MTN 107:13-14 Stranded Sea Turtles on the Coast of Paraíba -Brazil

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Stranded Sea Turtles on the Coast of Paraíba -Brazil

Rita Mascarenhas ¹, Robson Santos ¹, Douglas Zeppelini ^1,2
¹ Associação Guajiru:Ciência –Educação e Meio Ambiente,Golfo de San Fernando 143 Intermares,Cabedelo,Paraíba,58035-380 Brazil (E-mail: quelonia@ig.com.br;robsongsantos@uol.com.br)
² Departamento de Sistemática e Ecologia-Centro de Ciências Exatas e da Natureza,Universidade Federal da Paraíba.Campus I,Cidade Universitária João Pessoa,Paraíba,58059-900 Brazil (E-mail:zeppelin@dse.ufpb.br )

Paraíba State,Brazil is considered an area of great biological importance. The marine fauna includes sea turtles.Based on interviews with local ﬁshermen in different communities and site visits to various beaches and coral reefs,the Urban Turtle Project (UTP)has documented that juvenile and adult green turtles (Chelonia mydas) are present throughout the year,primarily feeding close to coral reef habitats.The 130km long coastline also hosts 11 municipalities and 37 ﬁshery communities (Aradi et al .2002). Most of the ﬁshery activities occur in shallow waters of the various estuaries,close to the coast. Of all ﬁshing boats in Paraíba,71%are rowboats and small sailing ships,and the predominant ﬁsheries are longlines (15%) and coastal gill nets (40%)(Dias et al.2000). Given the overlap between ﬁsheries activities and turtle occurrence,the UTP has been interested in documenting possible interactions between the two. Therefore,since 2002,the UTP has been collecting information on dead stranded turtles that occur on beaches,as these data may be used as an index of turtle-ﬁsheries interactions (Epperly et al.1996; Shaver & Teas 1999).

Data were collected from stranded turtles that were recovered in two ways. The ﬁrst was during our regular daily patrols of a 2.9km stretch of beach that is also nesting habitat for hawksbill turtles. Surveys were conducted throughout the hawksbill nesting season. The second was by being alerted by callers (both tourists and community members)who used our sea turtle hotline also known as
SOS-TURTLE. It is likely that not all dead stranded turtles were reported,despite the availability of the hotline,due to lack of commitment to or knowledge of our project.

When a dead sea turtle was encountered,we recorded as much of the following information as possible, depending on the state of the turtle carcass encountered: curved carapace measurements, sex(via necropsy), state of decomposition, injuries and their probable sources, anatomical deformities, epibionts, presence of tumour-like nodules, and the contents of the stomach and intestines. We also checked ﬂippers for tags and took photos of each turtle.

Table 1. Size classes and sex of stranded green turtles found in Paraiba, Brazil.Numbers in brackets indicate turtles with tumor-like growths thought to be associated with ﬁbropapillomatosis.

From September 2002 until August 2003,we recorded 67 green turtles (mean CCL=56.5 cm), 1 hawksbill (Eretmochelys imbricata)(CCL=53.2 cm), 1 olive ridley (Lepidochelys olivacea )(CCL=66cm)and 1 individual unidentiﬁed species. For the green turtles, the sizes of the stranded turtles ranged from small juveniles to large adults, and there was a female-biased sex ratio of turtles that were deﬁnitely sexed by examination of the gonads (Table 1). Several of
the green turtles also had signs of tumor-like growths, suggesting ﬁbropapillomatosis (Table 1).

Twenty ﬁve green turtles (37.3%)showed signs of human related injuries, including pieces of net or line wrapped around neck and ﬂippers, limbs severed by a sharp object, or missing plastron, presumably to allow meat to be taken. No tags or tag scars were noted.

The number of stranded turtles found varied by month, with higher mortality rates in November 2002, January 2003 and February 2003 (Figure 1). This increased mortality coincides with the period of low wind intensity in this area, when ﬁshery activities with longlines and coastal gill nets are increased (Dias,et al.,2000).

Figure 1. Number of stranded green turtles in Paraiba observed each month.

These results suggest that ﬁshery interactions are a major source of sea turtle mortality in Paraiba. To fully estimate the impact of this mortality on the population requires information on population size (Gerrodette and Taylor,1999). To date,this information is lacking for the green turtle population in Paraiba. We recommend that future research on this population of turtles includes tagging, genetic analyses, behavioral studies, etc. in order to more fully understand the status and possible threats to these green turtles.

Acknowledgments:We are indebted to the volunteers André de Souza dos Santos, Marilene Nobre, Luis Eduardo Pontes, Valdi Silva Moreira, Adailton Galdino, Athila Bertoncini Andrade, Leonardo Francisco Machado and Shirley Magalhães Alcântara.

ARADI, R.DE M., A.J.G. SANTOS & D.DE S. GUEDES. 2002. Peixes capturados pela pesca artesanal no litoral sul da Paraíba (Brasil). Bol. Técn. Cient. CEPENE 10:255-263.

DIAS, A.F., J.A. VASCONCELOS & S.N. BEZERRA. 2000. Boletim Estatístico da Pesca Marítima e Estuarina do Nordeste do Brasil. IBA-MA/CEPENE ed. 141p.

EPPERLY, S.P., J. BRAUN, A.J. CHESTER, F.A. CROSS, J.V. MERRINER, P.A. TESTER & J.H. CHURCHIL. 1996. Beach stranding as an indicator of at-sea mortality of sea turtles. Bulletin of Marine Science 592:289-297.

GERRODETTE, T. & B.L. TAYLOR. 1999. Estimating population size. In: K.L. Eckert, K.A. Bjorndal, F.A. Abreu-Grobois & M. Donnelly(Eds) Research and Management Techniques for the Conservation of Sea Turtles. Marine Specialist Group Publications No.4, pp.67-71.

SHAVER, D.J. & W.G. TEAS, 1999. Stranding and salvage networks. In: K.L. Eckert, K.A. Bjorndal, F.A. Abreu-Grobois & M. Donnelly(Eds) Research and Management Techniques for the Conservation of Sea Turtles. Marine Specialist Group Publications No.4, pp.152-155.