2012 COURSE DATES: AUGUST 4 – 17, 2012 - Sirenian International

Low genetic variation and evidence of limited dispersal in
the regionally important Belize manatee
M. E. Hunter 1,2 , N. E. Auil-Gomez 3,4 , K. P. Tucker 5 , R. K. Bonde 1,2 , J. Powell 4 & P. M. McGuire 2
1 Sirenia Project, Southeast Ecological Science Center, U.S. Geological Survey, Gainesville, FL, USA
2 Department of Physiological Sciences, College of Veterinary Medicine, University of Florida,Gainesville, FL, USA
3 Wildlife Trust, Belize City, Belize
4 Sea to Shore Alliance, St Petersburg, FL, USA
5 College of Marine Science, University of South Florida, St. Petersburg, FL, USA
Keywords
conservation genetics; low diversity;
microsatellite; mitochondria; marine
mammal; West Indian manatee.
Correspondence
Margaret E. Hunter, Sirenia Project,
Southeast Ecological Science Center, US
Geological Survey, 2201 NW 40th Terrace,
Gainesville, FL 32605, USA. Tel: +1 352
264 3484; Fax: +1 352 378 4956
Email: mkellogg@usgs.gov
Received 26 October 2009; accepted 13 June
2010
doi:10.1111/j.1469-1795.2010.00383.x
Introduction
Abstract
The West Indian manatee Trichechus manatus is a threatened
aquatic mammal found throughout the south-eastern United
States, Central and South America and the Caribbean. The
Florida manatee Trichechus manatus latirostris and Antillean
manatee Trichechus manatus manatus are the two recognized
subspecies of the West Indian manatee. A low reproductive
rate, environmental impacts and direct threats from the human
population have historically limited manatee population
growth. In 1982, the International Union for Conservation of
Nature classified all West Indian manatee populations as
vulnerable to extinction (IUCN, 2007).
During the 17th through 19th centuries, the Spaniards in
Belize and throughout the region severely exploited the
592
Animal Conservation. Print ISSN 1367-9430
The Antillean subspecies of the West Indian manatee Trichechus manatus is found
throughout Central and South America and the Caribbean. Because of severe
hunting pressure during the 17th through 19th centuries, only small populations of
the once widespread aquatic mammal remain. Fortunately, protections in Belize
reduced hunting in the 1930s and allowed the country’s manatee population to
become the largest breeding population in the Wider Caribbean. However,
increasing and emerging anthropogenic threats such as coastal development,
pollution, watercraft collision and net entanglement represent challenges to this
ecologically important population. To inform conservation and management
decisions, a comprehensive molecular investigation of the genetic diversity,
relatedness and population structure of the Belize manatee population was
conducted using mitochondrial and microsatellite DNA. Compared with other
mammal populations, a low degree of genetic diversity was detected (HE=0.455;
N A=3.4), corresponding to the small population size and long-term exploitation.
Manatees from the Belize City Cayes and Southern Lagoon system were genetically
different, with microsatellite and mitochondrial FST values of 0.029 and
0.078, respectively (P 0.05). This, along with the distinct habitats and threats,
indicates that separate protection of these two groups would best preserve the
region’s diversity. The Belize population and Florida subspecies appear to be
unrelated with microsatellite and mitochondrial F ST values of 0.141 and 0.63,
respectively (P 0.001), supporting the subspecies designations and suggesting
low vagility throughout the northern Caribbean habitat. Further monitoring and
protection may allow an increase in the Belize manatee genetic diversity and
population size. A large and expanding Belize population could potentially assist
in the recovery of other threatened or functionally extinct Central American
Antillean manatee populations.
Antillean subspecies for sustenance (Lefebvre et al., 2001).
By 1936, the population decline was so severe in Belize that
Manatee Protection Ordinances were introduced to preserve
the population (McCarthy, 1986). Today, the Belize manatee
is listed as endangered by the Belize Wildlife Protection
Act of 1981, Part II, Section 3(a) (Auil, 1998, 2004). A
Manatee Recovery Plan was also proposed requesting
information on habitat use and movement patterns to aid
the development of conservation policies for the protection
of the Belize manatee (Auil, 1998).
While studying Caribbean manatee populations, O’Shea
& Salisbury (1991) concluded that ‘Belize remains one of the
last strongholds for the species in this part of the world.’
From 1977 to 1991, the Belize manatee population size
appeared stable, however, an overall negative trend in
Animal Conservation 13 (2010) 592–602 c 2010 The Authors. Animal Conservation c 2010 The Zoological Society of London