Seed production and juvenile rearing of the tropical abalone Haliotis varia Linnaeus 1758

Abstract

Spawning, larval and juvenile rearing of the tropical abalone Haliotis varia L. were studied. Brood stock abalone were induced to spawn by exposure to air for 2 h at 27 °C. Female abalone spawned a mean of 76,530 eggs. Fertilised eggs measured 180 μm in diameter. Seventy percent survival was obtained during larval rearing. Larvae passed trochophore, veliger, gliding and creeping stages and were induced to settle on a mat of diatoms containing Nitszchia sp. and Navicula sp. The larval rearing period of H. varia ranged from 4 to 6 days at 27 °C. The settled spat vigorously fed on the diatom mat until the 50th day of postfertilisation and coralline red algal film, until the 70th day of postfertilisation. First respiratory pore was formed on the 27th day of postfertilisation. Juvenile abalones were reared on three algal diets such as coralline red algae, green filamentous algae and Ulva lactuca from the 71st to 200th day of postfertilisation. Those fed with coralline algae showed best and consistent growth. Shell colour of juveniles was affected by diet. The present study on the production of juveniles in the hatchery is a baseline information to initiate abalone aquaculture in India and to help augment the natural population.