Update of green turtle interactions with marine debris in Uruguayan coastal waters

Teryda N1,2, Rodriguez D3, Vlez-Rubio GM1,4.

1 KARUMBE, Biodiversidad y Conservacin. Av. Rivera 3245, Montevideo CP 11400, Uruguay2 Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Prov. de Buenos Aires. correo: 1260 correo central 7600 Mar del Plata, Argentina. [email protected]

3 Instituto de Investigaciones Marinas y Costeras, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata. Conicet. correo: 1260 correo central 7600 Mar del Plata. [email protected] B.S.c (HONS.)Adviser4 Instituto Cavanilles de Biodiversidad y Biologa Evolutiva, University of Valencia, Aptdo. 22085, E-46071 Valencia, Spain

The aim of this work is to update

previous studies about the

interaction of immature green

turtle with marine debris in

Uruguayan coastal waters.

INTRODUCTION

Anthropogenic debris accumulation in marine environments has become

a serious problem in the last decades (Derraik, 2002).

Green turtles (Chelonia mydas) interact with marine debris in all their life

stages and in different geographic areas (Schuyler et al., 2013).

In the Southwestern Atlantic Ocean the ingestion of marine debris is one

of the main threats for immature green turtles when reach to neritic

habitats after their oceanic life stage (Gonzalez - Carman et al., 2013).

MATERIALS & METHODSDuring 2005 to 2013 three studies of marine debris interaction were

conducted (see table 1) with the same methodology, in Uruguay.

Digestive contents samples were collected from dead green turtles stranded

along the Uruguayan coast. Curve Carapace Length (CCL) was measured to

each turtle using a flexible tape.

The digestive track content was collected and was separated into esophagus,

stomach and intestine sections (Fig. 2).

Diet items were separated and identified to the lowest possible taxonomic

level. Dietary item was quantified by frequency of occurrence (FO) and relative

volume (RV).RESULTS

The first study, analyzed stranded green turtles along the Uruguayan coast trough 2005 to 2007, the mean SD

curved carapace length (CCL) = 39.7 6.0 cm (range 32.3 - 61.5 cm). 73.0% presented marine debris in their gut

contents (Table 1,[1]).

The second study, analyzed stranded green turtles along the Uruguayan coast trough 2009 to 2013, the mean

SD CCL = 40.0 7.0 cm (range 29.862.0). 72.2% presented marine debris in their gut contents (Table 1,[3]).

The last study, was performed during 2010 just in the Marine Protected Area Cerro Verde and adjacent areas, the

turtles presented mean SD CCL = 39.4 7.8 cm (range 29.8 58.5 cm). 82.6% of the turtles ingested marine

debris (Table 1,[2]).

In the three studies, the presence of marine debris decrease according with the turtle growth rate, with a

remarkable peak in study [3] from 80% in turtles shorter than 35 cm CCL to 58.8% in larger than 40 cm CCL.

CONCLUSIONIn the last 10 years the presence of marine debris in green turtles has increased in great numbers in Uruguayan coastal waters. This updaterepresents the first step for a comprehensive review of the impact of marine debris for the green turtle stock located in this area of the SouthWestern Atlantic, and for the developing of future actions to mitigate this threat.

Study Type Study Area Reference (study years)

N Turtles Analyzed

% Solid Debris

Diet/Debris(Stranding)

All the coast Calvo et al. 2003 (2001) 7 14.3

All the coast Asaroff et a.l 2009 (2005-2007) [1] 56 73.0

MPA - Cerro Verde Murman et al. 2011 (2011) [2] 23 82.6

All the coast Vlez-Rubio et al. In prep (2009-2013) [3] 54 72.2

StrandingMonitoring MPA - Cabo Polonio Rios & Feijoo 2008 (2005-2006) 10 20.0

Mortality (Stranding)

MPA - Cerro Verde Alonso & Vlez-Rubio 2011 (2008-2011) 123 34.9*

All the coast Vlez-Rubio et al. 2013 (1999-2010) 150 24.9*

Alive Turtles MPA - Cerro Verde De Franco & Martinez Souza (2011) (2010) 25 76.0

LITERATURE CITED

Derraik, J.G.B., 2002. The pollution of the marine environment by plastic debris: a review. Mar. Pollut. Bull. 44, 842852.

Framian, M.B., Brown, O.B., 1996. Study of the Ro de la Plata turbidity front. Part I. Spatial and temporal distribution. Cont.

Shelf Res. 16 (10), 12591282.

Schuyler, Q., Hardesty, B.D., Wilcox, C., Townsend, K., 2013. Global analysis of anthropogenic debris ingestion by sea turtles.

Conserv. Biol.. http://dx.doi.org/ 10.1111/cobi.12126.

Gonzalez - Carman, V., et al., 2014. Young green turtles, Chelonia mydas, exposed to plastic in a frontal area of the SW Atlantic.

Mar. Pollut. Bull. 78 5662.

ACKNOWLEDGMENTS

Authors are really grateful to all Karumb members and volunteers who once formed part of the NGO. Also to all the persons (fishermen, Naval

Prefecture, life guard service, rangers, civil organizations and citizens). Also thanks for the support of all the ISTS 2015 sponsors.

Table 1: Review of studies conducted by Karumb along the Uruguayan coast between 2001 2013. Red square marks the studies analyzed in the present study. *Dead turtles due to marine debris ingestion.

Fig 2. A) Green turtle intentionally capture in the MPA-Cerro Verde by karumb technicians in 2014.B) Stomach contents of a stranded green turtles in Uruguay in 2013.

Fig 1: Map of the Uruguayan coast. Three zones can be distinguished in coastal waters based on the differences in hydrologicalcharacteristics: [IEZ] inner estuarine zone (350 km), [OEZ] outer estuarine zone (130 km) and [OZ] Oceanic zone (230 km). The lettersindicate the most important protected areas for juvenile green turtles in Uruguayan coastal waters: A, Marine Protected Area of CerroVerde; B, Marine protected area of Cabo Polonio. The red circles indicate the green turtles stranding locations of Vlez-Rubio et al. inprep. (2009-2013, N=54).

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Update of green turtle interactions with marine debris in Uruguayan coastal waters

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