OCCURRENCE OF MACROZOOPLANKTON IN TAMPA BAY, FLORIDA, 

 AND THE ADJACENT GULF OF MEXICO ' 



By John A. Kellv, Jr., and Alexander Dragovich, Fishery Biologists. Bureau of Commercial Fisheries 

 Biological Laboratory, St. Petersburg Beach, Florida, 33706 



ABSTRACT 



This report describes a 12-month (September 1961 

 through August 1962) study. Plankton was collected at 

 14 locations with a No. 000, one-half meter net, which 

 strained an estimated 35 m.' of water per tow. Wet plank- 

 ton volumes varied from < 0.5 to 92.0 ml. and averaged 

 7.0 ml. per tow. Fift>-two percent (by volume) of the 

 plankton was collened in the summer, 25 percent in the 

 fall, 18 percent in the spring, and 5 percent in the winter. 

 Lucifer faxoni, the most numerous organism, accounted 

 for 18.5 percent of the total plankton volume. 



Sixteen species, 24 genera, 30 families, and 21 taxonomic 

 categories higher than family were identified. Decapod 

 crustaceans accounted for 87 percent of the total number of 



zooplankters collected. The most numerous organisms, in 

 descending order were Lucifer faxoni, larval porcellanids, 

 brachyurans, chaetognaths, copepods, larval polychaetes, 

 carideans, appendicularids, larval fish, fish eggs, thallas- 

 sinids, cladocerans, and larval stomatopods. Larval forms 

 of commercially important species were Penaeus duorarum, 

 Bretoortia spp., Anchoa sp., Trachinotus spp., Leiostomus 

 xanthurus, Cynoscion spp., and Soleidae. 



Observed temperature ranged from 12.8° to 32.0° C. and 

 salinity from 19.00 to 36.00 p.p.t. In relating the abundance 

 of zooplankton to temperature and salinity the data sug- 

 gested that low temperatures and salinity values were more 

 restrictive than high ones to most of the organisms. 



A study of macrozooplankton was under- 

 taken as part of an investigation of estuarine 

 biology in the eastern Gulf of Mexico. The pri- 

 mary aim was to determine temporal and 

 spatial variations in the abundance of macro- 

 zooplankton in the surface waters of Tampa 

 Bay and the adjacent Gulf of Mexico, and to 

 relate the occurrence of frequently collected 

 taxa to water temperature and salinity. 



The abundance and composition of zooplank- 

 ton provide an important index of biological 

 production in estuaries, because zooplankters 

 are the basic food of many marine organisms. 

 Mysids, euphausids, amphipods, larval stomato- 

 pods, and fish larvae are frequent in stomachs 

 of commercially important fishes (King, 1954). 

 The bulk of this plankton, however, reaches 

 large fish indirectly through their consumption 

 of foraging organisms. 



The literature on zooplankton in the coastal 

 waters of west Florida is limited. No reports 

 deal with the seasonal composition of zooplank- 

 ton throughout Tampa Bay. Published material 



^ Contribution No. 27. Bureau of Commercial Fisheries Biological 

 Laboratory. St. Petersburg Beach. Fla. 



FISHERY BULLETIN: VOLUME 66, NO. 2 



Published April 1967. 



includes: a description of certain biological, 

 taxonomic, and ecological aspects of the chae- 

 tognaths of the west coast of Florida (Pierce, 

 1951) ; notes on chaetognaths from the Gulf of 

 Mexico (Tokioka, 1955) ; the seasonal distribu- 

 tion of penaeid larvae from the lower portion 

 of Tampa Bay, Fla., and the adjacent Gulf of 

 Mexico waters (Eldred, Williams, Martin, and 

 Joyce, 1965) ; a qualitative and quantitative 

 seasonal study of the copepods of Alligator 

 Harbor (Grice, 1956) ; studies of the taxonomy 

 of several calanoid copepods in the eastern 

 Gulf of Mexico (Fleminger, 1957a and 1957b) ; 

 a preliminary report on the plankton of the 

 west coast of Florida with a discussion of the 

 distribution and occurrence of copepods and 

 other crustaceans (King, 1949) ; and records of 

 various taxa from the marine and brackish 

 waters of south Florida (Davis, 1947, 1948, 

 1949, 1950; Davis and Williams, 1950; and 

 Dragovich, 1963). 



DESCRIPTION OF THE AREA 



Tampa Bay is a shallow embayment consist- 

 ing of five sub-areas, also identified as bays — 



209 



