Status and threats analysis for the Florida manatee (<i>Trichechus manatus latirostris</i>), 2016

Abstract

For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment-visit http://www.usgs.gov or call 1-888-ASK-USGS.For an overview of USGS information products, including maps, imagery, and publications, visit http://store.usgs.gov.Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. AcknowledgmentsThe work described in this report would not have been possible without the extraordinary efforts of the field biologists, data managers, and analysts who have studied Florida manatees over the last three decades. We are particularly grateful to Cathy Beck, Howard Kochman, Gaia Meigs-Friend, Claudia Peñaloza, and Amy Teague of the U.S. Geological Survey; Martine AbstractTrichechus manatus (West Indian manatee), especially T. m. latirostris, the Florida subspecies, has been the focus of conservation efforts and extensive research since its listing under the Endangered Species Act of 1973. To determine the status of, and severity of threats to, the Florida manatee, a comprehensive revision and update of the manatee Core Biological Model was completed and used to perform a population viability analysis for the Florida manatee. The probability of the Florida manatee population falling below 500 adults on either the Gulf or East coast within the next 100 years was estimated to be 0.42 percent. This risk of quasi-extinction is low because the estimated adult survival rates are high, the current population size is greater than 2,500 on each coast, and the estimated carrying capacity for manatees is much larger than the current abundance estimates in all four regions of Florida. Three threats contribute in roughly equal measures to the risk of quasi-extinction: watercraft-related mortality, red-tide mortality, and loss of warm-water habitat. Only an increase in watercraft-related mortality has the potential to substantially increase the risk of quasi-extinction at the statewide or coastal level. Expected losses of warm-water habitat are likely to cause a major change in the distribution of the population from the regions where manatees rely heavily on power plant effluents for warmth in winter (Southwest and Atlantic regions) to the regions where manatees primarily use natural springs in winter (Northwest and Upper St. Johns regions). The chances are nearly 50 percent that manatee populations in the Southwest and Atlantic regions will decrease from their 2011 levels by at least 30 percent over the next century.A large number of scenarios were examined to explore the possible effects of potential emerging threats, and in most of them, the risk of quasi-extinction at the coastal scale within 100 years did not rise above 1 percent. The four...

Reconstructing population dynamics of a threatened marine mammal using multiple data sets

“…Our results support the finding that such red tide events (classified as intense) affect calves particularly (Supplementary Fig. S13, online) 11 . In contrast, the cold event of 2010, which led to 247 recovered carcasses in the southwest region, did not appear to lead to a net drop in population, according to our model.…”

“…Survival probabilities of younger animals are key parameters in population viability analyses of Florida manatees 11,23,25 . But these probabilities have long been extrapolated from one study of manatees in a small management unit on Florida's east coast 26 .…”

“…Life cycle diagram of Florida manatees, adapted from Runge et al 11,23 Stage-specific survival (s) and reproductive (γ) probabilities govern the transitions between stages. Females (♀) and males (♂) are both modeled.…”

Integrating encounter theory with decision analysis to evaluate collision risk and determine optimal protection zones for wildlife

“…We illustrate our approach with a case study of collisions between Florida manatees ( Trichechus manatus latirostris ) and watercraft. Watercraft collisions are one of the largest sources of human‐caused mortality for the federally protected Florida manatee (Runge et al., ). The establishment of protection zones to regulate the speed of watercraft is a primary management action taken to reduce manatee mortality (Calleson & Frohlich, ; USFWS, ); however, these protection zones may impose burdens on waterway users (Aipanjiguly, Jacobson, & Flamm, ).…”

Humanatees : character responsibility and the efficacy of serious games

“…West Indian manatees were primarily chosen as the subject of the lecture to lower the likelihood of participants knowing the information before having played the game. This information was obtained from a number of different sources (Gaspard III et al (2013), Bauer (2010), Quintana-Rizzo et al (2008), Reynolds (1981), and Runge et al (2017)). This scene is the same for participants in both conditions.…”