Air Pressure and Offshore fishing?

[SunnyCoastrunner]

What effect does air pressure have on offshore fishing?
I understand what it does to the wind and swell but what about how it reacts with the fish feeding etc?

[Captain Seaweed]

My thoughts are:
High pressure, water weighs more therefore fish stomach maybe is smaller and fish feels less full. In a low the stomach has less pressure stomach is larger and fish feels full. Just my silly idea on it. I am sure this is probably wrong but hey makes more sence than scientology and jumping on couches.

Marty

[finding_time]

Here's my thoughts....

I atmosphere ( ata) is about 1010 hpa

1 atmosphere is also equlivilent to 10m of salt water

so at 10 m below the surface you have around 2020 hpa at 20m 3030hpa at 30m 4040 hpa at 40m 5050 hpa and so on!

Now do you think a 20 hpa change is going to be that noticable to a fish at 40m??? Or to put it another way if a fish is at 10m and swims to 10.2 m it experiences the same pressure change it would get if the weather suddenly changed from a 1010 hpa low to a 1030 high???

Another way to think about it would be if there was a moderated 1m swell running and the fish stayed at the same depth, inbetween the peeks and the troughs it's experiencing a 101 hpa change every 4 or 5 seconds!! Again do you think it's going to notice a 20 hpa change over a few hrs??

Now do i think air pressure effects the fishing.... I dont really know but the above makes it seem doubtful , but the fish do seem to bite when a high is comming across or just before the pressure drops quickly! Maybe there still more to it that we dont understand??/

ian

[sleepygreg]

we have proven, as many others have, that a rapidly dropping barometer triggers a big increase in feeding activity in freshwater fish on the impoundments and freshwater reaches of rivers. I have also noticed it occuring in the shallow nsw estuaries. This is relation to those summer storms and 'southerly busters' you get down there. Fish affected were Bass, Yelowbelly, Murray Cod, Silver Perch...didnt seem to make a difference with Redfin. Bream, flathead, whiting and luderick all became active in similar situations.

Many fishos have been caught out offshore because the fish were on the bite, rather than head for home because of the obvious approaching storm.....this is anectdotal and not based on scientific research. Just based on my experience fishing these waters over the last 45 years.

I would think it would have some effect, as atmospheric presure affects seawater. Re fishes ability to detect minute changes in pressure.....I wouldnt doubt it.

Greg

[SunnyCoastrunner]

Yeh i have noticed that when storms approach the fishing is hot usually why I end up drenched but happy!

[Noelm]

I agree there would be hardly a dam/impoundment/creek fisherman who would not tell you the fish are affected by rising and falling air pressures, but these changes in pressure will also influence insect and bug hatches and stuff which to some extent may also be the "trigger" for a hot bite, but then I also agree with the argument that a fish only needs to swim a tiny bit deeper or shallower to have 10 times the impact air pressure could possibly have on them, true or false, I guess I tend to go for the true rather than false, kind of the same as a tide change to buggery out over the shelf can invoke a bite as well, why is anyones guess.

[lampuki]

Greg, we used to call it the sucker punch....the captain needs to know when to call it quits based on the abillity of his vessel and his abillity to handle the conditions.

[onerabbit]

Some interesting replies,

I have found BP at or above 1024 and rising to be best, the higher the better.
While i have found lower BP, say 1016, almost not worth spending the money on fuel for.
How these figures actually affect the fish at over 200m is a mystery to me too,

butI find the best days to be the ones where we have a big High in the centre of the country with an arm extending towards and over the coast.

As far as tide changes "to buggery over the shelf is concerned",
NoelM, we NEVER go out there anymore unless the moon will be visible in the sky
while we are fishing, I gues this ties in with tide changes associated with the moon. When the moon disappears, so do the fish.

Just my opinion,

Muzz

[sleepygreg]

Lampuki....I totally agree. I have had many deckies over the years whinging and moaning cos I told em to up lines and lets get the flock out of here. They understood why.....only after we hit the ramp and the storm/buster hit at about the same time or just before. They didnt whinge on the second trip.

Greg

[griz066]

Now my Pappy always used to tell me 1020 and the fish are plenty.