A cull to save the kelp

Ah, kelp. It’s an amazing seaweed, which is supposed to grow in profusion all over the place. (Well, I don’t know about your part of the world, but certainly in mine.) In recent years people who care about the ocean environment have been alarmed at the decrease in kelp. What is up with that? Apparently there are a number of causes, and many community groups are working to change the situation and encourage kelp growth.

If you’re not familiar with kelp (or even if you are!) you might want to see Lost Coast’s page on kelp. That has a good photo, and a lot of fascinating facts about the plant.

Now on to this article from Hakai Magazine: A cull to save the kelp.

Terry Herzik has been diving for red sea urchins in Southern California for more than 40 years. He supports his family by selling the spiny invertebrates’ gonads as the sushi delicacy uni. Yet over the past century, Southern California’s giant kelp ecosystems—the red urchin’s home turf—have been under assault. Spurred on by human-induced environmental degradation, a booming population of voracious, kelp-munching purple urchins has helped turn these once-lush forests into barren wastelands. In such a diminished habitat, the red urchins’ numbers (and their gonads) have shrunk.

So, three years ago, Herzik joined an ambitious project spearheaded by the nonprofit The Bay Foundation to restore Southern California’s kelp forests, and he’s been killing purple urchins in droves ever since.

“We go down with geology hammers and smash them,” Herzik says. Their approach isn’t particularly high tech, but it works.

To date, Herzik and the other project participants (including biologists, fishers, and community volunteers) have killed 3.3 million purple urchins, clearing 142,000 square meters of seafloor of the animals. As a result, the kelp has bounced back. [continue]

I hadn’t heard of this approach. On the west coast of Canada, we have a number of groups working to restore kelp beds. The strategies I’ve heard them talk about are things like re-seeding kelp beds, encouraging boaters to not use motors in kelpy areas (because propellors slice through kelp), and so forth. But sea urchin smashing? Who knew that would work?