Smaller Fish After Alewife Die-Off

  • Alewife (Alosa pseudoharengus). The fish is not common in Lakes Superior or Erie. (Image courtesy of Wisconsin SeaGrant)

This past year, the size of salmon in some Great Lakes
is getting smaller because their main food source is dying off in some
areas of the lakes. The Great Lakes Radio Consortium’s Lester Graham
reports:

Transcript

This past year, the size of salmon in some Great Lakes is getting smaller because
their main food
source is dying off in some areas of the lakes. The Great Lakes Radio Consortium’s
Lester
Graham reports:


In the 1960’s, fish and game officials introduced Pacific salmon such as chinook,
coho and
steelhead to control the invasive species alewife. That’s a small fish that moved
in from the
Atlantic. The salmon are popular fishing. But since the alewives are not native…
they’re
especially susceptible to quick weather changes. And fisheries managers suspect
competition
with zebra mussels for food also affects alewives. Recently, alewife populations
have crashed in
some places. Jim Dexter is with the Michigan Department of Natural Resources…


“The primary reason that there are not alewives in Lake Huron and you get
fluctuations in Lake
Michigan is related more to the climate. You know, now, zebra mussels are tied into
that, into the
equation at some point but not probably to the affect that the climate is having on
those.”


So, without as many alewives, salmon don’t have as much to eat… and they’re smaller
than usual.
Fisheries managers say the effect is probably temporary.


For the Great Lakes Radio Consortium, this is Lester Graham.

Related Links

The Business of Fish Management

  • Similar scenes can be found up and down the eastern shore of Lake Michigan.

Now that summer’s officially here, beaches around the region are packed with
tourists and locals. But this year many beaches have been plagued with
unwanted visitors: tens of thousands of dead fish in the water and on the
sand. It’s a revolting sight-and smell – but in fact, the fish play an
important role in the lakes…and present an ongoing management challenge to
biologists. The Great Lakes Radio Consortium’s Wendy Nelson explains: