Natural spawning, early development and larviculture of the ornate goby Istigobius ornatus in captivity were studied for the first time. I. ornatus spawned 46 times from 31 October 2013 to 31 October 2014. Fecundity ranged from 246 to 10,214 eggs per clutch, with an average hatching rate of 77.8% ± 9.9% (M ± SEM). Fertilized eggs (1.31-1.54 × 0.46-0.50 mm in diameter) were adhesive demersal and oval-shaped.Embryonic development lasted 84 hr at 27.5 ± 0.5°C. Newly hatched larvae [2.12 ± 0.04 mm in total length (TL)] transformed to the juvenile stage completely when TL was 7.79 mm. Effects of different water temperatures (24, 28 and 32°C) and salinities (10, 15, 20, 25, 30, 35 and 40 g/L) on per cent survivals (%) and survival activity indices (SAIs) were tested. Survival was not significantly different under different temperatures; SAIs was significantly higher at 28°C. Larvae showed the significantly higher survival and SAIs at salinities 10-30 g/L than at 35 and 40 g/L.Effect of different prey densities on survival was significantly higher in 7 days post hatch larvae fed 20 and 30 rotifers/ml. These findings could guide future programs in captive breeding technology development and commercial production of other marine ornamental gobies. K E Y W O R D S early development, Istigobius ornatus, larviculture, marine ornamentals, spawning, survival activity index How to cite this article: Chiu P-S, Leu M-Y, Meng P-J. Yearround natural spawning, early development, and the effects of temperature, salinity and prey density on captive ornate goby Istigobius ornatus (Rüppell, 1830) larval survival. Aquac

White-barred goby Amblygobius phalaena is a highly valued marine ornamental fish, but its captive reproduction and early life history are poorly understood. In this study, the captive reproductive behavior, early development, and optimal temperature and salinity for the larval survival and viability of A. phalaena were investigated for the first time. Spawning occurred between 11:00 and 13:00, with the breeding pairs naturally spawning 24 times from 1 June 2021 to 30 June 2022. The fecundity ranged from 11,022 to 95,858 eggs per spawning event. Hatching occurred approximately 81 h and 26 min after fertilization at a temperature of 27.0 ± 0.9 °C. Newly hatched larvae had a total length (TL) of 1.91–2.03 mm with 24–26 somites. The larvae transformed into juveniles at 30 days post-hatch. Experiments were conducted at different temperatures (21, 24, 27, 30, and 33 °C) and salinities (18, 24, 30, and 36 ppt) to determine the optimal conditions for larval survival and viability. The results indicate that the most suitable conditions in terms of temperature were in the range of 21–27 °C and 30 ppt for salinity. These findings provide valuable insights for the future development of captive-breeding techniques and the commercial production of other marine ornamental gobies.

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