黄海北部大连沿岸虾夷扇贝天然苗采集技术研究

Natural spat collection of introduced scallop Patinopecten yessoensis in coastal areas of Dalian,Northern Yellow Sea

在调查了2005、2006年黄海北部大连海域虾夷扇贝的繁殖期、浮游幼虫的时空分布的基础上,对虾夷扇贝海区天然采苗进行了研究。结果表明,2005、2006年该区域的獐子岛海域、大长山岛海域、广鹿岛海域养殖的虾夷扇贝的繁殖期在4月初至5月上旬,盛期在4月15～25日。4月上旬至6月中旬,在此区域均可发现大量的虾夷扇贝浮游面盘幼虫,不同区域浮游幼虫密度变化很大。5月底至6月初是面盘幼虫集中的附着变态时期,在海区投放附着袋可进行虾夷扇贝天然苗的采集。从各海区虾夷扇贝浮游幼虫的拖网调查和采苗结果看,在虾夷扇贝主要养殖区獐子岛、大长山岛海域和广鹿岛海域,浮游幼虫在浮游的初始阶段能够形成较高的密度,但在附着阶段密度极低,不能采集到大量苗种,但在远离虾夷扇贝养殖区的大李家湾和凌水湾,浮游幼虫的出现比养殖区晚,在幼虫附着期能达到较高密度。能够采集到大量天然苗种。2005年在凌水湾的采苗数量达526±131个/袋(壳长0.6～1 mm),2006年在大李家湾的采苗数量达673±200个/袋(壳长0.6～1mm)。

The technique for natural spat collection of introduced scallop Patinopecten yessoensis in the field was reported, based on assessments of spawning period and temporal-spatial distributions of larvae in Northern Yellow Sea in 2005 and 2006. Spawning period of the scallops started in early April and ended in early May around Zhangzi Island, Da Changshan Island and Guanglu Island, and peaked during April 15-25. From early April to mid June, pelagic larvae were found in these areas. Larvae densities varied greatly with locations. Late May and early June were the primary periods for settlement of scallops, when settlement mesh bags should be put out to sea for spat collection. Survey by dragnet sampling and seed collection showed that higher densities of early stage larvae appeared around the three islands, although the biomass of eyespot larvae was too low to support a viable spat collection. Far from the scallop cultivation areas, the pelagic larvae appeared later in the Bays of Lingshui and Da Lijia, where the peak density of eyespot larvae and spat settlement also occurred. In 2005, the highest density of spat collection was 526±131 ind./bag （shell length 0.6～1 mm）, found in Lingshui Bay; while in 2006, the highest density was 673±200 ind./bag （shell length 0.6-1 mm）, found in Da Lijia Bay.