The Life History of the Blenniid Fish, Blennius yatabei JORDAN et SNYDER

• Main Authors: 道津, 喜衛, 森内, 新二
• Format: Other/Unknown Material
• Language: Japanese
• Published: 長崎大学水産学部 1980
• Subjects: Crassostrea gigas
• Online Access: https://nagasaki-u.repo.nii.ac.jp/record/9868/files/suisan49_017.pdf

The blenniid fish, Blennius yatabei JORDAN et SNYDER is distributed in the centoral and southern Japan and in the southern Korea. The fish is generally considered to inhabit tide pools and among stones lying in tidal zone, while the authors often collected them from various kinds of substances such as "Rens" of the oyster farm, net sacks stuffed with the oyster shell and a bouy which were hung and submerged in coastal waters of Nagasaki and Kumamoto Prefectures in the western Kyushu. The fish grows to a maximum size of 9cm in total length, and it seems to be mature in two years. It is omnivorous, feeding mainly on attached diatoms, algae as well as serpulid worms, barnacles, amphipods and other tiny animals. Sex dimorphisms of the fish appear in the crest and the anal fin. Four egg masses of the fish were collected in Nomo Bay near Nagasaki City on June 16 and 18, 1974. The eggs were laid on inner surface of empty shells of the oyster, Crassostrea gigas, which were stuffed in net sacks and hung from a raft and submerged at from one to three meter depth. Each egg mass was guarded by the male parent. Numbers of eggs in each of two egg masses were enumerated as about 450 and about 1,200, respectively. A pair of mature fish collected from empty oyster shell at the spawning ground on June 16, 1974 were kept in a table aquarium and spawned in a nest of oyster shell set in the aquarium three days after capture. The eggs were spherical but somewhat flattened in shape and ranged from 0.58 to 0.65mm in longer axis and from 0.40 to 0.45mm in shorter axis. Each egg was provided with an adhesive pedestal. Hatching took place in nine days after morula stage at the water temperature varying from 23.8 to 25.2℃. Melanophores appearing on the yolk remarkably changed in form during the embryonic development. The newly hatched larvae, having 34 or 35 sometes, were from 2.6 to 2.9mm in total length before fixation. The larvae were kept and reared in a 30-liter plastic vessel at the water temperature varying from 25 to 30℃. They were ...