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), we 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.