FOOD, GROWTH, MIGRATION, REPRODUCTION, AND ABUNDANCE OF 

 PINFISH, LAGODON RHOMBOIDES, AND ATLANTIC CROAKER, MICRO- 

 POGON UNDULATUS, NEAR PENSACOLA, FLORIDA, 1963-65 



By DAVID J. HANSEN, FISHERY BIOLOGIST 



BUREAU OF COMMERCIAL FISHERIES BIOLOGICAL FIELD STATION 



GULF BREEZE, FLORIDA 32561 



ABSTRACT 



The abundance, growth, age composition, food, mi- 

 gration, and reproduction of the two species were 

 studied at two locations for each species from August 

 1963 to December 1965. The materials comprised 22 

 fish collections at each station, taken in about 500 

 hours of trawling. 



The stomach contents of 3,577 piniish and 2,520 

 Atlantic croakers indicated that pinfish are omnivorous 

 and croakers carnivorous. Principal foods were vegeta- 

 tion, crustaceans, and polychaetes for pinfish and 

 annelids, fish, and arthropods for croakers. Types of 

 food in pinfish stomachs were similar at all sizes and 

 seasons, but the relative amount of each type differed 

 by season and size of fish. Foods in croaker stomachs 

 differed at the two stations but were similar from year 

 to year. The average food volume in the stomachs varied 

 with time of year, location, and fish size. Volumes of 



food in stomachs of both species decreased when the 

 fish moved from the estuary. 



Length-frequency distributions can be used to 

 estimate age in both species. Pinfish, and possibly 

 croakers, form annuli on their scales. Growth of pinfish 

 and Atlantic croaker varied from year to year. 



Some fish of both species had developing gonads in 

 the fall of their first year of life and may spawn. Both 

 species migrate offshore in the fall to spawn. The fry 

 and some adults return to the estuary in the winter 

 and spring. 



Abundance of pinfish and Atlantic croakers was 

 highest in late spring and early summer. Pinfish at 

 both stations and croakers at one station were less 

 abundant in 1964 than in 1963 or 1965. Yearly differences 

 in abundance of croakers were not large at the other 

 location. 



Pinfish, Lagodon rhomboides, and Atlantic 

 croaker, Mlcropogon undulafus, are -two of the 

 most abundant species of fish in the Pensacola area 

 and other estuaries in tlie Southeastern States. The 

 life history of pinfish from areas other than Pensa- 

 cohi has been investigated by Reid (1954), Kilby 

 (1955), Caldwell (1957), and others; and that for 

 Atlantic croaker has been studied by Pearson 

 (1928), Hildebrand and Cable (1930), Wallace 

 (1940), Gunter (1945), Haven (1957 and 1959), 

 and others. The purposes of the present study were 

 to investigate the life histories of these species in 

 the Pensacola Estuary and to contribute to the gen- 

 eral knowledge of the biology of these fishes. 



Published November 1969. 



FISHERY BULLETIN: VOL. 68, NO. 1 



DESCRIPTION OF THE STUDY AREA 



The "Pensacola Estuary" (so termed for con- 

 venience) has an area of about 370 km.^ ; it encom- 

 passes three bays (two of which are shown in fig. 

 1 ) and a sound. The estuary supports commercially 

 liarvested stocks of fisli and sliellfish. 



Two stations in the lower estuary were selected 

 for study of pinfish. The sandy bottom at both 

 supports a dense growth of grasses — predomi- 

 nantly turtle-grass, Thalassia testudinum, and sea- 

 grass, Ruppia inaritima. Station I is on the north 

 side of Santa Rosa Sound across from Sabine 

 Island, site of the Bureau of Commercial Fisheries 

 Biological Field Station, Gulf Breeze, Fla. ; station 

 II is on the south side of Pensacola Bay. Average 

 depth at mean low water is 3.0 m. at station I and 



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