Key Threatening Process Nomination Form

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Criterion C: Adversely affected listed species or ecological communities
10. SPECIES ADVERSELY IMPACTED AND JUSTIFICATION Provide a summary of species listed as threatened under the EPBC Act, that are considered to be adversely affected by the threatening process. For each species please include: a. the scientific name, common name (if appropriate) and category of listing under the EPBC Act; and b. justification for each species that is claimed to be affected adversely by the threatening process.
^M^a^rⁱⁿ^e^t^ur^tles Australian waters are home to six of the world’s seven species of marine turtle. These species are all protected under the EPBC Act and listed under the Convention of International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the Convention for the Conservation of Migratory Species (CMS). Five of the species found within eastern Australian waters are also listed as endangered and critically endangered under the International Union for the Conservation of Nature’s (IUCN) Red List 2011 (IUCN, 2011). A marine turtle may take up to 30–50 years to mature (Marine Species Section, 2003), making them extremely vulnerable to impacts on population size. It is stated within the Federal Recovery Plan for Marine Turtles in Australia (Marine Species Section, 2003) that "Marine turtles are vulnerable to boat strikes when at the surface to breathe and rest between dives. This is particularly an issue in waters adjacent to large urban populations (Limpus & Reimer, 1994) where there are large numbers of boats and other pleasure craft... The marine turtle populations affected by boat strike have been identified as: loggerhead turtles from the eastern Australian population; green turtles from the southern Great Barrier Reef population; hawksbill turtles from the north-eastern Australian populations; and flatback turtles from Queensland." Records illustrate the olive ridley turtle to be victim to boat strike on occasion (e.g. Haines & Limpus, 2001). Furthermore, boat strike is regularly mentioned in a review of impacts ‘of greatest relevance to turtle populations in the World Heritage Area’ of the Great Barrier Reef (Dobbs, 2001). Australia is home to some of the largest nesting sites of the green, loggerhead and hawksbill turtles in the Indo-Pacific region, and the only nesting sites of the flatback turtle (Marine Species Section, 2003). A summary of the numbers of turtles known to have been killed by boat strike in Queensland between 1998 and 2002 is presented in Table 3, with data being obtained from the Queensland Department of Environment and Resource Management (DERM) Marine Wildlife Stranding and Mortality Database Annual Reports. Table 3: Marine turtle mortalities cause by boat strike in Queensland waters between 1999-2004 From 1998-2002, confirmed boat strike accidents accounted for an average of 80 annual turtle mortalities along the Queensland shoreline alone, although this is probably an underestimation since cause of death could not be determined in 57% of cases, plus we can assume many carcasses are not discovered. The majority of those killed were green turtles. Boat strikes have proven to be one of the leading causes of turtle fatality from human-induced causes. Between 1999 and 2002 an annual average of 36.8% of all sea turtle mortalities in which cause of death could be determined (15% of all strandings and mortalities) within Queensland waters were due to boat strikes, with injuries consistent with propeller damage and fractures (Table 4). Table 4: Records of documented turtles mortalities for Queensland waters from 1998-2002 showing the percentage of confirmed mortalities attributed to boat strike
	Year	Total number of dead or stranded marine turtles	Number for which cause of mortality could be determined	Number of turtles killed due to anthropomorphic causes	Number attributed to boat strike	% of confirmed deaths due to boat strike
	1999	554	195	150	84	56.0*
	2000	495	172	130	78	60.0*
	2001	529	168	139	83	59.7*
	2002	526	172	149	65	43.6*
	2003	527	140	117	60	51.3*
	2004	574	173	156	75	48.1*
	Total	3,205	1,020	841	445	52.9*

* = boat strike caused more than or as many deaths than any other anthropogenic activity recorded

It is worth noting that were cause of mortality proportions to remain consistent throughout the marine turtle strandings which were unconfirmed or had an unidentifiable cause of death, the number that would be attributable to boat strike (currently 445/1,020) would rise to approximately 1,400 individuals. Even this figure, focusing only on mortality on the Queensland coastline, is likely to represent only a fraction of actual mortality rates due to many instances going undetected or unreported. When considering this, it is clear that boat strike is a key threatening process to EPBC Ac t listed marine turtles in Australia.
The impact of boat strike on turtles is recognised in the Marine Turtle Recovery Plan (2003) as being particularly significant in the Moreton Bay and Harvey Bay areas. The Recovery Plan aims to increase turtle populations in the wild by reducing human induced mortality. Incidence of boat strike on marine turtles is of significance not only in Moreton Bay and Harvey Bay, but also in the Hinchinbrook area which is of increasing concern due to marine traffic and consequent injuries to turtles increase with increasing development (Limpus et al., 2002).
The impact of boat strike on green and loggerhead turtle populations is most evident through the data outlined in Table

3, and these species will be focused on in more depth later in this nomination. This will also be the case with the leatherback turtle, which warrants closer scrutiny due to its conservation status as Critically Endangered internationally (IUCN, 2011) and listing under all State / Territory with coastline (ACT being the only exception) threatened species legislation.

Flatback (Natator depressus), olive-ridley (Lepidochelys olivacea), and hawksbill (Eretmochelys imbricata) turtles are recognised as threatened Federally under the EPBC Act, Internationally through CMS, IUCN and CITES, and under various State / Territory laws. They are uncommon in the Great Barrier Reef region and data is correspondingly lacking in DERM’s Marine Wildlife Stranding and Mortality Database Annual Reports, thus little data is available regarding cause of mortality. However, these Annual Reports, the most recent of which is Greenland et al. (2006), show that between

1999-2004 one flatback, five hawksbill, and seven olive ridley turtles were recorded as stranded or killed by boat strike on the Queensland coast. Thus, even though data that fulfils the criteria for inclusion in the KTP is not comprehensive, it should be considered that three additional rare turtles in Australian waters are affected by this process, and may be more severely in other areas throughout their Australian range where they are more common.

Prior to 2012 there was no coordinated data collection on boat strikes in Western Australia, however efforts now include Ningaloo and elsewhere. The Western Australian Department of Parks and Wildlife hope to use StrandNet to collate records from the past 60 years, but approximately 6 months away from completion of the process they are not yet confident to release data (pers. comm., XXX XXX).
Green turtle (Chelonia mydas)
Australian conservation status:

National: Listed as Vulnerable, Marine and Migratory species under the Environment Protection and Biodiversity

Conservation Act, 1999.

New South Wales: Listed as Vulnerable under the Threatened Species Conservation Act, 1995.

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Western Australia: Listed as Vulnerable under the Wildlife Conservation Act, 1950

International conservation status:

^{- Li}^s^ted^oⁿ^A^pp^eⁿ^d^ix^I^o^f^th^e^C^oⁿ^v^en^ti^oⁿ^o^f^In^t^e^r^na^ti^ona^l^Tr^a^d^eⁱⁿ^E^ndaⁿ^ge^r^e^d^S^p^e^c^ies^o^f^F^aun^a^an^d^Fl^o^r^a⁽^C^I^T^E^S).

- Listed as Endangered on the International Union for Conservation of Nature and Natural Resources (IUCN) Red

List of Threatened Species.

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According to Queensland Government’s Marine Wildlife Stranding and Mortality Database Annual Reports (see Table 3), green turtles account for approximately 87.2% of boat strike mortalities to marine turtles in Queensland. Annual mortality rates attributable to boat strikes surpass mortality rates from any other cause, including all natural causes combined and such anthropogenic impacts as shark net entanglement and traditional hunting.
Of the total confirmed green turtle mortalities where the cause of death could be determined contained within the Marine Wildlife Stranding and Mortality Database Annual Reports, greater than 50% (360/705) featured fractures and injuries consistent with boat strike and propeller damage (Table 5). Comparatively, only 15.2% of cause of death confirmed stranding and mortalities were due to natural causes such as disease and depredation, a figure which indicates the severe stress boat strike incidents are placing on non-impacted green turtle population dynamics.
Table 5: Records of reported green turtle mortalities in Queensland waters from 1998-2002 showing the percentage of confirmed mortalities attributed to boat strike

Year	1999	2000	2001	2002	2003	2004	Total
^T^o^tal^c^on^fⁱ^r^med^m^o^r^ta^lⁱ^ty	¹³⁴	¹⁰⁸	¹²⁵	¹¹⁸	¹⁰⁸	¹¹²	⁷⁰⁵
^N^at^u^r^al^c^a^u^s^e^s	²⁶	²²	²⁰	²⁰	¹⁶	³	¹⁰⁷
Anthropogenic	108	86	105	98	92	109	598
^B^o^at^S^t^rⁱ^ke	⁶⁹	⁵⁷	⁶⁶	⁵⁵	⁴⁸	⁶⁵	³⁶⁰
^%^aⁿ^t^h^r^o^.^b^o^atst^rⁱ^ke	^63.9*	^66.3*	^62.9*	^56.1*	^52.2*	^59.6*	^60.2

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It is worth noting that boat strike was the leading confirmed cause of mortality of reported incidents on the Queensland coast in all of the six years for which data was collected, significantly higher than any other factor. It is stated within Hazel et al. (2007) that “Individual green turtles are known to maintain long-term fidelity to their coastal foraging areas, with only brief absences during breeding migrations spaced several years apart (Limpus et al. 1992, 1994). Thus, for each individual turtle in a foraging area that receives vessel traffic, the risk of collision persists over decades”. This behavioural trait may be a significant factor in why instances of boat strike on green turtles are so common.
A study (Hazel et al. 2009) showed that the large majority of green turtles spent 89-100% of their time at depth of equal to or less than 5m below surface. Additionally, for 80% of their time they were in charted (low tide) depths of 3m or less i.e. locations such as bay margins (Moreton Bay) where human activity is greatest. These locations often coincide with near shore foraging grounds.
The severity of the threat of boat strike to green turtles is rivalled only by that of Indigenous traditional hunting. It is however a threat that is relatively straightforward to abate compared to the indigenous use. If the threat of boat strike were to continue the species will continue to decline. Together with the loggerhead turtle (below), it meets the KTP listing criterion that the threatening process adversely affects an EPBC Act listed species.

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