SAN FRANCISCO – Inside a spare bedroom in Richard Ross’ home sits a massive aquarium system, where the scientist is attempting to raise and mate a species of octopus so rare it hasn’t yet been assigned a scientific name.
For now, they’re called the larger Pacific striped octopus – a name that belies their relatively small size.
The 100-gallon aquarium, which is among six in Ross’ room, is the breeding ground for two females and three males, which measure between 8 and 10 inches from the tip of one of their eight arms to another. The animals’ bodies, which are called their mantles, are about the size of apples.
The creatures were unknown to science until about 20 years ago, when a Panamanian biologist first described them in an unpublished report. He discovered them while diving off the coast of Nicaragua in the 1970s.
In Nicaragua, the cephalopods live along the coast at depths of more than 130 feet. They prefer areas near the mouths of rivers, where currents stir up sediments that make it difficult for divers to spot the octopuses, said marine biologist Roy Caldwell, a University of California, Berkeley professor of integrative biology who is breeding and studying the animals in his own laboratory along with Ross.
The two men hope to mount an expedition to study them in the wild, said Caldwell, who studies aquatic evolution. Caldwell is raising six of the Larger Pacific Striped Octopuses at the Berkeley lab, and calls them the most beautiful octopuses I have ever seen.
When Ross has mated and reared enough of his rare octopuses, he plans to move some into the Steinhart Aquarium at the California Academy of Sciences.
Ross certainly has experience raising and breeding octopuses. For the last four years, he has been studying a smaller cousin of the larger ones.
These animals lay large eggs three to six weeks after mating. When the eggs hatch, tiny, swimming octopuses emerge that are easy to feed with tiny prey-like shrimp and sand fleas, Ross said.
By contrast, the larger octopuses are a mystery. Their eggs are tiny and hatch after 20 to 50 days. The offspring are so small they look like plankton lying on the bottom of the aquarium.
The really hard part is feeding them, because we still don’t know what they eat, and if we can crack that mystery, it will open up all kinds of doors to raising them, Ross said.
Now his rare larger octopuses are living together in their own 100-gallon home, surrounded by five other tanks.
Already, the scientists have observed differences between these octopuses and others.
Many octopus species live solitary lives and get together only briefly to mate and die. These animals from Nicaragua are far more gregarious, Caldwell said.
They can cohabitate in pairs, the females can lay clutches of eggs again and again, and they sometimes share the same den, while groups of them are reported to live in colonies of 40 or more individuals, he said. They are the only octopuses known to mate beak to beak’ – a position that may be viewed as dangerous considering their cannibalistic nature.