A grey future for the grey nurse
In the early 1900's, the shark was hunted for its flesh (for human consumption), its skin (for use as leather and sandpaper) and its liver (for oil that powered Sydney's street-lamps). In the 1960's, the animal was incorrectly blamed for shark attacks at Sydney's beaches and hunted and killed by spearfishers and gamefishers. The decline of the population led the NSW Government to declare the shark a protected species in 1984. In doing so, the species became the first protected shark in the world. Unfortunately, the shark's numbers have continued to decline because of accidental captures by commercial and recreational fishers. As a result, the Grey Nurse sharks was declared a threatened species in May 1999 and is currently listed as "Endangered" under Section 7A of the New South Wales Fisheries Management Act (1994).
The Grey Nurse shark is an inshore, coastal-dwelling species that occupies boulder or sand-filled gutters, caves and overhangs in rocky reefs in waters 15-50 m deep. The shark's life-history means that it matures quite late in life, lives a long time (at least 25 years), and only produces two pups every second year. These attributes, combined with its inshore distribution and requirements for specific habitat, make the species particularly vulnerable to fishing.
Prior to 1998, there was minimal information concerning the ecology of Grey Nurse sharks in south east Australian waters. What was known was mainly derived from research done on the east coasts of South Africa and the USA. Research by NSW Fisheries over the past five years has therefore focused on documenting the: (1) distribution and abundance; (2) population demography; (3) movements; (4) critical habitats; (5) human-induced threats; and (6) the degree of genetic variability of the sharks comprising the population in SE Australian waters.
This paper summarises the results of this research and provides several independent lines of evidence that demonstrate that the Grey Nurse shark population in SE Australian waters is in a very precarious position. The paper also highlights those areas where veterinary input could contribute to a greater understanding of hooking damage to the sharks and the shark's reproductive biology.