33.10 Barometer How High Is That?

[fishinwrench]

I do 80% of my fishing in less than 7' of water. I can tell you for a fact that baitfish or their predators do not evacuate the shallow flats during high pressure days....I can see them!

In most places where I fish the deepest the plankton can go is 3-4ft. unless they burrow into the bottom.

I just don't think it's about plankton, but I could be wrong.

And if it was all about sunlight penetration then seeking out and fishing various degrees of shade would save the day. No, there are days when LAKE fish just flat shut down, simultaneously, over a large area, sometimes almost statewide.

River fish seem to be more reliable, possibly less effected by the atmosphere above the water surface, that is a fact.....but what does that tell us ?

[Champ188]

Am I the only one whose head wants to explode from threads like this? I think we've crossed the line from a practical discussion on the effects of barometric pressure on fish activity into a theoretical symposium.

[abkeenan]

Am I the only one whose head wants to explode from threads like this? I think we've crossed the line from a practical discussion on the effects of barometric pressure on fish activity into a theoretical symposium.

x 2. I think I am worse off now than before I've read through the comments

[fishinwrench]

LMAO Yep, the harder I think the dumber I get.

Fish are just flakey, period. Should just leave it at that and accept it.

You can't reason with them....ever.

You say "what's the matter?"

They say "NOTHING'A!"

OOOO-Kaaay'a ! But you KNOW there's "something'a, and you're gonna pay for it.

[dtrs5kprs]

I... don't think so. When they get the simple stuff wrong, one has to wonder about the rest;

"Here’s how it works. In simple terms, barometric pressure—or atmospheric pressure—is the weight of the air pressing down upon us."

Atmospheric pressure acts on us from all directions, up, down, sideways, and even inside out (when you inhale). A inflated balloon would be pretty flat if atmospheric pressure only pushed down.

That said, the weight of the atmosphere can only push down on the surface of a terrestrial body of water, so one might conclude it has a downward force on objects in the water. That would be wrong though. Once below the surface, pressure is distributed equally in all directions.

Think the key was "in simple terms".

This is less so. Most interesting bit is in the "Results" where not only is pressure discussed, albeit briefly, but also the effect of wind. Of course this may not be definitive as it focuses on marine life, not freshwater systems.

http://www.cnrs.edu.lb/info/LSJ2005/No2/alnajjar.pdf

For those not interested in the entire work, an excerpt:

" A notable increase in the surface zooplankton biomass in the area of Yachting club

pool (21.73 mg m-3) compared with other sampling sites which might be attributed to the high

nutrient levels in this area due to human sources such as yachts washing and uncontrolled

discharge of some organic compounds. These differences in the distribution were in

agreement with the values of nutrients and chlorophyll a, primary production in the study area

(Al-Najjar et al., 2003). As for vertical distribution, the biomass values of this study were

generally less at 25m than at 50m water depth. Environmental factors may affect zooplankton

production in a given sea area directly and/or through that in other regions (Aoki et al., 1999).

Among environmental parameters, the air pressure may affect zooplankton biomass. The

lower air pressure leads to a higher zooplankton biomass (Tomosada & Odate, 1995). It is

probable that the disturbance of sea surface layer by low air pressure, which induces windy

conditions and decrease of air temperature cause vertical mixing and subsequent nutrient

enrichment (Manasrah et al., 2004).

Currents have also different respective effect on zooplankton abundance and

distributions of zooplankton from site to site. It is possible that the water is subject to a

positive effect when it shifts north - eastward. In such analysis, it would be needed to consider

the time lag between changes in zooplankton biomass and driving environmental variables.

These time lags probably differ among variables, and a number of combinations of input

variables with different time lags are assumed."

Have not been able to locate the piece by Tomosada and Odate that is referenced, but it turns up in multiple works by other researchers. It might in fact be the definitive answer, at least for marine systems. An example of its use as a reference:

http://pices.int/publications/scientific_reports/Report35/Sci_Rep_35_Japan_pp57_84.pdf

Excerpt :

"If winds are reduced by future warming of the ocean,

the primary production in the seas around Japan may

be reduced because of reduced vertical mixing in

winter. Warming could also reduce the nutrient

supply to the subarctic gyre and thus decrease

primary production in the Oyashio region. However,

variation in zooplankton biomass off Sanriku had a

positive correlation with sea surface temperature

(SST) and sunshine at Nemuro and a negative

correlation with sea level pressure at Nemuro in the

Oyashio (Fig. 20, Tomosada and Odate, 1995).

Thus, higher SST and stormier conditions would

improve productivity, although low zooplankton

biomass in the Oyashio, Kuroshio and transition

waters during the 1980s may have been caused by

mass predation by Japanese sardine (Taniguchi,

1999). In general, the impacts of climate and ocean

changes vary among areas and species, and the

impacts are poorly understood, but it is clear that

climate and ocean conditions are major influences in

the production of fishes in the seas around Japan."

The Tomosada piece appears to provide the accepted analysis of the effects of pressure, at least on zooplankton. Apparently it was published in 1995 in a Japanese journal. Have seen many citations of it, but no links or PDF's of the doc.

Wow...and to think that was actually more interesting than the CE I did yesterday.

[dtrs5kprs]

Am I the only one whose head wants to explode from threads like this? I think we've crossed the line from a practical discussion on the effects of barometric pressure on fish activity into a theoretical symposium.

Or in other words an old episode of In Fisherman.

[Champ188]

That's part of the lure of fishing ... trying to figure the silly things out and all the while knowing we never will.

[mjk86]

dtrs....and you would trust something from the lebanese science journal?? Whats the impact factor of that journal??? haha just kidding, its a great read. thanks for posting!

[dtrs5kprs]

dtrs....and you would trust something from the lebanese science journal?? Whats the impact factor of that journal??? haha just kidding, its a great read. thanks for posting!

Well at least the Lebanese one is available in English.

Seems like the research would support the conventional wisdom of low pressure good, high pressure bad, and further provide some insight as to why fish go deep on bluebird days (besides light penetration).

The little boogers really do just follow the food most of the time.

[Bill Babler]

Whew!!! Got what I asked for. The deal for me fishing most everyday, is the higher the sky the tougher the fishing. Usually the higher the sky the higher the pressure. Good old low pressure cloudy slight ripply days that don't vary to much either in temperature are the ticket.

Most often the same old same old is the deal. The more consistant the weather the better I like it.

Good Luck