Flickr/Richard Ling

Management

Grey nurse shark management is inherently contentious. Hook and line fishing has been identified as the major threat to the species survival and is the largest source of grey nurse shark mortality; causing approximately 12 known mortalities per annum. “Hook and line fishing in areas important for the survival of threatened fish species” was listed as a Key Threatening Process affecting grey nurse sharks in 2002 by the NSW Fisheries Scientific Committee.

Grey nurse sharks are susceptible to accidental hooking at aggregation sites and while moving between sites. Accidental hooking can result in direct mortality from injuries and infection, and can also cause non-fatal injuries that may impair feeding and reproductive ability.

Grey nurse shark rescued from fishing gaff in Byron Bay

Grey nurse sharks occur in shallow inshore coastal waters that are subject to significant recreational and commercial fishing activity, and proposals to mitigate fishing impacts on grey nurse shark are perceived as a threat to access by commercial and recreational fishers.

The large placid nature of grey nurse sharks combined with their aggregating behaviour also underpin a major dive tourism industry, resulting in high levels of community awareness and concern about grey nurse shark interactions with hook and line fishing gear.

Saving the species

Anybody with a half-scientific mind will realise by looking at the last decade of data on grey nurse sharks that we cannot just sit around and do nothing. This species needs our help and not just for its own sake.

Considerable effort has gone into determining the size of the grey nurse shark population over the last decade. Total population size has been the subject of much debate, with a range of views held in the community about its size and whether it is declining, static or recovering.

Tips on diving with grey nurse sharks

The most recent estimate commissioned by the Commonwealth Government suggests the total population size is less than 1500 individuals. This also concurs with genetic analysis that suggests the population size is between 1000 – 1500 individuals.

All of the population estimates to date are lower than the minimum optimal population size of 5000 required for long term persistence, and modelling suggests that the population is likely to be declining under current levels of known fishing mortality.

How can you help?

Reef Check Australia suggests the following:

Opportunistic encounters: Are you a diver or fisher who occasionally encounters grey nurse sharks? If you have a good quality side photo of any of these sharks, you can submit your sighting and/or photographs on line at any time during the year using a simple on-line form. Please sign up as a member to be able to submit your data and photos.

Scheduled surveys: Are you a regular diver-photographer who would like to become a site custodian? Can you commit to a more intense survey at your favourite local site between July/August and January/February? If so, nominate yourself as a site custodian before the first scheduled survey period. First sign up as a member by providing your details, then indicate your nominated site and season. Already a member? Login and then edit your member details to become a GNSW and/or nominate yourself as a site custodian.