New publication on winter habitat preferences for Florida manatees
Dear colleagues, We are pleased to announce that the following paper on Florida manatees is now available at http://dx.plos.org/10.1371/journal.pone.0058978: D. W. Laist, C. Taylor, and J. E. Reynolds, III. (2013) Winter habitat preferences for Florida manatees and vulnerability to cold. PLoS ONE8(3): e58978. doi:10.1371/journal.pone.0058978 Abstract To survive cold winter periods most, if not all, Florida manatees rely on warm-water refuges in the southern two-thirds of the Florida peninsula. Most refuges are either warm-water discharges from power plant and natural springs, or passive thermal basins that temporarily trap relatively warm water for a week or more. Strong fidelity to one or more refuges has created four relatively discrete Florida manatee subpopulations. Using statewide winter counts of manatees from 1999 to 2011, we provide the first attempt to quantify the proportion of animals using the three principal refuge types (power plants, springs, and passive thermal basins) statewide and for each subpopulation. Statewide across all years, 48.5% of all manatees were counted at power plant outfalls, 17.5% at natural springs, and 34.9 % at passive thermal basins or sites with no known warm-water features. Atlantic Coast and Southwest Florida subpopulations comprised 82.2% of all manatees counted (45.6% and 36.6%, respectively) with each subpopulation relying principally on power plants (66.6% and 47.4%, respectively). The upper St. Johns River and Northwest Florida subpopulations comprised 17.8% of all manatees counted with almost all animals relying entirely on springs (99.2% and 88.6% of those subpopulations, respectively). A record high count of 5,076 manatees in January 2010 revealed minimum sizes for the four subpopulations of: 230 manatees in the upper St. Johns River; 2,548 on the Atlantic Coast; 645 in Northwest Florida; and 1,774 in Southwest Florida. Based on a comparison of carcass recovery locations for 713 manatees killed by cold stress between 1999 and 2011 and the distribution of known refuges, it appears that springs offer manatees the best protection against cold stress. Long-term survival of Florida manatees will require improved efforts to enhance and protect manatee access to and use of warm-water springs as power plant outfalls are shut down. David W. Laist Senior Policy and Program Analyst Marine Mammal Commission 4340 East-West Highway, Rm. 700 Bethesda, MD 20814 main office: 301-504-0087 fax: 301-504-0099 e-mail: dlaist@mmc.gov
Dear colleagues, We are pleased to announce that the following paper on Effect of tissue decomposition on stable isotope signatures of striped dolphins Stenella coeruleoalba and loggerhead sea turtles Caretta caretta is now available here. Payo-Payo A, Ruiz B, Cardona L, Borrell A (2013) Effect of tissue decomposition on stable isotope signatures of striped dolphins Stenella coeruleoalba and loggerhead sea turtles Caretta caretta. Aquat Biol 18:141-147 ABSTRACT: Marine mammals and turtles are often studied using the carcasses of stranded dead individuals. Since decomposition processes might modify the stable isotope ratios of tissues, the present study tested the effects of decomposition on carbon (Δsup>13C) and nitrogen (Δ15N) stable isotope ratios in 2 tissue types of striped dolphin Stenella coeruleoalba and loggerhead sea turtle Caretta caretta. Decomposing carcasses of 3 dolphins and 3 turtles were sampled for muscle and skin for 62 d. Following lipid extraction, samples were analysed regularly using a continuous flow-isotope ratio mass spectrometer. Samples reached decomposition stage CC4 after 62 d at ambient temperature, but no statistical change in Δ13C or Δ15N was observed over that period for either tissue or species. These results imply that muscle and skin samples from carcasses decomposing out of water at stage CC4 or lower can be used as reliable material for stable isotope analysis in these 2 species, and probably in other marine mammal and marine turtle species. The effects of decomposition on the stability of stable isotope ratios in other tissues, in carcasses at stage CC5, or in carcasses decomposing underwater require further study. Ana Payo Payo PhD Student anapayopayo@gmail.com IMEDEA-CSIC Carrer Miquel Marquès, 21, 07190 Esporles, Islas Baleares
participants (2)
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ana payo -
Cynthia Taylor