West Indian Manatee Population Genetics
Science Center Objects
Nuclear microsatellite markers have been developed and implemented on ~2,000 West Indian manatees. These markers provide individual genetic fingerprints for mark-recapture studies, population structure information for the conservation of unique or isolated populations, and pedigree and relatedness information for addressing inbreeding and breeding structure patterns.
The Science Issue and Relevance: Extensive USGS studies of the West Indian manatee provide an example of the various types of management-oriented questions that can be addressed through genetic research. The Florida manatee is an endangered marine mammal found in the coastal waters of Florida and is one of two subspecies of the West Indian manatee. Little systematic information was previously available to determine the genetic connectivity among various populations of the Florida manatee or whether they bred with the other West Indian subspecies, the Antillean manatee. USGS molecular research has helped resource managers better conserve the species.
Methodology for Addressing the Issue: The mitochondrial markers including the control region, and cytochrome b have been used to conduct phylogeographic analyses addressing evolutionary relationships of manatees throughout their range. Florida manatees were found to have no variation at these loci, and so population structure information could not be elucidated. Therefore, nuclear microsatellite markers (36) have been developed and implemented on ~2,000 West Indian manatees. These markers provide individual genetic fingerprints for mark-recapture studies, population structure information for the conservation of unique or isolated populations, and pedigree and relatedness information for addressing inbreeding and breeding structure patterns.
Future Steps: To date, many manatee populations have been addressed with both the mitochondrial and nuclear markers. These populations include Florida, Belize, Puerto Rico, Mexico, and Brazil. Future studies include population-level analyses in Cuba and Brazil and a range-wide study of the West Indian species. Additionally, unique genetic fingerprints are being generated for ~1,000 samples. These fingerprints will be combined with a long term photo-identification data set for a joint analysis mark-recapture study. For the first time, unscarred individuals, unaffected by encounters with boats, can be factored into the analysis of population trends. This will lead to more encompassing survival estimates and better assessment of the population size and extinction risk.
Additionally, pedigree reconstruction is using newly developed statistical tools that will shed light on the reproductive strategy of successfully breeding males. Work is also underway on conservation genetics of the West African and Amazonian manatee species.
Hunter, M. E., Mignucci-Giannoni, A. A., Tucker, K. P., King, T. K., Bonde, R. K., Gray, B. A. & McGuire, P. M. Puerto Rico and Florida manatees represent genetically distinct groups. Conservation Genetics, in press.
Luna, F. O., Bonde, R. K., Attademo, F. L. N., Saunders, J. W., Meigs-Friend, G., Passavante, J. Z. O. & Hunter, M. E. (2012). Phylogeographic implications for release of critically endangered manatee calves rescued in Northeast Brazil. Aquatic Conservation: Marine and Freshwater Ecosystems, in press.
Hunter, M. E., Tucker, K. P., Beck, C. A., Clark, A. G., Bonde, R. K., Oli, M. K. & McGuire, P. M. (2012). Low genetic diversity and minimal population substructure in the endangered Florida manatee: implications for conservation. Journal of Mammalogy, in press.
Hunter, M., Auil-Gomez, N. E., Tucker, K. P., Bonde, R. K., Powell, J. & McGuire, P. M. (2010). Low genetic variation and evidence of limited dispersal in the regionally important Belize manatee. Animal Conservation 13, 592-602.
Hunter, M., Broderick, D., Ovenden, J. R., Tucker, K. P., Bonde, R. K., McGuire, P. M. & Lanyon, J. M. (2010). Characterization of highly informative cross-species microsatellite panels for the Australian dugong (Dugong dugon) and Florida manatee (Trichechus manatus latirostris) including five novel primers. Molecular Ecology Resources 10, 368-377.
Pause, K. C., Nourisson, C., Clark, A., Kellogg, M. E., Bonde, R. K. & McGuire, P. M. (2007). Polymorphic microsatellite DNA markers for the Florida manatee (Trichechus manatus latirostris). Molecular Ecology Notes 7, 1073-1076.