Sea Turtles and the Environmental Management of Industrial Activities in. North West Western Australia. Kellie Lee Pendoley

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1 Sea Turtles and the Environmental Management of Industrial Activities in North West Western Australia Kellie Lee Pendoley This thesis is presented for the degree of Doctor of Philosophy Murdoch University 2005

2 I declare that this thesis is my own account of my research and contains as its main content work which has not been previously submitted for a degree at any tertiary educational institute Kellie Lee Pendoley

3 Abstract The nesting demographics of sea turtles using beaches within the Barrow, Lowendal, Montebello (B-L-M) island complex on the North West Shelf of Western Australia were examined in the context of their spatial and temporal distribution and potential for exposure to industrially based artificial light sources. The distribution of overnight turtle tracks throughout the island complex confirmed high density nesting of Chelonia mydas (green turtles) on deep, sandy and high energy beaches and Natator depressus (flatback turtles) on deep, sandy and low energy beaches, while Eretmochelys imbricata (hawksbill turtle) tracks were most visible on shallow, sandy beaches adjacent to near shore coral reef habitat. The three species exhibited a summer nesting peak. Hawksbill turtles commenced nesting in September and continued through to January, green turtles commenced in November and decreased in March. Flatback turtles displayed the most constrained nesting season reported to date in Australia with 86% of the animals visits recorded in December and January only. Nesting population sizes estimated for the three species suggest that on a national scale the B-L-M complex is a moderately large green turtle and a large flatback rookery site. The hawksbill rookery is large on an international scale. While none of the green turtle nesting beaches fell within a 1.5 km radius of industrially based artificial light sources an estimated 42% of nesting flatback turtles and 12% of nesting hawksbill turtles were potentially exposed to these light sources. Testing of green turtle and hawksbill hatchling response to different wavelengths of light indicate that hatchlings from the B-L-M region respond to low wavelength much like hatchlings tested in North America (Witherington 1992a). Flatback hatchlings displayed a similar preference for low wavelength light however their responses to

4 discrete light wavelengths between 400 nm and 700 nm suggest that this species may not discriminate well between wavelengths that lie between 450 nm and 550 nm. This response may be related to the rapid attenuation of visible light that occurs in the turbid near shore habitats favoured by this species. Field based arena studies carried out to investigate hatchling behaviour on nesting beaches with light types commonly used in industrial settings found green turtle and flatback hatchlings are significantly attracted to these lights compared to controls. Lights that emit strongly in the low wavelength range (i.e. metal halide and fluorescent) caused hatchling misorientation at lower intensities than the test light that emitted relatively poorly in this range (high pressure sodium vapour). Hawksbill hatchlings tested in situ under the influence of actual oil and gas onshore and offshore facility based lighting were disrupted from the most direct line to the ocean by these light emissions. Emergence fan mapping methods that measure hatchling orientation on nesting beaches were refined and are proposed as an alternative monitoring tool for use on beaches that are logistically difficult to access for large scale experimental orientation studies. The hatchling behaviour was clearly complicated by beach topography and moon phase. Satellite tracking of post nesting female green and hawksbill turtles from North West Shelf rookeries has identified the Western Australian location of migratory corridors and foraging grounds for these species while Scott Reef turtles migrate from their south Timor Sea rookery to Northern Territory waters. Green turtle nesting on Barrow Island and Sandy Island (Scott Reef) forage at feeding grounds km from their nesting beaches. Hawksbill turtles nesting at Varanus Island and Rosemary Islands forage at locations km from their nesting beaches. While all of the nesting beaches within the B-L-M island complex are protected under the Barrow-Montebello

5 Marine Conservation Reserves, the only foraging ground similarly protected is the Northern Territory foraging ground used by Scott Reef green turtles. None of the foraging grounds used by North West Shelf green or hawksbill turtles is currently protected by conservation reserves.

6 TABLE OF CONTENTS Abstract...3 Acknowledgments...10 Chapter 1 Introduction Context of research Objectives Thesis outline...5 Chapter 2 Background Sea turtle life cycle and developmental habitats Case Study area physical characteristics Location Geomorphology and marine habitats Climate Status of sea turtles in Western Australia and the study area Regional Western Australia Case Study area Barrow, Lowendal, Montebello (B-L-M) island complex Industrial activity ( )...35 Chapter 3 Sea turtle beach usage and beach light exposure Introduction Background Research questions Chapter outline Literature Review Species track identification Nesting habitat requirements Nesting population census techniques Methods Track identification Physical characteristics and light environment of beaches Track count survey beach selection, access and timing Track counts Results...60

7 3.4.1 Track identification Survey of beach physical characteristics and light environment Beach preferences Length and peak of nesting season Track to nest ratio Distribution of track counts between and within the B-L-M island groups Beach usage, Barrow Island and Lowendal Islands Discussion Track identification Beach/foreshore characteristics favoured by each species Nesting season length, peak and population size Nesting beaches exposed to industrial light in the B-L-M island complex 91 Chapter 4 Hatchling wavelength preference experiments Introduction Background Research questions Chapter outline Literature Review Methods Test species Animal collection and teatment Test equipment Statistical treatment Results Discussion Chapter 5 Spectral measurements of natural and artificial light sources Introduction Background Research questions Chapter outline Literature Review...122

8 5.3 Methods Study site selection Light sources Equipment Data manipulation Flare operating conditions Results Natural sources Flares Electric lights Discussion Chapter 6 Field surveys - Hatchling orientation Introduction Background Research question Chapter outline Literature Review Effects of photopollution on sea turtle hatchlings Light direction Shape and form vision Influence of lunar cycles Orientation cues non visual Illuminance measurements Methods Arena experiments Controlled light sources - arena studies Uncontrolled light sources arena studies Fan mapping Results Controlled light source experiments - Arena studies Barrow Island Uncontrolled light source experiments Fan mapping...189

9 6.4.4 Industrial Case Study results Discussion Effects of artificial illumination on hatchling seafinding Fan mapping as a monitoring tool and beach topography effects 202 Chapter 7 Satellite telemetry Introduction Background Research questions Chapter outline Literature Review Methods Ptt deployment LC filtering and data mapping Results and Discussion Location class Tagging details Mapping Internesting Migratory pathways Swimming speed and mid migration grazing Foraging grounds Threats and Conservation priorities Chapter 8 General Discussion Bibliography APPENDIX APPENDIX APPENDIX

10 Acknowledgments All field work was carried out under CALM licenses , , , , , and Murdoch University Animal Ethics permits 766R/99 and R975/03. Logistical and in-kind support was provided by ChevronTexaco (formerly Chevron and WAPET) for work carried out on Barrow Island and by Apache Energy for work carried out in the Lowendal and Montebello Island groups. This study would not have been possible without this support. Nor would it have been completed without the support of my field assistants over the 7 years of field surveys; BJ Landau, Anna Vitenbergs, Peter Pendoley, Peter Salinovich, Helen Ford, Libby Howitt, Lisa Di Giacomo, Jane Wilshaw, Emma Barr, Cindy Ong, Helen Allison, Keith Morris, Corey Beggs, Pat Cullen and Myles Hyams. The support, advice and encouragement of Keith Morris and Dr. Bob Prince (WA CALM) has been inspiring. Seed funding for the satellite telemetry program was supplied by NHT Grant #9924 ($65,000) (in conjunction with A/P Stuart Bradley, Murdoch University). Additional funding was subsequently supplied by Apache Energy ($10,000 plus in-kind logistical support), BHP Billiton ($35,000), ChevronTexaco Gorgon ($10,000 plus in-kind logistical support), Santos ($10,000) and Woodside ($10,000). This funding was only supplied because of the support of the following company environmental staff for the project, Russell Lagdon (ChevronTexaco), Iva Stejskal (Apache Energy), Stephan Fritz (ChevronTexaco), Oleg Morozow (Santos), Greg Oliver (Woodside), Edward Pinceratto (BHP) and Brian Starkey (BHP).

11 Personnel providing valuable support and advice on the satellite telemetry project include; George Balaz, Rod Kennett, Guan Oon (ARGOS Australasia), Kevin Lay (Sirtrack New Zealand), Luke Smith (AIMS), Crew of the Kimberley Explorer and of the Port Walcott, management and field staff of Varanus Island and Barrow Island. I also wish to acknowledge support and help of Mike Coyne, creator or the Maptool program for analysis of the satellite telemetry data and graphics. Maptool is a product of SEATURTLE.ORG. (Information is available at Special acknowledgement must go to my fellow alumni and college room mate (Florida Institute of Technology, USA, ), fellow student (PhD candidate Rutgers University, New Jersey USA) and loyal friend, BJ Landau, for giving up her own research and family time every January for 4 years to travel from the depths of the New Jersey winter to the Pilbara to be my field assistant. I owe you girl. I wish to thank my friend and fellow student Dr Helen Allison for giving me direction with the manuscript when I really needed it, Libby Howitt for her stellar effort in editing the final draft of the manuscript, Peter Chalmer (Environmental Drafting) for his drafting support and Sarina Aston for making sure the text didn t look like a dogs breakfast. This work would not have even begun without Kit Armstrong (Chevron Overseas Petroleum) nudging me at the right moment, and Dr Louis Evans and Dr. Peter Hick believing in me all those years ago. My Supervisor Prof Stuart Bradley has been remarkably patient and calm in seeing me through my reprogramming and has done the bulk of the statistical testing on the data. I am proud to reach the end of this 7 year project still able to call him a mentor and a friend.

12 Finally to the two most important men in my life, my husband and best friend of 24 years Peter Pendoley, and my son and fellow graduate (7 th grade, 2005) Scott Pendoley, thanks for the patience guys.