Anthropogenic stress, bioerosion, and farming damselfish : potential interactions and effects on coral reefs in American Samoa

Abstract

Damselfish algal gardens are a prominent feature of coral reefs around the world, and can occupy, in some cases, up to 50 percent of the solid benthic substrate (Klumpp and Polunin, 1989; Sammarco and Williams, 1982). Therefore, the relationship between damselfish and coral, and their effects on the structural integrity of coral reefs, is an important aspect of coral reef ecology that deserves attention. Because farming damselfish can readily establish algal gardens on recently dead coral, eutrophication or other forms of anthropogenic stress that kill coral tissue are expected to be positively correlated with the abundance of damselfish and damselfish algal gardens. To date, the abundance and distribution of farming damselfish have not been correlated with eutrophic conditions or local anthropogenic activities. By examining the effects of anthropogenic stress on bioerosion and the abundance of damselfish and their algal gardens at a number of sites, this thesis suggests how human activities, specifically in coastal environments, may have direct and indirect effects on the structure of coral reef habitats and the diversity and composition of species found there.