Effects of inter-specific density and food supply on survivorship and growth of newly settled benthos

Abstract

Using a laboratory model system comprised of newly settled oysters Crassostrea virginica and established fouling species (BotryLloides sp initially, and others including Styela claw and Ciona intestinalis as the experiment progressed), w e tested how differences in food supply and competitor density may affect post-settlement sunivorship and growth of sessile marine invertebrates over a 44 d period. After 15 d, results were mixed but ind~cated that both food and density conditions affected growth and survivorsh.ip significantly, with some suggestion of high food levels ameliorating high density effects However, 44 d after settlement, oysters had reduced survivorship and growth when competitors were present regardless of food level. Thls study suggests that localized food depletion by juveniles and/or adults of resident species may have a negative effect on recruitment in fouling communities, even when space is not limiting.