consistent with duration of high temperature. Besides isothermal lines, the central fishing ground was also closely related with the flow direction of Kuroshio Current in East China Sea. The intense volatility of output was not only relevant with its own biomass level, but also with changes in marine environment and fishing factors.