Ecological studies on fishes of Zostera bed at the mouth of Ago Bay, Mie Prefecture - III. Development of eggs, larvae and juveniles of the tidepool gunnel Pholis nebulosa, reared in the laboratory.

Abstract

Embryonic, larval and juvenile development of the tidepool gunnel Pholis nebulosa were described based on a series of laboratory-reared specimens. The eggs were demersal, almost spherical in shape, measuring 1.70-2.18mm in diameter, and with a large oil globule and several small ones. Neighboring eggs adhered to each other to form a spherical egg mass. Hatching occurred between 25 and 35 days after spawning at a water temperature of 11.5-13.5°C. Newly hatched larvae measured 8.3-11.6mm TL, and possessed 85-88 myomeres. Absorption of the yolk was completed at about 11.5mm TL. Flexion of the notochord started and finished at about 15mm and about 25mm TL, respectively. Aggregate numbers of all fin rays were com-pleted at over 27mm TL, when the larvae reached the juvenile stage. Squamation started in juveniles over 30mm TL.