Love them or hate them, we need sharks on this planet

Okay, not everyone loves sharks like I do, that's something I am willing to accept.

What I'm not willing to accept, however, is the relentless slaughtering of them, either for their fins, through culling or fishing.

Mako Shark caught in New Jersey

Overfishing is the main cause of the rapid decline in shark populations. It is mostly due to overfishing that many shark species are threatened with extinction. Demand for high value fins, the primary ingredient for Asian shark fin soup, is a main driver of shark fisheries, but demand for shark meat, particularly in Europe, is also strong and has led to serious depletion of several shark populations.

Sharks are crucial to marine ecosystems. They maintain a balance in populations of prey species and keep the ocean healthy by removing ill or diseased animals. They are an important resource supporting local economies through fishing and as an attraction to dive tourists.

Sharks are often the apex predator in their ecosystem, meaning they are at the top of many food chains. As adults they have no or few natural predators. Typical traits of apex predators is that they feed on many different species and change food sources when one prey animal becomes hard to find. In this way sharks help maintain a balance that ensures no one species over-populates and depletes the species on which it feeds. To see how removing apex predators affects marine ecosystems we need to study marine areas that have had little exposure to human impacts, especially fishing. Studies of remote reefs have revealed ecosystems that are very different from those we know today.

A study of reefs in the Northwestern Hawaii Islands found that apex predators, including sharks, comprise over half of the fish biomass compared to less than 10% on reefs that are fished. On the unaltered reefs the sharks are bigger and populations of all species are far greater. Additionally the unaltered reefs are home to a larger variety of other species than regularly fished reefs.

The first sharks appeared over 400 million years ago, more than 150 million years before the first dinosaurs took to the land. Most modern sharks first appeared around 100 million years ago. By comparison the first humans evolved only around 200,000 years ago.

Sharks occupy every marine environment. Some also venture into freshwater such as the bull and the river shark. Roughly 500 species from the dwarf lantern shark at around 7 cm to the whale shark - the world’s largest fish - up to 12 metres. Sharks eat a great variety of prey. Most sharks are predators, but some are scavengers, while whale and basking sharks are filter feeders with eating habits similar to a baleen whale.

Whatever your individual opinion on sharks is, we need them on this planet. They're a vital and irreplaceable part of the eco system.