Great White Shark Research Program

Great White Shark

Great White Sharks: Population Recovery or Headed for Extinction?

Mention the great white shark and most people think of golfer Greg Norman or picture a vicious "man-eater" but this is not really the case. The bad rap they got from the media and movies, meant these sharks were feared by most. There are actually very few shark attacks on humans and some argue that these attacks may be the result of the shark mistaking humans for its natural prey, such as sea lions and seals.

As sharks don't have hands to feel, it is natural for them to bite first to see if the object is edible and then retreat. Attacks are often due to a shark's instinctive curiosity, and are really only a test bite.

What may not be widely known is that the great white shark is under threat. These sharks are never abundant being at the top of the food chain and they have been protected in Australia for more than 10 years.

"Great white sharks are a critical part of the ocean ecosystem, playing an important top-down role by keeping prey populations in check, like sea lions and elephant seals."

Professor William Gladstone, Head of the School of the Environment at the University of Technology, Sydney (UTS) has extensive experience in shark and fish research, and in marine conservation said, "We want to inspire appreciation and understanding of great white sharks through research and education. This means increasing public knowledge about the important ecological role that this species plays in our oceans and why their future needs to be ensured."

"Great white sharks are a critical part of the ocean ecosystem, playing an important top-down role by keeping prey populations in check, like sea lions and elephant seals. The presence of great white sharks ultimately increases species' stability and the diversity of the overall ecosystem. Declines in shark numbers have a knock-on effect that can completely disrupt the marine ecosystem," said Gladstone.

The professor explained UTS is supporting a joint Great White Shark Research Program in conjunction with the Hunter-Central Rivers Catchment Management Authority, CSIRO and NSW Department of Primary Industries, by undertaking aerial surveys in the Port Stephens area. This research aims to improve our understanding of the migratory patterns and provide estimates of the population of threatened great white sharks on the east coast of Australia.

UTS has lengthy experience with shark research, and marine animal research in general. The University also has strong research ties with CSIRO.

The aerial survey data compiled by Gladstone and his project team is being integrated with a CSIRO program to tag juvenile white sharks and track their movements. CSIRO aims to continue tagging juvenile white sharks each year and acoustically monitor their annual return to the Ports Stephens nursery area to provide estimates of juvenile survival. Gladstone's aerial surveys are helping to pinpoint when white shark numbers around Port Stephens are at their highest and this will help maximise the number of juveniles tagged by CSIRO during future tagging expeditions.

"This project will provide evidence that helps assess the recovery of great white shark populations. It will deliver information on the movements of juvenile sharks when they leave the nursery ground and identify other areas that might be important for their survival," said an enthusiastic Gladstone.

Great white sharks are vulnerable, because they reproduce infrequently (once every two to three years), they produce few young (two to ten pups per litter), are slow growing, and don't reach sexual maturity until a relatively late age (females at 12-18 years, and males at 8-10 years).

"The sharks are also at risk from commercial and recreational fishing."

Gladstone said, "The sharks are also at risk from commercial and recreational fishing. Although great whites are no longer targeted for fishing, they may still be incidentally captured. They are also at risk from beach shark meshing programs and being a migratory species, they are at risk from fishing in international waters, or fishing in other nations where they are not protected."

Traded products that come from these sharks include fins, jaws, teeth and meat, cartilage, and skin for leather. Liver oil is used in medicines, and the carcass can be used for fish-meal and fertiliser. The demand for shark fin escalated further during the 1990s, making it one of the most expensive fishery products. Jaws and teeth are the most valuable products in trade.

The primary goal is to recover their numbers to a level that will see the species removed from the Environment Protection and Biodiversity Conservation Act of 1999."

Gladstone explained funding for past research came from Save Our Seas Foundation, and the current research has been funded by the Hunter-Central Rivers Catchment Management Authority (CMA) with support from the NSW and Australian Governments. There has been significant in-kind support for the research and satellite tags have been provided by organisations like the Melbourne Aquarium.

"Past and current funding has been provided for short term research projects so there is no ongoing source of funding for the research ... the gap is $50,000 per year and further funding is being sought from a range of sources. UTS does not have a source of regular continuing funds for research projects such as this, therefore we are seeking external funding to ensure that this important program continues," said Gladstone.

CSIRO will prepare an annual update and interpretation of the records of the movements of tagged sharks. Raising additional funds could be used to extend the project lifespan or to undertake more in depth research.