Mollusk Habitats and Fisheries in Kiribati: An Assessment from the Gilbert Islands

Biological and ecological attributes of 24 species of edible bivalves and gastropods from the Gilbert Islands Group, Kiribati, Micronesia, were assessed for their resilience by examining size at maturity, intertidal burying, adjacent subtidal populations, benthic mobility, and larval type. Foraging for mollusks is largely con®ned to the intertidal and shallow subtidal regions, although modern diving gear and outboard motors now provide human foragers access to offshore resources. Changes brought about by human demographic pressures have resulted in overexploitation of a number of molluscan resources. It is suggested that the sustainable use of invertebrates and other marine species for food and nonfood purposes in Kiribati rests on a remodeled form of marine tenure. Atolls present a variety of marine environments and molluscan resources that have provided subsistence living to generations of Paci®c islanders (Tebano et al. 1993, Taniera 1994). Kiribati (Figure 1) is but one of more than 20 nations in the Paci®c, each of which possessed a rich inshore ®sheries tradition and lore. In recent years, however, traditional ecological knowledge (TEK) has suffered the inevitable decline that characterizes similar bodies of knowledge throughout most of Oceania. High human population density, urban drift, more ef®cient extractive technologies, and expanding market opportunities all have inevitably affected the ocean resources of these islands. In this study, I examined the prey biology and ecology of mollusk ®sheries in Kiribati, Gilbert Islands, looking at factors distinguishing vulnerable from resilient resources, and their effect on subsistence. Can traditional ecological knowledge be wedded with modern technology to revive the ®sheries? Because the thrust of this paper is limited to prey biology and ecology in the context of mollusk ®sheries, details of analytic methodology related to foraging ef®ciency are not discussed here, but can be found in Thomas (1999). Data on molluscan resources of the Gilbert Islands date back to the 1950s when Banner and Randall (1952) described the invertebrates of Onotoa Atoll, but identi®cations were poor and there were few detailed descriptions of exploitive strategies. A major interdisciplinary environmental survey on the main atoll of Tarawa, Republic of Kiribati (Abbott and Garcia 1995), expanded species identi®cation and habitat description, and provided an assessment of the impact of human activities (Figure 2). The Tarawa Lagoon Project of 1992±1994 (Paulay 1995) is a major study of the lagoon, and data from that project are included in this study. materials and methods Several communities engaged in subsistence and commercial exploitation of mollusks were investigated intermittently between 1993 and 1998. Research focused on four atolls in the central Gilberts: Abaiang, Tarawa (both urbanized and rural sectors), Maiana, and Abe77 1 Financial support from the University of Hawai`i's Arts and Sciences Advisory Council; funds provided by Alison Kay through a University of Hawai`i Foundation Grant and Research Assistantship; Sigma Xi (The Scienti®c Research Society) Grant-in-Aid of Research nos. 2710 and 8326; the Hawaiian Malacological Society; two grants from Conchologists of America, Inc.; and travel funds provided by Temakei Tebano at the University of the South Paci®c. Manuscript accepted 1 February 2000. 2 Ogden Environmental and Energy Services, 680 Iwilei Road, Suite 660, Honolulu, Hawai`i 96817. Paci®c Science (2001), vol. 55, no. 1:77±97 : 2001 by University of Hawai`i Press