Yes, there are tons of statistics on this. The lampryes' spread to the Great
Lakes and its later abundance exacerbated the decline of several large
native species, including several ciscoes (Coregonus), lake trout
(Salvelinus namaycush), and walleye (Stizostedion vitreum), among others.
Consequently, there was a collapse in the commercial fisheries during the
1940s and 1950s in many parts of the Great Lakes, particularly in lakes
Huron and Michigan, and in eastern Lake Superior. Lake trout catch in Lake
Huron fell from 3.4 million pounds in 1937 to virtual failure in 1947. In
Lake Michigan, U.S. catch fell from 5.5 million pounds in 1946 to 402 pounds
in 1953. In Lake Superior, catch dropped from an average of 4.5 million
pounds to 368 thousand pounds in 1961.
See the Great Lakes Fishery Commission website at http://www.grfl.org
What's barely mentioned, though, is that the sea lamprey was not the only
"invader." The Great Lakes were seriously overfished and on the verge of
collapse anyway. The sea lamprey arrived just in time to finish the lake
trout fishery off -- and to provide a convenient scapegoat when it nearly
did. Humans have a tendency to brush aside blame for the environmental
consequences of their actions. It's difficult to admit that we are often our
own worst enemy. Especially when therešs a repugnant "eel" to take the fall
instead.
Chris Scharpf
Baltimore
/-----------------------------------------------------------------------------
/"Unless stated otherwise, comments made on this list do not necessarily
/ reflect the beliefs or goals of the North American Native Fishes
/ Association"
/ This is the discussion list of the North American Native Fishes Association
/ nanfa_at_aquaria.net. To subscribe, unsubscribe, or get help, send the word
/ subscribe, unsubscribe, or help in the body (not subject) of an email to
/ nanfa-request_at_aquaria.net. For a digest version, send the command to
/ nanfa-digest-request_at_aquaria.net instead.
/ For more information about NANFA, visit our web page, http://www.nanfa.org