Relative Abundance and Distribution of Sand Seatrout (Cynoscion arenarius) in Relation to Environmental Conditions, Habitat, and River Discharge in Two Florida Estuaries

Abstract

The sand seatrout, Cynoscion arenarius (Ginsburg, 1930), is an abundant recreational and commercial species that resides primarily in the nearshore and estuarine waters of the Gulf of Mexico. We examined relative abundance and distribution of sand seatrout [individuals >100 mm standard length (SL)] in relation to environmental conditions and river discharge in the Tampa Bay (1997-2004) and Charlotte Harbor (1999-2004) estuaries on the west coast of Florida. Fish were collected during a long-term fisheries-independent monitoring program with a 183-m purse seine. Sand seatrout were most abundant over deep, muddy substrates devoid of seagrass. Smaller sand seatrout between145 mm SL and 175 mm SL were found in low-salinity areas near river mouths and larger sand seatrout > 175 mm SL were found in high-salinity areas in the lower portion of the estuaries. We found a negative relationship between relative abundance and mean river discharge in both estuaries and a positive relationship between relative abundance and 2-yr lagged river discharge in Tampa Bay. Annual relative abundance of sand seatrout captured via purse seine in Tampa Bay and Charlotte Harbor was significantly correlated to annual changes in recreational and commercial harvest on the west coast of Florida. Differences and changes in environmental conditions, habitat, and river discharge clearly affected the relative abundance and distribution of sand seatrout, making habitat alterations and water-allocation decisions important to sand seatrout and the fishery they support.