Schmid: Marine turtle populations on the west-central coast of Florida 
599 
unknown locality in November, presumably in re- 
sponse to changes in water temperature. Ogren 
(1989) suggested a seasonal offshore movement of 
Kemp’s ridley turtles in the northern Gulf on the 
basis of capture of subadult turtles in deeper waters 
off Apalachicola Bay during the winter (Rudloe et 
al., 1991). Satellite telemetry has demonstrated that 
Kemp’s ridley turtles on the Atlantic coast respond 
to a decrease in water temperature by moving to 
warmer waters southward or offshore (Renaud, 
1995). Marine turtles in the Cedar Keys area could 
be moving westward to deeper waters offshore or 
southward within the shallow coastal waters. Alter- 
natively, some Cedar Key fishermen believe that 
turtles overwinter in the remote coastal waters by 
“burying up” in mud bottom holes (Carr and Caldwell, 
1956; Schmid and Ogren, 1990). Loggerhead turtles 
have exhibited this behavior in the Port Canaveral 
ship channel at water temperatures below 15°C (Carr 
et ah, 1980; Ogren and McVea, 1982). Water tem- 
peratures as low as 12-14°C were recorded at the 
Cedar Keys study area from December to February. 
The possibility of winter dormancy or migration (or 
both) by west coast turtles requires additional infor- 
mation (Ogren and McVea, 1982) and could be in- 
vestigated by attaching satellite transmitters to 
turtles during the fall. 
Recaptures of Kemp’s ridley turtles tagged and 
released in the northeastern Gulf of Mexico have 
provided information on their use of coastal forag- 
ing grounds. Carr and Caldwell ( 1956) observed that 
Kemp’s ridley and green turtles released from Ce- 
dar Key returned to the Withlacoochee-Crystal River 
fishing grounds within a short period of time. The 
authors implied that the turtles may be exhibiting a 
homing behavior and maintaining home ranges at 
the site of initial capture. Schmid and Ogren (1990) 
suggested that Kemp’s ridley turtles in the Florida 
panhandle region were transitory because of the lack 
of long-term recaptures (Rudloe et al., 1991). By com- 
parison, recaptures in the Cedar Keys area were in- 
dicative of a more residential aggregation. Although 
the majority of Kemp’s ridley turtles tagged near the 
Cedar Keys were recaptured within a year of initial 
capture, almost equal numbers of turtles were re- 
captured within netting seasons and between net- 
ting seasons. Recaptures within a netting season 
suggest that some turtles remain in the vicinity of 
Corrigan Reef during their seasonal occurrence in this 
region. Recaptures between netting seasons indicate 
that some turtles return to the previously utilized oys- 
ter bar habitat annually and may do so for up to four 
years. Efforts are currently underway to determine the 
activity patterns and habitat associations of Kemp’s 
ridley turtles in the Cedar Keys area (Schmid, 1994). 
Kemp’s ridley turtles were numerous in the coastal 
waters of Florida prior to the 1950s (Carr, 1980). Data 
provided by Carr and Caldwell (1956; p. 21, Fig. 3) 
indicated that approximately 1% of the Kemp’s rid- 
ley turtles captured at the Withlacoochee-Crystal 
River fishing grounds were early to mid-subadults 
(20-40 cm), 88% were mid- to late subadults (40-60 
cm), and 11% were adult (60+ cm). There was also 
an unconfirmed report of a vitellogenic female weigh- 
ing 42 kg with an estimated length of 75 cm. The 
presence of adult turtles in this 1955 survey corre- 
sponds to a period when there were relatively large, 
though declining, nesting aggregations of Kemp’s 
ridley turtles (U.S. Fish and Wildlife Service and 
National Marine Fisheries Service, 1992). The lack 
of 20-40 cm turtles may be indicative of lower sub- 
adult recruitment resulting from the intensive egg 
harvesting that was occurring at this time (Hilde- 
brand, 1982). In contrast, the catch at the Cedar Keys 
from 1986 to 1995 comprised 24% early to mid-sub- 
adults and 76% mid- to late subadults. Observations 
and captures of adult Kemp’s ridley turtles at sea 
have become extremely rare owing to the greatly re- 
duced nesting population, whereas the higher fre- 
quency of 20-40 cm turtles may suggest higher sub- 
adult recruitment as a result of nesting beach pro- 
tection (Ogren, 1989). 
Carr and Caldwell (1956) also described an appar- 
ent, though not statistically significant, seasonal shift 
in the mean carapace length of Kemp’s ridley turtles 
taken in the commercial turtle fishery. Larger turtles 
(mean=54.9 cm) were captured early in the April to 
November fishing season, whereas smaller turtles 
predominated the mid- and late season catch 
(mean=50.3 cm and 52.1 cm, respectively). The sea- 
sonal mean carapace lengths reported in this earlier 
study were 5-10 cm greater than those recently re- 
corded at the Cedar Keys. The authors’ description 
of their measurement technique (“. . . from the cen- 
ter of the anterior end of the carapace and the great- 
est posterior projection of the carapace.”) corresponds 
to the standard straight-line carapace length. Fur- 
thermore, the entanglement nets used in the present 
study were the same mesh size as those used in the 
commercial turtle fishery. The perceived difference 
could be due to preference by the former turtle fish- 
ermen for larger, higher-priced turtles. Alternatively, 
the smaller mean carapace lengths of the present 
study may be indicative of an increased aggregate of 
smaller Kemp’s ridley turtles along the west coast of 
Florida. 
Despite numerous tagging studies, there is very 
little information available on the growth rates of 
wild Kemp’s ridley turtles (Marquez M., 1994). The 
data treatments used to analyze Kemp’s ridley turtle 
