mr. mr

Ekman Transport and the Dreaded Upwelling

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Great explanation of the upwelling phenomenon. So, basically what you're saying, is the south wind sucks. I agree with you.

But, just like every rule, there is the exception. I'm an old guy, and I remember the stooopid bass/bunker blitzes back in the late 90's thru the late 00's. These would typically occur on a June day, bright skies, and our typical summertime afternoon weather pattern, which is south winds. In other words, the exact opposite of the dark, low pressure conditions that we typically fish for bass in.

The worst effect of a south wind is a prolonged stretch of south, which creates the upwelling, and the sudden temp change that comes with it. This will close the fishes mouth for a few days, till the pattern changes.

Good read.

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I'm a few years into surfcasting and haven't understood something about water temp and biting fish.  Are we talking all fish or just stripers?

In the spring or fall, I thought the optimum water temp for stripers is in the  60 degrees range.  So, I read around those times of year the water might be too cold in the spring or too warm in the fall.  That's for whatever stripers are around NJ at the time.

In the warm summer months, with south wind and upwelling, the water is colder but not cold.  Ie, it goes from say 75-65, putting it at a good temp., I think, for whatever stripes are around plus other fish in NJ.  So why does the drop in temp reduce feeding?  65 still isn't a cold enough temp to make fish lethargic, I would think.

Or, is the deeper, colder water much colder than 65 and when mixed with the warm water ends up at 65? And, the fishes feeding is turned off by the much colder water?  What is that colder water temp?

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Well done!  

 

I was waiting for you to toss in something about vectors and maybe even the pythagoreum theorum!

 

Thanks for posting. 

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Posted (edited)

2 hours ago, Sam3631 said:

I'm a few years into surfcasting and haven't understood something about water temp and biting fish.  Are we talking all fish or just stripers?

In the spring or fall, I thought the optimum water temp for stripers is in the  60 degrees range.  So, I read around those times of year the water might be too cold in the spring or too warm in the fall.  That's for whatever stripers are around NJ at the time.

In the warm summer months, with south wind and upwelling, the water is colder but not cold.  Ie, it goes from say 75-65, putting it at a good temp., I think, for whatever stripes are around plus other fish in NJ.  So why does the drop in temp reduce feeding?  65 still isn't a cold enough temp to make fish lethargic, I would think.

Or, is the deeper, colder water much colder than 65 and when mixed with the warm water ends up at 65? And, the fishes feeding is turned off by the much colder water?  What is that colder water temp?

Fish are cold blooded. A sudden drop in water temp effects them and how they feed. If you've ever dropped a fish into a tank with water a few degrees cooler it sorta stuns then and they are very lethargic.  

Edited by adams54

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2 hours ago, 55555s said:

Well done!  

 

I was waiting for you to toss in something about vectors and maybe even the pythagoreum theorum!

 

Thanks for posting. 

Lol, thank you. Thought it was a worthwhile topic to add to the knowledge on this site. 

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3 hours ago, Sam3631 said:

I'm a few years into surfcasting and haven't understood something about water temp and biting fish.  Are we talking all fish or just stripers?

In the spring or fall, I thought the optimum water temp for stripers is in the  60 degrees range.  So, I read around those times of year the water might be too cold in the spring or too warm in the fall.  That's for whatever stripers are around NJ at the time.

In the warm summer months, with south wind and upwelling, the water is colder but not cold.  Ie, it goes from say 75-65, putting it at a good temp., I think, for whatever stripes are around plus other fish in NJ.  So why does the drop in temp reduce feeding?  65 still isn't a cold enough temp to make fish lethargic, I would think.

Or, is the deeper, colder water much colder than 65 and when mixed with the warm water ends up at 65? And, the fishes feeding is turned off by the much colder water?  What is that colder water temp?

Sudden changes up or down in temp play a big role. Steady temps, even colder water, not so much.

If the water is warm and the temps drop fast due to an afternoon S wind, the bite will (usually) shut down.

However, the only 100% rule is that there is no 100% rule, especially with fishing and women.

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3 hours ago, Sam3631 said:

I'm a few years into surfcasting and haven't understood something about water temp and biting fish.  Are we talking all fish or just stripers?

In the spring or fall, I thought the optimum water temp for stripers is in the  60 degrees range.  So, I read around those times of year the water might be too cold in the spring or too warm in the fall.  That's for whatever stripers are around NJ at the time.

In the warm summer months, with south wind and upwelling, the water is colder but not cold.  Ie, it goes from say 75-65, putting it at a good temp., I think, for whatever stripes are around plus other fish in NJ.  So why does the drop in temp reduce feeding?  65 still isn't a cold enough temp to make fish lethargic, I would think.

Or, is the deeper, colder water much colder than 65 and when mixed with the warm water ends up at 65? And, the fishes feeding is turned off by the much colder water?  What is that colder water temp?

My belief is that it’s not so much about the temperature of the upwelling as it is about the sudden change in temp. Bass, in my opinion, are very dependent on feeding patterns. At any given point in the year, a bass is going to put itself somewhere and have an expectation of what the conditions should be like, what the bait presence is like, when the best feeding times are, etc—that’s what I mean by pattern.
 

For our summer resident surf bass, those fish put themselves in the surf because of the abundance of bait and expect (or become accustomed to) the summer conditions in the surf: clear and shallow water, bright sun, warm temps. They respond to those conditions by taking advantage of the best feeding windows, like a good tide at night. 
 

All of this is to say that when bass are accustomed to feeding in typical summer conditions and then those conditions change drastically within the span of one or two tides, the change (usually) causes the fish to lock down. I believe that if, for example, the upwelling conditions persisted for a long period of time, those fish would adapt and find a new pattern either in the surf or elsewhere. 
 

I’m sure other factors play a significant role too, like the change in temperature causing a bass’ (and the bait’s) metabolism to slow or changing bait presence/movement. 
 

You’re absolutely right that 65 degrees is a primo bass fishing temp, and in a few months when the water cools to that temp the fishing should be excellent. But the difference is that the 65 degree water in the fall will come after a gradual change and the bass will be able to go through many different patterns before getting there. 

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Thanks mr. mr. for the good original post and follow up explanation.  Also, thanks to Sudsy and adams54 for your responses.  

Good explanations as to why a sudden decrease to 65 slows a bite while a gradual decrease that ends at 65, like in the fall, might increase or result in a good bite.  I didn't know the sudden decrease causes lockjaw vs the final resulting temperature and how we end up at that temperature and the adaptation that goes along with it.

It also explains why the south winds in summer cause a crappy fluke bite I experienced on half day afternoon fluke trips on party boats vs morning summer trips with less or no south wind.  Which brings up another question.  Why are there almost always south winds in the afternoon in the summer?  I found this from Rutgers.  This might answer my question but gets pretty complicated.

 

https://marine.rutgers.edu/cool/weather/wind_analysis/seabreeze.pdf

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it is because of the coroilis effect, that toilets flow clock wise in the northern hemisphere

 

sphere and counter clock wise in the southern hemisphere.   In theory toilets should flush strait down with no swirl at the equator.   

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The OP is damn spot on trying to replicate a laymen's term's analogy of an upwelling on the atlantic coast.  (<<< You may want to write a book/article on this with figures, because about 99% of the world has no idea what an upwelling truly is... and sometimes, many don't even fully understand rip tides so to speak).  You did an A+ job in explaining in as basic terms as you can.

 

The drastic anomaly we have with this current upwelling that ended the other day(this week) is - this has been going on in Jerz since mid-July.  Almost 2 STRAIGHT weeks of cold temps during some of the peak average/summer water temps coming in.

 

Of course, many times, we get relieved by the N or NE winds with hopeful currents to break down an upwelling, but sometimes the upwelling doesn't give way.  And the phenomena stays steady...

 

Which is what we had for the past couple weeks since mid-July.  Sometimes, when you notice anomalies like this - you really really have to THINK like the fish to find them.  I still did well during the upwelling, but it definitely, for the most part, will hurt the bite for most species.  

 

Just relieved... it's finally over.  For now.. or until the next one.

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On 8/3/2022 at 11:18 AM, Basstid said:

it is because of the coroilis effect, that toilets flow clock wise in the northern hemisphere

 

sphere and counter clock wise in the southern hemisphere.   In theory toilets should flush strait down with no swirl at the equator.   

That has been debunked, however what is missing in these explanations is the role evaporation has on temperature.

 

When water has a phase change from liquid to gas a significant amount of energy is converted. I'm not a scientist but consider why it is always cooler at the water's edge.

 

It is the same principle that refrigeration/air conditioning works on. You feed energy into condensing a gas and then evaporating it to absorb energy.

 

I didn't mean to be so long winded but I never bought into the standard upwelling idea.

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