RE: NANFA-- exotic species impact

Mark (
Thu, 27 May 2004 10:36:00 -0400

At 10:21 AM -0400 5/27/04, Bruce Stallsmith wrote:
>A major stressor of native fishes in the desert springs and streams
>of the Southwest has been the introduction of a long list of
>exotics, including bass, crayfish, mollies and dambusia. Also, you
>could throw in most of the state of California where the original
>(short) list of natives has been severely stressed by the
>introduction of fishes from eastern North America, for instance the
>Sacramento Perch is on the ropes from both habitat alteration and
>exotics. As to aquarium releases, that has been part of the story
>especially in smaller springs. And some state agencies have
>introduced game fishes in these areas for the usual stupid reasons,
>and this has apparently been supplemented by freelance "bucket
>So the short answer is yes.

Good points, Bruce. I wonder then if the primary mode of escape of
harmful exotics is deliberate release of the animals by people. I
guess not with round gobies and zebra mussels as far as we know.
Aside from those limited habitats of the southwest, which were very
fragile to begin with, I also wonder to what extent the problems in
California are primarily the result of habitat degradation by humans
rather than competition from aggressive exotics like LMB, green
sunnies and bluegill.

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