Albion Fisheries Research Centre, Ministry of Ocean Economy, Marine Resources, Fisheries and Shipping, Albion, Petite Rivière, Republic of Mauritius
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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.
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.
Hughes, G.R. 2010. Loggerheads and leatherbacks in the Western Indian Ocean. Indian Ocean Turtle Newsletter 11: 24- 31.
Mangar, V. & R. Chapman. 1996. The status of sea turtle conservation in Mauritius. In: Status of Sea Turtle Conservation in the Western Indian Ocean (eds. Humphrey S.L. & R.V. Salm). UNEP Regional Seas Reports and Studies No. 165. Pp. 121-124. IUCN/UNEP: Nairobi, Kenya.
Newson, S.E., S. Mendes, H.Q.P. Crick, N.K. Dulvy, J.D.R. Houghton, G.C. Hays, A.M. Hutson, C.D. MacLeod, G.J. Pierce & R.A. Robinson. 2009. Indicators of the impact of climate change on migratory species. Endangered Species Research 7: 101-113.
Papi, F., P. Luschi, E. Crosio & G.R. Hughes. 1997. Satellite tracking experiments on the navigational ability and migratory behaviour of loggerhead turtle (Caretta caretta). Marine Biology 129: 215-220.
Patel, S.H., S.J. Morreale, V.S. Saba, A. Panagopoulou, D. Margaritoulis & J.R. Spotila. 2016. Climate impacts on sea turtle breeding phenology in Greece and associated foraging habitats in the wider Mediterranean Region. PLoS ONE 11: e0157170. doi:10.1371/journal.pone.0157170.
Pilcher, N.J., L. Perry, M. Antonopoulou, M.A. Abdel-Moati, T.Z. Al Abdessalaam, M. Albeldawi, M. Al Ansi, S.F. Al-Mohannadi, R. Baldwin, A. Chikhi, H.S. Das, S. Hamza, O.J. Kerr, A. Al Kiyumi, A. Mobaraki, H.S. AlSuwaidi, A.S. Al Suweidi, M. Sawaf, C. Tourenq, J. Williams & A. Willson. 2014. Short-term behavioural responses to thermal stress by hawksbill turtles in the Arabian region. Journal of Experimental Marine Biology and Ecology 457: 190-198.
Ratsimbazafy, R. 2003. Sea turtles. In: The Natural History of Madagascar (eds. Goodman, S.M. & J.P. Benstead). Pp. 210-213. University of Chicago Press: Chicago IL, USA.
Seminoff, J.A. 2004. 2004 Global Assessment – Green turtle (Chelonia mydas). Marine Turtle Specialist Group. The World Conservation Union (IUCN); Special Survival Commission; Red List Programme. Pp. 71.
Videira, E.J.S, M.A.M. Pereira, C.M.M. Louro & D.A. Narane. 2008. Monitoring, tagging and conservation of marine turtles in Mozambique: Historical data and annual report 2007/08. Pp. 85. Maputo, Mozambique Turtle Working Group (GTT).
Videira, E.J.S, M.A.M. Pereira, C.M.M. Louro & D.A. Narane. 2011. Monitoring, tagging and conservation of marine turtles in Mozambique: annual report 2010/11. Pp. 10. Maputo, AICM/ GTT.
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