Urchin barren
Starfish also eat sea urchins. The sunflower starfish is the only animal that regularly eats the purple sea urchin. Even sea otters like red sea urchins more than they like purple sea urchins. When a disease in 2013 killed most of the starfish on the Pacific coast, there were many more purple sea urchins left. One study showed that the number of purple sea urchins in one reef off the coast of Oregon increased 10,000% in the five years between 2014 and 2019. They either ate or crowded out the red abalone and red sea urchins that humans like to eat. The abalone fishery in California closed in 2018, a loss of US$44 million per year.