NORTH ATLANTIC RIGHT WHALE DISTRIBUTION IN RELATION TO SEA-SURFACE TEMPERATURE IN THE SOUTHEASTERN UNITED STATES CALVING GROUNDS |
| |
| Authors: | Ché rie A.,Keller Leslie I.,Ward-Geiger William B.,Brooks &dagger Christopher K.,Slay &Dagger Cynthia R.,Taylor § Barbara J.,Zoodsma &# |
| |
| Affiliation: | Florida Fish and Wildlife Conservation Commission, Florida Wildlife Research Institute (FWRI), 100 Eighth Avenue SE, St. Petersburg, Florida 33701, U.S.A.; U.S. Fish and Wildlife Service, 6620 Southpoint Drive South, Jacksonville, Florida 32216, U.S.A.; New England Aquarium, Edgerton Research Laboratory, Central Wharf, Boston, Massachusetts 02110, U.S.A.; Florida Fish and Wildlife Conservation Commission, Florida Wildlife Research Institute (FWRI), 100 Eighth Avenue SE, St. Petersburg, Florida 33701, U.S.A.; Georgia Department of Natural Resources, One Conservation Way, Brunswick, Georgia 31520, U.S.A. |
| |
| Abstract: | Standardized aerial surveys were used to document the winter (December–March) distribution of North Atlantic right whales in their calving area off the coasts of Georgia and northeastern Florida (1991–1998). Survey data were collected within four survey zones in and adjacent to federally designated critical habitat. These data, including whale‐sighting locations and sampling effort, were used to describe right whale distribution in relation to sea‐surface temperature (SST) from satellite‐derived images. Locations where whales were sighted (n= 609) had an overall mean SST of 14.3°C ± 2.1° (range 8°–22°C). Data from two survey zones having sufficient data (including the “early warning system” (EWS) zone and the Florida nearshore) were pooled by season and stratified by month to investigate changes in monthly ambient SST and fine‐scale distribution patterns of right whales in relation to SST within spatially explicit search areas. Using Monte Carlo techniques, SSTs and latitudes (means and standard deviations) of locations where whales were sighted were compared to a sampling distribution of each variable derived from daily‐search areas. Overall, results support a nonrandom distribution of right whales in relation to SST: during resident months (January and February), whales exhibited low variability in observed SST and a suggested southward shift in whale distribution toward warmer SSTs in the EWS zone; while in the relatively warmer and southernmost survey zone (Florida nearshore), right whales were concentrated in the northern, cooler portion. Our results support that warm Gulf Stream waters, generally found south and east of delineated critical habitat, represent a thermal limit for right whales and play an important role in their distribution within the calving grounds. These results affirm the inclusion of SST in a multivariate predictive model for right whale distribution in their southeastern habitat. |
| |
| Keywords: | North Atlantic right whale Eubalaena glacialis sea-surface temperature southeastern U.S. calving grounds endangered species GIS |
|
|
