Rainbow lobster catches exaggerated by social media, says Halifax zoologist

Lobster catches across the Maritimes this season have, despite the odds, proven to be very colourful. 

Four blue lobsters, a yellow and an albino lobster have all been caught in the last two weeks.

While chances of catching a yellow lobster are ten times less frequent than blue ones, the odds of catching an albino lobster are one in 100 million. 

• Colourful lobsters being hauled in across the Maritimes

Andrew Hebda, a zoologist with the Nova Scotia Museum of Natural History, explains two to three uniquely-coloured lobsters are caught every year. And while these latest catches may seem unusually frequent, Hebda says they don't necessarily represent a shift in the statistical odds of finding one.  

"[The odds] basically indicate how many have been reported based on how many lobsters have been landed," Hebda said in an interview with CBC's Maritime Noon.

"It's one of those statistical things that depends on the numbers that go into the Department of Fisheries." 

Hebda said the advent of social media helps to spread the news of these catches sooner, and to a wider audience.

The science

The reason for multi-coloured lobsters boils down to genetic mutations in a lobster's pigmentation, Hebda said. 

"Mix yellow, blue and red pigments," he said. "It just depends on which one dominates."

Blue pigmentation is caused by a genetic protein called crustacyanin. If it's in large volumes, Hebda explains it can overpower the principal red pigment protein, called astaxanthin.

Hebda said the opposite is also true of the pigment balance. If there's an absence of pigment, then a lobster will appear to have very little or no colour at all. 

But, finding a rare, colourful lobster may not mean their siblings will look the same. Hebda says it all depends on the lobster's phenotype — how its genes are expressed.

Survival of the colourful

Colourful lobsters may live at a disadvantage. Hebda says they may have a difficult time passing on their genes to future crustacean generations. 

"If you get a large crustacean-eating carnivore then [the lobsters] certainly stand out — but not because of the colour, but because of the contrast." 

As for the human palette, Hebda said the rarer the lobster doesn't make it more flavourful. But, he says the cooking process may be made more visually interesting by a lobster's colouring.

"You take a blue [or green] lobster and put it in that pot and bring the water to a boil, and it will turn red," he said.

"If you take a white lobster and you stick it in the water and boil it, then it doesn't turn any colour — it's lacking that other pigment."