Marine turtles life cycle it’s very complex, with long generational times and late maturing, alternating between reproduction areas and feeding and/or development areas, finding within the last areas, individuals from different nesting beaches (López-Mendilaharsu et al., 2006).

The Western South Atlantic (ASO)is an area of high activity for these turtles (González Carman et al., 2011) and particularly the Uruguayan coast is an important feeding and development area and migration corridor between areas of ASO for juveniles of C. mydas (Estrades et al., 2007).

Different diseases affecting sea turtles directly influence at their survival. Recently, a neoplastic disease called fibropapillomatosis, it has become important. Another of the most common diseases of sea turtles is about infestation by parasites. These marine reptiles are affected by a variety of endo-parasites; however, are only parasitized by a few ecto-parasites species like, for example, some species belonging to the genus Ozobranchus (Santoro e Mattiucci, 2009).

Are commonly reported the species Ozobranchus branchiatus and Ozobranchus margoi. Parasitism by these organisms can kill their host by anemia and skin lesions (Peralta, 2003). Furthermore, studies implicate this ecto-parasitas as possibles mechanical vectors of transmission of the sea turtle’s herpes virus (Greenblatt, et al. 2004). However, little is known about that parasite-host relationship (Mc Gowin, et al. 2011). Because the exposed above, the aims of this research are:

INTRODUCTION

(1) Identify which species of marine leeches parasite juveniles of Chelonia mydas at the Coastal-Marine Protected Area of Cerro Verde and La Coronilla Islands, Uruguay;

(2) Determine species relative abundance;

(3) Analyze possible inter-specific interactions between the leeches species;

(4) Analyze the relationship between the occurrence of these ectoparasites and tumors on C. mydas.

Study area (Figure 1)

4 campaigns – January to April, from 2007 to 2010

Sampled individuals - Intentional capture and stranded individuals

Features relieved

Leeches

Retired

Preserved in formalin 4%

Identified (stereoscopic microscope - Sawyer, 1975)

Weight (Kg)

Curved carapace length (LCC)

Curved carapace straight (ACC)

Tumor presence and epibionts (leeches)

OCCURRENCE OF ECTOPARASITES OF THE GENUS Ozobranchus (MENZIES, 1791) ON JUVENILE Chelonia mydas IN CERRO VERDE, URUGUAY

Data analyses

Relative abundance from registered species – formula de Magurran, 1989: Pi= ni/∑ni

Analysis of possible interspecific interaction between parasite species that co-occur on C. mydas – correlations between the abundance of each parasite specie on the same host – Spearman test.

Intensity of infestation by one specie of leech in relation to the presence or absence of the other specie – Fisher test.

Relationship between the prevalence of tumors and the occurrence of individuals of genus Ozobranchus – logistic regression models .

661 juvenile marine turtles of C. mydas (Table 1) – 6.495 leeches - 132 individuals couldn’t been identified

Registered species

Negative correlation (Spearman coefficient =-0.3852791 (p< 0,01) (Figure 3)

Parasites turtles with parasites intensity higher than 50 parasites of O. margoi present none or a few individuals of O. branchiatus (Fisher test, p<0,01) (Table 2)

To lower intensity of two parasites species, both co-occurred over the same host

The body of sea turtles is the habitat of these leeches and competition between species on the same host could influence various aspects of fitness of parasites. As can be seen, there is an approximate minimum number of parasites in which both species of leeches exclude each other completely or partially.

Figure 3 – O. branchiatus intensity versus O. margoi intensity on C. mydas juvenile individuals.

No significant relationship between the occurrence of tumors and the occurrence of parasites of the genus Ozobranchus was found.

It was found a significant relationship between the size of turtles (LCC) and the occurrence of parasites (p<0,01) (table 3)

Table 3 – Generalized linear model (MLG) using logistic regression, describing factors associated with the prevalence of parasitism of all leeches on C. mydas juveniles.

NOTA: SE= Standard error; P= p value; LCC= Curved carapace length; Mes (month= parasitism variation from January to April for each campaign.

O. branchiatus first record to this region

This specie has a cosmopolitan distribution that depends on its host, which has migratory behavior, which allows dispersed over a wide geographic range.

Because migratory connectivity for C. mydas recorded between Uruguay and Brazil, where was already recorded Ozobranchus branchiatus, it is considered that the alleged absence of this specie in Uruguay is because few studies on leeches in this region.

Baptistotte, C. 2007. Caracterização espacial e temporal da fibropapilomatose em tartarugas marinhas da costa brasileira. PhD dissertação, Universidade de São Paulo, Piracicaba, Brazil.Beldomenico, P.M., e M. Begon. 2009. Disease spread, susceptibility and infection intensity: vicious circles? Trends in Ecology and Evolution 25 (1): 21– 27. Christoffersen, M.L. 2008. A Catalogue of the Piscicolidae , Ozobranchidae , and Arhynchobdellida (Annelida , Clitellata , Hirudinea) from South America. Neotropical Biology and Conservation. 3(april):39-48.Estrades, A., M.N. Caraccio, F. Scarabino, e H. Caymaris. 2007. Presencia de la tortuga Carey (Eretmochelys imbricata) en aguas uruguayas. III Jornadas de Conservación e Investigación de Tortugas Marinas en el Atlántico Sur Occidental. Libro de Resúmenes. pp. 56.Fredensborg, B.L., e R. Poulin. 2005. Larval helminths in intermediate hosts: does competition early in life determine the fitness of adult parasites? International Journal for Parasitology. 35: 1061–1070.González Carman V., K.C. Alvarez., L. Prosdocimi, M.C. Inchaurraga, R.F. Dellacasa, A. Faiella, C. Echenique, R. González, J. Andrejuk, H.W. Mianzan, C. Campagna e D.A. Albareda. 2011. Argentinian coastal waters: A temperate habitat for three species of threatened sea turtles. Marine Biology Research, 7: 500-508.Greenblatt R.J., T.M. Work, G.H. Balazs, C.A. Sutton, R.N. Casey, e J.W. Caseya. 2004. The Ozobranchus leech is a candidate mechanical vector for the fibropapilloma-associated turtle herpesvirus found latently infecting skin tumors on Hawaiian green turtles (Chelonia mydas). Virology, 321: 101-110.López-Mendilaharsu M., A. Estrades, M. L. Caraccio, V. Calvo, M. Hernandez e V. Quirici. 2006. Biología, ecología y etología de las tortugas marinas en la zona costera uruguaya. Bases para la conservación y el manejo de la costa uruguaya. Vida Silvestre Uruguay, Montevideo, pp 247-257. Mc Gowin, A.E.; T.M. Truong; A.M. Corbett; D.A. Bagley; L.M. Ehrhart,; M.J. Bresette; S.T. Weege e D. Clark. 2011. Genetic barcoding of marine leeches (Ozobranchus spp.) from Florida sea turtles and their divergence in host specificity. Insect Biochemistry and Molecular Biology. 11: 271-278.Peralta A.S.L., 2003. Ocorrência do parasitismo em Chelonia mydas e Caretta caretta (Testudines, Cheloniidae) por Ozobranchus branchiatus e O. margoi (Hirudinea, Ozobranchidae) no litoral norte de São Paulo. Proceedings of the 30th Brazilian Congress of Veterinary Medicine, Volume 1.R Development Core Team (2008). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0, URL http://www.R-project.org.Ringuelet R.A., 1981. Los Hirudineos del Museo de Historia Natural de Montevideo. Comunicaciones Zoologicas del Museo de Historia Natural de Montevideo, nº 146, Volumen XI, p: 1-39.Santoro M. e S. Mattiucci. 2009. Sea Turtle Parasites. Atlantic. pp: 507-519.Sawyer R.T., Lawler A.R., Oversrteet R.M. 1975. Marine Leeches of the Eastern United States and the Gulf of Mexico with a key to the species. Journal of Natural History. 9: 633 – 667.

María Silvina Bevilacqua1; Luciana Alonso2 y Pablo M. Beldomenico3, 4, 5

1 – Fac. de Humanidades y Ciencias, Univ. Nacional del Litoral, CU, P. El Pozo s/n. Santa Fe, Argentina. E-mail: mariasilvinabevilacqua@gmail.com2 - Karumbé, Avda. Gral Rivera 3245, CP 11600, Montevideo.

3 – Fac. de Ciencias Veterinarias, Universidad Nacional del Litoral (FCV-UNL), R. P. Kreder 2805, Esperanza, Santa Fe, Argentina. 4 - Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina.

5 - Global Health Program, Wildlife Conservation Society, Bronx, NY, USA.

The absence of tumors in turtles with smaller size, match the information recorded for other areas of feeding and development of juveniles C. mydas, located in the Brazilian coast (Baptistotte, 2007).

According to Baptistotte (2007), the absence of tumors in turtles sizes under 80 cm, could be associated to the vector of transmission of the disease is distributed in coastal areas. The longer residence time of larger turtles in neritic areas, increase the exposure time with this vector, which could explain the results found in this work.

Table 1 – Statistics of turtles sampled in the ACMP Cerro Verde e Islas de La Coronilla during the sampling period.

NOTE: n = number of turtles measured and/or weighed, X = mean, DS = standard deviation, CV (%) = coefficient of variation, MAX = maximum value, MIN = minimum value MIN.

O. branchiatus (Relative abundance = 0,38; n= 2.453)

O. margoi present a greater ability to infect than O. branchiatus. Teorically, O. margoi has a preference for Caretta caretta sea turtle specie as host, but this specie has also been recorded in association with other species of sea turtles, as well as other taxa. This would indicate a greater ability of O. margoi compared O. branchiatus to parasitize, which would explain their greater abundance in he environment

Furthermore, according to the results of this study, O. margoi shows greater dominance over O. branchiatus, since at high intensities of O. margoi individuals on a host, the presence of O. branchiatus is inhibited, whereas at high intensities of O. branchiatus, moderate amounts were allowed for O. margoi. This could explain the fact that, unlike O. branchiatus, O. margoi parasite successfully other host besides C. mydas.

O. margoi (Relative abundance =0,62; n=4.042)

RESULTS and DISCUSION

Figure 2 - Individuals of Ozobranchus branchiatus and O. margoi registrations on individuals of Chelonia mydas from ACMP the Cerro Verde e Islas de La Coronilla, Uruguay.

O. margoi Absence Presence

Intensity Low 58 45O. Branchiatus High 5 3

Fisher test - p= 1

O. branchiatus Absence Presence

Intensity Low 20 79O. margoi High 10 2

Fisher test - P= 0,00003

Table 2 – 2x2 contingency table, where the presence or absence of one of the species of the genus Ozobranchus relative intensity, high or low, the other related species.

(Figure 2)

LITERATURE CITED

AIMS

METHODOLOGY

Figure 1 – Study area: Marine Protected Area “Cerro Verde e Islas de La Coronilla”, Uruguay .