2008年夏秋季东海区北部沙海蜇资源状况分析

根据2008年夏秋季在东海区北部对沙海蜇的定点资源监测和生物学测定数据,对2008年夏初沙海蜇生物量较低的原因进行了分析,并对其不同生活阶段的温盐度属性进行了探讨,同时讨论了其伞径变化规律并对产卵时间进行推测。研究表明:6月中旬,沙海蜇出现站位平均资源密度133 kg/h,出现范围33°00′~33°30′N、123°00′~124°00′E,出现率仅为4.76%;9月上旬,沙海蜇出现站位平均资源密度976 kg/h,出现范围30°30′~33°30′N,出现率45.07%,高生物量分别在32°30′~33°30′N、123°00′~124°00′E之间的南黄海中央海域和济州岛东南部外海靠近韩国专属经济区海域。生物学伞径以8月下旬最大,从6月中旬至8月下旬为逐渐增大的趋势,而从8月下旬至9月下旬为逐渐减小的趋势。2008年夏初沙海蜇出现率和生物量较低的原因可能和该年份东海区春末夏初比常年水温偏低有关。在6~8月份的快速生长期,沙海蜇表现为高温低盐的特性;在9月份以后的生长衰退期,表现为低温高盐的特性。

Analysis on the resources of Stomolophus meleagris in the northern Part of East China Sea in summer and autumn of 2008

Based on the fixed-point resource and biological resource monitoring data in the northern part of East China Sea in the summer and autumn of 2008, the paper analyzed the reasons for low biomass of S.meleagris in the early summer of 2008, and their thermohaline property at different life stages was discussed, as well as the changes of their umbrella diameter, thus further speculation on their spawning time was made. The results showed that: in mid-June, the average resource density of S.meleagris appearing in the stations is 133 kg/h, the scope is 33°00′-33°30′N, 123°00′-124°00′E, and the occurrence rate is 4.76%; in early September, the average resource density of S.meleagris appearing in the stations is 976 kg/h, the scope is 32°30′-33°30′N, and the occurrence rate is 45.07%. The high biomass appeared in the area of the central waters between the South and the Yellow Sea and the south-eastern waters off the Jeju island near the Korean Exclusive Economic Water Zone, namely in the area of 32°30′-33°30′N and 123°00′-124°00′E. Umbrella diameter was the largest in late August, increasing gradually from mid-June to late August and decreasing gradually from late August to late September. The low jellyfish occurrence and biomass in early summer of 2008 may be caused by the lower temperature in the period compared with that of the average year. In the rapid growth period from June to August, the growth property of area for S.meleagris is high temperature and low salinity; while in the recession period after September, it is low temperature and high salinity.