Insects and other foods the trout may be eating:
1.    Blue-winged Olives
2.    Midges
3.    Sculpin, Minnows (Streamers)

Fishing Cold Water - Part Nine

There were several other things that I learned from both the aquarium experiments and
actually fishing experiences during the seventies. One very important thing was how changing
water temperatures affected fish.
To make this simple, there's a certain amount of time
it takes for a fish to adjust to a sudden change in water temperature.
I still wonder
exactly what it is that causes fish to slow down their consumption of food and in some cases,
stop eating for a short period of time following drastic changes in water temperature. I don't
know why this occurs for a fact, and I'm not certain anyone else does, but I could be wrong.
I'm sure there's plenty of speculation about it and I have my own idea as to why this happens
but it too, is pure speculation. I think since fish are cold blooded and their body is going to get
about the same temperature as the water surrounding them, the change takes some time. It
probably also takes some time for their bodies to adjust to the change. Us humans (warm
blooded animals) feel the change instantly because we feel "cold". We feel the difference in
98.6 degrees and whatever the air temperature is. Fish don't feel a difference. They don't feel
cold in the sense humans do.  

When a cold front passes through an area that's strong enough to drastically and abruptly
drop the water temperature several degrees, it always causes a short pause in their intake of
food. By the way, the same thing is true when the exact opposite thing occurs and the water
temperature increases. The time factors are different, however.

The length of time this "delay" takes place depends on just how much the temperature
changes, the species of fish,
and most importantly, the beginning temperature from
which the change occurs
. It is usually only a few hours. For example, In the case of
largemouth bass, if the water the bass are surrounded with drops from 60 to 55 degrees
within two or three hours, it seems to slow down their intake of food for about an hour or two
following the change. From 60 to 50 may slow things down for about three hours. I'm not
saying they won't eat anything because they will still obviously eat some, but there will be a
noticeable change. If the change takes place over a period of 4 hours and reduces the water
temperature from 60 to 45, it will slow things down for as much as 4 hours. After this slowdown
transpires, the fish will resume eating.

Here is the important point about it. Although when they resume eating the total amount
of intake of food will be less due to their lower metabolism, they will still eat far, far more than it
takes to catch them.
How much food they consume is completely irrelevant. The key to
it is the fish won't expend much energy eating. They won't chase down baitfish, for example.
Remember too, that the drop in water temperature also affect their food. Minnow and baitfish
also become much less active.
The food must be close by for them to eat it. This is a
necessary for their survival. They can't expend more energy than they can replace.

Here is another misunderstood and very important point that relates to fishing
regarding this. This is also true of trout.
If the food is put there and is easily for them to
acquire in the much colder water, they will still continue to eat it. In fact, they will gain weight
and continue to grow if enough food is immediately available. If the food isn't there, they can
survive a relatively long time without eating because they don't need the food for energy. How
do you think trout that are fed in "trophy trout" waters get big? How do you think spring creek
trout that live in water that's 50 degrees year-round get huge?

Fishing for bass or fishing for trout, this means two simply things for anyone that wants to
learn to catch them from cold water. You have to
present the lure or fly very close to the
for them to eat it. You also have to present it slowly. They will be in still or slow
moving water and the food they eat will be moving slowly.
Copyright 2011 James Marsh
I'm not trying to write an autobiography. It's my way of explaining how water temperature affects gamefish and in
the end, how it relates to trout. I think it's a greatly misunderstood subject by many if not most anglers, and my
intent is to try to give those interested a better understanding of the subject.