Largest known gathering of octopuses discovered off California

The largest known octopus garden in the world has been discovered off the central California coast.

A new study published in Science Advances reveals the existance of a hot springs close to Monterey Bay where some 20,000 female pearl octopuses are believed to gather each year to protect their eggs.

“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, forming the largest known aggregation of octopus on Earth,” the abstract of the study reads.

The publication of the study of the octopus garden represents a breakthrough for a team of researchers who first came across the gathering of octopuses accidentally in 2018 while on an expedition to explore an inactive underwater volcano in the same area.

The researchers on the expedition that day were transfixed.

“Sometimes you recognise immediately the magnitude of something special that you’ve found,” Dr Amanda Kahn, one of the researchers, toldThe New York Times. “And I think that was one of those really special moments.”

Now, five years later, we know much more about what those octopuses were doing that day. According to the study, the octopuses were drawn to the hot spring because heat speeds the timeline on which the octopuses’ eggs hatch — positively affecting their reproductive prowess.

According to the Times’ reporting, the researchers used remote cameras as well as temperature and oxygen probes to watch and gather data on the octopuses and their chosen environment atop the hot spring. They found that in the octopuses’ chosen nesting place, the temperature of the eggs was 52 degrees as opposed to just 35 degrees in the open ocean water.

The increased temperature can be pivitol for baby octopuses, as a shorter nesting time reduces the chance that an egg will be harmed. It also can help female octopuses, who do not eat while brooding and die after they reproduce.

James Barry, a marine ecologist who led the research team, told the Times that the recent findings have begged more questions about octopus behavior and opened new avenues for research in the years ahead. Mr Barry said his team has already found another octopus garden five miles north of the initial site and said there could be more elsewhere along the California coast — providing more insight into octopuses and the ocean’s broader importance.