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Marine biologists have captured a rare sight of a giant pod of over 1,500 dolphins leaping and swimming off the California coast.
The “super pod” of Risso’s dolphins was spotted in Carmel Bay, off central California’s coast.
This species, which can grow to over 10ft long and weigh as much as half a metric tonne, is identified by its white scarring. It has adapted to live near continental shelves where it can search for prey at depths of about 600 metres.
Carmel Bay is considered a haven for marine life with its nutrient-rich waters supporting rockfish, leopard sharks, bottlenose dolphins, and sea lions. The bay extends from shallow pools to a submarine canyon that reaches depths of nearly 150 metres.
While the Risso’s dolphins usually travel in pods of 10 to 30 animals, the sighting of them in an extremely large cluster of hundreds of individuals is rare, scientists say.
The dolphins usually form smaller, more stable subgroups within large pods, with fidelity between members. Studies have shown long-term bonds between adult males of the species.
Researchers initially planned to take a trip to track migrating Gray whales but were amazed to see over 1,500 dolphins swimming around their boat.
“They were just having a great time. So they were breaching everywhere, tail slapping, coming right over to the boat. They looked like they were having a big party,” marine biologist Colleen Talty from the Monterey Bay Whale Watch Center said.
“They were on the horizon I feel like as far as I could see,” Evan Brodsky from the Monterey Bay Whale Watch said.
Sightings of dolphins in newer areas such as off of the subarctic Norwegian coast indicate that the species is expanding its range.
Research suggests increasing noise in the oceans due to human presence threatens Risso’s dolphin populations. Low-frequency noise of motorised boats appears to disrupt the acoustic behaviour, including the clicks and buzzes, the dolphins use to find prey.
