Is cold water natural?

[sea lamprey]

Regarding the concerns about warm water on the Delaware: I fish a good-sized freestone stream in Pennsylvania that by July heats up into the low 80s. It has wild browns and rainbows. And it has good hatches until late June. By July, it becomes a smallmouth fishery, but by mid-Septmber, the trout have become active once again, and so have the insects. My guess is that the fish find a deep hole, cold-water tributary, or spring to ride out the summer. Isn't that what happens on the Delaware during the summer? It's certainly deep enough and has enough tributaries. I remember reading in Joe Humphreys's book that trout will migrate long distances to find cold water in the summer. So while ice-cold releases in the heat of the summer might be good for fishing, is it necessary for the fish? Just curious, that's all.

 

[bjmiller]

Cold water is good for the fish. They will be active and will feed often. There growth rates will be good because of that and they will remain fat. In warm water, they won't feed much, because they're mainly trying to breath. They will lose weight and will start to die at some point.

Bruce

 

[sea lamprey]

Well... this freestone stream certainly has healthy-looking fish. And some large ones, too. They might not feed much in the summer (I honestly don't know), but they sure seem to be in good shape by September.

 

[flyin]

any wild fishery is there because there are refuges (from both water levels and temps) for the trout. it varies a LOT by watershed. So, cold water (less than 75) is necessary or healthy for trout, but a stream or stream segment that heats up into the 80s will have thermal refuges somewhere for the fish to flee.

 

[bjmiller]

Don't you think the trout would be better off if they weren't stressed in the Summer?

Bruce

 

[bjmiller]

Flyin,

there are exceptions, some tailwaters have become wild trout fisheries because of cold water release schedules, where they may have been marginal before or even non-existent. There are lots of examples around the country.

Bruce

 

[sea lamprey]

This is an interesting discussion, and I appreciate people's thoughts. I think "stress" is a natural part of many fishes' lifecycle. It's perfectly natural for native brookies to get stressed in August when flows are at a trickle. They'll seek out those deep holes or undercuts and remain fairly inactive for weeks. If you catch one, it will appear very dark in color, which generally indicates stress in fish. My question about the Delaware is this: is the goal to regulate flows so that the trout can survive the summer months, or is to create an artificial fishery where people can dry fly fish at high noon in the middle of July? Because they sound like two different goals to me.

 

[bjmiller]

I think the "ideal" situation for the fishery would be to have hatches all day and be able to fish at high noon with the dry fly as you say, but I think all agree that that is just a pipe dream. I believe the goal is somewhere in between, where the bulk of the trout are not stressed to the point of death (which could happen, believe it or not).

Bruce

 

[flyin]

Bruce,

Yes, I was hasty in my original assessment. By "wild fishery" I was thinking of a natural wild fishery, not an ar "artificial" wild fishery like a tailwater. I think the statement that I made is true for natural wild fisheries: for wild fish to exist in them, there have to be thermal refuges, or access to the same, in the stream or stream segment. As you know, there are underground springs that exist all over the place. The main stem of even a small stream (small being less than 20 ft across) can be up near the dangerous level, yet having cold water seeps along the banks that provide enough refuge for the fish to make it through even the hottest weather. Of course you're right about the ideal situation.

Pertinent to sea lamprey's original question, I don't think it's fair to compare the Delaware system to "natural" wild fisheries. There are just too many differences making it more of an "apples to oranges" type comparison.

-- Rob

 

[bjmiller]

Rob,

I agree!!

Bruce

 

[BEAMOC]

I may be wrong but it seems the driving force behind maintaining the Delaware is economics. Many people in the small towns along the rivers course have built their livelyhoods on it being a quality fishery for a good portion of the year. However, I also believe that these individuals chose this path because they truly care about the fish, the river, and the environment, junkies who worked hard to create a job which they love. As far as cold water being benificial to the fish, I don't see how it could ever hurt.

Keith

 

[bjmiller]

Well said, Keith!!

Bruce