Tuna Crabs, Neither Tuna Nor Crabs, Are Swarming Near San Diego

by | May 11, 2024 | Science

SAN DIEGO — When Anna Sagatov, an underwater cinematographer, goes on her usual night dives off La Jolla Shores in San Diego, she’s used to spotting the “occasional octopus, nudibranch and horn shark.” But what she witnessed on a late April plunge was shocking: a seafloor turned red by what she described as an “overlapping carpet of crabs.” Swirling and shifting in the current, the creatures stretched “as far as my dive lights could illuminate,” she said.The swarming red crustaceans she and other observers have been spotting on San Diego’s coast are called tuna crabs, but they are actually squat lobsters. And the shallows around Southern California are not their usual home.Sign up for The Morning newsletter from the New York TimesThe animals typically live on the high seas, around Baja California in Mexico. But this is their second appearance in six years in the area. Some experts say they may have been pushed to San Diego’s near-shore canyons by nutrient-dense currents set off by El Nino, when warmer oceans release additional heat into the atmosphere, creating variable currents and air pressure fluctuations over the equatorial Pacific.The event could signal shifts in the region’s climate. At the same time, the aggregation of tuna crabs offers scientists and divers like Sagatov a close-up of a sea creature that usually turns up inside a tuna’s stomach.Some of the observations took twisted turns, like when she began to notice what she called “mass cannibalism” among the …

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[mwai_chat context=”Let’s have a discussion about this article:nnSAN DIEGO — When Anna Sagatov, an underwater cinematographer, goes on her usual night dives off La Jolla Shores in San Diego, she’s used to spotting the “occasional octopus, nudibranch and horn shark.” But what she witnessed on a late April plunge was shocking: a seafloor turned red by what she described as an “overlapping carpet of crabs.” Swirling and shifting in the current, the creatures stretched “as far as my dive lights could illuminate,” she said.The swarming red crustaceans she and other observers have been spotting on San Diego’s coast are called tuna crabs, but they are actually squat lobsters. And the shallows around Southern California are not their usual home.Sign up for The Morning newsletter from the New York TimesThe animals typically live on the high seas, around Baja California in Mexico. But this is their second appearance in six years in the area. Some experts say they may have been pushed to San Diego’s near-shore canyons by nutrient-dense currents set off by El Nino, when warmer oceans release additional heat into the atmosphere, creating variable currents and air pressure fluctuations over the equatorial Pacific.The event could signal shifts in the region’s climate. At the same time, the aggregation of tuna crabs offers scientists and divers like Sagatov a close-up of a sea creature that usually turns up inside a tuna’s stomach.Some of the observations took twisted turns, like when she began to notice what she called “mass cannibalism” among the …nnDiscussion:nn” ai_name=”RocketNews AI: ” start_sentence=”Can I tell you more about this article?” text_input_placeholder=”Type ‘Yes'”]
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