|Scientific Name:||Aipysurus duboisii|
|Species Authority:||Bavay, 1869|
Aipysurus australis Sauvage, 1877
Pelagophis lubricus Peters & Doria, 1878
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Lukoschek, V., Guinea, M., Milton, D., Courtney, T. & Fletcher, E.|
|Reviewer/s:||Livingstone, S.R., Elfes, C.T., Polidoro, B.A. & Carpenter, K.E. (Global Marine Species Assessment Coordinating Team)|
This species is widespread but patchily distributed. It is found in coral reef habitats and adjacent open habitats. There have been declines in population recorded in Ashmore Reef although no declines at Scott Reef. Threats in those areas are unclear. There have been declines of sea snakes caught in trawl fisheries over the last few decades, however, it is unknown if these declines are due to abundance reduction or changes in fishery patterns. There have been some regional declines. This species is listed as Least Concern, however it is recommended that bycatch be monitored and efforts made to reduce bycatch with exclusion devices.
A. duboisii occurs throughout tropical northern Australia from Exmouth Gulf, Western Australia to the southern Great Barrier Reef, east Australia (Cogger 2000). Its distribution extends east to reefs in the Coral Sea (Heatwole 1975, Zimmerman et al. 1994), Chesterfield Reefs (Minton and Dunson 1985) and New Caledonia (Ineich and Rasmussen 1997).
Native:Australia; New Caledonia; Papua New Guinea
|FAO Marine Fishing Areas:||
Indian Ocean – eastern; Pacific – southwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
A. duboisii has a patchy distribution and typically occurs at low densities throughout its range (Guinea and Whiting 2005; Guinea 2006, 2007). Thus, it is often among the least abundant species of any recorded at a particular geographic location, as demonstrated by records and sighting rates in Australia’s Timor Sea Reefs (Guinea and Whiting 2005; Guinea 2006, 2007) and the Great Barrier Reef (Lukoschek pers. ob.s 2009, Heatwole 1975). Since 1998, records of sea snakes from Ashmore Reef, Australia have shown severe declines, however, Aipysurus duboisii was not previously recorded as very abundant on the Timor Sea Reefs (Guinea and Whiting 2005; Guinea 2006, 2007) so it is unclear to what extent populations of this species have been affected.
This species is rarely captured by trawlers in Australia’s Northern Prawn Fishery (NPF), which encompasses all of Australia’s northern coastline from the tip of Cape York in the east to Cape Londonderry, Western Australia (>700,000 square km): only 36 individuals of this species were recorded as being captured between 1976 to 2005 (Milton et al. 2008). A. duboisii is, however, it was the third most commonly caught species in the Queensland Red-Spot King Prawn fishery, which fishes closely adjacent to coral reefs in habitat that overlaps with this species’ preferred habitat type (Courtney et al. 2010). It accounted for ~20% of all sea snakes caught in this fishery, and 12% of sea snakes caught throughout Queensland east coast waters from all trawl fisheries combined (Courtney et al. 2010). In the literature, past records of captures of this species in trawl fisheries may differ from more recent records, possibly due to changing patterns in the areas fished (Courtney et al. 2010).
On a trip to the Marion Reef (Southern Coral Sea) in June 2008, on fifteen dives, sea snakes were encountered on almost every dive, but in small numbers, the most on one dive was a maximum of ten, most dives encountering two to six snakes. E. annulatus was the most common (ca. 70%, A. laevis was the next most common. A. duboisii and A. peronii were seen in smaller numbers in shallow water (N. Marsh pers. comm. 2009).
|Habitat and Ecology:||
A. duboisii primarily occurs in shallow-water habitats adjacent to coral reefs (Heatwole and Lukoschek 2008), including sea grass beds, among gorgonians and broken corals, and over sand (Ineich 2007). It typically occurs at depths ranging from 0.02-50 m, although there is a record of it being caught at 58 m in prawn trawls (Courtney et al. 2010) and depths of 80 m have also been recorded (Ineich and Laboute, 2002). Its diet includes various reef fish species. This snake may be encrusted with algae, bryozoans, polychaetes and tubeworms (Zann et al. 1975).
A specimen of 140 cm TL was captured South Groote Eylandt (12/11/07) sample housed in Museum and Art Gallery of the Northern Territory (M. White pers. comm. 2009).
This species may be impacted by degradation of coral reef habitat from expanding oil and gas development in northwestern Australia. In northeastern Australia, a possible threat is trawling activity in the vicinity of reefs.
This species is strongly associated with coral reefs and the degradation of this habitat is likely to pose a threat to species persistence. Mass coral bleaching occurs in association with episodes of elevated sea surface temperature and results in significant losses of live coral (Hoegh-Guldberg 1999). This reduces habitat complexity, with a consequent decrease in prey abundance (Pratchett et al. 2008) and the loss of refuge sites. Climate change may thus threaten all sea snakes which are coral reef specialists (Francis 2006).
Increased sea surface temperatures, coral bleaching, and resulting changes in sediment structure may be linked to localized population declines of sea snakes on Ashmore Reef, northern Australia (Francis 2006). The reasons for the declines on Ashmore Reef are unknown.
There are no species-specific conservation measures in place, however, this snake is found in some MPAs. There are currently no sea snake species protected under CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora).
Sea snakes are protected in Australia since their addition to the ‘Listed Marine Species’ by the Department of Environment and Water Resources in 2000. They are protected in Australia under the Environment Protection Biodiversity and Conservation Act 1999. This requires that all Australian industries interacting with protected species, directly or indirectly, demonstrate sustainability for the species impacted by their activities (Milton et al. 2008). The Australian Fisheries Management Act 1991 requires fishing efforts to avoid captures of threatened and protected species such as sea snakes.
The Northern Prawn Fishery (NPF) in Australia has the largest impact on sea snake populations of any Commonwealth-managed fishery. The EPBC Act and the NPF’s commitments under its Strategic Assessment by the Department of the Environment and Water Resources, led to the commencement of a three year study on developing and implementing a long-term bycatch monitoring program for Australia’s NPF; ‘Design, trial and implementation of an integrated, long-term bycatch monitoring program, road tested in the Northern Prawn Fishery’ FRDC PN 2002/035 (Brewer et al. 2007 as cited by Milton et al. 2008). In addition, the NPF is required to demonstrate that its activities do not adversely impact sea snake species. Since 2003, the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the Australian Fisheries Management Authority (AFMA) have jointly run industry workshops to train crew-member observers in the identification, photography and recording of information on sea snakes caught in the NPF tiger and banana prawn seasons.
Commercial trials of different Bycatch Reduction Devices (BRDs) used in Australia’s trawl fisheries showed that two devices (Fisheye and Popeye Fishbox BRDs) can reduce sea snake catch by between 40 and 85% (without significant prawn loss) when set closer to the cod end than the minimum legally required distance, but <10% of fishers have responded to these findings by moving their Bycatch Reduction Devices closer to the cod end (Milton et al. 2008). Recommendation would be to reduce the number of individuals taken as bycatch in the prawn trawl fishery using appropriate exclusion devices and placement within nets (T. Courtney and E. Fletcher pers. comms. 2009).
|Citation:||Lukoschek, V., Guinea, M., Milton, D., Courtney, T. & Fletcher, E. 2010. Aipysurus duboisii. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 25 May 2013.|
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