飼育アサリのサイズと成熟,産卵の関係

概要

論文の詳細を見る
Manila clams Ruditapes philippinarum of 16.1-36.0mm in shell length, collected from Tokyo Bay, were divided into 5 size groups every 4.0mm (groups A to E) and conditioned for 100 days at 18°C with supplementary feeding of cultured microalgae Pavlova lutheri. Groups A and B were estimated to be almost 0 yr old by previous investigation; group C, 0-1 yr; group D, 1 yr; group E, ≥ 1 yr. In the experiment, sampled clams were subjected to thermal spawning stimuli at intervals of 14-15 days. In each size group, gonads developed to a ripe stage as the condition factor was continuously increased, and spawning was successfully induced on and after 72 days. The relative growth rate reduced with increasing clam size. The histological ripe stage was attained earlier in large size groups and the number of eggs released per spawned female reached a maximum at day 100 in groups A to C, at day 86-100 in group D, and at day 86 in group E. Small clams at 0 yr old (groups A and B) could produce as many eggs per soft tissue weight as larger clams at ≥ 1 yr (groups D and E). No significant differences in egg diameter, percent fertilization, and larval survival from straight-hinge to pediveliger stage were observed between clam size groups.
公益社団法人日本水産学会の論文