-----Original Message-----
From: Jack Bowling [SMTP:jbowling at direct.ca]
Sent: Sunday, January 10, 1999 2:41 AM
To: tweeters at u.washington.edu
Subject: Re: Removing non-native species

Ned wrote:

<snip>
>I think the introduction of exotic species hovers up there with the top 10
>most brain-dead things we've done over the years, and we have, are, and
>will continue to suffer the consequences (zebra mussels in the Great Lakes
>is a great example, albeit I believe they were accidentally introduced . .
<snip>

It may be of interest in passing to note that Environment Canada has
rumored that
the introduced population of Zebra Mussels in the Great Lakes may have had
a
salutary effect leading to the noticeable recent decrease in the level of
pollutants there. Seems they are extremely efficient filter feeders. And
many more
scoters now overwinter on the lakes than before the mussels took hold.
Question:
are the scoters now experiencing higher levels of dissolved metals, etc.
from
eating the mussels?

---------------------------
Jack Bowling
Prince George, BC
jbowling at direct.ca

Michelle Blanchard (from Michigan) added a tidbit about the Zebra Mussels
that supports your notion that the Lakes, Lake Erie at least, has become
crystal clear since they've taken hold. The reduction in pollutants from
their filter feeding is nice, but Michelle added that the lake has become
oligotrophic (reduced level of organic matter -- kind of like a normal high
mountain lake), and the fish have suffered from a lack of available
nutrients. While the scoters may enjoy the mussels (we certainly don't),
I've gotta figure that the disruption in the food chain must be wreaking
havoc on the system, and many other birds (piscivores at least) are looking
elsewhere for the food they're used to.

Ned McGarry
Kirkland, WA
nmcgarry at gte.net