Issue Number 111 January 2006 ISSN 0839-7708 in THIS ISSUE
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Issue Number 111 January 2006 Leatherback turtle fitted with harness, Tortuguero Beach, Costa Rica (Troëng et al. pp. 6-7). IN THIS ISSUE: Editorial: Does the Mediterranean Green Turtle Exist?...............................................................................................N. Mrosovsky Comment on the Guest Editorial by Paul J. Ferraro...............................................................................P.C.H. Pritchard Response to Comment by Peter C.H. Pritchard..............................................................................................P.J. Ferraro Articles: Report on Long-Term Transmitter Harness Retention by a Leatherback Turtle.........................................S.Troëng et al. Marine Turtles on the Southern Coast of Bioko Island (Gulf of Guinea, Africa), 2001-2005....................H. Rader et al. Incidental Capture of Marine Turtles in Marine Fisheries of Southern Spain...........................................J. C. Báez et al. First Evidence of Leatherback Movement from Africa to South America...................................................A. Billes et al. Notes: Charybdis hellerii, a Non-indigenous Portunid Crab from the Gastrointestinal Contents of a Kemp’s Ridley Sea Turtle (Lepidochelys kempi) in Georgia, USA..................................................................................... M. Frick & K. Williams An Update on Eritrea’s Marine Turtle Programme and First Record of Olive Ridley Turtle Nesting in the Red Sea......... ..................................................................................................................................................................N. Pilcher et al. Epibionts Associated with Chelonia mydas from Northern Brazil............................................................S. Pereira et al. Small Leatherback Found in Dominica.......................................................................................R. Byrne & S.A. Eckert MTSG Update Announcements News & Legal Briefs Recent Publications Marine Turtle Newsletter No. 111, 2006 - Page 1 ISSN 0839-7708 MTN Online - The Marine Turtle Newsletter is available at the MTN web site: <http://www.seaturtle.org/mtn/>. Subscriptions and Donations - Subscriptions and donations towards the production of the MTN should be made online at <http://www.seaturtle. org/mtn/> or c/o SEATURTLE.ORG (see inside back cover for details). Editors: Online Editor: Brendan J. Godley & Annette C. Broderick Michael S. Coyne Marine Turtle Research Group A321 LSRC, Box 90328 Centre for Ecology and Conservation Nicholas School of the Environment and Earth Sciences University of Exeter in Cornwall Duke University Tremough Campus, Penryn TR10 9EZ UK Durham, NC 27708-0328 USA E-mail: [email protected], Fax: +44 1392 263700 E-mail: [email protected] Fax: +1 919 684-8741 Editorial Board: Nicholas Mrosovsky (Founding Editor) Colin Limpus University of Toronto, Canada Queensland Turtle Research Project, Australia Karen L. Eckert (Editor Emeritus) Roderic B. Mast WIDECAST, USA Conservation International, USA George H. Balazs Nicolas J. Pilcher National Marine Fisheries Service, Hawaii, USA Marine Research Foundation, Malaysia Lisa M. Campbell Manjula Tiwari Duke University Marine Lab, USA National Marine Fisheries Service, La Jolla, USA Angela Formia Kartik Shanker University of Florence, Italy ATREE, Bangalore, India Matthew H. Godfrey Roldán Valverde North Carolina Wildlife Resources Commission, USA Southeastern Louisiana University, USA Jeanette Wyneken Florida Atlantic University, USA We are grateful to our major donors: Marine© Turtle Marine Newsletter Turtle No. Newsletter 111, 2006 - Page 1 EDITORIAL: Does the Mediterranean Green Turtle Exist? N. Mrosovsky Department of Zoology, University of Toronto, 25 Harbord Street, Toronto, Ontario, Canada M5S 3G5 (E-mail:[email protected]) Problems in red listing of widespread species. Green turtles in the Mediterranean. When a widely distributed species is abundant and increasing in For sea turtles only one such subpopulation listing has been made some places but perilously depleted in other places, how should it so far, that for Mediterranean green turtles, listed as Critically be categorized on lists of threatened species? If weight is put on Endangered separately from other green turtles which were listed the depleted populations, and a high degree of threat is assigned to as Endangered (Baillie & Groombridge 1996; IUCN 2004). The the species as a whole, that may influence in inappropriate ways present article argues that this subpopulation listing is currently the regulations that are applied to the thriving populations. But inappropriate and not justified by IUCN’s own criteria. if more weight is put on the populations that are doing well, on The evidence from studies of DNA strongly suggests that there the logical grounds that they will be likely to prevent the species is genetic interchange between green turtles in the Mediterranean as a whole from going extinct, then it may affect the enthusiasm and those elsewhere in the Atlantic (Roberts et al. 2004). Male and attention devoted to conservation in areas where the species is mediated gene flow is thought to contribute importantly to this barely clinging on. interchange, on the basis of comparisons between mitochondrial The obvious solution is to list different populations separately, (mt) and nuclear (n) DNA (Roberts et al. 2004). rather than the species as a whole. At the 24th Turtle Symposium What this amounts to is that one must distinguish between in Costa Rica in 2004, the Red List Authority (RLA) of the IUCN green turtles in the Mediterranean -- a regional matter -- and the Marine Turtle Specialist Group (MTSG) spoke optimistically Mediterranean green turtle. The latter does not exist. The current about a regional approach. But IUCN either instructed or strongly evidence indicates that there is exchange of genetic material encouraged the MTSG first to make a listing for the species as a between turtles in the Mediterranean and those in other regions. whole. Therefore, green turtles in the Mediterranean should not be However, IUCN also allows listing below the species level. classified in the Red Lists as a separate subpopulation. Examples of subpopulations listed differently from the species as a whole occur with gray whales and Irrawaddy dolphins. The Three assumptions. Asian stock of gray whales is considered Critically Endangered In arriving at this conclusion, three assumptions have been made. (formerly Endangered), but the species as whole is put in a lower First, it is assumed that for determining whether individuals in risk category (Baillie & Groombridge 1996; IUCN 2004). Some a particular area constitute a genetically isolated subpopulation, subpopulations of Irrawaddy dolphins are listed as Critically the onus of proof is on those who propose this is so. The default Endangered, but the species as a whole is in the Data Deficient option, in the absence of data, must be that animals in that region category (Baillie & Groombridge 1996; IUCN 2004). are part of a larger population. Otherwise small numbers of But for listing a subpopulation separately, in a different category animals in marginal habitats at the edge of a species’ range could from that of the species globally, certain considerations should be designated as subpopulations and then, probably, given some be kept in mind. One must distinguish between regional listing threatened status. and subpopulation listing. Anyone can make a list of threatened Second, it is assumed that a combination of mt and nDNA animals in a particular region. They can use the IUCN regional provides a more complete and therefore better basis for criteria (IUCN 2003a), or some other criteria (e.g., De Iongh et understanding population structure than relying on mtDNA alone. al. 2003). But, although IUCN encourages regional listing, it The latter, being maternally inherited, limits its use to evaluating does not permit such listings to be part of its official Red Lists. To the population structure of females. Genetic interchange through exert quality control on such a potentially huge number of listings the males may be missed. To learn about genetic isolation/exchange appears to be beyond its resources. and about differences in life histories between males and females, In contrast, subpopulations may be part of the official IUCN Red data on both mt and nDNA are helpful, but for the purposes of Lists, provided that they meet the definition of a subpopulation: red listing subpopulations as defined by IUCN, the information on nDNA is the more important. And after all, it is the nDNA that Subpopulations are defined as geographically provides the principal coding for the proteins and the physiological or otherwise distinct groups in the population and behavioural phenotype of the animal. between which there is little demographic or Third, it is assumed that in the definition of subpopulation genetic exchange (typically one successful migrant given above, for slowly maturing species with a long generation individual or gamete per year or less). time, to base genetic isolation on one or fewer migrants or gamete (IUCN 2001) exchanges per year is inappropriate. Indeed one wonders whether those who drafted this section really meant gamete exchange per generation, rather than per year. Using generation times is one of Marine Turtle Newsletter No. 111, 2006 - Page 1 the few concessions the Red Lists allow for species differences. diverse populations in their various