Gold and Richardson: Sciaenops ocellatus from Mosquito Lagoon 



59 



test the hypothesis that red drum from Mos- 

 quito Lagoon and other U.S. waters are geneti- 

 cally homogeneous. Red drum in Mosquito 

 Lagoon are of particular interest because they 

 may represent a self-contained, at least par- 

 tially isolated subpopulation. Evidence for the 

 latter includes documentation within the sys- 

 tem of both post-spawning females and red 

 drum eggs (Murphy and Taylor, 1990; Johnson 

 and Funicelli, 1991). In addition, physical ac- 

 cess to the Atlantic from the lagoon is limited. 

 In brief, Mosquito Lagoon (Fig. 1) is long and 

 narrow (54 km x 4 km) and is separated from 

 the Atlantic by a barrier beach. The lagoon 

 represents the northern part of the Indian 

 River lagoonal system and has two narrow 

 outlets: one, Ponce de Leon Inlet, is a natural 

 pass to the Atlantic located at the northern end 

 of the lagoon; the other, Haulover Canal, is a 

 man-made passageway at the southern end of 

 the lagoon that leads into the Indian River. 

 Access to or from the Atlantic through Ponce 

 de Leon Inlet is restricted because of a series 

 of islands and small passageways in the north- 

 ern part of the lagoon. Access to or from the 

 Atlantic through Haulover Canal (completed in 

 1929) would only be recent, and the nearest 

 outlet to the Atlantic south from Haulover ca- 

 nal is roughly 90-100 km. We also were inter- 

 ested in studying red drum from Mosquito 

 Lagoon because our earlier work (Gold et al., 

 1993, in press) did not include red drum from 

 the east coast of Florida, an area of potential 

 importance to tests of hypotheses regarding ge- 

 netic subdivision between red drum from the 

 northern Gulf and the U.S. Atlantic (Gold et 

 al., in press). Finally, adult red drum from Mos- 

 quito Lagoon form a large part of the 

 broodstock used by the Florida Department of 

 Natural Resources (FDNR) to supplement and 

 enhance the red drum fishery in Florida wa- 

 ters. The genetic composition of Mosquito La- 

 goon red drum is thus important to research 

 in stocking hatchery-raised fish. 



Materials and methods 



Red drum were collected from Mosquito Lagoon 

 during fall 1988, spring 1990, and spring 1991. 

 Fish were captured with trammel nets. Tissues 

 (heart, spleen, and muscle) were removed and 

 placed in liquid nitrogen for transport to Texas A&M 

 University where they were stored at -80°C. Ages 

 of all but yearling (age zero) individuals (i.e., speci- 

 mens less than 300 mm total length) were deter- 



Ponce de Leon Inlet 



10km 



Figure 1 



Mosquito Lagoon, east-central Florida, showing Ponce de 

 Leon Inlet and Haulover Canal. 



mined from annuli on otoliths by using methods 

 described in Bumguardner (1991). 



Individuals sampled in 1988 (41 total) were sur- 

 veyed for variation at nine polymorphic allozyme 



