Researchers with the University of Minnesota Sea Grant program think there's a lesson or two here for North Americans.
The first is that Portugal and Spain may represent a large untapped export market for Great Lakes lamprey. Indeed, government-funded programs are already catching and destroying many of these fish.
As part of its lamprey sterilization program, for instance, the Great Lakes Fishery Commission, a bilateral agency funded by the United States and Canada, traps up to 100,000 lamprey annually an estimated one-eighth of the spawning population. All females, which constitute roughly half the catch, are landfilled as trash. Males that can't survive a round trip to the lab for treatment meet a similarly untimely end.
"It's been debated for 40 years whether the Great Lakes sea lamprey are palatable," says Jeff Gunderson with Minnesota Sea Grant, in Duluth. "It's time to seriously address this question in a country where lamprey are traditionally consumed and demand a price high enough to make the effort worthwhile."
Toward that goal, his program sent 40 live lamprey -- all females -- to Portugal in mid June, and another 40 during the second week of July. That second batch was captured in the St. Marys River. Straddling the border between Michigan and Ontario, Canada, this waterway -- a prime lamprey-spawning ground -- connects Lakes Superior and Huron.
Under a program headed by Paulo Vaz-Pires, at Escola Superior De Biotechnologia, in Porto, the lamprey have been distributed to Portuguese restaurants. Explains Gunderson, although North American lamprey belong to the same species as those consumed in Europe, the concern is that freshwater rearing may impart a different flavor to those caught in the Great Lakes. So Portuguese chefs will be comparing how well lamprey raised in the New World fit into their Old World recipes.
Vaz-Pires will also survey how well European diners accept what would for them be out-of-season lampreyperhaps the equivalent of cranberries in July. While European sea lamprey spawn between January and May, the Great Lakes fish can probably not be caught in exportable quantities until July.
"So far, the word we've gotten back from Portugal has been positive," Gunderson says. If all continues to go well, coolers of live North American lamprey will wing their way across the Atlantic again next year, destined for sites including Spain.
Meanwhile, Gunderson's program is also exploring a domestic market for these critters, as illustrated by a taste test it hosted in Duluth on June 10. Chef Bob Bennett of Bennett's Bar and Grill, in town, cooked up four lamprey entrees. In addition to serving adaptations of two traditional Portuguese recipes (one is below), he concocted two originals. He says the latter two went over enormously better than the European ones. "The Portuguese [recipes] are very light," he says. "With both, the full flavor of the lamprey comes through." Which, Bennett believes, is precisely the problem.
His own Americanized entrees call on bolder accompanying flavors. For instance, his stew used a heavily reduced red wine, a rich veal stock, and hearty vegetables such as carrots, celery, and onions. He served it on mashed red potatoes (with the skins on), seasoned with sour cream and garlic.
He suspects this offering, the hands-down favorite [its recipe is reproduced below], "was so popular because of all the intense flavors involved -- which tended to mask the true flavor of the lamprey."
So, would Bennett serve lamprey in his own establishment? "Yes," he told Science News Online, but only after "developing more American-style items." While the panel of taste testers assembled by the Sea Grant program generally found all the lamprey dishes edible, most participants told Bennett they would consider ordering and paying only for the items he had developed.
Before he puts lamprey on his menu, Bennett would also like some advice on the best way to kill these fish. "I tried to stun them, like you usually do a fish. I put a knife into their head. Nothing seemed to work," he said. "It was terrible."
Indeed, cooks who are squeamish would be advised to avoid live lamprey.
Bennett's came bagged in oxygenated water. Once he liberated the fish into his 30-inch-deep prep sink, some jumped onto the floor as others squirmed across counters and into his grill. "It was like they were turbocharged," he says. Even after trapping the fish, keeping a grip on them proved challenging. "It was like trying to hang onto a slimy gyroscope," Bennett recalls.
Photo: Sea lamprey on lake trout. Credit: Great Lakes Fishery Commission
So what does lamprey taste like? "I would have to say it tastes like lamprey," says Chef Bob Bennett, "because it does not have a flavor that you can associate with anything else."
When pushed further, he volunteered that "its taste is not offensive. A lot of delicacies that I've been introduced to over the course of my career are a lot less palatable -- such as the sea urchin."
Though he detected an earthiness to the lamprey, a bit reminiscent of the dirtlike flavor of escargot, Bennett says that lake trout share this flavor at spawning. Since the lamprey he served had been caught at spawning, he notes that this earthiness might not characterize lamprey at other times.
Then again, this may be the essence that discriminating diners seek. One comment relayed back to Jeff Gunderson from Portuguese taste panels sampling Great Lakes lamprey was that the fish "had a strong flavor resembling turf, which they liked."
Though some members of the Duluth taste panel likened the lamprey to liver, Bennett says it resembles liver not in flavor so much as its dry texture. Personally, he found its texture "more like that of lobster -- chewy and meatier than most fish." Jeff Gunderson said certain of Bennett's offerings also had a crunch -- a little like eating chicken gristle -- owing to the fact that the chef had retained the fish's cartilaginous spinal cord. For the adventurous gourmand who develops an insatiable passion for this underappreciated North American fish, Gunderson adds a final word of caution: Historical accounts indicate that "King Henry I of England died of overeating lamprey."
Photo: Two members of the lamprey taste panel in Duluth. Credit: National Resources Research Institute, U. of Minn./Duluth.
The sea lamprey (Petromyzon marinus), which evolved some 250 million years ago, belongs to a near-extinct family of jawless fishes. Its downward slanting mouth consists of a large, tooth-lined sucking disc. Once it has latched onto the side of another fish, the lamprey opens a hole in its host by wiping its raspy tongue across the skin. The parasite then secretes an anticoagulant that keeps this wound open so that the lamprey can feed on the prey's blood and tissue.
A native of salt water, the lamprey has long foraged the brackish St. Lawrence River and followed migrating Atlantic fish into Lake Ontario. When the Welland Canal opened a passage between Ontario and the rest of the Great Lakes in 1829, the lamprey was free to move into the Midwest. And it did, with some lamprey eventually adapting to a fully freshwater lifecycle.
Though it was nearly a century before anglers first spotted lamprey in Lake Erie, the parasite was firmly established in Lake Huron by 1932, and in Lake Michigan a few years after that. By 1938, lamprey had been netted in Lake Superior.
It takes from 3 to 14 years for lamprey to mature out of their plankton-feeding larval stage. They survive only another year or 18 months before spawning and dying. But over that relatively short adulthood, each lamprey can kill roughly 40 pounds of prey -- such as a trout, salmon, or whitefish.
Indeed, within a few decades of moving west of Lake Ontario, commercially important trout fisheries in each of the other Great Lakes teetered on the brink of collapse. This upset the entire ecosystem, allowing populations of game-fish prey -- such as the notorious alewife -- to explode.
Since the late 1950s, fish-resource managers around the Great Lakes have employed chemical lamprecides to help control the parasite's dominance over prized game fish.
But these programs are costly, labor-intensive, and frequently targeted by budget cutters. In some regions, such as the St. Marys River spawning ground, they also have met with only marginal success.
Photo: Lamprey and the wound it made. Credit: Great Lakes Fishery Commission
So you're hauling in a Lake Superior trout and find (to your surprise and disgust) that you've landed more than you bargained for -- a lamprey. Here's a way to get even: Serve it up for dinner, with some recipes passed along by Minnesota Sea Grant.
Photo: Sea lamprey feeding off a lake trout. Credit: Great Lakes Fishery Commission
After killing the fish, pop it into boiling water for a few seconds. Chef Bennett says the slimy mucus coating will practically melt away after this blanching. Though a knife will often be all that's needed to scrape it away, as a bit of extra insurance you can remove any remaining vestiges by rubbing the skin with a rough cloth. Cut off the tail (usually about 6 inches long), then tie a string around the head and suspend the fish over a bowl filled with a tablespoon of vinegar. Open bronchial holes on the side of the fish and allow the blood to empty into the bowl.
Some recipes call for using lamprey blood. If yours does, wash the lamprey with a cup or so of red wine, then mix this wine with the vinegar and blood, making sure that the latter doesn't start to coagulate.
Now remove the intestines and notocordium (the long, dark bitter-tasting organ running down the abdomen). Rinse the fish again and then decapitate it by slicing around the body and pulling off the head. If you don't want crunchy lamprey, make sure the thick, bony cartilage comes out with the head. Discard both.
by Bob Bennett
Bennett's Bar and Grill, Duluth
Photo: Chef Bob Bennett of Bennett's Bar and Grill in Duluth stirs up an original concoction, which turned out to be the taste panel's overwhelming favorite: Lamprey Stew. Credit: National Resources Research Institute, U. of Minn./Duluth.
3 lamprey cleaned, peeled, and cut into 1/2-inch pieces
2 carrots, peeled and diced into medium size chunks
1 yellow onion, diced into medium chunks
2 stalks celery, diced into medium chunks
2 cups hearty red wine
2 cups fortified veal stock
1 bay leaf
2 tbsp. olive oil
salt and pepper to taste
Heat oil in a medium-size, heavy-gauge stock pot. Add lamprey and vegetables, then sear until vegetables are tender. Add the wine and reduce liquid by two-thirds. Add veal stock and bay leaf, reduce heat and simmer for 2 to 3 hours. Season with salt and pepper and serve on a bed of mashed potatoes as prepared below.
2 lbs. red new potatoes
2 tbsp. butter
1 tbsp. minced garlic
3 tbsp. sour cream
salt and pepper to taste
Boil potatoes until soft, then drain. Place in a mixing bowl with the rest of the ingredients and mix with electric hand mixer until smooth. Keep warm until ready to serve.
Adapted from A Cozinha Ideal
by Manuel Ferreira, Lisbon, 1988.
Slice the lamprey into 1.5 to 2-inch pieces and marinate in a mix of salt, pepper, parsley, a bay leaf, wine, and pieces of carrot and onion for at least 2 hours -- ideally for 5 or more.
Brown the marinated lamprey slices in a pan with about 6 tablespoons of olive oil, some pieces of garlic, salt, and pepper. Add small amounts of water to make approximately one quart of sauce. When it comes to a boil, turn down the heat, cover, and continue cooking for 1 hour. Season to taste.
Add about 1 pound of rice to the sauce and when the sauce returns to a boil, turn down the heat slightly and continue cooking slowly until the rice is done.
Be sure that the sauce remains liquid throughout the rice's cooking.
Serve very hot.
Photo: Slices of raw, skinned lamprey displayed at the Duluth taste testing. Credit: National Resources Research Institute, U. of Minn./Duluth.
Bob Bennett, Bennett's Bar and Grill, 319 W. Superior St., Duluth, MN 55802.
Forney, J.L. 1983. Parasitic phase of the sea lamprey (Petromyzon marinus) in Oneida Lake, NY. Great Lakes Fishery Commission (August).
Houston, K.A., and J.R.M. Kelso. 1990. Relationships of size and proportion of male sea lamprey with salmonid populations in the Great Lakes. Great Lakes Fishery Commission.
Koonce, J.F. and R.L. Pycha. 1985. Observability of lake trout mortality due to attacks by sea lamprey. Great Lakes Fishery Commission (September).
Nora Kubazewski, Natural Resources Research Institute, 5013 Miller Trunk Hwy., Duluth, MN 55811. E-mail: firstname.lastname@example.org
Meyers Resources, Inc. 1989. Public opinion on sea lamprey in the Great Lakes. Great Lakes Fishery Commission (May).
Minnesota Sea Grant, 2305 E. 5th St., Duluth, MN 55812. Ph: 218-726-8108. Web: http://www.d.umn.edu/~seagr/.
Great Lakes Fishery Commission, 2100 Commonwealth Blvd., Ste. 209, Ann Arbor, MI 48105-1563. Contact: Mark Gaden. Ph: 313-662-3209. WEB: http://www.glfc.org/.
This week's Food for Thought is prepared by Janet Raloff, senior editor of Science News.