Diet, growth, and abundance of two seagrass bed fishes along a pollution gradient caused by milkfish farming in Bolinao, northwestern Philippines

Abstract

The present study clarified the impacts of aquaculture pollution on the surrounding seagrass bed fishes by comparing the diet, growth, and abundance of Parupeneus barberinus and Acreichthys tomentosus along a pollution gradient caused by intensive milkfish Chanos chanos farming in Bolinao, northwestern Philippines. The two fish species and potential food items exhibited increasingly enriched δ13C values with greater distance from the milkfish farming area, thereby indicating that stable carbon isotopes facilitated good discrimination between fishes from polluted and unpolluted areas. P. barberinus fed on epi-/benthic crustaceans, whereas A. tomentosus consumed a wide range of food, including invertebrates and plant materials in the unpolluted areas, but zooplankton were the most commonly predated food items in the polluted areas for both species. The growth rate of P. barberinus was marginally lower in the polluted area than in the unpolluted area, whereas that of A. tomentosus did not differ between the two areas. The abundance of both species did not differ significantly between the polluted and unpolluted areas, but the growth patterns of the two species suggest that A. tomentosus has greater physiological tolerance of the polluted environment than P. barberinus.