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

Molecular Ecology (2007) 16,
17–18 doi: 10.1111/j.1365-294X.2006.03252.x
Blackwell Publishing Ltd
NEWS AND VIEWS
PERSPECTIVE ARTICLE
Whose turtles are they, anyway?
JEANNE A. MORTIMER, *† PETER A. MEYLAN‡
and MARYDELE DONNELLY§
* Department of Zoology, University of Florida, Gainesville, Florida 32611, USA, † Island Conservation Society, Victoria, Mahe,
Seychelles, ‡ Natural Sciences, Eckerd College, St. Petersburg, Florida 33711, USA, § Caribbean Conservation Corporation, Gainesville,
Florida 32609, USA
Abstract
The hawksbill turtle ( Eretmochelys imbricata),
listed since 1996 by the IUCN as Critically
Endangered and by the Convention on International Trade in Endangered Species (CITES)
as an Appendix I species, has been the subject of attention and controversy during the past
10 years due to the efforts of some nations to re-open banned international trade. The most
recent debate has centred on whether it is appropriate for Cuba to harvest hawksbills from
shared foraging aggregations within her national waters. In this issue of Molecular Ecology,
Bowen et al.
have used molecular genetic data to show that such harvests are likely to have
deleterious effects on the health of hawksbill populations throughout the Caribbean.
Hawksbill trade involves ‘tortoiseshell’, the translucent
scales covering the hawksbill plastron and carapace, which
has been considered a precious material on par with ivory
and rhinoceros horn since antiquity (according to legend,
Cleopatra bathed in a tub made of tortoiseshell). Efforts
to scientifically manage this resource were, in the past,
hobbled by ignorance about key aspects of the hawksbill’s
life cycle, most notably delayed sexual maturity (20–
30 years in the Caribbean and longer elsewhere) and the
migratory nature of the species. Flipper tags, used in the
context of much-reduced hawksbill populations and
widely dispersed foraging habitats, revealed little about
hawksbill migrations. Molecular genetics, however, have
provided the technological breakthrough needed (Bass
et al.
1996). The study of Bowen et al.
(2006) expands on that
earlier work adding significantly to our understanding of
the migrations of immature hawksbills. The authors use
proven molecular techniques to examine the nesting beach
origins of hawksbills on eight foraging grounds, four from
previous literature and four newly sampled. The feeding
grounds studied span the tropical West Atlantic from
southern Texas to the US Virgin Islands, and include
Inagua in the Bahamas and a site on the south coast of the
Dominican Republic.
The authors report that populations from 8 of 10 Caribbean
nesting beaches studied are sufficiently distinct that
their contribution to feeding aggregations can be estimated.
The feeding aggregations show less genetic differentiation
than nesting beaches but still exhibit significant differences.
© 2006 The Authors
Journal compilation © 2006 Blackwell Publishing Ltd
Both maximum-likelihood and Bayesian mixed-stock analyses
are used and yield similar results. Each of the feeding
grounds (except Texas, which is the only sample consisting
of pelagic-phase turtles) has significant contributions from
multiple nesting beaches. Further analysis of the Bayesian
results reveals strong relationships between feeding grounds
and nesting beach populations: a direct relationship with
nesting population size and an inverse relationship with
distance between nesting and feeding sites. The management
question that these authors ultimately address is how
harvest of this species in one nation might affect populations
elsewhere. Their mixed-stock analysis strongly corroborates
evidence from tag returns, satellite tracking and
previous genetic study, that harvests in any part of the
Caribbean impact the species throughout the region.
These results have important implications for conservation
and for CITES. During 1970–92, Japan imported
∼405
178 kg of ‘bekko’ (tortoiseshell) from 25 countries in
Atlantic Latin America and the Caribbean (Milliken &
Tokunaga 1987; Japanese Trade Statistics). This is equivalent
to some 302 371 Caribbean hawksbill turtles (1.34 kg/
turtle). By the mid-1980s many countries had acceded to
CITES and stopped exporting shell, but Japan took a CITES
reservation or exception on hawksbills, and continued to
import shell until 1992 when international pressure forced
her to drop the reservation and stop importing bekko. During
those 22 years, Cuba harvested about 5000 turtles
annually on their foraging grounds, contributing ∼33%
of
the total shell imports from the region (Carrillo et al.
1999).