Artificial light on water attracts turtle hatchlings during their near shore transit.
We examined the effect of artificial light on the near shore trajectories of turtle hatchlings dispersing from natal beaches. Green turtle (Chelonia mydas) hatchlings were tagged with miniature acoustic transmitters and their movements tracked within an underwater array of 36 acoustic receivers placed in the near shore zone. A total of 40 hatchlings were tracked, 20 of which were subjected to artificial light during their transit of the array. At the same time, we measured current speed and direction, which were highly variable within and between experimental nights and treatments. Artificial lighting affected hatchling behaviour, with 88% of individual trajectories oriented towards the light and spending, on average, 23% more time in the 2.25 ha tracking array (19.5 ± 5 min) than under ambient light conditions (15.8 ± 5 min). Current speed had little to no effect on the bearing (angular direction) of the hatchling tracks when artificial light was present, but under ambient conditions it influenced the bearing of the tracks when current direction was offshore and above speeds of approximately 32.5 cm s(-1). This is the first experimental evidence that wild turtle hatchlings are attracted to artificial light after entering the ocean, a behaviour that is likely to subject them to greater risk of predation. The experimental protocol described in this study can be used to assess the effect of anthropogenic (light pollution, noise, etc.) and natural (wave action, current, wind, moonlight) influences on the in-water movements of sea turtle hatchlings during the early phase of dispersal.
Australian Institute of Marine Science c/o The UWA Oceans Institute (MO96), University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia; Indian Ocean Marine Research Centre and UWA Oceans Institute, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
Michele
M
Thums
Marine Science Program , Department of Parks and Wildlife , 17 Dick Perry Avenue, Kensington, Western Australia 6151 , Australia.
Scott D
SD
Whiting
School of Civil, Environmental, and Mining Engineering (M015), University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia; The Ocean Cleanup Foundation, Torenhove, Martinus Nijhofflaan 2, 18th floor, Delft 2624 ES, The Netherlands.
Julia
J
Reisser
Pendoley Environmental Pty Ltd , 2/1 Aldous Place, Booragoon, Western Australia 6154 , Australia.
Kellie L
KL
Pendoley
Indian Ocean Marine Research Centre and UWA Oceans Institute, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia; School of Civil, Environmental, and Mining Engineering (M015), University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
Charitha B
0000-0003-2229-6183
CB
Pattiaratchi
Instituto de Oceanografia , Universidade Federal do Rio Grande , Avenida Italia km 08, Rio Grande, Rio Grande do Sul 96203-900 , Brazil.
Maira
M
Proietti
Indian Ocean Marine Research Centre and UWA Oceans Institute, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia; School of Civil, Environmental, and Mining Engineering (M015), University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
Yasha
Y
Hetzel
Australian Institute of Marine Science c/o The UWA Oceans Institute (MO96), University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia; Indian Ocean Marine Research Centre and UWA Oceans Institute, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
Rebecca
R
Fisher
Australian Institute of Marine Science c/o The UWA Oceans Institute (MO96), University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia; Indian Ocean Marine Research Centre and UWA Oceans Institute, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
Mark G
MG
Meekan
VR2W positioning system; acoustic telemetry; coastal development; green turtle; in-water movement; light pollution