SURVIVAL ESTIMATES FOR FLORIDA MANATEES FROM THE PHOTO-IDENTIFICATION OF INDIVIDUALS |
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Authors: | Catherine A Langtimm Cathy A Beck Holly H Edwards Kristin J Fick-Child Bruce B Ackerman Sheri L Barton Wayne C Hartley |
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Institution: | U. S. Geological Survey, Florida Integrated Science Center, Sirenia Project, 412 NE 16th Avenue, Gainesville, Florida 32601, U. S. A. E-mail:;Florida Fish and Wildlife Conservation Commission, Florida Marine Research Institute, 100 Eighth Avenue SE, St. Petersburg, Florida 33701, U. S. A.;Mote Marine Laboratory, 1600 Thompson Parkway, Sarasota, Florida 34236, U. S. A.;Florida Park Service, Blue Spring State Park, 2100 W. French Avenue, Orange City, Florida 32763, U. S. A. |
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Abstract: | We estimated adult survival probabilities for the endangered Florida manatee ( Trichechus manatus latirostris ) in four regional populations using photoidentification data and open-population capture-recapture statistical models. The mean annual adult survival probability over the most recent 10-yr period of available estimates was as follows: Northwest - 0.956 (SE 0.007), Upper St. Johns River - 0.960 (0.011), Atlantic Coast - 0.937 (0.008), and Southwest - 0.908 (0.019). Estimates of temporal variance independent of sampling error, calculated from the survival estimates, indicated constant survival in the Upper St. Johns River, true temporal variability in the Northwest and Atlantic Coast, and large sampling variability obscuring estimates for the Southwest. Calf and subadult survival probabilities were estimated for the Upper St. Johns River from the only available data for known-aged individuals: 0.810 (95% CI 0.727–0.873) for 1st year calves, 0.915 (0.827–0.960) for 2nd year calves, and 0.969 (0.946–0.982) for manatee 3 yr or older. These estimates of survival probabilities and temporal variance, in conjunction with estimates of reproduction probabilities from photoidentification data can be used to model manatee population dynamics, estimate population growth rates, and provide an integrated measure of regional status. |
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Keywords: | survival probabilities capture-recapture Trichechus manatus latirostris manatee photo-identification sighting probabilities temporal variance Program MARK |
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