Since sharks are predators at the top of the ecosystem, they are key in maintaining a balance in living species in the region. If their numbers dwindle, the species they normally eat will increase and the imbalance can trickle right down to plant life.

An extreme example of this is the creation of Lake Guri in Venezuela - one of South America's largest human-made lakes that formed due to the construction of a hydroelectric dam. The lake caused many top predators - like jaguars, eagles and armadillo - to flee the area (some drowning as a result) since the remaining islands didn't provide them with enough space to live. The effect on the vegetation was especially devastating since the number of herbivores increased dramatically and they proceeded to devour all the plant life!

We probably don't want to get to that stage near the Galapagos Islands, especially since it's an area with so many unique species. Luckily, I can't afford a bowl of shark fin soup so perhaps I am doing my bit to help the environment?

For more info:

UNESCO - World Heritage Centre - Galapagos Islands - Ecuador
http://whc.unesco.org/en/285/

Urban Animal - Shark Fin Soup: An Eco-Catastrophe?
http://www.sfgate.com/cgi-bin/article.cgi?file=/g/archive/2003/01/20/urbananimal.DTL

Video: Sharks [Firstscience presents]
What shark species is the most deadly? And where in the world is it least safe to venture into the water? We travel across the world from Australia to California to find out.