Fisheries biologists, especially those who work in reservoirs, have
developed some models and indices that relate TDS to fish standing crops.
Assumption is that increased TDS results in increased fertility and
increased fish production.
Fish ecologists, especially those who work in streams, prefer measuring
conductivity. I think this is because some of the ions that contribute to
increased conductivity of the water may be more important to fish
osmoregulation than to primary productivity and may thereby restrict some
species of fishes from some reaches and enhance occurrence of other fishes.
Examples include some of the salt ( = high conductivity) tolerant species
that predominate in some southwestern streams where "mineral streams" and
gypsum deposits result in some higher conductivities. Conversely, some
species of wetland fishes seem to do best in waters of low conductivity.
-----Original Message-----
From: archimed_at_netdoor.com
Sent: Thursday, October 19, 2000 9:32 AM
To: nanfa_at_aquaria.net
Subject: NANFA-- TDS and Conductivity
Wel, I got my new TDS meter today and as I was playing around
with it I got to wondering exactly what is being measured. Is there
an exact correspondence between TDS and conductivity? If not,
why do some people feel the latter is important?
Prost,
Martin
------
It makes me mad when I go to all the trouble of having Marta cook up about
a hundred drumsticks, and the guy at the Marineland says, "You can't throw
chicken to the dolphins. They eat fish." Sure they eat fish, if that's all
you give them. Man, wise up.
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