Preliminary trials on incubation of sablefish eggs ( Anoplopoma fimbria)

Incubation of sablefish eggs was investigated as part of a larger collaborative project on sablefish culture. Gametes of ripe adults, trap-caught, were transported separately to the laboratory in a cold chest at 3–4°C. Fertilizability of the eggs declined to 50% following 36 min immersion in 35‰ salinity sea water; under identical conditions sperm fertilization potential declined to 50% 1 min after addition of milt to sea water. From these data a fertilization procedure was developed that provided 85–90% egg fertilization. Under short-term “dry” storage (3–6°C), sperm motility remained high for 300–500 h; data on egg storage was not obtained. Fertilized, water-hardened eggs were 2.07–2.11 mm in diameter. From fertilization to hatching incubation times were obtained from 2.2 to 6.6°C; times to a number of embryonic stages were obtained from 3.6 to 7.9°C. The eggs are extremely fragile and easily damaged in culture. Percentage survival to hatching (20–35‰ salinity, 2.1–8°C) was 0–12.9%. Maximum survival to hatching occurred at salinities of 34–35‰ and temperatures of 4–6.6°C. Total length of larvae of few hours to several days after maximum hatch was 4.7–5.3 mm. Neutral buoyancy of developing eggs and larvae varied in a complex manner. From these data and related observations a model is presented indicating where developing eggs and larvae are likely to be found in the natural water column, a model that also could lead to the provision of oxygen requirements during the planktonic drift stages of egg and early larval development.