Sharks and Rays   Leave a comment

What do you know about the fascinating world of sharks and rays? And, why the hell is that important anyway? Well, simply put, if we didnt have sharks in our oceans you wouldn’t be able to read this blog. The catastrophic effect that this would have on the food chain would be enough to eventually create an imbalance at a planktonic level.

What most people don’t realise is that most of our oxygen comes from the sea not from the rain forest. Burn the Amazon and there would be a tragic loss of species and beauty. Kill the sharks and there would eventually be very few species left all together.

This is how it works… First we fish out the sharks. The next level of life in the ocean (e.g. the tuna) become the new apex predators. Unfortunately, these dont have such a slow, self regulating reproductive cycle as sharks so they multiply rapidly (now that there are no sharks around to keep their numbers in check). The inevitable over abundance of tuna then decimates the species on which they normally feed (e.g. mackerel). The mackerel stocks quickly fall below the level where they can sustain the population of tuna and the tuna start to starve. The lack of mackerel also means that the different varieties of baitfish that are their normal prey go through a massive population explosion. The baitfish then consume the plankton and the planet loses its largest producer of oxygen. Its a primitive model but the logic is sound.

To give a better idea of the measurable effects that a drop in the levels of phytoplankton can create we can look at the studies conducted in the early 90’s on the oxygen levels off the coast of California. Using previously recorded oxygen statistics researchers set out to find out what effect pesticide run off was having on plankton levels. Their findings were astounding; in the space of a decade the O2 levels that were generated by near shore plankton had dropped by 70%.

The message is simple: No sharks = no plankton = no oxygen = no people. So you want to go shark fishing?

So, shouldnt we take an interest in Sharks and Rays in order to help protect them (and ourselves). Maybe or maybe we should leave it to our governments or people like myself who are active and vocal about the plight of sharks. Thats fine, I’m not expecting any converts just yet but if you’re even vaguely interested in shark behavior, pictures of sharks, what its like to swim with sharks in the ocean, how you can help to protect them, their evolution, and much more, then follow this blog now and then. Or better still, visit Elasmodiver where you can find more shark and ray information than you can poke a speargun at. Its a massive site that has thousands of shark pictures and links to hundreds of pages that are not all dry boring facts like the ones I just subjected you to.

For the sharks,

Andy Murch
Andy is the Staff Photographer at Shark Diver Magazine and the host of Elasmodiver.com which is one of the largest sources of information about sharks and rays on the internet.

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Posted May 19, 2006 by Andy Murch in Environment, Nature, Photography, Sharks

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