A father and son fishing in Casco Bay Thursday morning caught a rare, blue lobster that will be preserved in a tank at one of the Portland waterfront’s best-known restaurants.

The lobster, which is bright blue, was caught in the ocean waters beyond Peaks Island, said Luke Rand, who serves as sternman on his father’s boat, the Audrey B. Rand. Rand, 36, has been fishing since he was 16.

Mark and Luke Rand, fishing Thursday morning in Casco Bay, caught a rare, blue-colored lobster. Photo courtesy of Luke Rand of Falmouth

“We’ve never pulled one this color or even seen one to throw back,” said Rand, who lives in Falmouth. His dad, Mark Rand, has been fishing for more than 40 years.

Rand described the lobster as a legal-size, healthy-looking male crustacean. For the time being, father and son will keep the lobster alive by feeding it fish before moving the critter into a tank at Becky’s Diner, 390 Commercial St. Luke’s mother, Becky Rand, owns Becky’s Diner, and has agreed to put it on display.

Rand hopes the lobster will entertain the diners who flock to Becky’s Diner, especially during the hectic summer season. Over the years, Becky’s has earned a reputation as a popular gathering place for politicians, dignitaries and performers. Among those who have dined at Becky’s are Taylor Swift, First Lady Jill Biden, Tipper Gore, Bobby Brown, and former President Bill Clinton.

When the Rands showed the lobster to their dealer on Custom House Wharf Thursday, it caused quite the stir, Rand said. Tourists took photos.

“It’s not something that you see every day,” Rand said. He had not chosen a name for the blue lobster, but said he probably should come up with something.

Blue lobsters are extremely rare.

According to the University of Maine Lobster Institute, the chance of finding a blue lobster are 1 in 2 million.

The Lobster Institute, in stories posted on its website, states that the unusual blue coloration comes from a genetic defect that causes the lobster to produce an excessive amount of a particular protein. The institute has served as a source over the years for numerous media stories about blue lobsters and how rare they are.

Most lobsters are a greenish-brown color, but sometimes are blue. They can also be yellow, orange, white or multicolored. A lobster of any color (except white) will turn red when it is cooked.