Analysis of the Fish Community on Tidal-Freshwater Constructed Reefs

Abstract

ANALYSIS OF THE FISH COMMUNITY ON TIDAL-FRESHWATER CONSTRUCTED REEFS By Briana C. Langford, B.S. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at Virginia Commonwealth University. Virginia Commonwealth University, 2012 Major Director: Dr. Stephen McIninch, Environmental Science Constructed reefs are used successfully in marine systems to enhance spawning habitat; this study examines the effectiveness of constructed reefs in a tidal-freshwater river. Fish abundance, species diversity and richness, residency, water column position, reproductive guilds, and feeding guilds were analyzed on two constructed reefs in the tidal-freshwater James River and compared to silted regions representing the primary substrate in the river. Reefs were sampled using hydroacoustics, electroshocking, gillnetting, trawling, and egg mats. The constructed reefs had a greater proportion of fish that broadcast spawn over hard substrate and a trend of more overall individual, residential, and demersal fish. The results suggest that the reefs may be attracting a different fish community than their respective comparison sites, though additional research on the effectiveness of constructed reefs in tidal-freshwater rivers is recommended.