168
The Biology of Sea Turtles, Vol. II
Island between 1985 and 1987. It appears that larger Kemp’s ridley turtles either do
not make much use of this habitat (Morreale et al., 1992) or are more successful in
emigrating from northern waters prior to the onset of lethal winter temperatures
(Standora et al., 1992).
Smaller turtles also succumb more quickly than larger animals (Witherington
and Ehrhart, 1989). In their study on cold-stunning events in the Indian River Lagoon,
Witherington and Ehrhart (1989) noted that the smallest turtles were found on the
first day of the cold snap, and largest turtles on the last day; over the 9 years of the
study, nearly half of the green turtles recovered were in the 0–10 kg size class (SCL
ranged from 24.6 to 75.4 cm).
It is also likely that there are species differences in susceptibility to hypothermia.
Witherington and Ehrhart (1989) reported that the loggerhead cold-stunning death
rate was less than that for green turtles, and suggested that this was because loggerheads are a more temperate zone species, whereas the Indian River Lagoon appears
to be the northernmost limit of the green turtles’ winter range. Leatherback turtles
nest on tropical beaches, but are seen as far north as the waters off Newfoundland,
FIGURE 6.1 Species–habitat-specific susceptibility to cold-stun events at two different U.S.
locations: the Indian River Lagoon, FL (south), and Cape Cod Bay, MA (north). Only large
cold-stun events are shown: 1977–1985 data are from Florida (adapted from Witherington,
B.E. and Ehrhart, L.M., Hypothermic stunning and mortality of marine turtles in the Indian
River Lagoon system, Florida, Copeia , 1989, 696–703, 1989); 1995–2001 data are from
Massachusetts (adapted from Still et al., 2000 and Still, B., Griffin, C., and Prescott, R.,
Factors affecting cold-stunning of juvenile sea turtles in Massachusetts, in: Proceedings of
the 22nd Annual Symposium on Sea Turtle Biology and Conservation , J. Seminoff (compiler),
U.S. Dept. Commerce NOAA Tech. Memo. NMFS-SEFSC, Miami, FL (in press). (With
permission.)
1123 book.book Page 168 Monday, November 11, 2002 11:11 AM
The Biology of Sea Turtles, Vol. II
Island between 1985 and 1987. It appears that larger Kemp’s ridley turtles either do
not make much use of this habitat (Morreale et al., 1992) or are more successful in
emigrating from northern waters prior to the onset of lethal winter temperatures
(Standora et al., 1992).
Smaller turtles also succumb more quickly than larger animals (Witherington
and Ehrhart, 1989). In their study on cold-stunning events in the Indian River Lagoon,
Witherington and Ehrhart (1989) noted that the smallest turtles were found on the
first day of the cold snap, and largest turtles on the last day; over the 9 years of the
study, nearly half of the green turtles recovered were in the 0–10 kg size class (SCL
ranged from 24.6 to 75.4 cm).
It is also likely that there are species differences in susceptibility to hypothermia.
Witherington and Ehrhart (1989) reported that the loggerhead cold-stunning death
rate was less than that for green turtles, and suggested that this was because loggerheads are a more temperate zone species, whereas the Indian River Lagoon appears
to be the northernmost limit of the green turtles’ winter range. Leatherback turtles
nest on tropical beaches, but are seen as far north as the waters off Newfoundland,
FIGURE 6.1 Species–habitat-specific susceptibility to cold-stun events at two different U.S.
locations: the Indian River Lagoon, FL (south), and Cape Cod Bay, MA (north). Only large
cold-stun events are shown: 1977–1985 data are from Florida (adapted from Witherington,
B.E. and Ehrhart, L.M., Hypothermic stunning and mortality of marine turtles in the Indian
River Lagoon system, Florida, Copeia , 1989, 696–703, 1989); 1995–2001 data are from
Massachusetts (adapted from Still et al., 2000 and Still, B., Griffin, C., and Prescott, R.,
Factors affecting cold-stunning of juvenile sea turtles in Massachusetts, in: Proceedings of
the 22nd Annual Symposium on Sea Turtle Biology and Conservation , J. Seminoff (compiler),
U.S. Dept. Commerce NOAA Tech. Memo. NMFS-SEFSC, Miami, FL (in press). (With
permission.)
1123 book.book Page 168 Monday, November 11, 2002 11:11 AM