Two sharks sizing each other up.

We’re all familiar with shark feeding frenzies. Get a bunch of sharks together in the same area, throw some food in the water, and watch chaos ensue with just a hint of madness thrown in for flavour. In fact when people hear the word shark it is quite often one of the first things that pop into their heads, apart from JAWS of course. But have you ever wondered why we never see any pictures or videos of white shark feeding frenzies? Is it because it was so intense that the camera men just never made it out? Actually the answer may surprise you. There is no footage of a white shark feeding frenzy because they never happen. In fact when there is a group of white sharks in an area with a ready source of food, white sharks are rather diplomatic with how they procede to eat the food. They may even be more diplomatic than some politicians.  Read more »

You can see a cluster of parasitic copepods on the shark’s nose and out the back of its last gill slit.

To many, white sharks are the big bad king of the oceans. Nobody messes with them, not unless they want a big chunk taken out of them. This, however, is a fallacy  and for more reasons than one. Today I will be talking about a unique set of organisms that completely uses white sharks for their own gain without giving anything back to the shark. In scientific terms this is known as a parasitic relationship. There are a lot of organisms that utilize a parasitic relationship to survive. We have all been warned to thoroughly cook pork, for example, least we get tapeworms. Well, tapeworms, and in fact many worms that we worry about getting into our bodies (round worms and flukes), are a category of parasitic worms that can invade our bodies and usually live in our intestines absorbing nutrients from the food we eat while giving nothing back to us.

White sharks suffer the same problems, only with different species than what affects us. One of the more common parasites on white sharks is Pandarus satyrus. These are a type of copepod that will latch onto the surface of white sharks and hitch a ride on the shark. They are usually found on the trailing edges of fins, in the gills, reproductive organs for females and the snout. They are large enough to be seen by the naked eye and can even be used by researchers to identify different individuals based on the amount and location of the parasites.

We can identify individuals based on the size and location of parasite clusters.

White sharks, like many other animals on this planet, are also susceptible to worms. There is a species of worm, Clistobothrium carcharodoni, that uses dolphins to get into its white shark host. They will actually localize themselves on the tail, back, belly and groin regions of dolphins. This isn’t by chance either. These happen to be the sites that white sharks target when attacking dolphins and seem to be some of the first areas of the dolphin the shark consumes. Thus, their location on the dolphin actually increases the chances they get consumed by the shark and can then take up residency inside the shark. You can read more about it here.

On a similar topic, though it doesn’t affect sharks, there is an isopod that can successfully replace a fish’s tongue. This parasite enters the fish through its gill slits and attaches itself to the base of the fish’s tongue. It’ll then draw blood from the fish’s tongue, slowly causing it to atrophy until the tongue eventually withers away. The parasite will then attach itself to the muscles of the base of the tongue and the fish can essentially use the parasite like a new tongue. This is the only known case in the world where a parasite can functionally replace an organ in its host.

Timing is everything in this game.

With my current project of taking pictures of dorsal fins to later catalogue I am afforded many opportunities to practice my photography skills. And after three months of practice almost every day out on the water, I’m finally starting to get some good pictures out there. Now that we’re heading into winter, it’s going to be prime photographing conditions for white sharks. Given this in mind I do see a lot of people out on the water who don’t know how their camera works. Some of them even look like they’ve just bought the camera right before they left on vacation and only took it out of the box to charge the battery. So I’m writing up this tutorial for both beginner and advanced photographers alike.  Read more »

It’s a whale! No it’s a fish! No! It’s a… whale shark? Yes, that’s right. The largest fish in the ocean is in fact a shark! This behemoth commonly reaches sizes of up to 12 meters and weigh up to 21.5 tonnes! Thats twice as long as the largest white shark and more than ten times its weight. But surely the whale shark must have a monstrous appetite. I mean if it’s that much bigger than the white shark, and those eat sea lions (cape fur seals are actually sea lions, contrary to their namesake), then whale sharks must eat things the size of … well, whales, right? Actually the largest fish in the ocean survives solely on some of the smallest things in the ocean.  They mostly eat krill and plankton. How can they do this, you ask. Well the whale shark ingests large volumes of water either by swimming with it’s mouth open or by actually sucking in the water. The water then goes to the gills, but not before passing over filtering pads. These pads filter out all plankton and the shark gets an easy meal. Looking at the mouth of a whale shark, you may think that it has no teeth; that evolution has caused them to lose them all. Well, evolution did play a role in this, but it didn’t cause them to lose their teeth, they’re just really small. They’re so small that they don’t even have a use anymore. So believe it or not there are sharks out there that don’t use their teeth (The basking shark is another example of a shark that doesn’t use its teeth).

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Most people know who Ocaerch is. They are the self proclaimed Shark Wranglers (the name should give hints as to their true motives) on the NatGeo channel. But how many of us know what’s really going on behind the cameras? Sadly the general public still remains ill informed about what these people do.

If you ask any white shark researcher you will probably get an earful about how these men are not real researchers (they are just glorified fishermen going after “the big one”) and how their ‘state of the art’ tags are really doing more harm than good and how the two previous head researchers have actually distanced themselves from Ocearch. They’ve already admitted they killed 3 sharks, how many more deaths have they swept under the rug? Read more »