Gut contents of larval fishes from Iight trap and plankton net collections at Enmedio Reef near Veracruz, Mexico

Abstract

Traditionally, it has been assumed that re­ef fish recruitment is a density dependent pro­cess determined by adult population size and resource limitations (Sale 1978). More recent ideas on factors regulating population size in­clude the concept that reef populations are strongly influenced by pre-recruitment limita­tions (Victor 1986, Richards and Lindeman 1987, Doherty and Williams 1988). Variation in larval survival rates due to starvation can strongly affect year class strength. Finding ap­propriate planktonic prey within a few days of hatching is critical to larval survival. However, little is known about the diets of early (prefle­xion) larval reef fishes, thus studies of their feeding ecology would provide insight into survi­val and subsequent recruitment to reefs. A ma­ jor limitation to such studies has been the low yield of reef fish larvae in plankton tows (Victor 1986, Leis 1989). Light traps are an at­ tractive alternative since many fish larvae are attracted to light, and traps can be easily deplo­yed in shallow reef sites. We conducted a study to examine the diets of tropical fish larvae co­llected by light traps and plankton tows at dif­ferent habitats on a shallow coral reef. Our ob­jective was to collect first feeding preflexion larvae and to identify prey organisms in their guts. This information is needed for our long term goal of culturing coral reef fishes in the laboratory.