Understanding the Environmental Risks of Unplanned Discharges – the Australian Context: Marine Reptiles Jessica Oatesa aAstron, 129 Royal Street, East Perth WA 6004 September 2016 Document No. 1128_01_001/7_Rev1 Client: APPEA Document history Distribution No. copies Revision Author Recipients Organisation Date & format A J Oates T. Ridgway BMT Oceanica 1 x docm 03/07/15 The University of B J Oates K. Sanders 1 x docm 14/07/15 Adelaide C J Oates M Gagnon Curtin University 1 x docm 10/09/15 BMT Oceanica Project D J Oates M Bailey 1 x docm 11/12/15 Director D Hills APPEA Project Steering 1 x docm 0 J Oats L Smith 23/12/15 Group 1 x pdf R Smith A Taylor APPEA 1 x docm 1 J Oats 30/09/16 1 x pdf Review Revision Reviewer Intent Date A T. Ridgway Editorial review 08/07/15 B K. Sanders Technical review (biological) 07/08/15 C M Gagnon Technical review (project/hydrocarbon) 26/10/15 D M Bailey Final sign-off for submission 22/12/15 D Hills 0 L Smith APPEA Project Steering Group approval 17/08/16 R Smith 1 A Taylor Final submission 30/09/16 Contents Acronyms and abbreviations .................................................................................................... ii Abstract ...................................................................................................................................... 3 1. Introduction and background ........................................................................................... 1 1.1 Background ............................................................................................................ 1 1.2 Behaviour and fate of crude oil in coastal environments ................................... 2 1.3 This review ............................................................................................................. 3 1.4 Environmental Protection and Biodiversity Conservation Act ........................... 4 2. Biological and/or behavioural vulnerabilities .................................................................. 4 2.1 Temporal and spatial considerations ................................................................... 4 2.2 Surfacing requirements ......................................................................................... 5 2.3 Life stages .............................................................................................................. 5 3. Direct impacts on biota ..................................................................................................... 6 3.1 Surface fouling ....................................................................................................... 7 3.1.1 Marine turtles ................................................................................................ 7 3.1.2 Sea snakes ................................................................................................... 8 3.2 Toxicity associated with ingestion of oil .............................................................. 8 3.2.1 Marine turtles ................................................................................................ 8 3.2.2 Sea snakes ..................................................................................................10 3.3 Toxicity associated with inhalation of oil ........................................................... 10 3.3.1 Marine turtles ...............................................................................................10 3.3.2 Sea snakes ..................................................................................................10 3.4 Toxicity associated with absorption of oil ......................................................... 11 3.5 Impacts associated with dispersed oils and other contaminants .................... 11 4. Indirect impacts on biota ................................................................................................ 13 4.1 Food contamination and availability .................................................................. 13 4.2 Loss of habitat ..................................................................................................... 13 4.3 Developmental and behavioural changes .......................................................... 14 4.4 Compounding effects of multiple stressors ...................................................... 14 5. Capacity for recovery ...................................................................................................... 15 6. Conclusions ..................................................................................................................... 16 7. Acknowledgments ........................................................................................................... 18 8. References ....................................................................................................................... 18 List of Figures Figure 1.1 Conceptual model for the fate of petroleum in the marine environment ................. 3 Figure 3.1 Conceptual impact pathways for hydrocarbon spills on marine reptiles ............... 12 APPEA: Marine Reptiles i Acronyms and abbreviations AMSA Australian Maritime Safety Authority cm Centimetres DAE Deloitte Access Economics DNA Deoxyribonucleic acid DoE Department of the Environment (formerly DSEWPaC) DSEWPaC Department of Sustainability, Environment, Water, Population and Communities (now DoE) EPBC Act 1999 Environment Protection and Biodiversity Conservation Act 1999 FDEP Florida Department of Environmental Protection GBRMPA Great Barrier Reef Marine Park Authority GSMFC Gulf States Marine Fisheries Commission ha Hectares kg Kilograms km Kilometres km2 Kilometres squared µg Micrograms mg Milligrams ml Millilitres NMFS NOAA Fisheries NOAA National Oceanic and Atmospheric Administration (US) NRC National Research Council PAH Polycyclic aromatic hydrocarbon PTTEP PTT Exploration and Production Public Company Limited TPH Total petroleum hydrocarbon US United States US Dept Int United States Department of the Interior ii APPEA: Marine Reptiles Abstract Australian marine reptiles, comprising turtles, saltwater crocodiles and sea snakes, are protected under State and Federal legislation and have a high ecological, social and economic value. Marine reptiles are found throughout most marine habitats in Australia that may expose them to a range of potential impacts from unplanned discharges of hydrocarbons. In light of such potential risks, the aim of this review is to provide a current state of knowledge on the consequences of unplanned discharges for marine reptiles in Australia. Australian marine reptiles are variously threatened by impacts from marine debris, habitat modification, climate change and commercial fishing by-catch. Acute impacts from unplanned discharges are considered to be less threatening. However, there are large gaps in the understanding of species' distributions, basic ecology and abundances in Australia, as well as limited information on the effects of hydrocarbons on these marine organisms. This review relies on several key laboratory studies of toxicity effects and reports of the Ixtoc I, West Atlas and Deepwater Horizon hydrocarbon spill incidents, with almost all the data available on marine turtles. There is a significant lack of data available for sea snakes and saltwater crocodiles. The available literature, focussed heavily on marine turtle species, indicates acute impacts occur primarily through direct contact and/or ingestion of surface oil, with dermal tissues and membranes particularly sensitive to direct exposure. The earlier life stages are generally more vulnerable to impacts, whereby fresh oil is known to induce turtle egg mortality but weathering may reduce the toxic effect to the point of little or no effect. Other sub-lethal impacts include digestive tract impaction from tar balls, changes to blood chemistry and enzyme levels indicating an immune response, and inability to maintain salt and water balance. Indirect impacts include contamination or mortality of food sources, impairment of bacteria that aid digestion within the gut, and loss of habitat. Studies have shown reduction in both trophic niche breadth and habitat use of turtles due to the reduced availability of most food sources in polluted areas. The toxicity of dispersed oil to marine reptiles is unknown and no experimental evidence has been generated to date. More field research is required to provide robust guidance as to the appropriate spill response depending on the circumstances. Aside from the physical, chemical and biological conditions of the unplanned discharge, the potential consequences for marine reptiles in Australian waters will depend on a number of factors including population size, distribution and certain life-history characteristics. Aspects of marine reptile biology and behaviour such as no avoidance behaviour, air-breathing, low reproductive and growth rates predispose them to a high risk of impacts from hydrocarbon spills and may slow recovery. Restricted distributions and limited inter-population exchange of some species, particularly sea snakes, may also reduce recovery potential. APPEA: Marine Reptiles iii 1. Introduction and background 1.1 Background Marine reptiles in Australia consist of marine turtles, sea snakes and the saltwater crocodile. Six of the world's seven marine turtle species occur in Australian waters, and all six – green (Chelonia mydas), hawksbill (Eretmochelys imbricata), loggerhead (Caretta caretta), flatback (Natator depressus), leatherback (Dermochelys coriacea) and olive