Acklins iguana
Cyclura rileyi nuchalis
By William Hayes and Richard Montanucci
Description
The Acklins iguana can be distinguished from the San Salvador and White Cay iguanas by a combination of several scale features, including four rows of scales between prefrontals and frontals, three rows of loreals, and eight supercilliaries (Schwartz and Carey 1977). As in San Salvador iguanas, the caudal verticils in Acklins iguanas are not as enlarged as in White Cay iguanas and the enlarged postsacral scales form a shorter row. In addition, recent data suggest that the Acklins iguana has significantly more femoral pores than the other two subspecies (W. Hayes and R. Carter, unpublished data). Like the other subspecies of C. rileyi, adult Acklins iguanas are strikingly handsome, resembling San Salvador iguanas with orange/yellow highlights on a darker gray to brown background. Juveniles are also similar to those of young San Salvador iguanas.
Distribution
Natural populations of Acklins iguanas are found only on Fish Cay and North Cay in the Acklins Bight, Bahamas. They formerly occurred on at least Long (Fortune) Cay, and probably once roamed other cays in the vicinity, including the much larger Crooked and Acklins Islands. An additional introduced population with five founding individuals became established on a small cay in the early 1970s.
Status of populations in the wild
The two remaining populations in the Acklins Bight appeared to be reasonably healthy when visited by D. Blair in 1991 (Blair 1992a). All size classes were well represented on Fish Cay, but fewer juveniles were seen on North Cay. In May, 1997, R. Carter and W. Hayes estimated iguana populations on North and Fish Cays to be approximately 3,000 and 10,000 individuals, respectively. R. Ehrig and R. Montanucci visited the introduced population in 1993. They estimated 140 to 180 individuals present on the cay, presumably all descendents of five founder animals from the Acklins Bight (S. Buckner, personal communication). By 1997, the introduced population was assessed by R. Carter and W. Hayes to consist of 300 individuals. The total population is currently estimated at 13,000 or more iguanas.
Ecology and natural history
Only anecdotal information on the natural history of this subspecies is available. Like other rock iguanas, male Acklins iguanas appear to be highly territorial. Males have been observed in jousting matches involving open-mouthed territorial displays, and will chase other males out of defended areas. Scars in the form of bite marks have been observed which probably result from these activities.
Habitat
Habitat on Fish and North Cays has not been adequately evaluated. The introduced population is probably at or near carrying capacity. Vegetation on this cay appears to be in excellent condition as determined by R. Moyroud.
Threats
No evidence of feral animals or other threats have been identified in the Acklins Bight populations. Introduced hutia (Geocapromys ingrahami) may be affecting the vegetation on the cay adjacent to that harboring the introduced population, although they have not yet crossed the channel separating the two cays. Further, with only five founder animals, genetic heterozygosity of this population may be compromised. On all cays, the potential for illegal poaching remains a threat.
Current conservation programs
W. Hayes and R. Carter are currently evaluating body size and genetic relationships among the three populations. They visited the Acklins Bight in 1996, as well as the introduced population, in order to obtain blood samples and measurements from the iguanas and to evaluate their status.
Critical conservation initiatives
- Acquisition of North and Fish Cays as a park by the Bahamas National Trust. Both islands will need to be purchased, as they are privately owned.
- Institutional strengthening of responsible agencies to develop enforcement capabilities.
- Initiation of a national education program.
Priority projects
- Accurately census the three extant populations to determine population size.
- Assess current threats to each population. Should they become a problem, introduced hutia will need to be controlled.
- Explore the potential for restocking vacant cays in the Acklins Bight with iguanas.
- Conduct genetic studies similar those being carried out for the San Salvador iguana. In particular, the introduced population should be examined.
Contact persons
William Hayes
Department of Natural Sciences
Loma Linda University
Loma Linda, CA 92350 USA
Tel: (909) 824-4300 ext. 48911
Fax: (909) 824-4859
E-mail: whayes@ns.llu.edu
Ronald Carter
Department of Natural Sciences
Loma Linda University
Loma Linda, CA 92350 USA
Tel: (909) 824-4300 ext. 48905
Fax: (909) 824-4859
E-mail: rcarter@ns.llu.edu
Richard Montanucci
Department of Biological Sciences
132 Long Hall
Clemson University
Clemson, SC 29643 USA
Tel: (803) 656-3625
Fax: (803) 656-0435
E-mail: rrmnt@clemson.edu
Robert Ehrig
Finca Cyclura
29770 Mahogany Lane
Big Pine Key, FL 33043 USA
Tel/Fax: (305) 872-9811
E-mail: ehriguana@aol.com
David Blair
Cyclura Research Center
PMB #510, 970 West Valley Parkway
Escondido, CA 92025 USA
Tel: (760) 746-5422
Fax: (760) 746-1732
E-mail: critter@herpnut.com
Sandra Buckner
Bahamas National Trust
PO Box N4105
Nassau, The Bahamas
Tel: (242) 393-3821
Fax: (242) 393-3822
Email: sbuckner@bahamas.net.bs
