Off the coast of California lies an extraordinary sight: the largest congregation of deep-sea octopuses ever discovered on Earth. Over 6,000 octopuses gather around an extinct underwater volcano in the black, cold ocean depths, guarding nests full of eggs. Researchers have found that warm water seeping from the seafloor speeds up the growth of the octopus babies, leading to such large numbers of octopuses in this area. This discovery sheds light on how hydrothermal vents on the ocean floor create isolated patches of warmth that support deep-sea life. Scientists estimate that there could be thousands of these sites along coastlines.
https://www.npr.org/2023/08/23/1195028955/heres-why-6-000-octopuses-like-to-be-under-the-sea-at-an-octopus-garden