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NFC: Re: Goldfish chase trout away
It's always going to be a big gamble to introduce another exotic to control
an exotic. There must be something about that lake that these goldfish
really like. Maybe it's because it's an unnatural, manmade habitat that
isn't really suitable for native SW species. Mademade impoundments usually
lack the diverse and developed cover and habitat features that exist in
natural lakes. It shouldn't be any great surprise that an adaptable exotic
has colonized it and used the unused niches. I don't think rainbow trout
are really a lake-type species anyway. I would suggest either removing the
dam and turning it back into a natural river, or trying to develop habitat
that will be suitable for natives.
By the way, I would think that goldfish would be easy prey for trout. The
problem must be that the habitat can be better exploited by the goldfish
than the trout. And didn't they mention that it's been warm the last few
years. Last I heard, trout don't like warm water. So maybe the goldfish
aren't to blame after all.
One more interesting anecdote to complicate the matter - I learned recently
that there had been a chemical spill that killed lots of fish in the
Olentangy River in central Ohio. Turned out the most abundant species in
the river (based on counts of dead fish) was... drum roll, please...
goldfish! This was in spite of the fact that seining surveys had not
revealed the prevalence of this species. Again, testament to their
adaptability. I have yet to see solid evidence that goldfish and carp are
the terrible destroyers of game fish and natives that everyone claims. And
our rivers are turbid, not because of carp rooting, but because of
intensive agriculture and development. I think these Asian cyprinids are
just able to take advantage of the low quality habitats that we have made
from our natural rivers and lakes. Maybe we should be glad that anything
is willing to live there.
Columbus Ohio USA <))><
mbinkley at earthling_net