Alternate Title

Early Life History of the Black Drum Pogonias cromis (Pisces: Sciaenidae) in Tampa Bay, Florida


The distribution, relative abundance, habitat, age, growth, and feeding habits of larval and juvenile black drum (Pogonias cromis) from Tampa Bay, Florida, are described. Spawning took place in the lower bay or nearshore Gulf waters from November through May, with the majority of spawning occurring in March. Spawning peaks often coincided with, but were not dependent on, the new or full moon and were seemingly influenced by tidal period. Most spawning occurred during rising temperatures and occurred earlier in Tampa Bay than in northern latitudes. Most larvae were collected during March and April, and more were found in incidental surface dip-net collections in Bayboro Harbor than from regular plankton-net collections in the bay. Larvae collected in the middle and upper bay were larger (2.9-7.3 mm) than those collected in the lower bay (1.8-5.8 mm). Plankton-net collections from midwater depths at the single night station and from bottom depths at the three day stations contained the majority of larval black drum. Juveniles 30-60 mm SL were abundant in May and June in rivers and tidal creeks with low to moderate salinities and unvegetated mud bottoms. At lengths >100 mm SL, juveniles began dispersing throughout the bay. Ages determined from counting daily otolith rings agreed with ages determined by using length-frequency progressions and showed that black drum larvae had a growth rate of 0.2-0.3 mm/ day, whereas juveniles 35 to 150 mm grew 0.8-0.9 mm/day. Forty-eight percent of the larval stomachs examined were empty; stomachs with food contained primarily cope pods. Mollusks were the major food group in juvenile black drum stomachs; small (<60 mm) juveniles consumed mainly bivalve siphon tips, whereas larger (>75 mm) juveniles consumed more fish, bivalves, and gastropods.