To Cull Or Not To Cull

I try to avoid being too controversial here but this is something I feel strongly about so I hope you’ll bear with me this time.

When I mentioned in a recent blog post how the survival rate of baby bobtails is low due to predatory birds a commenter on this blog - hello, David - reminded me about the importance of predators in maintaining a healthy natural balance. He is quite right, too. All the evidence suggests that if you remove apex predators things start to go awry. Populations of some animals explode and that in turn has follow on effects right across the board. 

Western Australia, where I live, has a vast coastline and like most of Australia, the bulk of the population lives along that coastline, particularly in the south western corner - and we do love our beaches. They are pretty spectacular - miles of pure white sand and crystal clear water with many impressive surf breaks on the edge of the Indian Ocean. Surfing is popular - driving along the coast you'll see large numbers of folk out on their boards every day but so is swimming and for those of us who prefer not to use a surfboard, the waves are ideal for body surfing. There's good fishing, too, for any who like such activities, both from the beach and by boat. Add in long and very hot summers - we've already had several days over 40°C in Perth this summer and inland it's been much hotter - and as you can imagine the beaches and the ocean get a lot of use.

But with all this watery living there is a problem. Oceans have fish and a large fish population brings with it predators. Dolphins preying on fish frequent harbours, bays, estuaries and lower reaches of some rivers, and hunt along the coast and sea lions are found on many of the off shore islands. Further out to sea in some areas there are much larger predators in the form of orca pods. We accept these without question acknowledging that they need to eat and largely interactions with them are positive. Mind you I for one wouldn't want to risk taking a dip if a pod of orcas happened to be nearby. Beautiful they might be but they are fearsome hunters and might mistake me for something more to their taste.

I haven't mentioned sharks yet, have I, but obviously they're here. They don't have the same warm acceptance as the other predators partly because they do on occasion come into contact with us - and when that happens the outcome is rarely good. In Western Australian shark attacks are mainly by great white (Carcharodon carcharias) and tiger (Galeocerdo cuvier) sharks in the ocean and bull sharks (Carcharhinus leucas) in rivers and estuaries. I get that these are fearsome creatures and being attacked by a shark if not fatal almost invariably leads to terrible injuries and I wouldn't wish a shark attack on anyone. 

That said, while horrific and shocking, they are relatively rare - in the last thirty years there have been 21 fatalities - which means while there are always going to be sharks out in the ocean your chances of being attacked by one are pretty slim if you’re a swimmer. Board riders are at more risk and there's some evidence that sharks confuse people wearing black wet suits for seals or sea lions, and take an exploratory bite before realising their error. As the majority of fatalities have been surfers and were not devoured it makes me suspect this may well be the case. 

My problem is that whenever there's a shark attack there is an immediate public outcry and demands for a cull including nonsensical talk of "rogue" sharks as if they are deliberately seeking out people and if we cull them the problem will go away. There are a number of things wrong with this approach in my opinion.

1. For a start how do we know the shark we cull is the one that attacked? Obviously we don't and we risk taking out sharks that never have and never will attack a person.

2. Sharks are long lived creatures and if we remove a number of mature breeding females we could completely disrupt the balance of the natural ecosystem because older sharks are not being replaced.

3. We know that when an apex predator is removed from an ecosystem on land the effects are huge. Why can't we grasp that the same will happen in the ocean?

4. When you remove one large predator the likelihood is that another will quickly move in to take its place.

Obviously there is a problem but as you can guess I don't see culling as the answer. 

So how do we deal with the problem? Well, first off we need to accept that the ocean is the shark's natural habitat and not ours. We are land creatures and while we may like to swim and surf by doing that we are entering an alien environment, one where there are dangers. As well as choosing sensible times to go in the water - like avoiding dusk and dawn and dull cloudy days - we can mitigate the dangers by netting swimming beaches. Unfortunately it's expensive and experience shows such enclosures can cause creatures other than sharks to get trapped in the netting. There's been some experimentation with shark deterrent lines at beaches recently, too, which are still unproven but look hopeful. We can patrol the most popular beaches and warn swimmers and surfers to leave the water when a shark is sighted. This is very effective at swimming beaches and has been in place here for many years. It's now being augmented by helicopter flights along the metropolitan coast line. Finally we can ensure that whale carcasses and anything similar attractive to sharks are removed from the vicinity of beaches as a matter of urgency, closing beaches where necessary. 

All of this will help but the truth is if we choose to swim or surf - particularly at times or places where sharks are likely to be - we have to accept there is always a risk. I write this as someone who grew up swimming and body surfing daily in the summer and who was taught from an early age to be aware of my surroundings and to be mindful of the potential dangers. By taking reasonable precautions we can be fairly safe but there can never be a guarantee, something we had drummed into us early on. I can't begin to imagine the horror victims go through and their families' suffering. It's something I hope would never happen to anyone ever but if we choose to enter the water we put ourselves into a place where a different set of rules apply and we have to accept that.