Alternate Title

The Distribution and Abundance of Fishes Caught with a Trawl in the St. Andrew Bay System, Florida


Fish collections were made by trawling bi-weekly at 12 stations in the deeper portions (1.5-12.2 m) of the St. Andrew Bay system, Florida, from September 1972 through August 1973. In 312 trawl hauls, 207,44 7 fishes were caught, and 128 species (51 families) were identified from the collections.

The St. Andrew Bay system is characterized by high salinity and low turbidity waters similar to the coastal waters of the Gulf of Mexico. This permits the occurrence of many marine shore fishes in the bay and greatly increases the faunal diversity. In general, these shore species are more numerous in, but not restricted to, the higher salinity waters of the lower bay area.

One subarea, however, was more typical of other estuaries of the northern Gulf of Mexico due to its lower salinity waters and occurrence of significantly greater numbers of juveniles of estuarine dependent fishes such as the gulf menhaden (Brevoortia patronus), spot (Leiostomus xanthurus), and Atlantic croaker (Micropogon undulatus). This nursery area, North Bay, receives most of the fresh water that is discharged into the system.

An unusual abundance of Atlantic threadfin (Polydactylus octonemus) occurred during the latter half of the sampling period. This abundance was also observed over a widespread area in the northeastern Gulf of Mexico.

Marked seasonal abundance of the catches was observed. The numbers of fish that were caught during the winter declined to about 6% of the total catch. Movements out of the sampling area in response to low water temperature is inferred. Other movements into and within the bay system are discussed.

Size analysis for some of the more abundant species shows that smaller individuals were found in the lower salinity area and the larger were more frequently observed in the higher salinity water.