42 



Abstract— Mayan cichlids ^Cichlasoma 

 urophthalniiis) were collected monthly 

 from March 1996 to October 1997 with 

 hook-and-line gear at Taylor River. Flor- 

 ida, an area within the Crocodile Sanc- 

 tuary of Everglades National Park, 

 where human activities such as fish- 

 ing are prohibited. Fish were aged by 

 examining thin-sectioned otoliths, and 

 past size-at-age information was gen- 

 erated by using back-calculation tech- 

 niques. Marginal increment analysis 

 showed that opaque gi'owth zones were 

 annuli deposited between January and 

 May The size of age-1 fish was esti- 

 mated to be 33-66 mm standard length 

 (mean=45.5 mm) and was supported 

 by monthly length-frequency data of 

 young-of-year fish collected with drop 

 traps over a seven-year period. Mayan 

 cichlids up to seven years old were 

 observed. Male cichlids grew slower but 

 achieved a larger size than females. 

 Growth was asymptotic and was mod- 

 eled by the von Bertalanffy growth equa- 

 tion L,=263.6( l-exp[-0. 166( ?-0.001 1] ) 

 for males (/•'''=0.82, ;i=581 ) and Z,,=21.5.6 

 (l-e.\p|-0.197(r-0.058ll I for females !;■-= 

 0.77, n =639). Separate estimates of total 

 annual mortality were relatively con- 

 sistent 1 0.44-0.60 ( and indicated mod- 

 erate mortality at higher age classes, 

 even in the absence of fishmg mortality. 

 Our data indicated that Mayan cichlids 

 grow slower and live longer in Florida 

 than previously reported from native 

 Mexican habitats. Because the growth 

 of Mayan cichlids in Florida periodi- 

 cally slowed and thus produced visible 

 annuli, it may be possible to age intro- 

 duced populations of other subtropical 

 and tropical cichlids in a similar way. 



Age, growth, and mortality of the Mayan 

 cichlid (Cichlosoma urophthalmus) from the 

 southeastern Everglades 



Craig H. Faunce 



Estuanne and Marine Research Group 



Tavernier Science Center, Audubon of Florida 



115 Indian Mound Trail 



Tavernier, Florida 33070 



E-mail address cfaunceaaudubonorg 



Heather M. Patterson 



Florida Manne Research Institute 



Florida Fish and Wildlife Conservation Commission 



100 Eighth Avenue SE 



St Petersburg, Flonda 33701-5095 



Jerome J. Lorenz 



Estuanne and Manne Research Group 

 Tavernier Science Center, Audubon of Flonda 

 115 Indian Mound Trail 

 Tavernier. Florida 33070 



Manuscript accepted 1 August 2001. 

 Fish. Bull. 100:42-50 (2002). 



The Mayan cichlid, Cichlasmna uroph- 

 thalmus (Giinther),is native to the fresh 

 and brackish waters of the Atlantic 

 slope of Central America from Mexico 

 to Nicaragua (Miller, 1966), where it 

 is exploited commercially in artesanal 

 fisheries and aquaculture (Martinez- 

 Palacios and Ross, 1992). The first 

 collections of the Mayan cichlid in 

 the United States were made in 1983 

 from a freshwater habitat and a man- 

 grove creek within Everglades National 

 Park, Florida ( Loftus, 1987 ). Although it 

 remains unknown how or where Mayan 

 cichlids first entered Florida waters, 

 there is evidence that the discovery 

 of this exotic fish was made shortly 

 after their introduction (Loftus, 1987). 

 Since their discovery, Mayan cichlids 

 have expanded their range to include 

 a variety of habitats from Naples 

 (26°05'N, 81°48'W) to West Palm Beach 

 (26°45'N,80''04'W). The species remains 

 abundant in the man-made freshwater 

 canals and estuarine mangrove habi- 

 tats of the region (Trexler et al., 2000). 

 The introduction of the Mayan cich- 

 lid into southern Florida has had both 

 economic and ecological significance. 

 This species supports a small sport fish- 

 ery because it is edible, attractive, and 



aggressively takes baits and artificial 

 lures (Shafland, 1996). Anglers, howev- 

 er, have mixed feelings towards this fish 

 because it readily takes artificial baits 

 and fights hard on light tackle, and it 

 can interfere with the pursuit of larger 

 gamefishes, such as the common snook 

 (Centropomus undecinialis). In some ar- 

 eas, the Mayan cichlid is the most com- 

 mon fish caught by recreational anglers 

 and is targeted by subsistence anglers. 

 There is concern, however that the in- 

 teraction between Mayan cichlids and 

 native fishes could alter the ecology of 

 the Everglades and Floi'ida Bay region. 

 Although the role of Mayan cichlids as 

 food for higher trophic-level fishes has 

 not been quantified, they themselves are 

 omnivorous and prey upon native fish- 

 es (Martinez-Palacios and Ross, 1988; 

 Howard et al.^). 



Previous studies of the Mayan cichlid 

 have focused almost entirely on its suit- 

 ability for aquaculture in Mexico (e.g. 



' Howard, K. S., W. F Loftus, and J. C. Trexler. 

 199.5. Seasonal dynamics of fishes in arti- 

 ficial culvert pools in the C-111 basin, 

 Dade County, Florida. Final Rep. CA5280- 

 2-9024. 34 p. and append. South Florida 

 Research Center, Everglades National Park, 

 Homestead, FL. 



