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Help the Kelp: How to Save California's Kelp Forests by Eating Sushi

We recently posted a sea urchin dissection video (which you can check out here), where we explained the anatomy and physiology of these fascinating echinoderms. In the video, we take a look at both the green sea urchin–found in the Atlantic Ocean–as well as the purple sea urchin–found in the Pacific Ocean. Although the green and purple sea urchins share many characteristics, one thing that they vastly differ in, is that purple sea urchins pose a serious threat to their ecological community. That’s right, the purple sea urchins' insatiable appetite is decimating California’s kelp forests.

A California kelp forest
A California kelp forest

Kelp forests are one of the most diverse and productive ecosystems on the planet. The marvelous underwater columns of kelp sustain marine biodiversity by providing habitat, shelter, and food for multiple species of fish and invertebrates, prevent erosion by acting as a trash fence, counters global warming by absorbing and holding carbon that would otherwise end up in the atmosphere, and even serves as a major source of antibiotics and other innovative medicines.

A California kelp forest decimated by purple sea urchins
A California kelp forest decimated by purple sea urchins

Unfortunately, many of these kelp forests worldwide are in danger of disappearing, and the kelp forests facing the most imminent threat of destruction are the ones lining the coasts of California and Oregon. Why? The big picture answer is climate change–which nearly all environmental problems can in some ways be traced back to–and the smaller picture answer is purple sea urchins. A huge species of sea stars called the sunflower sea star (which you can learn more about here) have historically been the main predators of purples sea urchins, keeping the sea urchin population at bay along the coasts of California. However, the climate change induced marine heatwave event of 2013 (commonly referred to as “The Blob,” and the mysterious sea star wasting disease induced by “The Blob” (which you can learn more about here), have wiped out the sunflower sea star population in the Pacific coast. Similarly, sea otters–another main predator of the purple sea urchin–have largely disappeared from the Pacific coast due to environmental stressors and overhunting. In the absence of their two most prominent predators, the purple sea urchin population along California's coasts have increased nearly 10,000% since 2014. Bull kelps are one of the purple sea urchin’s favorite foods, and thus millions of purple sea urchins have infested the bull kelp forests of California, and have consequently devoured more than 90% of the bull kelp in the forests.

 An Urchinomics test ranch facility at the UC Davis Bodega Marine Lab testing sea urchin
An Urchinomics test ranch facility at the UC Davis Bodega Marine Lab

However, all is not lost. Scientists have devised multiple strategies to combat the skyrocketing purple sea urchin population–my favorite being using a giant tube to suck sea urchins out of the ocean–and they have settled on a solution with great potential to solve the crisis at hand. It’s surprisingly simple–eat more sea urchins. The technique of balancing the sea urchin population by consuming them as food is called “sea urchin ranching,” and there’s a little more to it than just picking up and eating a sea urchin. Urchinomics is an organization at the forefront of pioneering the sea urchin ranching technique, and their model for sea urchin ranching holds great potential. First, purple sea urchins would be collected from the kelp forests, then the sea urchins would be fed until they reach a marketable size. Once the sea urchins have grown nicely, they are shipped to markets all around the world in Japan, Norway, NYC, etc. The entire process of sea urchin ranching would solve the environmental crisis at hand, while creating new jobs and spurring the economy. In the words of Denise MacDonald, the director of marketing at Urchinomics, sea urchin ranching “turn[s] this environmental challenge into an economical, ecological and social opportunity.”

Sea Urchin gonad uni helping kelp forests
A Japanese uni dish

Now you may be thinking: how in the world do you eat a sea urchin? Although the spiky exterior may suggest otherwise, the gonads of the sea urchin–often referred to as ‘uni’–are edible orange morsels of absolute decadence. Uni is described to have a thick, buttery, rich texture and a umami, briny flavor. Even though uni is most associated with Japanese cuisine, Spanish, Italian, and French cuisines also prominently feature uni. Culinary experts often compare uni to avocados, since just like avocados, the possibilities are endless when it comes to cooking with uni–mix uni into brioche dough, incorporate uni into marinades, grill/deep-fry uni, etc. If that wasn’t enough to convince you, uni is also high in protein, healthy fats, vitamin A, vitamin E, iodine, calcium, fiber, and low in carbohydrates and calories. Most importantly, you get to say you’re helping the kelp simply by enjoying a delicious meal.


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