Mystery fishes

By Paul Greenberg, Safina Center Fellow

This past week while circling Newfoundland on the National Geographic Explorer, we were forced to make an unscheduled detour. Endangered northern right whales had been spotted in the vicinity and we needed to avoid a collision at all costs. Right whales forage near the surface. They’re slow and a little bit clumsy (that and the fact that they float cursed them to be named the “right” whales to hunt). Our previous plan had been to cross over and land in Quebec but since 28 right whales have been killed in the last two years and just a few hundred remain, we were obligated to follow the mystery course nature had laid out for us and tacked east.

And all kinds of mysteries abound in nature. Walking on the bog land, alive with a cornucopia of mosses, dwarf trees, lichen and liverworts I came across the skull of a fish that seemed entirely out of place for Newfoundland. It was a substantial head, 4 inches across and baring a healthy set of conical teeth. It was not a codfish nor a pollock or any other of the number of “groundfish” that might have once haunted these waters prior to overfishing. One of the naturalists on the trip threw out bluefish as a possibility. And while I knew that striped bass had taken advantage of warming waters in recent years and were being seen as far north as Labrador it seemed a little far-fetched that that nearly subtropical bluefish could have braved northern Canuck climes.

Mystery fish skull. Photo: Paul Greenberg

But what was this thing? With a fresher head, the intrepid piscine CSI investigator might have been able to prise out an ear bone or “otolith.” Otoliths are good indicators because their shapes and sizes vary wildly across different fish taxa and can often be easily associated with a given species:

Otoliths from juvenile petrale sole, Eopsetta jordani. Photo: California Department of Fish and Game/Flickr

You can also tell a fish’s age by counting the rings in an otolith just as you count the rings in a tree.

Cross-section of a splitnose rockfish otolith, or ear bone, which accumulates analogous growth-rings. Photo: Bryan Black/Oregon State University/Flickr

But we had no otolith so, like any good crime scene investigator we turned to the dental records. One in our party thought the animal might have been a wolfish, which is indeed endemic to the area and does have quite big chompers. But a comparison of a wolfie’s dentures to this creature’s didn’t produce a match.

Comparison by Paul Greenberg

Once we looked carefully and saw that the mystery fish had a double row of nearly uniform conical front teeth we were able to parse a few sources like Joseph S. Nelson’s Fishes of the World and find a likely match.

Our mystery fish was Zoarces americanus more commonly known as the ocean pout.

Ocean pout, Newfoundland, Canada. Photo: Derek Keats/Flickr

And, curiously our mystery fish led us to another more famous mystery fish that has an interesting connection with Newfoundland and the Maritimes. Back in the 1980s a genetic engineering startup called AquaBounty was asked to look into a way to grow salmon in the icy cold waters of Newfoundland and Labrador. It turns out that the ocean pout contains a gene to produce anti-freeze and AquaBounty’s scientists set about trying to map the DNA and to see if that gene could be spliced into a salmon.

But then things took another turn. As AquaBounty’s one-time CEO Ronald Stotish explained to me a while back “Once the research progressed, we realized that these interesting proteins had other potential applications.” The most interesting was faster growth.

“We were interested in exploring whether or not we could improve the growth rates and economics of growth for Atlantic salmon by adding a second copy of a salmon growth hormone gene,” Stotish told me. Since researchers had figured out how to turn the ocean pout antifreeze gene on and off, they realized they could use those same “switches” in association with the salmon’s growth gene. A trial was run, and researchers witnessed spectacular increases. With more research and development, AquaBounty was eventually able to create a salmon that grew twice as fast as the already double-growth speed of selectively bred salmon.

The new mystery fish, trademarked as the AquAdvantage Salmon, was just approved for consumption in the US by the Food and Drug Administration. But it can’t be grown in the US. For the moment, the genetically modified salmon is being hatched right next to Newfoundland in Prince Edward Island.

Screenshot from Google Earth

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