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Cold Water Streams vs Warm Water Streams

2010/11/4 15:45
From Cranberry TWP PA
Posts: 0
Ok, I know that I have asked several questions regarding fly fishing for trout in western PA. Now I have a question that may seem very basic and not real interesting for most of the people on this site. But what is the difference between cold and warm water streams. I am not use to fishing streams and want to learn more to understand the eco systems in each of these types. So the connie is considered a warm water stream... Why? The Slippery Rock and Ness. is considered cold water streams. Why? Can some one explain this to me in way that will help me and other new to stream fishing?


Posted on: 2010/11/6 10:21

Re: Cold Water Streams vs Warm Water Streams
2006/9/9 19:16
From Dallastown, PA
Posts: 1679
Under the chapter 93 of the PA Bulletin there is a classification of stream designations of protection ranging from:

WWF = warm water fishes
TSF = trout stocked fishery
CWF = Cold water fishes
HQ-CWF = High Quality Cold Water Fishes
EV-CWF = Exceptional Value Cold Water Fishes

So basically you have streams capable of supporting warm water species and you have streams capable of supporting cold water species of fish and other organisms.

TSF is really a WWF that stays cold enough in the spring to provide a recreational fishery for trout.

Each of the classifications under CWF are a notch better than the previous and warrant increased protection from environmental impacts of industry.

Trout are a cold water species and if present during warm months of the year can elevate the stream status and subsequent protections. Trout reproduction and biomass levels of trout populations elevate the status even greater to HQ or EV CWF.

Once the PF&BC surveys or local group or municipality recognizes these features of a stream, they petition the Environmental Quality Board (EQB), a leg of the DEP, who evaluates the request to elevate the status of a said stream and makes a determination usually based on the scientific data found by the PF&BC in addition to the evaluations and public comment during the review process.

Posted on: 2010/11/6 14:31
Don't hit me with them negative waves so early in the morning. Think the bridge will be there and it will be there. It's a mother, beautiful bridge, and it's gonna be there. Ok?

Re: Cold Water Streams vs Warm Water Streams
2006/9/9 17:32
From Gettysburg
Posts: 439
As a VERY general and unscientific can consider any stream in PA that holds trout or is stocked with trout as a "coldwater" stream. Warm water streams - at least when associated with fly fishing - usually implies streams that are fished for bass and sunfish etc.

The state of PA does classify streams as cold or warm water but I'm not sure of the criteria and whether water temp really plays a role (one would think it would). Some of those designated by the state as coldwater here in my neck of the woods definitely don't have trout.
I'd stick with the definition I suggested above. Perhaps Mike can clarify this but, at least here in PA, "cold" tends to be associated with trout fishing.

Posted on: 2010/11/6 14:36

Re: Cold Water Streams vs Warm Water Streams

2006/9/13 10:18
From LV
Posts: 714
In the simplest of terms a couple of degrees of temperature, but the are cool water stream sections where you find a mix of warm and cold water species as well as cool water species. The natural progression of a stream is from cold water to cool water to warm water.
It can happen very quickly over a very short distance. For instance a 100 yard length of un-shaded riparian area along a cold water stream can alter the stream temperature four degrees or more. A pond on a stream can wamr the water temerature ten degrees or more.

Posted on: 2010/11/8 21:10
George Orwell warned, "The further a society drifts from the truth, the more it will hate those who speak it."

Re: Cold Water Streams vs Warm Water Streams

2008/6/28 15:57
Posts: 44
Practically speaking, "coldwater fish" consist of trout, salmon, whitefish, and grayling- all of which prefer water temperatures below 70 degrees.

Brown trout and rainbow trout can tolerate water up to the low-mid 70s, but it isn't good for them.

Brookies really want temps below 65 degrees F. And 68 is about the limit for them. Some sources say 70, but I've never known of a wild brookie stream that ran that warm, even on the hottest day of the summer.

"Warmwater fish" can tolerate cool water temperatures, but they prefer habitat conditions with water temperatures between 70 and 80 degrees during their prime growing season, in the spring and summer. (Stream water rarely gets much over 80 degrees, and most warmwater game fish prefer temperatures slightly cooler- more like 72-75 degrees.)

Therefore, a cold water stream habitat typically remains below 70 degrees year round.

A warm water stream habitat typically runs between 70 and 80 degrees in the late spring and summer.

A stream like Penn's Creek above Weikert is considered a cold water habitat even though the average water temperature often rises above 70 degrees in the summer, because it has enough stream tributaries and springs contributing water at colder temperatures to allow coldwater fish to hold over and survive. But almost all anglers decline to fish Penn's in the heat of July and August, because the temperatures are typically too marginal for trout to survive the strain of being caught.

The biggest reason for the difference between coldwater and warmwater fish species is that the coldwater species require more dissolved oxygen in the water, and colder water retains more dissolved oxygen than warm water. Trout and salmon prefer a mix of around 10 parts oxygen to a million parts water. Warmwater fish are fine with 5 ppm (parts per million) or even a bit less.

Oxygen "dissolves" in water from the air above the surface- which is why trout often like to hold in plunge pools and pocket water, because fast currents like that pull air bubbles into the water and help to dissolve more oxygen. But bubbling rapids alone aren't enough to support trout- the water temps have to stay low enough that the water can store enough oxygen to keep the levels around 10ppm. Trout start to die off below around 5ppm DO, that's about the bare minimum for survival for them. They're basically gasping for breath at that point. A heat-stressed trout in summer usually settles low in the stream without moving much of anything except for it's gills, which fan in and out as if it's panting for breath. Which is pretty much what's happening.

This is one reason why anglers like to carry stream thermometers.

Thermometers can also tell when the best feeding and insect hatching temps are. Trout are usually most active in water between 50 and 65 degrees. 55-60 degrees F is about perfect. Smallmouth bass seem to like it best right around 70-75 degrees F.

Posted on: 2010/11/9 17:29

Re: Cold Water Streams vs Warm Water Streams

2010/11/4 15:45
From Cranberry TWP PA
Posts: 0
Thanks for the detail info. I will keep this in mind when heading out when the temps are getting warm.

Posted on: 2010/11/9 21:12

Re: Cold Water Streams vs Warm Water Streams

2007/3/17 20:20
Posts: 0
I came upon this thread and thought you might be interested in this paper discussing Coolwater streams in Michigan and Wisconsin.Google documents

Posted on: 2010/11/12 0:05

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