菲律宾蛤仔莆田群体与大连群体生物学比较

Biological comparisons between putian population and dalian population of manila clams Ruditapes philippenarum

对菲律宾蛤仔莆田和大连群体形态及生物学进行了比较.菲律宾蛤仔大连群体和莆田群体的生物学零度(BZP)分别为6.77℃和10.99℃;有效积温(EAT)分别为315.21和172.79 ℃·d.通过人工促熟,大连群体繁殖期比自然海区提早1个月,莆田群体比自然海区提早5个月.莆田的蛤仔第1次最高产卵量可达104万粒,大连的蛤仔最高产卵量可达65万粒,大连的蛤仔卵径(66.13±2.40)μm(n=40),莆田的蛤仔卵径(71.88±3.14)μm(n=40),二者差异显著(p＜0.01).大连的蛤仔D形幼虫大小平均96.13(±5.83)μm×76.75(±4.46)μm(n=40);莆田的蛤仔D形幼虫大小平均107.63(±5.55)μm×82.88(±4.22)μm,二者差异显著(p＜0.01).莆田的蛤仔幼虫整个浮游期平均日增长9.63μm×9.79μm,大连的蛤仔幼虫整个浮游期平均日增长12.20μm×12.47μm,后者快于前者(p＜0.01).大连的蛤仔在水温25℃以上条件下,浮游期为10d左右,附着大小为179.9μm×174.4μm,附着至变态需8～9d,变态大小230.0μm×220.0μm,相同条件下,莆田的蛤仔浮游期仅5～6d,附着至变态只需4～5d,附着大小为174.9μmX171.4μm,变态大小仅为196.7μm×190.8μm.

This study compared the morphology and biology of Manila ℃lams Ruditapes philippenarum between Putian （Fujian Province ） and Dalian populations （Liaoning Province）. The biological zeros point of gonadal development for the Dalian population was found to be 6.77℃ and that for the Putian population was 10.99℃. The mean effective accumulative temperature for the Dalian population in different experiments was 315.21 ℃. day and that for the Putian population was 172.79 ℃. day. With indoor artificial conditioning, the first spawning of Dalian and Putian clams occurred one and five months earlier than in natural waters, respectively. The fecundities of Dalian and Putian clams were 6.5× 10^5 and 1.04× 10^6 eggs per clam, respectively. The eggs produced by Dalian clams were smaller than those by Putian clams（66.1±2.4）μm vs. （71.9±3.1）μm ; p〈0.01）. D-larvae from the Dalian population were also smaller than those from Putian population（shell length × width： （96.1±5.8） × （76.8±4.5） vs. （107.6±5.6）μm× （82.9±4.2）μm; p〈0.01）. However, larvae of the Dalian population grew faster than those of the Putian population （12.20μm × 12.47μm vs. 9.63μm × 9.79μm per day; p〈0.01）. At water temperatures of 〉25℃ ,the swimming stage of larvae from Dalian population lasted about 10 days,while the duration from setting to metamorphosis lasted 8-9 days; setting and metamorphosis sizes were 179.9μm × 174.4μm and 230.0μm × 220.0μm,respectively. Under similar conditions, the swimming stage and duration from setting to metamorphosis of larvae from the Putian population lasted 5-6 and 4-5 days, respectively; setting and metamorphosis sizes were 174.9 × 171.4 and 196.7μm× 190.8μm,respectively.