EXPERIMENTAL ABALONE RANCHING ON ARTIFICIAL REEF IN PORT PHILLIP BAY, VICTORIA

Abstract

Outplanting abalone seed on artificial reef can potentially achieve the dual aim of stock enhancement and habitat improvement. This study examines the feasibility of ranching with hatchery-reared juvenile Haliotis laevigata Donovan and H. rubra Leach, in northern Port Phillip Bay, Victoria, Australia, and compares growth and survival of outplants on various artificial substrata. The experiments involve seeding 1,440 hatchery-reared juveniles, 10–30 mm size and aged 8–15 mo, at densities of 20–40 m−2, onto concrete and basalt rock artificial reefs. On concrete artificial reefs, the mean survival of H. laevigata was 15% after two years, with a mean annual growth rate of 39 mm·yr−1. For H. rubra, survival was 9% over three years, and growth rate was 22 mm·yr−1. No significant difference in juvenile survival was detected on noncomplex concrete artificial reef versus complex concrete plus basalt rock habitats. Important lessons for ranching and stock enhancement on artificial reefs are discussed.