Researchers have made a groundbreaking finding into the reproduction habits of pearl octopus, after a real life “octopus garden” inhabited by thousands of the creatures was discovered about 90 miles south and two miles deep off the coast of central California.
First recorded in 2018 by scientists from the Monterey Bay National Marine Sanctuary and Nautilus Live, the nest—which is the largest known aggregation of octopus on Earth—was found situated on the base of an extinct underwater volcano. Octopus tend to be solitary creatures, so to see so many huddled together on the sea floor came as a shock to the experts, to say the least.
Over the course of three years, the research team visited the underwater nest 14 times. Using a high-resolution subsea mapping system, they created landscape-scale maps and image mosaics to confirm an initial hunch. The heat seeping from the warm, underwater hydrothermal springs helps octopus eggs hatch in a fraction of the time, improving their odds of survival.
When the researchers first came across the deep sea nursery, they estimated its brood duration to be at least five to eight years. However, they were amazed to learn that the eggs hatched in just under two years.
“Deep off central California, thousands of octopus (Muusoctopus robustus) migrate through cold dark waters to hydrothermal springs near an extinct volcano to mate, nest, and die,” notes the study. “Warmth from the springs plays a key role by raising metabolic rates, speeding embryonic development, and presumably increasing reproductive success.”
In addition to developing successfully, octopus embryos must avoid predators such as snails and shrimp, as well as infection and injury. And when the female adult octopus die off after successfully reproducing, they in turn provide a food source to other creatures in the underwater ecosystem.
Though the part of the garden examined in the study contained roughly 6,000 octopus, researchers believe the grapefruit-sized creatures likely number more than 20,000 total. Additionally, the garden is probably one of many in other parts of the ocean that have yet to be discovered. Unfortunately, threats like underwater mining have the potential to jeopardize underwater communities that scientists still have much to learn about.
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