The real threat with sharks is extinction


With Shark Week under way, it is time for the millions of fans and their friends to get serious about shark conservation. While the documentaries might lead you to believe that every time you dip your toe in the water there is a shark lurking, the story is more complex — and dire.

The oceans are in trouble. A quarter of shark and ray species are threatened with extinction, and populations of many of the largest species have declined to the point where they probably do not serve their ecological function any longer. Add this to coral bleaching, ocean acidification, coastal development, pollution and overfishing in general, and there is serious reason to be concerned.

But, all is not lost, and there are reasons for optimism. We are seeing signs of recovering white shark populations on both coasts of the United States, and populations of many species appear to at least have stabilized in countries where there is strong fishery regulation and enforcement.

As part of the Global FinPrint team, we have begun surveying coral reefs around the world and are actually seeing some glimpses of species once thought to be virtually eliminated in some areas. Are there enough? Not by a long shot. But, it suggests that if we get conservation and management, international development and policies right we can rebuild populations to meaningful levels.

Why should we care about having lots of sharks in the oceans?

First, at least some species appear to be very important for maintaining healthy ecosystems, which benefits people too. For example, our studies in the vast seagrass meadows of Western Australia show that healthy fisheries and stores of carbon that help hedge against climate change rely on sharks. Tiger sharks keep sea cows and green turtles from over-grazing seagrass beds.

This allows huge pastures to develop with tons of habitat for fish, crabs, and shrimp that grow up to be caught by fishers and support a thriving ecosystem. On coral reefs, sharks may play important roles in both the middle and top of the food web. Their presence in adequate numbers could be critical to maintaining the billions of dollars a year that coral reefs provide in economic value to humans.

Beyond the tangible benefits of healthy shark and ray populations, the popularity of Shark Week hints that there are deeper reasons to care. We are captivated by these amazing animals and will take the time to watch them on TV and pay to see them up close. Scientists are learning that they have personalities — from tiny Port Jackson sharks to large lemon and bull sharks.

Manta rays may even recognize themselves in mirrors! There is so much more to learn about these incredible fish that will fuel Shark Week for decades to come and ensure we spark the imagination of the next generation of ocean enthusiasts and scientists while ensuring that the oceans remain healthy. But, we have to make sure that we keep these animals in our oceans. In some cases, protecting what is left may be enough. But our focus also needs to be on rebuilding populations.

There are a few simple things that people can do to help sharks.

▪ Use seafood guides to make sure that your choices are from sustainable fisheries.

▪ Don’t buy products that use sharks unnecessarily, including cosmetics and supplements.

▪ Support legislation to create marine protected areas, develop sustainable fisheries, and stop trade in endangered species.

▪ Finally, pass the word. Yes, sharks are big predators that can be dangerous, but losing sharks from our oceans is an even bigger threat.

Mike Heithaus serves as the dean of the College of Arts, Sciences & Education at FIU. Previously, he was a staff scientist at the Mote Marine Laboratory’s Center for Shark Research.