Monday, June 18, 2012

We Are the Apex Predators

Guest Blog
by AJ Sablan

For more than one hundred years, we’ve been aware of the importance of apex predators – animals without natural predators – to the order of the world around us. When it comes to the food chain, they are tops. On land, apex predators include species such as lions, tigers, and bears (oh my!). In the ocean, the ultimate predators are sharks.

Aldo Leopold, one of the founders of the environmental movement in the United States, linked the existence of predators and prey by depicting the relationship between wolves, erosion, and deforestation. In an essay called “Thinking Like a Mountain,” Leopold recalls how in his youth, the conventional thinking was that fewer wolves meant more deer. However, without wolves, there was nothing left to keep the deer populations in check. The populations of deer exploded and overgrazed bark and leaves growing on trees, killing the trees. When the trees died, there was nothing to hold the soil in place, and so the mountain eroded into the rivers.

As with the wolves, we are witnessing a similar effect in the oceans, as shark populations decline. Sharks may reign in the ocean, but they are not the top predators on the planet; humans are. Each year up to 73 million sharks are caught and killed for their fins, which are used as the namesake ingredient in shark fin soup. Humans also use their livers for oil, their skins for leather, and their teeth for jewelry and souvenirs. Sharks are also caught as bycatch (non-targeted catch), and frequently die when caught in nets or on lines, or after they are thrown back into the water. Through these largely unrestricted fisheries, many shark species have become threatened with extinction. The International Union for the Conservation of Nature has determined that a third of all shark species are threatened or near threatened with extinction. And while fish populations can rebound with proper management, extinction is forever.



A case-in-point example: the Pew Environment Group and Jim Toomey, creator of Sherman’s Lagoon, illustrate the apex predator-prey relationship in a new Youtube video posted last week for World Ocean’s Day. Simply put, in the ocean, there are small fish, big fish, and apex predators. Apex predators, such as sharks, eat the big fish, which in turn eat the small fish. Small fish feed upon algae. When apex predators are taken out of that equation, the big fish overwhelm the small fish. With the small fish gone, there is nothing to keep the algae in check. Algae then overtake corals, killing coral reefs. So, you see, sharks are key to keeping our oceans alive and well.

Sitting at the very top of the food chain, you and I have a role to play in ensuring that balance is maintained in our marine ecosystems. Right now, we are less than a year out from the 16th meeting of CITES, the Convention on International Trade in Endangered Species of Flora and Fauna, during which delegates from 175 nations will vote to create (or to not create) conservation measures for a number of shark species. Obviously, this offers an important opportunity to institute broad, sweeping policies to protect sharks and ecosystems, and to ensure that solid management plans are in place for every member party.

On a more localized level, we have seen nations, states, territories, and even a region jump on board with creating shark sanctuaries. We’ve discussed on the Shark Defenders blog before how sanctuaries are the gold standard of shark conservation measures, and this is an important point. Prohibiting commercial shark fishing and catch in protected areas – and, in the instance of recent sanctuaries, the possession, sale, and trade of shark products – is like the abstinence message of the sea: it’s the only 100% fail-safe method of preventing unwanted species decline and ecosystem destruction.

Creating sanctuaries, ending commercial overfishing, establishing science-based fisheries management plans: These are the ways in which humans can work to protect sharks. It is our onus to do what we can, as the “ultimate” apex predators, to keep our oceans healthy. This is the first and potentially the biggest step that we can all pitch in and take.

Alyssa Sablan is Shark Defender's student intern.

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