Alaska News

New DNA research changes Alaska pollock classification

During the winter months of the Alaska fishing season, fisherman will continue to bring in one of Alaska's staple contributions to the U.S. fish market, Alaska pollock, but this year it will be scientifically labeled under a different name.

Alaska pollock, also known as walleye pollock, is the most commonly used fish in the United States for fish sticks, imitation crab meat and fish sandwiches. In 2012, Alaska pollock was the fifth most consumed fish in the United States, with the average American consuming 1.167 pounds of the fish that year. However, recent research into the genealogy of the fish has led to the fish being reclassified as a more specific member of the cod family.

While the differences between pollock and cod are numerous, both species belong to the same scientific family called Gadidae, the family members of which include pollock, cod, hake, haddock and whiting. The Gadidae family is further divided into a genus called Gadus, which is the specific group in the family tree that includes cod species. Pollock had been previously classified under a different genus, Theragrama, but new evolutionary studies have found that Alaska pollock is more closely related to the Pacific, Atlantic and Greenland variations of cod.

"This whole process began by looking at molecular sequence data," said Duane Stevenson, a research fisheries biologist for the NOAA. "As technology moves forward, there is a renewed interest to getting DNA sequences for a lot of things, including fishing. The research that went into this was mostly a DNA bar-coding effort. One of the ways that we try to find out about fish is sequencing their DNA. Pollock look very different from cod, but just because two things look very different does not mean that they aren't related."

According to Stevenson's estimates, research into the Alaska pollock's relationship to cod began 10 to 15 years ago, but as the technology in the fields of DNA sequencing and the sciences of classification, or taxology, have been improving, so have capabilities of researchers to answer genealogical questions.

"Basically, the simplest way to understand this research is to compare it to the concept of fingerprinting," said Stevenson. "We take a tissue sample from an organism, in this case of a fish, and then extract the DNA from that tissue and sequence it. Then we can see the genome for that organism. We then take that same DNA and sequence it against a large or small number of samples, which gives us an evolutionary history. It is a whole lot of chemistry, getting chemical reactions against the DNA and comparing to the reactions of other DNA samples, and that's how we get an animal's evolutionary history, if it all goes well. Forensic teams use a similar technology when trying to find a criminal based off of a DNA sample. Those teams just use different parts of the genome that are much more individual. When comparing fish species, we look at a less variable part of the genome. What we are trying to figure out is not figure out if one Pollock is related to another, we are trying to figure out how Alaskan or Walleye pollock and the cod family were related to each other 10,000 years ago."

As the scientific name change is being accepted by scientific journals and researchers, the common name for the fish will most likely remain the same. The general consuming public of Alaska pollock will most likely remain unaware of the name change, as the new scientific name for the fish will not appear on the packaging of fish sticks or be mentioned on a typical restaurant menu.

"Generally when consumers and marketers talk about fish, they talk about the common name, so I don't know how this is really going to the change the marketing of Alaskan pollock if it does at all," said Stevenson. "Walleye and Alaskan pollock is the same fish, but I imagine that it is marketed as Alaskan Pollock in a lot of cases just to clarify where it comes from. At the end of the day, we as researches just wanted to get the scientific name for the fish more in line with what we believe to be true about the evolutionary history of the pollock."

Whether or not the marketing of the fish changes over time to make way for the new scientific name change remains to be seen, but according to Stevenson, a drastic change in consumer marketing based on a scientific name change is unlikely.

"We've seen a continuing buildup of evidence over the past few years that support our findings, and because of that we are getting a lot of questions from scientists and laymen alike," Stevenson said. "As far as the marketing of the fish goes, why change the name is the public has already accepted the name Alaskan pollock? I expect no one in the consumer market is going to notice, to be honest."

This story first appeared in The Bristol Bay Times/Dutch Harbor Fisherman and is republished here with permission.

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