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.

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The distribution of intertidal barnacles was investigated at 558 sites in Tokyo Bay during 2004 and 2005. Ten species of barnacle were found in Tokyo Bay: Fistulobalanus albicostatus, Amphibalanus amphitrite, A. eburneus, A. improvisus, F. kondakovi, Balanus trigonus, Chthamalus challengeri, Tetraclita japonica, Megabalanus rosa, and M. volcano. Amphibalanus eburneus, A. improvisus, and F. kondakovi were found in the inner part of the bay, while T. japonica, M. rosa, and M. volcano appeared in the outer part of the bay. Fistulobalanus albicostatus, A. amphitrite, C. challengeri, and B. trigonus were found throughout the bay. Cluster analysis based on similarity of barnacle species composition classified the sites into two clusters, and Cluster 1 was further divided into three sub-groups. While Clusters 1 and 2 both consisted of sites in the outer part and inner part of the bay, Cluster 1 included sites exposed to open-shore conditions and Cluster 2 comprised sites on semi-sheltered shores. The distribution of the barnacles in the bay seems to depend on salinity at the macro scale, as between the inner bay and the outer part of the bay, but on wave exposure at the micro scale of less than several kilometers.

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