Sharks have survived relatively unthreatened for over 400 million years, but sadly without some intervention they may be gone within the next few decades. Marine life within the oceans which cover over 70% of our planet, has always existed with – and in some respect thanks to – sharks. But now the growing demand for delicacies such as shark fin soup, and the fact that many sharks are becoming by-catch from large commercial trawlers, has increased the slay of sharks to such a great extent that many species are already nearing extinction.
Sharks play a vital role in the ocean environment, yet receive an unprecidented and largely unwarranted amount of bad press. So we thought it was time to let the world know why they are so awesome! These guys are at the top of the food chain and keep the rest of the ecosystem in order in almost EVERY ocean around the world! Sharks tend to eat carefully, usually only eating the old or the sick in any given population of fish, which keeps that population both healthier and in balance.
Sharks also regulate grazing patterns of other species of prey through intimidation. A great example of this is in Hawaii, where scientists were researching a transient school of Tiger Sharks in an area where native turtles graze on sea grass. They found that in the absence of Tiger Sharks, the turtles spent all of their time grazing on the best quality, most nutritious sea grass, and as a result these habitats were destroyed. When tiger sharks were around, however, turtles grazed over a larger area and did not overgraze one region, thus keeping the eco system healthy.
Sharks come in all shapes and sizes, from the Bamboo Shark which grows to a maximum of 57cm, to the Whaleshark which can grow up to 12m and is the largest fish in the sea! In their millions of years dominating our planet’s waters, they have evolved spectacularly to survive. The Epaulette Shark can even walk on land! Contrary to popular opinion (and no thanks to Steven Spielberg!) sharks do not spend a great deal of time hunting. In fact most most sharks eat only 2% of their body weight – pretty much the same as an average human. And when food supplies are short, they can go without food for weeks if needs be – unlike the average human! It’s a little known fact that over 85% of the world’s oxygen – which us humans are obviously heavily reliant on – comes from the ocean. Even photosynthesis which takes place on land, requires oxygen which originates from our seas. So sharks are paramount to OUR survival on Earth, for if we do not take care of the species at the top of the marine ecosystem, there will be no ecosytem to care for at all, and much less oxygen for us to breath!
There is plenty that divers and snorkelers can do; we at Master Divers work with Shark Guardian, a UK charity that was set up to build shark and marine conservation project worldwide. We also contribute to Thailand eShark Project, which is an online database where anyone can input their sightings of sharks and rays to help with research. We also are involved on local efforts to raise money for shark awareness, such as the annual ‘Swim for Sharks’ campaign, and of course our Finathons.
For those who are interested in learning more about Sharks, why not become a PADI Shark Conservation Diver?