Spatial variation in the use of seagrass and unvegetated habitats by post-settlement King George whiting (Percoidei: Sillaginidae) in relation to meiofaunal distribution and macrophyte structure

Abstract

Post-settlement King George whiting Sillaginodes punctata and meiofauna were collected from seagrass and unvegetated habitats at 9 sites within Port Phillip Bay, Australia, in October and November 1997. Sites varied considerably in sediment characteristics, macrophyte structure and meiofauna distribution. We hypothesised that the relative use of seagrass and unvegetated habitat by post-settlement S. punctata would vary with the characteristics of sites. Overall, the abundance of S. punctata on seagrass relative to unvegetated habitats varied greatly among sites, ranging from an almost complete association with seagrass to an almost complete association with unvegetated habitat. The pattern of habitat use among sites by S. punctata was reflected by the distribution of small crustacea; differences in habitat use across sites for S. punctata and small crustaceans were highly correlated. Relative habitat use across sites by post-settlement S. punctata was also negatively correlated with length of seagrass plants. Results suggest a role for prey distribution and seagrass structure in producing these patterns. When data for habitats were pooled, abundance of S. punctata at sites was significantly correlated with meiofaunal crustacean abundance, suggesting that prey distribution was an important factor in broad-scale variability in recruitment.