Cathy A. Beck

Low genetic diversity and minimal population substructure in the endangered Florida manatee: implications for conservation

Abstract Species of management concern that have been affected by human activities typically are characterized by low genetic diversity, which can adversely affect their ability to adapt to environmental changes. We used 18 microsatellite markers to genotype 362 Florida manatees (Trichechus manatus latirostris), and investigated genetic diversity, population structure, and estimated genetically effective population size (Ne). The observed and expected heterozygosity and average number of alleles were 0.455 ± 0.04, 0.479 ± 0.04, and 4.77 ± 0.51, respectively. All measures of Florida manatee genetic diversity were less than averages reported for placental mammals, including fragmented or nonideal populations. Overall estimates of differentiation were low, though significantly greater than zero, and analysis of molecular variance revealed that over 95% of the total variance was among individuals within predefined management units or among individuals along the coastal subpopulations, with only minor portions of variance explained by between group variance. Although genetic issues, as inferred by neutral genetic markers, appear not to be critical at present, the Florida manatee continues to face demographic challenges due to anthropogenic activities and stochastic factors such as red tides, oil spills, and disease outbreaks; these can further reduce genetic diversity of the manatee population.

Diet of the Antillean Manatee (Trichechus manatus manatus) in Belize, Central America

9 INTRODUCTION 10 Antillean manatees in Belize 12 Belize Habitat 13 Objectives 14 Hypotheses 14 Background Review 15 MATERIALS AND METHODS 18 Subjects 18 Collection 19 Microhistological Analysis 20 Data Analysis 21 RESULTS 22 Overall Percent Frequency of Manatee Diet 23 Percent Frequency by Location 25 Percent Frequency by Sex 27 Percent Frequency by Size Classification 29 Percent Frequency by Season 32

Research on the impacts of past and future hurricanes on the endangered Florida manatee: Chapter 6J in Science and the storms-the USGS response to the hurricanes of 2005

U.S. Geological Survey (USGS) research on Florida manatees (Trichechus manatus latirostris) from 1982 through 1998 identified lower apparent survival rates for adult manatees during years when Hurricane Elena (1985), the March “Storm of the Century”(1993), and Hurricane Opal (1995) hit the northern coast of the Gulf of Mexico. Although our analysis showed that a significant number of our monitored individual manatees failed to return to their winter homes after these storms, their actual fate remains unknown. With the aid of new satellite technology to track manatees during storms and new statistical techniques to determine survival and emigration rates, researchers are working to understand how hurricanes impact the endangered species by studying manatees caught in the path of the destructive hurricanes of 2004 and 2005.