Whale watchers in Southern California were treated to a special sight last Friday when they spotted a white Risso’s dolphin.
“Today at Dana Wharf Whale Watch the sightings included 9 fin whales, 3 humpback whales, 2 Minke whales, Risso’s dolphin including a ʟᴇᴜᴄɪsᴛɪᴄ Risso’s, bottlenose dolphin and common dolphin, plus Henry the Masked Booby,” the Dana Wharf Whale Watch wrote on Facebook. “On the Ocean Adventures with Captain Chase Moore and deckhand Georgina Stone, we saw Risso’s dolphin on our first three trips today.”
“This included a mixed pod of both bottlenose and Risso’s and also a ʟᴇᴜᴄɪsᴛɪᴄ Risso’s dolphin. This dolphin has been seen at least three times since 2018 from San Dɪᴇgo to Catalina and most recently off Laguna Beach earlier this week,” she explained.
The Merriam-Webster Dictionary defines ʟᴇᴜᴄɪsᴍ as a ɢᴇɴᴇᴛɪᴄ condition that results in reduced pigmentation and is caused by a ɢᴇɴᴇᴛɪᴄ ᴍᴜᴛᴀᴛɪᴏɴ that inhibits melanin and other pigments.
Unlike ᴀʟʙɪɴɪsᴍ, the U.S. Navy Marine Species Monitoring blog says, ʟᴇᴜᴄɪsᴛɪᴄ animals “tend to retain some pigment in their skin and often have dark, normal colored eyes.”
White Risso’s dolphin are rare, and their white appearance is due to a ɢᴇɴᴇᴛɪᴄ ᴍᴜᴛᴀᴛɪᴏɴ that causes reduced pigmentation, a form of ʟᴇᴜᴄɪsᴍ.
Protected under the Marine Mammal Act Protection, Risso’s dolphin are often found in groups of 10-30, and can reach up to 13 feet long and 1,100 pounds and live up to 35 years.
Risso’s dolphins can be found offshore across the world in warm, temperate waters.