1973 - 1975 
Odell, D. K. (1976) Distribution and abundance of marine mammals in south Florida: 
preliminary results. Biscavne Bav: Past/Present/Future . A. Thorhaug and A. Volkes (eds). 
Symp. No. 1, Spec. Rep. 5, Info. Serv., University of Miami, Sea Grant Program, Coral 
Gables, FL. 203-12. 
The preliminary results of aerial surveys to study the distribution and abundance of the 
bottlenose dolphin ( Tursiops truncatus) and the manatee ( Trichechus manatus) in South 
Florida are reported. Light aircraft were used to survey the waters of the Everglades 
National Park from September 1973 through December 1975 and the waters of 
Biscayne Bay and vicinity from July 1974 through June 1975. Flights were made 
approximately every two weeks and the same flight path was followed on each flight in 
both the Everglades National Park and Biscayne Bay. Forty flights (100 survey hours) 
were completed in the Park and twenty flights (40 survey hours) in Biscayne Bay. 
Three hundred eighty-five (385) dolphin herds totaling 1137 individuals were counted 
in the Park. Sighting rate was 11.37 animals per survey hour. Herd size ranged from 1 
to 25 with a mean of 2.95 animals per herd. Six dolphin herds totaling 50 individuals 
were seen during the Biscayne Bay surveys. Sighting rate was 1.25 animals per survey 
hour. Herd size ranged from 3 to 13 with a mean of 8 animals per herd. Previous data 
of this type is not available for either area. Possible reasons for the difference in 
dolphin abundance in the two are given. These include geographic differences, food 
distribution and abundance, and direct and indirect human-related factors. Little 
information is available on the natural history of the bottlenose dolphin in the survey 
areas and a research program is outlined. No manatees were seen on the Biscayne Bay 
survey transects. A total of 575 manatees was seen during the 100 survey hours in 
the Park (5.75 per hour). The number of manatees seen per flight ranged from 0 to 75 
with a mean of 14.38 per flight. In the cases of both the dolphins and the manatees, 
some of the same individuals were probably seen on successive flights. Little 
information is available about the natural history of the manatee and the research 
program outline for the dolphin could apply to this animal as well. 
1973 - 1976 
Getter, C. D. (1976) The systematics and biology of the poeciliid fish, Gambusia 
rhizophorae, with an account of its hybridization with Gambusia affinis, and Gambusia 
punctata. M. S. Thesis. University of Miami., Coral Gables, FL. 129 pp. 
The systematics and biology of the mangrove gambusia, Gambusia rhizophorae Rivas 
(1969) (mangrove gambusia), were studied. Particular attention was paid to its 
intrageneric relationships, especially with G. punctata and G. affinis, with which it 
shares part of its range. G. punctata, a closely related species, is sympatric with G. 
rhizophorae in Cuba; a possible case of hybridization between the two species is 
reported, and the species status of G. rhizophorae reaffirmed. Coloration in life is 
described. G. rhizophorae is a tropical species with a distjunct range, which is native to 
marine and brackish waters of southeast Florida and northwest Cuba. It is typically a 
resident of sheltered mangrove areas. In Florida, the species is distributed from Fort 
Lauderdale, south along the mainland coast to Key Largo, throughout the Florida Keys to 
Key West; the Florida range appears to be correlated to the 16.7°C winter isotherm. G. 
rhizophorae appears to have differentiated from G. punctata in Cuba and to have been 
dispersed to Florida by currents. An integral part of the mangrove ecosystem, G. 
rhizophorae feeds on terrestrial insects, and is in turn fed upon by fish-eating birds and 
fishes. Maximum size for females is 50.8 mm SL, and 38.9 mm SL for males. Females 
begin to mature at about five months, becoming gravid by the eighth month. Senility 
begins after ten months. Few females survive over thirteen months. Males have a 
shorter lifespan. The species thus lives one year or less in nature. Males cease growing 
at maturity, which begins at 15 mm; 50% of the males mature by 28 mm. Maturity in 
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