Reproductive behaviour and early development in yellowtail kingfish (Seriola lalandi Valenciennes 1833)

摘要: The spawning behaviour of wild caught brood stock as well early egg and larval development were studied in yellowtail kingfish (Seriola lalandi). Spawning occurred naturally the austral spring/summer (November–February) when seawater temperature was above 17 °C. Courtship involved one male female, consisted a high-speed pursuit punctuated by stalling, nipping touching. This lasted for approximately 0.5–1.5 h until, immediately prior to spawning, would nip at female gonoduct, presumably induce spawning. At this stage, 50% spawns, second become involved. release gametes frenzied circling near bottom tank 22 s. daylight hours start season, but shifted around dusk latter part. Spawned eggs positively buoyant, had high fertilisation rate (N99%), ranged 1.33–1.50 mm diameter with single oil droplet 0.30–0.33 diameter, developed similar manner that described congenerics. Egg viability within floating fraction visually determined be 74%±17% over entire reproductive season. Indistinct cell margins asymmetrical cleavage most common blastomere deformities observed. volume found decrease 15–20% though no relationship between assessed date. incubation trials 16 24 °C indicated accelerated time hatch Q10 5.0. While larvae smaller length larger yolk sac warmer temperatures, there little difference maximum reached onset first feeding among rearing temperatures used. It is proposed reason higher hatching process faster than tissue deposition. findings from study are discussed terms biological significance implications larviculture species. (Less)