MTN 109:6-7 Report of Olive Ridley Nesting on the North Coast of Trinidad

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Report of Olive Ridley Nesting on the North Coast of Trinidad

Suzanne R. Livingstone
Division of Environmental and Evolutionary Biology, IBLS, University of Glasgow. Glasgow, UK.
(E-mail: s.livingstone@bio.gla.ac.uk)

The distribution of olive ridley turtles (Lepidochelys olivacea) in the Western Atlantic is limited primarily to the northern coast of South America where both foraging and nesting occurs (Plotkin et al. 1995; Pritchard 1969; Reichart 1989). Primary nesting beaches are found in Suriname, but there is also some nesting in French Guiana, Guyana, and Brazil (Marcovaldi 2001; Pritchard 1969; Schulz 1975). Sightings of the olive ridley in the insular Caribbean are rare, although there have been records of both nesting and foraging turtles in Trinidad. Carr (1956) first noted the presence of this species in Trinidadian waters when he mentioned the occasional capture of a sea turtle fitting the description of a ridley. In 1969, Bacon also documented that fisherman reported the capture of this species in fishing gear. In my interviews with fishermen it was noted that “batali” (the common name for olive ridleys in Trinidad) were rarely seen in the waters now, and that they could not remember the last time that one was caught in a net.

Nesting records of olive ridleys from Trinidad are primarily limited to the east coast beaches. The first record is from the east coast in 1969 on Matura Beach, where Bacon (1969) observed adult ridley tracks. A ridley hatchling was also collected by Dr. P. Morris on Manzanilla beach (east coast) in August of the same year (Bacon 1969). In addition, unpublished turtle survey records of the Trinidad and Tobago Field Naturalists Club note adult ridley tracks on Matura Beach in 1970 although the turtle was not actually observed. In 1979 an olive ridley was observed nesting on Matura beach and photographs confirm the observation. Chu Cheong (1984) mentions an adult sighting at Matura, and there is a record of an adult ridley carcass found on Fishing Pond beach (also on the east coast), although it is unknown whether the animal nested or was discarded by fishermen having been caught in their nets (Nathai-Gyan et al. 1987). There have been no other reports of olive ridleys nesting on the east coast beaches, which are currently comprehensively monitored during the turtle nesting season by the NGO Nature Seekers (since 1992) and the Fishing Pond Environmental and Community Group (Stephen Poon pers. comm.).

Nesting of olive ridleys on the north coast is limited to a single record by Sherwin Ruiz on Grande Riviere beach in 1995; however there were no measurements taken or photographic evidence (Fournillier & Eckert 1997). Other than this sighting there has never been any evidence of olive ridleys on the north coast beaches (Bacon 1969; 1981). However, this may partly be a result of the fact that little work has been done on the remote north coast beaches in the past due to their inaccessibility.

An olive ridley was observed nesting on Madamas beach on the north coast of Trinidad at 5:10am on the 23rd June 2003. The curved carapace length and width were measured with a flexible tape measure: 69cm and 68.5cm respectively. This is within the range of carapace lengths for olive ridleys found in the Guianas ([26-28 inches] 66-72 cm) (Pritchard 1969). The turtle had not been previously tagged and we did not apply tags, as we had no appropriate tags for this size of turtle. The turtle had a large part of the left rear of the shell and part of the rear flipper missing ( see the SEATURTLE.ORG image library: <https://seaturtle.org/cgi-bin/imagelib/index.pl?photo=1534>). The injury was completely healed and did not appear to hinder her nesting ability or movement on land. The damage was most likely inflicted by a shark bite, which is not uncommon in adult olive ridleys (Pritchard 1969). In his 1969 paper on sea turtles of the Guianas, Pritchard shows a very similar photograph.

During our extensive sea turtle surveys of the north coast of Trinidad (2000-2004), this is the first record of nesting by an olive ridley. No hatched nests or hatchlings were recorded. It appears that this was a rare occurrence. It is perhaps not too extraordinary, however, as Trinidad is relatively close to the South American coastline where olive ridleys commonly lay and forage. It seems that olive ridleys have been more common in Trinidadian waters in the past, and that this trend may be mirroring the population declines of some of the other South American ridley populations.

Figure 1. The island of Trinidad and field sites

Acknowledgements: Thanks to Dr Roger Downie, Dr Joanna Smith, Dan Thornham and the Glasgow University turtle expedition team 2003. Also thanks to Selwyn Gomes of the Trinidad and Tobago Field Naturalists Club for access to the club’s unpublished turtle data. I am grateful to Stephen Poon and Nadra Gyan from the Trinidad Wildlife Section, Forestry Division for their support of the north coast project and enabling us to carry out our research, to the Pawi, Sports and Eco Club for their assistance in the field and to Dr Scott Eckert who suggested reporting our recent sighting. The work was funded by The Darwin Initiative, The People’s Trust for Endangered Species and the British Chelonia Group.

BACON, P.R. 1969. Report of the Trinidad sea turtle conservation project. Annual report. Living World: Journal of Trinidad Field Naturalist Club.18-35.

BACON, P.R. 1981. The status of sea turtle stocks management in the Western Central Atlantic. WECAF Studies no. 7. Inter-regional Fisheries Development and Management Programme, Panama. 38 pp.

CARR, A.F. 1956. The Windward Road. Alfred Knopf, New York. 258 pp.

CHU CHEONG, L. 1984. The national report for the country of Trinidad and Tobago to the Western Atlantic Turtle Symposium, San Jose, Costa Rica, July 1983. In: Proceedings of the Western Atlantic Turtle Symposium. P. Bacon et al. Editors. pp. 398-408.

FOURNILLIER, K. & K.L. ECKERT. 1997. WIDECAST Sea Turtle Recovery Action Plan for Trinidad and Tobago. CEP Technical Report No.38. UNDP Caribbean Environment Programme, Kingston, Jamaica. 131 pp.

MARCOVALDI, M.A. 2001. Status and distribution of the olive ridley turtle, Lepidochelys olivacea, in the Western Atlantic Ocean. In: Marine turtle conservation in the wider Caribbean region: A dialogue for effective regional management. Editors: Karen L. Eckert and F. Alberto Abreu Grobois. pp. 52-56.

NATHAI-GYAN, N., C. JAMES & G. HISLOP. 1987. National report for the country of Trinidad and Tobago to the Western Atlantic Turtle Symposium II. Mayaguez, Puerto Rico, USA. October 1987. 228 pp

PLOTKIN, P.T., R.A. BYLES, D.C. ROSTAL & D.W. OWENS. 1995. Independent versus socially facilitated oceanic migrations of the olive ridley, Lepidochelys olivacea. Marine Biology 122:137-143.

PRITCHARD, P.C.H. 1969. Sea turtles of the Guianas. Bulletin of the Florida State Museum, Biological Series. 13:85-140.

REICHART, H.A. 1989. Status report on the olive ridley turtle. In: L. Ogren, F. Berry, K. Bjornal, H. Kumpf, R. Mast, G. Medina, H. Reichart, and R. Witham (editors). Proceedings of the Second Western Atlantic Turtle Symposium. NOAA technical Memorandum NMFS-SEFC-226. pp. 270-271.

SCHULZ, J. P. 1975. Sea turtles nesting in Surinam. Zoologische Verhandelingen 143:1-143.