越喜来湾に移植したおけるミネフジツボの再生産、成長および食性と養殖への課題

Abstract

The barnacle Balanus rostratus Hoek (Cirripedia, Crustacea) is well known as a fouling organism on cultured scallops in Japan, but recently it has been undergoing evaluation as an edible crustacean fisheries resource in Mutsu Bay. Its costs surpass those of scallops at present, and aquaculture of this species remains limited to small-scale private farming due to several problems involving co-existence with scallop culture and daily maintenance. Until now, Balanus. rostratus has not caused any fouling problems for other aquaculture organisms and facilities in Okkirai Bay along northeast coast of Honshu, although it lives there. Here we report on our studies of the possibilities for transplantation and cultivation of this species in Okkirai Bay as a new candidate for commercial exploitation through aquaculture. Reproduction, growth, and feeding habits of transplanted specimens were studied. They had reproductive cycles and growth potentials similar to those of barnacles from Mutsus Bay, and tend to feed on phytoplankton rather than zooplankton. They were able to grow with only scallop feces as a food source. These results indicate that this species may be a viable candidate for aquaculture if certain difficulties can be solved. Prospective problems for aquaculture of this species in Okkirai Bay are discussed and several solutions are proposed.