Urchin Slayers Are Trying to Save the Underwater Rainforest

This story was originally published on Grist, and is part the Climate Desk collaboration.
Grant Downie was out in the Pacific Ocean for approximately 10 minutes when he noticed that he couldn't see his right eye anymore.

Second-generation commercial divers had ventured deeper than usual to search for red urchins. These urchins are prized by restaurants for their uni (or sushi-grade gonads). In recent years, it was becoming harder to find red urchins in the underwater kelp forests. Each foot of additional depth brought more nitrogen into his bloodstream, increasing his chance of dangerous bubbles forming in his brain or body.

He feared that he had pushed his body too far, as half of his vision was obscured by black. Although his right eye function returned to normal 20 minutes later, the 33 year-old decided that he would no longer take such dangerous dives even though it could endanger his income.

Downie stated that he knew it was over for him, seven months after the incident off the coast from Fort Bragg, Northern California. I'll probably drop to 65 feet but I don't know if that will be enough. For those guys who are still trying, it is getting more difficult.

Anybody who lives on California's kelp forests can tell you there is something very wrong beneath the Pacific. The decline in red urchins is not limited to the population. Many of the kelp has disappeared, the dense, autumn-toned seaweed canopies that once protected hundreds of marine species, including abalone, sea otters, and rockfish, as well as food, shelter, and have been a safe haven for hundreds of species. The purple urchin has decimated entire underwater forests where once lush strands and bull kelp swayed like whips.

Because of their extraordinary hunger and remarkable survival skills, purple urchins are sometimes called the "zombies of the sea". They can live in starvation for many years. Purple urchins look like small, pinched pom-poms. They eat everything, from plankton and dead fish. They are especially fond of kelp and can chew through the anchors that attach each strand to its seafloor.

Divers call them urchin barrens. Scientists reported earlier this year that some Northern California Kelp forests had lost 95 percent of their original size since 2012.

The West Coast's marine biodiversity is largely dependent on kelp. Kelp, which is technically a type of brown algae, acts as a carbon sink, converting sunlight into carbon dioxide and creating canopies and leaves. Dead kelp, unlike trees which release much of their carbon back into the atmosphere, can sink to the bottom of a sea to provide a natural form sequestration. This cycle has been greatly disrupted by the destruction of kelp forests and the starving urchins that waited on the seafloor.

Were we losing very important systems? This would mean losing fisheries and recreational opportunities, losing carbon sequestration, coastal protection, and losing coastal protection. Fiorenza Micheli is a marine ecologist who also codirects Stanfords Center for Ocean Solutions. It is almost like losing the rainforest, except we don't see it.

Over a five year period, some parts of the West Coast saw a 10,000% increase in purple Urchins. Commercial divers have called them purps. They have shaken communities along California's coasts and Oregon's southern Oregon. Many kelp enthusiasts (recreational divers, fishermen, and scientists) have become increasingly desperate to rid the sea urchin population of their kelp. They often carry dive knives and hammers.