Survey for resource estimation of substrate spawning littoral fishes with using underwater video camera system

1.利用水下摄像系统和水肺潜水技术，对六角鱼、八爪鱼和六角鱼的繁殖行为进行了观察。主要研究结果如下：(1)3个物种的繁殖行为基本相似，属种间杂交，雌性对雄性otakii的求偶反应强烈。有一种可能性是，码头上的混凝土块放松了本地的生殖隔离。(2)在26次产卵中，有11次是在配对产卵后偷偷进行的。利用微卫星DNA对两个卵团进行亲子鉴定，结果表明，84%的卵子与领地雄鱼有亲缘关系，其余16%的卵子是偷猎者的父本。2.研究了哪些因素对双亲养殖鱼Hypoptychus dyBowskii早期生活阶段的存活率有影响。较早产卵的卵在胚胎阶段的死亡率较高。根据对潜水的观察，原因是六角星虫等鱼类的捕食。对耳石日增量的分析表明，较早产卵的个体在幼虫阶段也经历了较高的死亡率。然而，较早产卵的个体可以在成体阶段获得更大的体型。从胚胎到产卵阶段的存活是海藻林所要求的。3.通过组织学观察，观察了大闸蟹和头盔蟹的生殖周期。这两种蟹具有相似的繁殖周期，包括卵母细胞的生长、产卵、孵化、蜕皮和交配。一个周期的大闸蟹至少需要2到3年，但头盔蟹需要一年。雌性由于手无寸铁，在长时间的潜伏期内呆在沙底下。对孵化的雌蟹进行详尽的抗议，对保护蟹类资源具有重要意义。

1.The reproductive behavior of Hexagrammos otakii, H.octogrammus and H.agrammus was observed using an underwater video camera system and SCUBA diving. The following results were chiefly obtained.(1) The reproductive behavior of the 3 species was generally similar, so interspecific crossbreeding, in which female H.octogrammus responded to the courtship of male H.otakii. There is a possibility that concrete blocks of a quay loosen the native reproductive isolation.(2) Sneaking followed pair spawning is 11 of the 26 spawnings. Paternity discrimination for 2 egg masses using microsatellite DNA suggested that 84% of all the eggs deposited in the nest were kin to the territorial male, and the remaining 16% were sired by sneakers.2.It was examined which factor influenced to survivorship of the early life stages of a parental care fish, Hypoptychus dybowskii. Earlier spawned eggs underwent higher mortality during embryonic stages. The cause was predation by fishes such as hexagramids based on the observation with SCUBA diving. Analyzes on otolith daily increments suggested that earlier spawned individuals also underwent higher mortality during larval stages. However, earlier spawned individuals could gain larger body size upto adult stage. Survivorship during embryonic stages to spawning state required for seaweed forests.3.The reproductive cycles of hair crab and helmet crab were examined by using the histological observation. These 2 crabs have the similar reproductive cycle, in which consist of oocyte growth, spawning, incubating, molting, and copulating. One cycle of hair crab take at least 2 or 3 years, but that of helmet crab does one year. Females stay under sandy bottom during long incubation period because of defenseless. Exhaustive protest of incubating females is important to reserve the crab resource.