MONTEREY — In the days leading up to Halloween, a rare all-white dolphin named “Casper” has been frequenting the Monterey Bay. But sighting the perplexing creature isn’t a trick of the eyes, or just a spooky Halloween treat.
The dolphin actually visits the region quite often, according to Nancy Black, a marine biologist with Monterey Bay Whale Watch.
“You can see him any time of year, sometimes he stays for several months with his family and other Risso’s dolphins,” Black said.
Monterey Bay Whale Watch staff spotted Casper twice in the last week during their expeditions.
Black and other scientists think the dolphin is around 9 years old — still a juvenile since Risso’s can live up to 35 years. Casper frequently travels with his mother and has been seen as far north as Davenport, with pods of hundreds and even thousands of other dolphins.
Monterey Bay Whale Watch photographer Daniel Bianchetta first spotted Casper in 2015, and named the dolphin.
“It was magical,” Bianchetta said, “The name just seemed appropriate. We wouldn’t see him for six months at a time, so he was kind of like a ghost, you’d see him sometimes, and then you wouldn’t.”
The unusual dolphin may look albino to the untrained eye, but Black said she and other scientists believe he’s “leucisitic.” Leucism is a genetic mutation that, when present, represses melanin and other pigments which determine skin and hair color.
At least one other leucistic dolphin with white, pink and black-spots has been spotted off the Southern California coastline. Last year, a grey-white killer whale swam near Monterey.
While albino mammals typically have pink or red eyes, Casper does not.
“It’s pretty rare,” Black said of Casper’s bright white coloring. “I’ve been doing this for 30 years and he is the only one I’ve seen like that all this time.”
Casper’s personality even lines up with his friendly ghost namesake.
“Risso’s dolphins can be quite active — breaching, tail slapping, tail throwing, head slapping — they’re pretty social and playful and they’re always with other dolphins,” Black said.
Black, who studied the dolphins’ diet as a graduate student at Moss Landing Marine Labs, said the species prey only on squid. That’s a major reason Risso’s come to the Monterey Bay area, where market squid spawn from April to November.
“Risso’s are kind of wanderers, they go to where the squid is most abundant,” Black said. “When squid spawn they come in these massive schools, the Risso’s detect that and just like the fishing boats, follow them near shore.”
Black documented that Risso’s also feed on at least eight other squid species. Some of those prey can reach 10 to 11 feet, she said.
“It’s quite the mystery how they catch the squid,” Black said.
The way in which dolphins such as Casper hunt squid still perplexes scientists.
“No one has actually seen them eat a squid,” Black said, “It probably happens down below, in deep water.”
Casper and other Risso’s are often seen around the Monterey Canyon — one of the deepest underwater canyons across the Pacific. Scientists have documented the canyon extends to depths of more than 2 miles.
The white dolphin is a sight to behold for visitors and residents alike, but his uniqueness also helps scientists such as Black understand more about Risso’s dolphins.
Researchers don’t know exactly where the species travel throughout the year and why. The dolphins’ haven’t been formally tracked in a study yet, according to Black.
“Casper is kind of like a herd marker,” Black said. “He stands out so well that we can see how often the same groups of dolphins are around.”