Ecological and Population Aspects of Hawksbills Inhabiting the Nearshore Areas of Mona and Monito Islands, Puerto Rico

Van Dam, Robert; Diez, Carlos

Research report to the U.S. National Marine Fisheries Service. INTRODUCTION In the summer of 1992 we started a pilot project to test the feasibility of a small scale, but comprehensive and long term study of the population dynamics and ecology of the hawksbill (Eretmochelys imbricata) at Mona Island, Puerto Rico. The use of various techniques for turtle capture, sampling and tagging were explored and methods suitable for working at Mona were developed and optimized. The population at Mona Island is one of the most important hawksbill populations remaining in the Caribbean. As Mona Island has such a relative abundance of individuals, with an excellent representation of the different size classes and offering good accessibility of the animals for research, it is now being recognized as a prime location for studying hawksbill ecology and population dynamics. Current hawksbill conservation efforts are severely hindered by a lack of understanding of the basic biology of this endangered species. Our research is aimed at filling a number of these gaps. In particular, the work conducted in 1995 has yielded new information on hawksbill growth rates, diet, sex ratio's of immatures, and diving behavior. The methods used and data collected during 1995 on these topics, together with additional information, are presented in this report. Research results obtained previously are included whenever deemed appropriate and two submitted manuscripts concerned with hawksbill diving behavior are appended. More extensive analyses of the collected data are in progress and are being prepared for publication in peer reviewed, scientific journals.