LeRoy French - Underwater Stills and Videos and video sales

Underwater Photographer

Back to List of Articles

"The Great White Shark and the Marine Eco-System"

environmental issues You ask yourself what good can having the White Shark around be for the ecosystem? Well believe it or not as are most things in our complex marine ecosystem this animal plays a very important role. Before I tell you why he is important, let me first describe this animal to you so you can better understand him.

In latin terminology he is known as Carchardon carcharias. This shark became instantly well known after the film 'Jaws' came out. He was depicted in the film as a ferocious animal preying on human beings.

Well it's hard to say that he is not a ferocious animal considering he has the most devastating mouth of any sea creature, however he does not prey on humans. Attacks on humans are quite rare and in most cases accidents, where the shark thought he was attacking something else. In any case this animal is at the top of the marine ecosystems food chain. Known as an 'Apex Predator' this animal puts a 'cap' on the entire ecosystem. It's almost as though everything that goes on in the ocean takes place to feed the the white shark.

environmental issues As I mentioned previously he has an extraordinary mouth, consisting of as many as 3000 teeth ranging in length to 3". These are serrated teeth, as sharp as razor blades, and when one is broken off another is waiting to replace it. He can weigh as much as 5000 Ibs. and specimens have been recorded as large as 7000 Ibs. He grows to an average length of 10/15 feet and has been recorded as much as 19/21 feet. Wow, this is a big animal.

His main diet is seals, sea lions and elephant seals. He will also eat just about anything else, turtles, dolphins, small toothed whales etc. The lifespan of the white shark is between 40/60 years and may live up to 100 years. He virtually has no known predators, however there are accounts of Orcas or killer whales attacking the white shark, but this is quite rare.

Believe it or not the Dolphin can put up a good fight against the white shark. The Dolphin with its incredible speed will keep running into the shark with its beak until it actually makes a hole in the side of the shark, thus either killing the shark or sending it away.

He is solitary in nature and roams all the oceans alone. The west coast of Mexico and up along the north coast of California are very common areas for this animal. South Africa is also a common area along with Australia.

environmental issues Now that we have a better understanding of what this animal is, lets discuss why he is important to the ecosystem.

As mentioned, this shark is the 'Apex Predator', removal of top-level predators can cause a 'top down' effect on organisms lower in the food webs. This has been demonstrated in some parts of the ocean where a predators population was reduced to the point that the population of the main prey began to explode. When this happens, there are so many of the main prey that they eat themselves out of food, changing the ecology of the entire area.

It is thought that if the white shark became extinct, the seal, sea lion and othe main prey population would explode.

One of the important things to know is that the reproduction cycle of the white shark is very low. The female shark may have only 7/9 pups, reproducing twice in her entire lifetime. Their growth rate is about 25cm per year.

So, what does all of this tell us. It tells us that for millions of years this animal has been in existance. He is a definite asset to the ecosystem and cannot be removed. It does not mean that everytime you go in the ocean a white shark is going to come along. Finding a 'white shark' in the Caribbean for example is extremely rare.

environmental issues In this section of the newspaper we try to enlighten the public about different parts of our environment. As all of us who live on this planet must co-habitate it is important that we understand the animals that also live here with us.

The 'Great White Shark' is now protected in many parts of the world and though his name conjures up fear in many, he is an important part of our ongoing life cycle.

Check out the video by LeRoy entitled 'The Apex Predator', this is a white shark expedition off Guadalupe Island in Mexico.