Marketing Lamprey in Europe: A Good News/Bad News Story
A trammel net is used to harvest lamprey in Portugal. “This may offer a unique way to catch lamprey in Great Lakes tributaries — especially the large tributaries like the St. Marys River,” said Gunderson. The trammel net contains three nets hanging together like a high fence. It drifts downstream with the current. Lamprey swimming upstream on their spawning migration force the small mesh of the outside net through the large-mesh center net and are captured in a sort of bag that forms on the opposite side of the net. “This net is very effective at capturing migrating lamprey,” said Gunderson.
The good and the bad news about marketing lamprey in Europe were presented at a seminar held at the Great Lakes Science Center in Ann Arbor, MI, in June. Paulo Vaz-Pires, a Portuguese food science researcher working with Minnesota Sea Grant on this project, gave the good news. Great Lakes lamprey are marketable in Portugal both alive and frozen.
Vaz-Pires also described the lamprey situation in Portugal. Lamprey are highly prized and valuable. Lamprey numbers have declined in Portugal due to overfishing and loss of habitat. The Portuguese form secret clubs around lamprey consumption. It is expensive to belong to these exclusive clubs, whose primary purpose is to secure lamprey for it members.
Vaz-Pires described results of a mail survey conducted in the lamprey-eating region of Portugal (see March 1998 Seiche for results). On at least one Portuguese stream, local residents helped lamprey around a dam to allow their upstream spawning migration. “This is a very noble gesture considering the value of each lamprey if it were sold for food,” said Jeff Gunderson, project leader and Minnesota Sea Grant associate director. “It’s also very different from our attitude towards lamprey.”
The not so good news is that Great Lakes lamprey were not as well received in Spain. In a written report, Cruz Pascual Lopez, of the University of Santiago de Compostela, compared frozen Great Lakes lamprey to fresh and frozen Spanish lamprey in taste tests and also evaluated a specialty product, canned Great Lakes lamprey. Pascual offered these conclusions:
- Great Lakes lamprey had a more desirable texture than Spanish lamprey.
- Great Lakes lamprey contained eggs that could be used in a novel product.
- Great Lakes lamprey are smaller than Spanish lamprey.
- The over all acceptance of frozen Great Lakes lamprey was lower than for fresh and frozen Spanish lamprey (probably due to the much longer frozen storage period for the Great Lakes variety).
- While the canned lamprey did not rate highly, additional trials were recommended. Currently, a French company is attempting to expand its market for a canned lamprey product into Spain.
Now the bad news. Great Lakes lamprey have mercury levels that are too high to meet European Union standards. “The high mercury levels were a shock,” said Gunderson. “Originally our concern was that organic contaminants like PCBs, DDT, and others might bioaccumulate in lamprey because lamprey feed on lake trout that have relatively high levels of these compounds.”
Preliminary screening and analysis revealed that organic contaminants were not a problem. Since mercury is low in lake trout and other Great Lakes fish, it was not a major concern. Preliminary screening for mercury showed lamprey were within U.S. guidelines.
However, subsequent tests revealed mercury levels of 1.3 ppm. The European Union standard for mercury is 0.3 ppm. For comparison, the Minnesota Department of Health recommends limiting consumption to two meals per month for seasonal consumption of fish with this amount of mercury.
“No one knows why lamprey are so high in mercury,” Gunderson said. “They may pick up mercury during their non-parasitic stream life stage, or they may concentrate mercury from the blood of fish even though the host fish tissue shows low mercury levels, or lamprey may not be able to metabolize mercury as efficiently as more advanced fishes. The question of why lamprey have such high mercury levels is a good one and certainly will be explored further.
“At least we have an answer to the question that has been debated for nearly 40 years,” said Gunderson. “Yes, Great Lakes lamprey are marketable in Europe. Because of current control programs and experimental programs, a commercial harvest of lamprey would not have been a priority even if mercury levels were acceptable. But given time, a commercial harvest could fit into lamprey control and management.
“Lamprey are here forever and who knows if the funding for lamprey control will last that long,” said Gunderson. “If funding ever does wane, lets hope it’s not before mercury levels decline to acceptable levels so that lamprey harvest can be evaluated as part of a low-cost management program.”
This study was sponsored by the Great Lakes Protection Fund.
By Jeff Gunderson