This Species of Fish Has Neon Blue Flesh And No One Knows Why

The Lingcod, a fish native to the North American west coast, usually has brown-red or even greyish skin and white flesh, but about 1 in 5 specimens are actually neon blue both inside and out, and no one really knows why.

Popular both among recreational fishermen and seafood lovers for its delicious meat, the lingcod is a bottom-dwelling fish that can grow up to a size of 152 centimeters. It’s a voracious predator that feeds on virtually anything that moves and fits into its large mouth and has only a couple of species of seals and human fishermen to worry about. The Lingcod is sometimes referred to as ‘smurf cod’ due to the fact that about 20 percent of specimens have neon blue flesh that looks either alien or affected by nuclear radiation. Interestingly, while scientists have theories about this bizarre coloration, we have yet to establish why some lingcod have blue flesh.

Photo: NOAA Photo Library

In 2016, while on a spearfishing trip, marine ecologist Aaron Galloway encountered his first blue lingcod. After inspecting the fish, he noticed that it was blue both inside and out, but when trying to discover more about it, he discovered that there wasn’t much information available. While neon blue lingcod had been spotted before, no one had done any serious research on the subject.

We know that the blue color of some lingcod is the result of a bile pigment called biliverdin, but how it actually colors the flesh of fish, why it only affects some lingcod, or even where it comes from are still puzzles that need solving. Galloway tried to do just that in 2016, when he stumbled over a catch survey involving more than 2,000 lingcod caught along the US coastline.

“Basically, we looked at what factors correlate with blueness,” the marine ecologist told The Toronto Star. “There hadn’t been any systematic studies about this.”

Analyzing the data, the researchers were able to show that the probability of blue flesh was highest in females, particularly those caught in shallow waters and that were smaller in size. The incidence of blue lingcod ranged from 4 to 25 percent, depending on the region. However, none of these findings really answered the big questions.

Although sex was still the biggest predictor of flesh blueness, as 80 percent of all the blue ling cod were female, it wasn’t the only factor, as 20 percent of blue lingcod were male. The fact that most blue fish were caught in shallow water suggests that the color could provide better UV protection, while some believe that the biliverdin comes from specific food sources. At this point, we just need more scientific research to determine why some fish turn out blue.

“Our hypothesis, and some of the fatty acids we traced, indicate the blue fish might be starving, or going through some sort of nutritional stress,” Galloway said, adding that laboratory tests are needed to determine whether lingcod coloration is determined by stress and whether lingcod can change color depending on various factors.

In case you’re wondering if people actually eat blue lingcod, the answer is yes, and most of them probably don’t even know it, as the cooking process causes the flesh to go from neon blue to its usual white. Despite what you may read on various angling forums, blue lingcod meat is perfectly edible and quite delicious.

Posted in Animals        Tags: , , , , , ,