By Kathleen Schmitt
Article courtesy of Earthwatch Radio
October 05, 2001
Many fish call the Great Lakes home, but some will always
Alewives and rainbow smelt are exotic fish that are now
common in the Great Lakes, and Stephen Crawford says their
history shows how quickly people can accept a foreigner
as a native. Crawford is a fisheries researcher at the
University of Guelph in Ontario, and he wrote a book on
foreign fish in the Great Lakes that was published by
the National Research Council of Canada.
Alewives moved from the Atlantic Ocean into the Great
Lakes through the Welland Canal. Rainbow smelt spread
unexpectedly from inland ponds where people used them
for feed. Crawford says both species were unwelcome at
first. Their numbers exploded in the 1940s and '50s, and
that was followed by huge die-offs and piles of dead fish
on popular beaches.
Crawford says fishery managers tried to control the
problem by introducing salmon from the Pacific Ocean.
They used species such as chinook and coho, and as the
salmon ate up the pesky fish, they themselves became popular
among anglers as sport fish. Crawford says that as the
salmon became more popular, the status of the alewife
and rainbow smelt improved dramatically.
"And then you've got a very interesting turn
of affairs because the managers started to perceive the
alewife and the rainbow smelt not as a nuisance species
that had to be controlled, but rather as a resource that
had to be protected or conserved in order to protect the
recreational fishery for the Chinook and Coho salmon in
particular. So you've got kind of a 180 being pulled from
a nuisance species to something of value."
Crawford says there are now so many exotic salmon that
they've eaten up a lot of the alewives and rainbow smelt.
Some people are worried about the salmon going hungry,
so they've suggested stocking more alewives and smelt.
But Crawford says they should keep in mind that both the
salmon and their prey will always be foreigners to the
Great Lakes, and they should not be protected like native
"Salmonine Introductions to the Laurentian Great Lakes:
An Historical Review and Evaluation of Ecological Effects,"
by Stephen S. Crawford. National Research Council of Canada,
(Canadian Special Publication of Fisheries and Aquatic
Sciences 132), 2001.