FaLince et a\ Age, growth, and moitalily of Cichlasoma umphthalmus 



49 



numerous stresses not easily quantified, e.g. nest 

 prcdation, direct predation, and competition for 

 space (Trexler et al., 2000; senior author, un- 

 puhl. data). These stresses may afTect the pop- 

 ulation dynamics of native fishes by altering 

 their growth rate, increasing mortality, or de- 

 creasing reproductive success. During 1990-99, 

 till' Mayan cichlid population underwent a cycli- 

 cal "boom and bust" pattern of yearly abundance 

 typical of invasive species (Trexler et al., 2000). 

 Why these patterns occur requires a better un- 

 derstanding of the parameters of reproduction, 

 gi'owth. and moi'tality that drive the population 

 dynamics of this species. The presence of the Ma- 

 yan cichlid in the Everglades and Florida Bay es- 

 tuary warrants further research and monitoring 

 efforts in the region to firmly understand the life 

 history of exotics, native fishes, and their role in 

 the ecosystem. 



Acknowledgments 



80 



60 



40 



I 20 



n 



I 20 



z 



40 



Males 

 n = 140 



60 • Females 

 n = 449 



80 



t 



^ — I — I — I — I — I — I — I — I — I — I — I — I — I — I — I — I — I — I — I — I — I — I — I — I 



50 100 150 200 250 



Standard length (mm) 



Figure 6 



Length-frt'quency histoprrams for male and female Mayan cichlids col- 

 lected with hook-and-line gear. 



We would like to thank Roy Crabtree, Daniel 

 Merryman, Connie Stevens, and Rich McBride 

 for their assistance. Ron Taylor and Mike Murphy 

 shared their technical expertise with us, and 

 with their editorial suggestions, Joe Serafy, 

 two anonymous reviewers, and John Merriner 

 greatly improved the manuscript. This project 

 was funded by the U.S. Ai-my Corps of Engineers 

 through cooperative agi-eement 970092 between 

 Everglades National Park and the National 

 Audubon Society. 



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80 



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40 



"§ 20 





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012345678 

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Figure 7 



Age-frequency distributions for male and female Mayan cichlids col- 

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