FIRST ENCOUNTER OF A STRANDED LOGGERHEAD MARINE TURTLE ENTANGLED IN A GHOST NET ON THE SOUTHEAST COAST OF MAURITIUS ISLAND

SUNDY RAMAH^#, ANN TRACY CHUNG VOON & KESHINI BEETUL

Albion Fisheries Research Centre, Ministry of Ocean Economy, Marine Resources, Fisheries and Shipping, Albion, Petite Rivière, Republic of Mauritius

^#sramah@govmu.org / sundy.ramah@gmail.com

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On 10th October 2015, villagers found a marine turtle entangled in a ghost net and struggling on the beach of La Cambuse (20º27´18.6´´S, 57º41´57.1´´E), located on the southeast coast of Mauritius Island. The ghost net consisted of two diamond-shaped nets of mesh sizes 20 and 12cm entangled together and made of polyamide multifilament (polyester nylon), which were suspected to have been part of a trawl net. The total length of the net was ~5m, and no drops or floats were attached. The villagers freed the turtle from the ghost net and released it back to the sea. The turtle’s approximate size and weight were recorded and reported to the Fisheries Post of the Fisheries Protection Service located at Mahébourg. Information on the stranding and the morphometric measurements were further sent to the Albion Fisheries Research Centre, which is the lead organisation overseeing sea turtle protection and conservation under the Fisheries and Marine Resources Act 2007 of the Republic of Mauritius. The morphological measurements and photographs provided by the locals indicated that the species was a female loggerhead turtle (Caretta caretta) with an approximate curved carapace length (CCL) of 75cm and weight of 40-50kg. Based on the morphological details and measurements and according to Hughes (2010) study, the animal age was estimated to be ranged between 12 and 15 years old indicating that it may be a sub-adult female loggerhead.

Figure 1. Stranded loggerhead turtle entangled in ghost net at La Cambuse, Mauritius Island. (Photo credit: Amar Said Bauhadoor.)

Five species of sea turtles occur in the Southwest Indian Ocean, of which the green (Chelonia mydas) and the hawksbill (Eretmochelys imbricata) are the most widely distributed (Ratsimbazafy, 2003; Seminoff, 2004). Similarly, only green and hawksbill turtles have been previously reported within the waters of Mauritius (Mangar & Chapman, 1996) while loggerhead turtles are known to occur mainly in the waters of southern Mozambique and around South Africa where they also nest (Papi et al., 1997; Videira et al., 2008, 2011; Hughes, 2010). Therefore, the encounter of a loggerhead turtle at La Cambuse in October of 2015 may indicate the species’ occurrence in the waters of Mauritius or a possible shift in the migratory pathway and/or feeding grounds of regional populations due to climate change (Newson et al., 2009; Pilcher et al., 2014; Patel et al., 2016). Hence, new studies may be warranted on the population density and diversity of sea turtles, especially loggerheads, residing in and migrating through the waters of Mauritius.

Acknowledgements

We are thankful to Mr. S.A. Bahadour(Assistant Controller of the Fisheries Protection Service) for reporting this event and providing the required information and photographs; the Sea Turtles Network for their help; and Mrs. M. Hurbungs, Ms. D. Kaullysing, Mr. S. Khadun and Ms. D. Gopaul for their valuable views and comments.

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