Department of Primary Industries and Fisheries project leader David Welch said the research was aimed at understanding how various shark populations were connected and where they had lived over their lifetime.
“Ultimately, this research will help in determining appropriate management arrangements for shark on Queensland´s east coast,” Mr Welch said
“Sharks are an important component of the total commercial fishing catch in Queensland but currently species composition is relatively undefined.
“Independent monitoring of commercial fisheries indicates that the majority of catch is made up of blacktip sharks, scalloped hammerheads and milk sharks. Therefore our research is focusing on learning more about these populations and the movement of these species.”
Mr Welch said three different techniques were being used concurrently to determine whether there were distinctly different populations of blacktip sharks, scalloped hammerheads and milk sharks along the Queensland east coast.
“The techniques are genetics, microchemistry, and population characteristics,” Mr Welch said.
“Although it is still early days in the project, the team has made some significant developments.
“James Cook University PhD student Ron Schroeder has led the development of an innovative method for examining the micro-chemical make-up of shark vertebrae.
“Using this technique the chemical composition of vertebrae from sharks´ backbones are analysed to determine the chemical ´signature´ of individual sharks.
“This is the first time that these analytical methods have been successfully applied to sharks.
“It allows us to determine the concentration of various trace elements in shark vertebrae which then can tell us a lot about the history of individual sharks and where they have been living over their lifetime,” Mr Welch said.
Another breakthrough made by the team has been in developing genetic techniques to reliably identify two different species of blacktip shark that look identical.
Dr Jenny Ovenden and her team of scientists from the Queensland Department of Primary Industries and Fisheries, have developed genetic markers to identify the two blacktip shark species taken by fishers.
“We know that blacktip sharks are an important component of the commercial catch, but we have very little information on the relative proportions of each of the two species in that catch.
“Using this new genetic tool we have learnt that the common blacktip shark is much more frequently captured on the east coast than previously thought,” Mr Welch said.
“The team will now apply these tools in helping to determine the population structure of these shark species on the east coast.
“With assistance from local fishermen, researchers will collect and study shark samples from different parts of the east coast during the rest of 2009.”
DPI&F fisheries resource manager Mark Lightowler said that as part of new fishing rules for Queensland´s East Coast Shark Fishery which come into effect on July 1 this year, the total shark catch in Queensland had been reduced from 900 to 600 tonne and access to the fishery was to be limited.
“At this stage, we are taking a precautionary approach by reducing the catch to 600 tonne until new information such as this research can provide a more accurate assessment,” Mr Lightowler said.
“The concern with shark catch on Queensland´s east coast is that around 50 species are taken and current data means that we are unaware of the exact proportions of each species and their population in the wild.
“As part of introducing these new rules, DPI&F is committed to collecting better information on shark populations and catch, in particular species composition, for use in future fishery assessments,” Mr Lightowler said.
“After three years of collecting good species specific data, the DPI&F will be able to undertake a stringent stock assessment to establish an appropriate level of sustainable catch for individual species or groups of species of shark.”
The project is funded by the Fisheries Research and Development Corporation and is being jointly conducted between the Department of Primary Industries and Fisheries, James Cook University and the Great Barrier Reef Marine Park Authority.
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