THERE is evidence to suggest that the presence of sharks in the food chain is essential for the sustained health of the environment.
Professor Rod Connolly from Griffith University’s Australian Rivers Institute is co-author of new research that supports the idea of keeping large fish in the eco system.
He is currently looking at the issue of culling sharks and the impact of that on the environment. A shark cull was ordered in Perth last year following a spate of fatal shark attacks in the state in January 2014.
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Basically the research found that because sharks are at the top of the food chain they keep down numbers of other marine creatures including bottom feeders like crabs. Large populations of crabs have been blamed for disturbing the sea bed to the point where they are helping release stored carbon into the environment.
Professor Connolly explained that “when we take sharks or other large predators out of the sea the flow on effects through the food web and down to the seabed especially around the coastal margin where we have our wetlands, such as seagrass and mangroves, there’s less of the atmospheric carbon taken up in the sea and stored in the seabed for the long term”.
He said it is vital to make sure that any culls that are carried out are thought through very carefully “this is another piece in the jigsaw puzzle when we make that decision, there are human consequences and now we know there are also consequences that flow on to how we’re going to mitigate climate change”.
When it comes to large sharks Professor Connolly said “there are consequences when we taken them out of the ocean and we’ve known that for a while and the reason we do it is for things to do with human safety often but now we know there’s an additional piece of information which is that it’s also going to affect the amount of carbon that’s taken out of the atmosphere and stored long term in the sea bed”.
He finished by saying their research is ongoing, several groups are working on this and he hopes that in “one to three years we have a better handle on exactly the size of the effect of what it means, how many fish you can or can’t take out before you affect the amount of carbon stored”.
Eight sharks were spotted off the New South Wales coast during Tuesday’s shark summit in Sydney.
The Premier is open to any measures shark experts believe will work. But Mike Baird would not commit to making any changes during 2015.
There have been 13 attacks reported on the North Coast this year alone.
Tweed surfer Mick Fanning, who had a close encounter with a shark during a surf comp in South Africa in July has backed a push to get surfing included in Tokyo Olympic games.