Migratory patterns of Yucatan Peninsula hawksbills

The hawksbill population that nests in the Yucatan Peninsula (Mexico) is considered the largest in the Atlantic and one of the four largest in the world. However, from about 6,400 registered annual number of nests in 1999 (when the Mexican population represented about 43% of all recorded hawksbill nests in the Greater Caribbean), the population's reproductive output dropped to less than 2,400 nests/yr by 2004. No single cause has been demonstrated but as major nesting sites are under protection this alarming decline (a drop of 63% in 5 years) is suspected to be associated with threats impacting the species at foraging grounds or migratory routes. Unfortunately not only has there been no capacity to study and protect these habitats but, with the exception of studies by Byles and Swimmer (1994) and Gardu et al. (2003), there is also insufficient information on the routes taken and foraging destinations for the various rookeries in the region. To address these issues, the current satellite tracking project was instrumented to reveal the post-nesting migratory behavior of hawksbills in the Yucatan Peninsula, starting in 2006 with animals nesting in Campeche State, where about 50% of the reproductive output by the species in the whole Peninsula is concentrated.

Knowledge on the migratory routes and foraging sites will be helpful in identifying and mitigating potential threats in the marine habitats and for the establishment of research programs on the status of the habitats themselves. Furthermore, discovering whether or not these lie within or outside Mexican territorial waters has important consequences for the management strategies. If they are inside, the responsibility for addressing the hawksbills' conservation needs is totally Mexico's. If, on the other hand, some or all of the turtles cross into international waters or into other countries' jurisdictions it would indicate an internationally shared responsibility.

Future studies by the group will be directed towards tracking hawksbills nesting in the two other sates using similar techniques and learning from the lessons obtained from this season's experience.

Literature cited
-Byles, R. A. and Swimmer, Y. B. 1994. Post-nesting migration of Eretmocheyls imbricata in the Yucan Pen;nsula. In: K. A. Bjorndal, A. B. Bolten, D. A. Johnson and P. J. Eliazar (compilers). 1994. Proc. Fourteenth Ann. Symp. Sea Turtle Biol. and Cons. NMFS-SEFSC-351. p. 202.
-Gardu;o-Andrade, M., Schroeder, B. Balazs, G. and Lope, R. 2003. Migration and dive behavior of female hawksbills (Eretmochelys imbricata) in the Yucatan Peninsula. In: Seminoff, J. A. Compiler, Proceedings of the Twenty-Second Annual Symposium on Sea Turtle Biology and Conservation. NOAA Technical Memorandum NMFS-SEFSC-503, p. 285

CURRENTNESS REFERENCE: ground condition

SPATIAL DATA ORGANIZATION INFORMATION
Direct Spatial Reference: Vector

SPATIAL REFERENCE INFORMATION - GEODETIC MODEL
Horizontal Datum Name: D_WGS_1984
Ellipsoid Name: WGS_1984
Semi-major Axis: 6378137.000000
Denominator of Flattening Ratio: 298.257224

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