A Preliminary Study on Brood Management and Breeding Technique of Commercially Important Brackish Water Fish, Liza parsia

Abstract

The study was conducted on broodstock management and artificial breeding of Liza parsia from June 2010 to June 2011 at the Marine Biological Research Station of the FMRT Discipline, Dacope, Khulna; Gollamary Fish Seed Multiplication Farm; and the Fish Biology Laboratory, Khulna University, Bangladesh. The relationship between total length and body weight of the species was found to be linear (r² = 0.88), indicating that the weight of fish increased with an increase in total length. The condition factor ranged from 10.12 to 15.05. The fecundity of Liza parsia varied from 56,541 to 188,860, with a mean fecundity of 122,999 ± 30,035. The GSI values obtained in the present study varied from 7.90 to 17.61. Female brood fish were 18–21 cm in total length and 70–110 g in weight, while males were 12–15 cm in total length and 60–80 g in weight. The broodstock stocking rate of Liza parsia was 800–1,000 kg/ha in the broodstock pond. Water quality parameters of the broodstock pond were recorded as a temperature of 28.32°C, salinity of 7 ppt, pH of 6.5–8.5, and dissolved oxygen of 5–7 ppm. The captured brood fish were kept in a concrete cistern (2 m diameter × 1 m depth), filled with filtered underground water. Salinity was gradually increased to 10–12 ppt by adding 150 ppt brine over a period of 72 hours. Water temperature in the breeding cistern was maintained between 22 and 23°C using electric thermostats. Fish with a female-to-male sex ratio of 1:1 were kept in a similar cistern, and artificial breeding of Liza parsia was conducted using a single dose of hormone (Ovaprim) at 3 mL/kg body weight. The injection was administered intramuscularly at the base of the dorsal fin. The injected fish responded to the hormone within 50 hours and spawned. The fertilization rate was 56 ± 7% of the spawned eggs. About 30% of the fertilized eggs hatched 42–43 hours after spawning, but the embryos died within 2 hours. Further research should be conducted to improve broodstock management and develop seed production techniques for this species in Bangladesh.