FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

The top hat blenny, Omobranchus fasciolatoceps (Richardson, 1846), is distributed in the northwest Pacific, and inhabits reefs, estuaries, and coastal waters. It is an ornamental fish and is able to acclimate to brackish and fresh water. For the first time, our study evaluated the effects of captive breeding and juvenile acute transfer to different salinities (33, 16, and 0 psu) on feeding, survival, and growth performance of this species. In captivity, before spawning, the male attracted the female into a PVC pipe. The female then entered and laid eggs, and the male spread sperm on the eggs. After spawning, the female left, and the male guarded and cared for the egg clutches until hatching. The fertilized eggs, with a mean diameter of 0.99 ± 0.01 mm, were adhesive, demersal, spherical, and transparent. Embryonic development lasted 183 hr at 29.0–30.5 °C, and the accumulated thermal units were 221.1–232.5. Newly hatched larvae (3.20 ± 0.03 mm in total length [TL]) transformed into the juvenile stage completely when TL was 11.36 ± 0.48 mm. Over a period of 60 experimental days, the feeding rate (0.3–45.3%) of juveniles acute transferred to freshwater (0 psu) was significantly lower than that of those transferred to 33 psu (96.5–100.0%) and 16 psu (88.8–99.5%). The survival rate (100.0%) of juveniles acute transferred to 33 psu was significantly higher than that of those transferred to 16 psu (97.5%) and 0 psu (77.4 ± 0.6%) from 21 days. At 30 days, TL, body weight, daily weight gain, percentage weight gain, and specific growth rate of the juveniles at 33 psu and 16 psu were all significantly higher than at 0 psu. Our results could contribute to the development of captive breeding and low-salinity acclimatization technologies for other euryhaline ornamental blennies.