Distributions and Abundances of Early Life Stages of Fishes in a Florida Lake Dominated by Aquatic Macrophytes

Abstract

We sampled early life stages of fishes with tow nets and light traps in Orange Lake, Florida, from June 1983 to June 1984. Four habitats were sampled, one open water and three vegetated; vegetated zones were dominated by panic grass Panicum spp., hydrilla Hydrilla verti- cillata, or a community of mixed floating and emergent vegetation. Vegetated zones of any type were important nursery areas for the fish assemblage. Mixed vegetation was an important nursery area for juvenile fish of many species, perhaps due to its structural complexity, and the panic grass was especially important for larvae. Larvae of most species first appeared in Orange Lake at temperatures similar to those at which they appear in temperate lakes, but larvae were present on almost all sampling dates (including those in winter). Larvae of golden shiners Notemigonus cry- soleucas. threadfin shad Dorosoma petenense, and gizzard shad D. cepedianum appeared on earlier dates than in temperate systems. Larvae of individual species were present over a longer period than in temperate systems, reflecting longer spawning seasons in Orange Lake. Habitat use by larvae was variable for several species; larval bluegills Lepomis macrochirus. which are typically considered limnetic, inhabited panic grass and hydrilla, in addition to open water.