Observations on the distribution and biology of east-central Florida populations of the common snook, Centropomus undecimalis (Bloch)

Capture of 1167 juvenile and adult snook, Centropomus undecimalis, in marine,
estuarine and freshwater habitats of east-central Florida from 1974 to 1980 made possible determination
of spawning periods, migratory habits, growth rate, general feeding habits and principle
habitat associations. Although some juvenile recruitment to the estuary took place throughout
the year, recruitment peaked from June to August and October to January. Early juveniles, 15-20
mm SL were most abundant in freshwater and marsh habitats. After 4 to 6 mo, juvenile snook
reached 100-150 mm SL and were no longer caught in freshwater tributaries and marsh habitats.
Snook 150 to 300 mm SL (mean of 240 mm) long typically began to migrate into seagrass beds
during March. Age of a 240 mm snook is estimated at 7 to 9 mo. Seagrass beds 5 to 15 km away
from ocean inlets were preferred habitats for juvenile snook over 150 mm SL and significant correlation
was apparent between the percentage seagrass cover and number of snook caught per
unit effort. Snook remained in seagrass beds from 2 to 5 mo until they reached a length of 300
mm. Snook over 300 mm SL were found to occur in a variety of estuarine and marine habitats.
Snook as small as 11 mm SL were piscivorous in freshwater feeding primarily on neonatal Gambusia
affinis, secondarily on palaemonid shrimp and microcrustaceans. However, small marsh
snook fed principally upon microcrustaceans until large enough to take fish and palaemonid
shrimp. Seagrass bed snook preyed on abundant fishes (e.g., Anchoa mitchilli and Lagodon
rhomboides) and penaeid shrimp.