Wildlife

At SeaLife Center, scientists watch as mother octopus dotes on thousands of eggs

In less than a year, Dot will be dead.

This fall she laid thousands of eggs. If they are fertile -- which isn't known yet -- they will hatch in six to nine months, at which point the likelihood of even one surviving will be slim. But Dot will care for them all the same, keeping them clean, pushing water over them and covering them with her eight-legged body.

Dot is a giant Pacific octopus. She was collected in 2012 and brought to the Alaska SeaLife Center in Seward as an exhibit animal. Unlike many of the center's marine mammals or birds, she wasn't injured or orphaned; Dot was brought to the center for educational purposes.

"When she was on exhibit, people could actually spend time with her in this octopus encounter of sorts," SeaLife Center aquarium curator Richard Hocking said. "In some cases she'd actually reach out towards the people."

According to Hocking, when Dot arrived she was "the size of a grapefruit" and weighed only about 1 pound. Two years later, before she was put inside a tank to mate with a male octopus named Thumb, she weighed in at 40 pounds.

Thumb was collected at about the same time as Dot, from Thumb Cove on the east side of Resurrection Bay. Although their exact ages are unknown, Hocking said they are believed to be of similar age.

The two appeared to have mated first on Sept. 8 and then again at the end of the month. Shortly afterward, they were separated.

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Hocking said they determined it was time for Dot to mate when her typical behaviors changed and she began "wandering." In the ocean, when octopi are ready to mate, they leave their lives of solitude and search for mates.

"It is kind of hard to say if the two successfully mated and if the eggs are fertile at this point," said Hocking. He added that center employees couldn't see clearly if the two mated.

Hocking said that if the eggs are viable, dark spots will become noticeable on the embryos, visible to the human eye.

But in the meantime, Dot will care for them.

"She stays with them in the den," said Hocking. "The den is not the same shape as it would be in nature. They would blockade it, but in an aquarium she's laid them in an upper corner of the exhibit, and she covers them, pulls water over them to keep them oxygenated and also to keep them clean."

Hocking added that the eggs and Dot are in a location where visitors can see them.

In nature, octopi don't eat while tending their eggs. And giving the animals the most realistic experience they can is part of the center's goal -- so they aren't feeding her.

And like the female octopi that have given birth at the SeaLife Center before her, Dot is expected to die after her eggs have hatched, which should be next summer.

But the SeaLife Center uses water from Resurrection Bay, which is warmer than normal this year, so the water inside the octopus exhibit is also warmer. Hocking said the water is about 50 degrees. And if the water is warmer, he said, the eggs could hatch sooner.

Female giant Pacific octopi mate only once but are capable of producing more than 30,000 eggs. Males may have multiple partners. But neither will live long after the eggs are hatched.

"In captivity, females may linger on longer, although that is not our intent. In any case, they have ceased feeding and are surviving on diminishing reserves of energy," said Hocking.

Only one giant Pacific octopus has been successful in rearing an egg to maturity in the SeaLife Center's aquarium.

Thumb was released back into the wild shortly after mating. Hocking said he was in good shape and brought to a location close to where he was collected. Thumb appeared to be at the "peak of his health" and "capable of mating with more females."

Megan Edge

Megan Edge is a former reporter for Alaska Dispatch and Alaska Dispatch News.

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