"Weatherlawyer" wrote in message
...
On Aug 25, 3:26 pm, "Russel Sprout" wrote:
"Ian Sutherland" wrote in message

. uk... I have a friend
who is a keen fisherman. The lake where he often goes is
run by a man who told him that high atmospheric pressure can push the
oxygen out of the water and thus adversely affect the fish.

I would have thought that increasing the atmospheric pressure would
increase the dissolved oxygen content. A much bigger effect would be
caused by an increase in temperature of the water (reducing solubility).

All true Ian, but I suppose as wind is usually light or calm with high
pressure, there will be less transfer of gasses at the water/air
interface.
On the other hand it is more likely to be summy with high pressure, so the
aquatic plants may redress the O2/CO2 balance somewhat..

There is a wave that passes over the planet with the dawn and sunset.
And fish feed at those times.

With high atmospheric pressure, the weather tends towards fine and
that is poor fishing for some of the game fish.

Old but good...

http://jeb.biologists.org/cgi/reprint/19/1/92.pdf

Oxygen level has got to be important to fish activty (including feeding).

In windy weather, with waves and good exchange of surface layer of air, O2
concentration in the water would tend towards equalibrium with the
atmosphere and damp the water plants/animals effect. In calm weather the
time taken to reach equilibrium is increased, the rate may not be high
enough to to have much immediate effect of plants and amimals production or
use.

Atmospheric pressure would have a direct effect as if the total pressure is
greater, then the partial pressure of O2 would be greater. This is a small
effect, +/- 1% at most. An increase in temperature would decrease the time
taken to reach equilibrium with the atmosphere, but in calm weather, the
rate of exchage with the atmosphere would be limited.

I've only ever seen fish gasping for air in hot, still conditions - thundery
plume type weather in the UK, not usually anticyclonic conditions and also
not directly due to the air pressure.