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The presence of feeding turtles at sea has been confirmed from four northern WA at sea encounters with apparent sub-adult or adult size turtles as a result of networking with industry and community. These records comprise two capture and live release cases from fisheries, one from an inshore prawn trawl, and the other from a longliner working off the Pilbara coast.

A third turtle was recovered by recreational fishers at sea north of Broome while suffering from ‘floating syndrome’ and presented to a registered wildlife carer for attempted rehabilitation. The fourth turtle had been fatally entangled in floating marine debris and was reported by offshore oil industry personnel on the FPSO Northern Endeavour in the Timor Sea. All four cases have photographic records and case notes that can be viewed at:

<https://seaturtle.org/cgi-bin/imagelib/index.pl?cat=500&user=3607&thumb=1>.

Additionally, a stranded carcase was collected that is believed most likely the result of a fatal trawl capture somewhere off far northern Australia, with the carcase being retained frozen on board. Later translocation to and subsequent dumping to sea in the Perth region is suspected from a vessel home-porting in this area but usually fishing far away. A separate case report will be compiled for this turtle. Skeletal remains are registered with the WA Museum - R125596. Measurements of the carcase were: curved carapace length (CCL) 665 mm; curved carapace width = 650 mm; mass = 26.2 kg. Tail length (not recorded) suggested the turtle was male.

In addition to these at sea records, four nesting events by olive ridley turtles were documented from the Kimberley region in 2008 (3), and 2009 (1); the first of 2008 on the west Kimberley coast near Cape Leveque; and the others from Darcy Island in the Bonaparte Archipelago, northwest Kimberley, WA. The 2009 record was also from northwest Kimberley, WA, on the Langgi coast at the tourist location known as The Stone Warriors. These cases have photographic records, are specimen backed, and species identity has also been confirmed by species-specific genetic tests.

The Cape Leveque nesting record is from a single nest emergence discovered 23 April 2008 by visitors to the Kooljamon Resort. This comprised a group photograph of hatchlings at the nest site, photographs of one intact specimen being retained by the Bardi Jawi Rangers group, and remains of one mummified hatchling and 6 unhatched eggs excavated several weeks later from the same nest site as recorded by GPS. Photo scaling suggests that the straight carapace length (SCL) of the retained specimen was ~36 mm; the mummified hatchling SCL was ~37 mm. Maximum diameter of the unhatched eggs varied from 36.6 - 39.4 mm (mean 38.2 ± 0.4 mm SE). All eggs were later sacrificed in unsuccessful attempts to extract DNA samples.

The Darcy Island observations were made on 4 and 6 July 2008. Hatchlings from three nests were recorded. These comprised: a photograph only of one live hatchling from nest #3 excavation on 6 July; one retained specimen from nest #1 and four from nest #2 during emerged nest site excavations on 4 July. Field measurements were not taken. SCLs of the preserved hatchlings varied from 39.0 to 42.5 mm (grouped mean 40.3 ± 0.7mm SE).

The Langgi specimen was recovered late May 2009 at a nest site apparently disturbed by a dingo, but from which its siblings had apparently already escaped. Discovery times for the Kimberley hatchling samples recorded here are consistent with the pattern and timing of olive ridley nesting reported for the Tiwi Islands, NT, by Whiting et al. (2007). Ventral scalation patterns of all hatchlings that could be determined included four inframarginal or bridge scales. The expected inframarginal pores could not be visualised.

Dorsal scalation was variable. The 1^st costals contacted the nuchal in all cases. The maximum regular bilateral costal pattern was seven pairs. Other patterns included sub-divided or inserted scutes within basic six or seven pair patterns. Prefrontals were paired. These dorsal scale patterns are evident on the images that are posted at: <https://seaturtle.org/cgi-bin/imagelib/index.pl?cat=500&user=3607&thumb=1>.

Genetic analyses. DNA was extracted from two Darcy Island hatchling specimens originating from two different nests (WAM R169921 = DEC BP443 and WAM R169918 = DEC BP439), from the mummified hatchling (WAM R151598=Hatchling 2008) from the Cape Leveque nest, and from the hatchling from the fourth nest at Langgi (WAM R169923 = DEC BP2067). A 780 bp fragment of the mtDNA control region was amplified using primers LTEi9 and H950 (Abreu-Grobois et al. 2006). PCR product was checked for quality and quantity and purified prior to sequencing and negative controls were used to check for contamination. All samples were sequenced in both directions to confirm the results. The sequences were then compared with known olive ridley sequences from Australian nesting populations on Tiwi Islands, Northern Territory, the McCluer Group, Northern Territory, and Flinders Beach, western Cape York Peninsula, Queensland (Jensen et al. unpublished data).

Figure 1. Northern Australian nesting locations for olive ridley turtles with associated haplotype data.

Three haplotypes were found among the four samples and all of them were identified as being olive ridley sequences. The two Darcy Island samples had haplotypes LOIP-01 and LOIP-02. The one sample from Langgi also had haplotype LOIP-01, which is the most common haplotype found in ~75% of turtles nesting in the Northern Territory at the Tiwi Islands and the McCluer Islands group (Jensen et al. unpublished data). Haplotype LOIP-01 corresponds also to the short 470 bp haplotype J reported by Bowen et al. (1998). Haplotype LOIP-02 has been found at all three nesting populations sampled across northern Australia, but at low to intermediate frequencies (5 – 30 %). Interestingly, the sample from Cape Leveque had the haplotype LOIP-03. This haplotype is found in high frequency on western Cape York (Flinders Beach), Queensland, but only in very low frequency in the Tiwi Islands and is absent from the McCluer Group nesting population (Jensen et al. unpublished data). All three haplotypes above have been reported from Australian nesting populations only (Table 1). Locations mentioned in the text are shown in Figure 1.

Table 1. Samples results from the four Western Australian olive ridley hatchlings sequenced at their mtDNA control region haplotypes.

Information provided in this paper supports the view that the olive ridley turtle is part of the northwestern Western Australian region marine turtle fauna, having both nesting and foraging presence.

Acknowledgments: We thank Ben and Alexis Dodwell for reporting the Kooljamon nest emergence to the Bardi Jawi Rangers; Roy Teale for the Darcy Islands collections; and Emma Francis for the Langgi specimen. Nancy FitzSimmons’ comments on the text in preparation were most helpful. Photographic records of the at sea discoveries posted on the seaturtle.org Image Library are annotated as acceptable to the providers, for whom we are most grateful. The Bardi Jawi Rangers are part of NAILSMA and supported by the Kimberley Land Council. The DEC Biodiversity Survey programme supported the Darcy Islands collections. This paper is a report from the WA Marine Turtle Project.

ABREU-GROBOIS F.A., J.A. HORROCKS, A. FORMIA, P.H. DUTTON, R.A. LEROUX, X. VELEZ-ZUAZO, L. SOARES, P. MEYLAN & D. BROWNE. 2006. New mtDNA D-loop primers which work for a variety of marine turtle species may increase the resolution of mixed stock analysis. In: Frick M., A. Panagopoulou, A. F. Rees & K. Williams (Comps.) Proceedings of the 26th Annual Symposium on Sea Turtle Biology and Conservation. International Sea Turtle Society, Athens, Greece. Available from: <http://www.iucn-mtsg.org/genetics/meth/primers/abreu_grobois_etal_new_dloop_primers.pdf>.

BOWEN, B.W., A.M. CLARK, F.A. ABREU-GROBOIS, A. CHAVES, H.A. REICHART & R.J FERL. 1998. Global Phylogeography of the ridley sea turtles (Lepidochelys spp) as inferred from mitochondrial DNA sequences. Genetica 101: 179-189.

PRINCE, R.I.T. 1993. Western Australian Marine Turtle Conservation Project: an outline of scope and an invitation to participate. Marine Turtle Newsletter 60:8-14.

WHITING, S.D., J.L. LONG, K.M. HADDEN, A.D.K. LAUDER & A.U. KOCH. 2007. Insights into size, seasonality and biology of a nesting population of the Olive Ridley turtle in northern Australia. Wildlife Research 34: 200-210.