Exploring the status of Western Australia’s sea snakes

All sea snakes are listed marine species under the EPBC Act and three Australian endemic species are listed as Critically Endangered or Endangered, and as such are a national conservation priority. Recent findings of two Critically Endangered sea snake species (Aipysurus apraefrontalis and Aipysurus foliosquama) in locations outside of their previously defined ranges have highlighted the lack of information on species distributions along the North West coast of Australia. Data on sea snake sightings on previously collected baited remote underwater video surveys (BRUVS) and fisheries independent trawl surveys were used to assess the utility of these methodologies to accurately define relative abundance and distribution patterns of sea snakes in the North West Marine Region (NWMR), including within Commonwealth Marine Reserves (CMRs), to refine species’ status.

Presence/absence data from BRUVS were used to predict locations that are likely important habitats for sea snake populations within the NWMR, which included mid-shelf and oceanic shoals along the Kimberley and Pilbara coasts. Limited fisheries-independent trawl sampling data collected in Shark Bay and Exmouth Gulf highlighted patterns of interaction between sea snakes and trawl fishing, with survivorship curves indicating that most sea snake species encountered within these regions may be able to sustain low to moderate levels of trawl fishing. Trawl survey data also highlighted the need for additional fisheries interaction data to accurately assess the species-specific influence of fishing activities (e.g. trawl and trap fishing) on different life stages of sea snakes susceptible to incidental capture (bycatch). This project highlights the need for more data on sea snakes in regions lacking information (e.g. mid-shelf shoals of Kimberley coast, Pilbara coast and Rowley Shoals). In addition, further research is also required to assess the degree of connectivity between sea snake populations from offshore reefs that have seen recent declines, and those on adjacent mid-shelf and oceanic shoals.

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