The bright red tuna crabs are back in the Monterey Bay, having washed up on Del Monte Beach in droves.

Early Monday, residents and visitors started noticing the crabs, also known as the pelagic red crab or pleuroncodes planipes.

They creatures are hard to miss, their red shells a stark contrast to the sand of Del Monte Beach. There were hundreds of thousands on the beach Monday according to Andrew DeVogelaere, a research coordinator director with the Monterey Bay National Marine Sanctuary and the Sanctuary Integrated Monitoring Network.

DeVogelaere said the crab is usually found off the coast of Baja California but shows up other places during the El Niño weather pattern. Adults tend to live in the deep sea currents while their babies often wash up to shore, blown in by the currents.

Their arrival, according to DeVogelaere, is considered a natural oceanic event rather than something that is caused by humans.

“Animals tend to move with the water masses so crabs just kind of move with the current,” he said. “But during the stagnant warm water years as prevalent during El Niño, these crabs get carried up into the Monterey Bay.”

DeVogelaere said the creatures are harmless and aren’t for human consumption. They are an important source of food for fish, dolphins, seabirds and whales.

He added that if the crabs start showing up more frequently it might be an indicator of climate change.

“Mostly, it’s just an amazing thing to see,” he said. “The tourists are all excited about it and the birds are having a feast.”

According to DeVogelaere, the first major stranding on the Peninsula was in 1959 with another occurring in 1969. The crabs also appeared during the 1982 and ’83 El Niños.

Most recently, there was a stranding on the Peninsula in October when they washed up just north of Lovers Point and on Spanish Bay and Asilomar beaches. Last summer they had also blanketed beaches in San Diego and Orange County.

For Dan Albro, a senior guest experience trainer with the Monterey Bay Aquarium who deals with sea life on a daily basis, it was the first time he had seen them on local beaches.

“They’re actually a neat looking crustacean,” said Albro. “Traditionally off of Baja, they can be in the billions.”

Albro said that the current influx could have been why some 20 blue whales were spotted off of Moss Landing over the weekend.

“It’s very possible,” said Albro. “Blue whales are following food. While they’re traditionally krill eaters, they like the red crab and there’s a good chance the crabs were out there.”

Mostly, Albro said the crimson colored creatures are a good index of the water’s warmer temperature.

“They’re an indicator for those warmer water conditions in Monterey Bay,” said Albro.

Source: Monterey Herald