Re: NANFA-- introduced species

Bruce Stallsmith (
Mon, 17 Apr 2000 09:35:20 EDT

This is a huge topic, how adaptable fish are to new environments. I know
that the various Lepomis species, esp. gibbosus and macrochirus,
can be very opportunistic and shift their feeding ecology to an available
niche. In the 1970s & 80s a series of papers on Lepomis flexibility was
published by Earl Werner and associates (Mitchell, Gilliam) based on work
done at Michigan State University, appearing in the journals Science and
Ecology among others (I couldn't quickly find the exact refs). What they
found in brief was there is an ontogenetic shift in these species, i.e. the
juveniles all eat the same thing and become more specialized as they mature,
and also that in competition with other Lepomis species they specialize in
their niche so as to avoid direct competition. I would expect that Lepomis
species could do the same opportunistic shift if you introduced them to a
new environment such as Belgium. As to the other species, I'm not sure...

--Bruce Stallsmith
Huntsville, AL
"ground zero for Lepomis diversity"

>Hi everyone,
>I'm a biology student and i have to write a topic about introduced fish
>species (in Western Europe) and the effects of these introductions on the
>native fish fauna. So far, i have found some information about the grass
>carp, which originally comes from East-europe, and which was introduced in
>an attempt for weed-control.
>I would like information about some American species like : Lepomis
>gibbosus, Umbra pygmaea, Ictalurus nebulosis, etc...
>It seems like there are plenty more species in America than in Belgium, so
>there is a much stronger competition for niches in America. After
>introduction in Belgium, the introduced species apparantly come into an
>environment with less competition, but they seem to avoid competition in
>country by taking in any niche which is open. Does this idea follow any
>logic or do you think otherwise ?
>Please give me more info.
>Thanx !!!!!!!

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