The current shark debate in the region and wider media is looking like a media rehash of the 1970s cult classic jaws.
While a water lover, diver and surfer I feel it is my responsibility to consider I am part of and not controlling of a marine ecosystem.
I was fortunate enough to learn to dive at Julian Rocks back in 1983. A fellow long term diver expressed his deep regret at being part of a well intentioned but misguided movement that wiped out anything with a fin.
The belief was that this action would keep surfers, divers and swimmers safe. The result was almost wiping out the entire population of grey nurse sharks that frequented the area. – as a result we have fewer than 500 grey nurse sharks left on the east coast of Australia.
Anyone who has an understanding will realise this is almost less than a viable population. While this species has been subsequently protected for decades it has not been able to recover due to its complex reproductive biology.
When my son turned 12 we got his diving ticket – a big incentive was for him to be able to dive with grey nurses (critically endangered) before they no longer exist.
While the current debate exists around more harmful marine species – great whites – I still believe we are at risk of acting hastily and out of ignorance in the same ways we did as a culture back in the 70s.
Clearly there are more dangerous sharks in our waters and clearly we need to find a balance and solution. All sharks and rays are cartilaginous fish. This family’s movements and distributions are heavily reliant on the movement of currents, water temperature and prey.
At our fantastic local dive site at Julian Rocks in the summer months up until about March we will see manta rays and leopard sharks. The cooler months will see the few grey nurses left.
The movement of great whites similarly will be related to currents and as an apex predator will be related to prey supply, a flow-on effect in terms of this is also potentially overfishing in deeper waters of bait fish that are bringing the sharks closer to shore.
At this point the question remains – do we go with research, education and science to attempt to solve this ‘puzzle ‘ of why we are having such a ‘shark problem’ or do we go with the old guard (Google Vic Hislop and his macabre embalmed six-metre great white monster shark museum) and randomly wipe out and demonise our shark populations?
While the debate rages a worrying trend is that some are suggesting there is a ‘plague of sharks’. It is interesting that our current ‘plague’ is not in sufficient numbers to attack south of Evans Head or north of Byron.
To make the plague theory even more unlikely lets look at it. Great whites are already listed as vulnerable. This is for good reason – male sharks are thought to reach a sexual maturity at 26 years to be able to reproduce and females 33 years .
With reproductive biology like this it is unlikely they could ever reach ‘plague’ proportions.
A further relevant fact about all sharks and rays is that they are gifted with a biological apparatus known as the Ampullae of Lorenzinzi – basically a dense collection of electroreceptors that run from the nose across the head.
These electroreceptors are sensory organs that sense both temperature gradients and electromagnetic fields. It is for this reasons that shark pods and other technology are thought to be extremely effective in repelling sharks.
For some strange reason they are not being adopted in sharky territory. I understand the concern and have been out of the water but also suggest we haven’t looked at our own possible behavioral modifications in this respect.
Risk times at down and dusk could be avoided. Whale migration times could be avoided. Peak bait fish times could be avoided.
In the Northern Territory, north Queensland and northwestern Australian saltwater crocs are a way of life, yet people have adapted not slaughtered. For example when fishing in croc-infested areas people are advised ‘to never fish in the same place twice’ due to the fact they are sit and wait predators.
This approach is to be commended – people are part of and interrelate with the ecology of the area.
Question remains for Byron – are we a part of or wanting to manipulate and control the ecosystem hand we are being dealt?
Without scientific research to properly understand the problem will we replicate the mistakes of the 70s.
Sue Robertson, Federal
