EditorialA red urchin, right, with purple urchins during a removal event in Albion Cove in Little River, Calif., July 21, 2018. (Gabriella Angotti-Jones/The New York Times)
EditorialA portion of the purple sea urchins gathered by the commercial divers Byron Koehler and Gary Trumper off the coast of Albion, Calif., Aug. 24, 2021. (Dexter Hake/The New York Times)
EditorialSea otters, which can eat nearly 1,000 sea urchins a day, have seen their numbers along Alaska’s Aleutian Islands shrink by 90 percent in recent decades. (Scott Dickerson/The New York Times)
EditorialSea otters, which can eat nearly 1,000 sea urchins a day, have seen their numbers along Alaska’s Aleutian Islands shrink by 90 percent in recent decades. (Scott Dickerson/The New York Times)
EditorialSea otters, which can eat nearly 1,000 sea urchins a day, have seen their numbers along Alaska’s Aleutian Islands shrink by 90 percent in recent decades. (Scott Dickerson/The New York Times)