hatch triggers

[campfire]

The caddis thread reminded me of a question. A few weeks ago I was fishing the middle Weber and came across one hole where there were a lot of fish rising. I think they were rising to BWO as I caught several fish on a BWO emerger. I had a great time and have returned several times since at the same time of the day and found literally NO surface action. Now it happened to be a rather cloudy day while my return trips were better weather. My question is what triggers hatches? I have heard water tempature, the length of daylight contribute to timming of hatches but how about weather. How much of a factor is the daily weather? I would like to be able to predict hatches a little better if possible rather than just trust to fishermen's luck.

[jonescort]

But I know midges hatch if it is a warm enough day but I don't know if it has to do with if it is wind has an effect or anything like that. Hopefully someone much smarter will chime in and give some usefull info because I am curious of what causes BWO and caddis to hatch.

[cheech]

IMO, baetis LOVE the nasty weather. If there are clouds, rain, snow, they will be there. Caddis like sunny days, but they wait until night time to come out to play.

[JayMorr]

There a few things that trigger a hatch:

1. Water Tempature
2. Time of Day (Day Light)
3. Air Tempature

Cloudy skies and cooler weather bring out the Baetis. Baetis do not have moving mouth parts. They have no way of hydrating themselves or a way to eat. In order for Baetis to hatch successfully they need cooler weather so that their wings do not dry out and burn in the heat of the sun. You will find that overcast days and cooler weather bring out the BWOs.

Caddis on the other hand have workable mouth parts, can eat, and survive all summer long. They do not need the cooler weather to hatch out and survive. I believe an average Caddis fly adult can live up to 6months.

Cort to answer your question regarding wind, yes it does have an effect on the hatch. The wind will put a hatch down or often the hatch will come off and you will not see much of it. Weather plays a huge role in the hatch cycles. Its also the reason why we see a lot of hatches delayed this time of year or when we see a hatch come on earlier than expected.

I hope that answers some questions.



JayMorr

[FishOn!]

I too have thought a lot about this lately. I went out on the LP monday and the weather was textbook for a good Baetis hatch to start. There were fish rising here and there during the 3 or 4 hours I was on the water but only for several minutes did the fish start rising consistently. In my opinion it should have been going crazy...little wind, very cloudy, and the right time of day. But a big hatch never materialized...maybe the air temperature was too warm? Last year I went on a sunny day when there was a nice little breeze going and the hatch was absolutely off the hook...dozens and dozens of fish all poded up in the top of the water column inhaling adults of the top of the water for probably two hours or more...they were still coming off when I unfortunately had to leave to go to work or something. I guess the air temperature or some other factor must have been perfect, who knows?

With the caddis ive noticed stable, warm summer days will bring a good hatch on. I have been on the river late when a thunderstorm was brewing and it killed the hatch completely. But this leads me to a question. All caddis hatches that ive experienced have been short lived...where fish are rising all over the place for maybe 15-20 minutes. Is there any condition where a caddis hatch will start long before dark and go for say an hour or two?

[JayMorr]

Fishon,

Good observations. What a lot of people do not realize is that a hatch cycle can get delayed by weather conditions either being to hot or to cold and push the hatch from happening by days or even weeks. It pushes everything back in a way.

The Green River is a good example from this past weekend. Sporatic baetis but nothing consistant. Lots of wind all weekend and fairly sunny. I spoke to Charlie up there at FGL and he said 2 days prior to us coming it was calm, clear, slight overcast and baetis all over the water. The bigger hatch cycles will hit and I am sure its just a matter of days if the weather permits. A good hatch can be killed quickly if the conditions are not right.

Also air tempatures play a huge role. If its to hot....baetis will die quickly. The tiny veins in their wings will dry out killing them before they have a chance to mate and lay eggs. (Thats where John Gierach gets the term "Sex Death and Flyfishing" for one of his books ).


There are also other factors but these are the main ones. Some people who flyfish the middle provo a lot will recall how the Green Drake hatch's were put off for a number of years. It didnt really come back strong until after the restoration project was completed and the water quality and habitat came back. I still dont think I have seen a decent hatch on the Charleston section of the Provo yet.




JayMorr

[Tyson]

What I have learned is always be ready but don't hold your breath. Things change so fast hour to hour, minute to minute. Actually, the best way to trigger a BWO hatch is to leave all your BWO flies at home. Then you will probably find yourself in the epic hatch of the year. :-D

[ByteMe]

... All caddis hatches that ive experienced have been short lived...where fish are rising all over the place for maybe 15-20 minutes. Is there any condition where a caddis hatch will start long before dark and go for say an hour or two?

Sounds like you're going home to early. Some of the best caddis action happens after dark and can last for quite a while.

A good mother's day hatch can happen long before dark and last for hours. Here's an article with some nice pics.

http://www.yellowstoneangler.com/Mothersdaycaddishatch.asp

I've also seen really good caddis action early in the morning, but they weren't hatching.

[FishOn!]

Sounds like you're going home to early. Some of the best caddis action happens after dark and can last for quite a while.

No, I am pretty sure I stay late enough, I usually wait until the fish stop rising...I mean I do catch quite a few fish before the hatch, and many during, but it just seems that the actual surface activity only lasts around a half hour tops in my experience...it just seems to come on really strong and then quickly die off starting a bit after the sunset and tapering off quickly as it gets fully dark...after that I stop catching and usually head for the car under the light from my head lamp...is there some second wave of activity I am not aware of? Or maybe its just been too long and it seems like its over so quickly cuz the time flies when you're having fun...anyway...

I've never fished the caddis hatch on the MP, just the LP so maybe its not as strong...or maybe I just happen to hit the weaker days

A good mother's day hatch can happen long before dark and last for hours. Here's an article with some nice pics.

http://www.yellowstoneangler.com/Mothersdaycaddishatch.asp

Now thats a caddis hatch!! Wow! ...thanks for all the info, this is a fun conversation

[Jason]

I believe water temperature and barometric pressure are the biggest factors...and of course cloud cover.

[ryfly]

Good topic camp. Best day I have ever had fishing a hatch was 70+ degrees and sunny. Didn't make any sense to me but, I sure enjoyed it.

Last year I was fishing a still water, the dAMNsels were crawling on my pontoon thick, I sat on the bank, ate lunch and watch hundreds of them crawl up into the grass, dry out and fly away and didn't see one "swirl" all day. I did manage one or two on the pattern but, for whatever reason, they weren't keying on them. I had better success on other patterns. My point is to take this topic one step further. What makes fish key on the hatching bugs? Could it have been because it was sunny, the fish stayed deep? I'm not sure but, it was damn frustrating. The same hatch and venue is coming up shortly so, PLEASE HELP!!