“Octopus Garden”: A Californian “Jacuzzi” contributes significantly to the hatching of octopus eggs
WASHINGTON (AP) – Most octopuses lead solitary lives. So scientists were surprised to find thousands of octopuses huddled together on the sea floor off the coast of central California, protecting their eggs.
Now researchers may have solved the mystery of why these pearl octopuses congregate: The heat rising from the base of an extinct underwater volcano is helping their eggs hatch faster.
“There are clear advantages to basically sitting in this natural whirlpool,” said Janet Voight, an octopus biologist at the Field Museum of Natural History in Chicago and a co-author of the study, published in Wednesday scientific advances.
The researchers calculated that the heated nest site more than halved the time it took for the eggs laid there to hatch – and thus reduced the risk of being eaten by snails, shrimp and other predators.
The nesting site, which scientists dubbed the “octopus garden,” was first discovered in 2018 by researchers at the Monterey Bay National Marine Sanctuary and other institutions. The team used a remote-controlled underwater vehicle to film the flock of nearly 6,000 octopuses nesting at a depth of 2 miles.
The octopus – about the size of a grapefruit – sat on its eggs, which were laid on rocks heated by water rising from the sea floor.
“It was absolutely amazing – we suddenly saw thousands of pearly colored squid, all upside down, with their legs in the air and moving. “They chased away potential predators and turned their eggs over” to ensure an even flow of water and oxygen, said marine biologist Andrew DeVogelaere of the National Oceanic and Atmospheric Administration, one of the study’s co-authors.
Only the hazy glow of escaping hot water meeting the cold sea drew researchers’ attention to the hydrothermal seepage. But they still didn’t know exactly why the octopus had gathered there.
For three years, scientists monitored the site to understand the hatching cycle, recording both the developmental stage of eggs in 31 nests and the inevitable deaths of mother octopuses.
“After the hatchlings leave the nest and swim immediately into darkness, the mothers, who never left their nest and never took food during nest construction, soon die,” said James Barry, biologist at the Monterey Institute and co-author of the Study. author of the study.
The researchers found that the eggs at this site hatch after about 21 months — much shorter than the four or more years it takes for other known deep-sea octopus eggs.
“Typically, colder water slows down metabolism and embryonic development, and increases lifespan in the deep sea. But here at this point, heat seems to be speeding things up,” said Adi Khen, a marine biologist at the Scripps Institution of Oceanography, who was not involved with the study.
Mike Vecchione, a Smithsonian National Museum of Natural History zoologist who was not involved in the study, praised the researchers’ tenacity in “collecting so much detailed data about such a remote place.”
Such octopus gardens “could be widespread and very important in the deep sea, and we knew very little about them until now,” he said. “There is still so much to discover in the deep sea.”
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