Rogue Shark

Tragically, there have been two fatal shark attacks off WA in the past couple of weeks. The families of the two victims have my deepest sympathy and my heart goes out to them.

Predictably the media and politicians are jumping on the populist bandwagon with the usual cries of "Rogue Shark" and promises to hunt the maneater down and kill it or install shark nets on beaches that are completely unsuited to them. They appear to be oblivious to the fact that it's incredibly unlikely that it was the same shark and even if it was, these animals are an endangered species and protected in Australian waters. You can't have it both ways. Healthy oceans need top end predators. You can't protect them and hunt them down.

So why don't two attacks in 12 days automatically mean a rogue shark on the loose. Fairly simple really. Firstly, humans offer a very poor return on investment in terms of energy. Great whites that have eaten humans usually regurgitate us shortly afterwards. They really don't want to tie up their digestive system for several days with a meal that has such a low calorific value compared to a seal or dolphin. These animals are also smarter than your average fish. Having made the mistake once, they probably have the smarts not to make it again unless truly desperate.  You might say that energetically speaking, they can't afford to eat us.

This is also why young great whites generally swap from hunting fish to marine mammals at around the three to three and a half metre mark. The energy expended chasing fish isn't recovered in the size of the meal. Once they get big enough they would starve to death eating fish and are forced to go for larger fattier prey.

So lets have a look at the two recent attacks and see if we can learn anything. The more recent attack occured 500 metres off the coast of Rottnest Island, where a diver was attacked by a three and a half metre great white shark.  While media articles have talked about great whites following the whale migration there is a far more likely seasonal food source in this instance.

Fur seals are a favourite food for great white sharks and they can show up off seal colonies at any time of year, however they will travel long distances to get to colonies when the pups are weaning. The young pups are inexperienced and easier prey. Fur seals breed on Rottnest Island pupping in December and the pups wean nine to ten months later, just about now in other words. This is likely to mean more sharks in the area.

The water was reportedly murky. For a visual predator like the great white shark this makes prey harder to catch and they're more likely to go in hard and hit something that they weren't actually targetting, such as a diver. This is probably particularly true for a three and a half metre shark that is still learning to hunt larger prey and may not be as good at identifying prey as an older individual. it may also be hungrier and consequently more aggressive, especially if it has travelled a long distance to get to the colony.

The earlier attack was on a swimmer four hundred metres off Cottesloe Beach. He was out for his regular morning swim. It was early and the water was murky. Great white sharks are known to hunt most actively at dawn and dusk. It is thought that this behaviour takes advantage of the low angle of light falling on the water which causes glare and makes it much harder for animals at the surface to see a shark below the water.

In both of these cases the victims were exceedingly unlucky. However both were in the water at times or places that are known to be associated with a significantly increased risk of shark attack.

So why do these animals improve the health of our oceans. Why shouldn't we eradicate them completely ?

Well lets look at a terrestrial example, the big bad wolf. The wolf was pretty much eradicated in the continental United States although there were still some populations in Canada and Alaska. They were reintroduced to much outcry from ranchers and hunters in a few selected locations such as Yellowstone National Park. In Yellowstone the wolves primarily feed on elk, but will also take deer and occasionally they will take livestock. Elk have for many years been over grazing the park and deer and bison numbers have dropped. They have destroyed vegetation along rivers resulting in erosion and shallower, warmer water with less dissolved oxygen which supports fewer fish. With no riverine vegetation there were no sticks and beaver numbers had dropped dramatically.

When the wolves were reintroduced they went to work doing what they do best, eating elk. Bison and deer numbers recovered, along with other small grazing animals. The riverine vegetation recovered, shading the rivers and providing habitat for fish, aquatic invertebrates, insects, birds, reptiles, amphibians and all the species feeding on these things. Beavers came back and their dams provide deeper, cooler pools with more fish in them and which provide shelter for a range of other smaller creatures which coexist with the beavers. The richness and diversity of the ecosystem changed dramatically with the return of a top end predator.

So what about the livestock ? Well the government does have to compensate the odd farmer for a lost animal. However researchers have observed wolves stalking right through livestock to get to the elk on the other side. Like sharks, these animals know what they like and only deviate from their usual prey in very lean times. So the simple fact is that we need top end predators, without them we don't get a full range of biodiversity and without biodiversity we don't tend to get the stable and sustainable ecosystems that provide us with our habitat.

It seems that both Jaws and the Big Bad Wolf have had more bad press than they deserve. Are these animals potentially dangerous ? Yes they are, but we can coexist with them and if we learn more about them we can reduce our risk of being dinner.

Saturday Paddle with the Klan

Saturday morning, and the sun is shining, an unseasonably warm current has brough water down that is nearly 20 degrees centigrade and we're trying to get to the beach to put our boats in. Unfortunately our planning omitted the "Fat as Butter" rock gig and the road to our launch spot at Horseshoe Beach on the Newcastle Foreshore is closed. Luckily the three of us managed to hook up anyway and moved down the harbour to Carrington where we found a nice convenient put in point.

We paddled out of the harbour and down the coast as far as bar beach, with nice moderate conditions. There were dolphins and some bumpy water around he headlands. Newcastles beaches are fairly shallow so you tend to get a bit more dynamic water conditions as the swell kicks up and the rebound off the rocky coast generates some nice frolicsome water.

We had a new paddler along and he did very well, looking very comfortable in his boat and keeping pace nicely. I'd have to say my pace is pretty slow at present anyway as I've been having some back problems and have become enormously unfit. We turned around just north of bar beach and headed back to have lunch at kite point. This is a beautiful little beach, just inside the harbour but on the Stockton side. There we played happily after lunch wallowing, rolling and doing some edging and bracing practice with Shawn mentoringTony and me trying hard to remember how to do it myself after a winter virtually devoid of paddling.

I tried out Tony's boat too. A Riot Evasion. It was a nice little boat. The hull design is channeled and it kept a respectable pace for a shorter and quite manoeuvrable style of kayak. It was much easier to roll than my old Gecko as the deck is more contoured behind the cockpit and it's easier to get moving. It had a rather high and obtrusive seat back so a forward finishing roll was required but as that's my usual choice anyway it didn't affect me. The foot pegs are the sliding track kind to work the rudder so you lack a solid foot brace for optimal forward stroke although if the rudder is up you do get some support even if it feels spongy. The boat actually tracked pretty well without the rudder too. A top end touring boat it isn't but a decent little entry level kayak it certainly is. I'd probably rip out the seat back and put a backband in and replace the foot pegs.

On the way back we paddled past the "Fat as Butter" gig in full swing with four bands playing on separate stages. The kayaks were humming like sound boxes from the base being transmitted through the water. Even from a distance of 300m it was unpleasant and I felt priveledged to have spend a morning on the water instead of on the Newcastle foreshore. Not surprisingly, there were no dolphins to be seen.

Cold Water Conditioning.

There are two immutable facts about kayaking in cold water.

1. Cold water kills more kayakers globally than any other factor.
2. Always dressing for immersion is the only safe option.

There, that gets the formalities out of the way. There have been a few incidents and accidents recently that have had me thinking about cold water. I don't want to talk physiology, no cold shock or hypothermia treatises here. There's good information out there on this topic from folks far more knowledgable than me. You could start off with these if you wish.

http://www.seakayakermag.com/2008/Feb08/cold-shock.htm

http://www.coldwaterbootcamp.com/pages/home.html a site where you can see the immediate impacts of cold water.

http://beyondcoldwaterbootcamp.com/  a site for trainers and educators with resources for getting the message across to students.

Jim Kakuk and Eric Soares, the founder members of the Tsunami Rangers, have been saying for years that if you want to be a sea paddler, you should first of all be a sea swimmer. If you don't believe you could swim there, you probably shouldn't paddle there. I think this is pretty good advice and it highlights the need to be dressed for the conditions in the water. If you would need thermal protection to swim there then put it on to paddle there too.

Even when you're wearing you're cold water gear, the shock when you hit the water can be disorientating, even painful. It triggers shortness of breath, gasping, hyperventillation and can trigger panic attacks and vertigo.
And yet we see people in their togs (no synthetic rubber blubber suit) swimming in very cold water for fun. The Bondi Icebergs, the San Francisco Dolphins and plenty of others, get in and swim regularly without thermal protection. So are they immune from the cold ? Superhuman athletes with antifreeze for blood ?

So what do these guys do and could it be useful for us ?

The primary thing that they do is to acclimatize. They don't usually start off in mid-winter, they start in summer and then just keep going. They don't always swim very far either, (they wear a wetsuit if they do) and they're not immune to hypothermia far from it, but they do have a very good handle on what they can cope with and when to get out of the water. They're also very good at preparing their body for the shock of immersion. They will always splash some cold water on their face and neck three to five minutes before they go in. This works because our bodies are actually very bad at judging temperature. They're very good however at judging difference in temperature. Your body can't regulate blood flow to your face and neck like it can to your arms and legs so they don't go numb and the volume of blood flow is quite large. By cooling them and reducing the temperature difference you greatly reduce the level of shock. It's easier to control your breathing and there's less chance of your gasping down a lungful of the beautiful, briny stuff we like to paddle on.

A second and rather counter-intuitive thing that the swimmers do is to exhale as they go in. A long slow exhalation as they (and I'm quoting a swimmer here) "embrace the cold", accepting it, acknowledging it and not being paniced by it. Having done some fairly chilly swims myself I can vouch for this approach. It's hard to gasp in when you're deliberately blowing out. (You may also trigger the mammalian diving reflex, but that's another story).

So is acclimatisation going to keep you alive for hours in cold water?  Absolutely not, there is still no substitute for dressing up in rubber.

Acclimatization is really just giving your brain and body a chance to get used to cold water immersion. This seems to be helpful in assisting your body to adapt faster and your brain to keep charge. It may not eliminate the gasp reflex but it reduces it's intensity and makes you better prepared for it and more used to managing your breathing. That may give you a better chance at a reflexive roll, a quicker self rescue and if you do end up in the water maybe a couple of extra minutes of functional time to call for assistance before you lose the capacity to help yourself at all. If nothing else, do what the open water swimmers do, splash a bit of cold water on your face every few minutes as you paddle along, just in case. Neoprene hoods help too, but you can still benefit from splashing your face.

So do what I do, spend a few minutes thinking about dressing up in rubber clothes and then go and have a cold shower. What could be easier ?



PS: Just kidding about the rubber clothes, honest.

HKK Intro to spoon rocks.

It's been a long winter with not much paddling. Some back and shoulder problems have been keeping me far too dry. So after a long paddling draught I got out with the Hunter Kayak Klan for a nice paddle from Swansea Channel down to the sea caves of Wallarah National Park.

The sun shone, the seas were calm with a gentle offshore breeze. The water was turquoise, clear and clean with a view to the weed waving gently on the bottom. We got into the smaller of the caves which is always nice. There were whales, dolphins and sea eagles. There were sandy beaches, some rocks to play round good food, good company and good weather.

About twenty kilometres and a brisk finish against the last of the ebb tide through the channel with a light westerly headwind to finish off.

The team on the day were Owen, Anne, Selim, Dirk, Pieter, Marty, Col, Shawn, Linda, Carolyn and myself. While out we ran across Cambell who was attending the NSWSKC paddle from Swansea to Catherine Hill Bay with Matt Bezzina and David Fisher as well as Phil who was doing a lightning raid of the sea caves with his son. So with thirteen klanners out on three different trips on one 15 km section of coast line I think we can say that sea kayaking in the Hunter Valley has well and truly taken off.