The end of mayflies

A lot has been written lately about declining mayfly populations. Nobody's really sure what's happening or what to blame. Neonicotinoid pesticides, global warming, water quality...all of the above?

The decline on my home river is starting to feel like a complete collapse. I haven't seen a carpet hatch of BWOs on the Teton in about a decade. The last 3 or 4 years have been a massive decline. This fall, the small bug hatches were so pathetic it was hard to find enough trout schooled up to make putting on a dry worth my time. Used to be streamers before 1pm, then small drys the rest of the afternoon. I got out maybe 10 days this fall and I probably threw dries for 5 or 6 hours of that.

This used to be a totally normal sight in the fall, fish stacked up in the foam line sipping small bugs. Now, its almost nonexistent.

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Its happening all over. One of Harrops' guides wrote a blog about how he'd kept notes on every 18"+ fish he or a client had caught over decades on the RR Ranch. 20 years ago, the majority of big fish where caught on a mayfly pattern. Now, the majority are caught on terrestrial patterns.

Anybody else experiencing the end of mayflies?

The year I started fishing the Missouri about ten years ago seems to be the year after they had their last big late October baetis explosion. You could still get them on tiny pseudo patterns but after five years of trying to find the "big bugs" I gave up. Maybe others who fish Craig more often than I do can weigh in.

My experience on the ranch is limited to about five years. I seemed to hit a big rise most of the times I'd wade there then. The past two years, it's been a heck of a time finding a good rise in June. Sure the season was early or late. This year out of ten days, 8 of them almost no risers. Some bugs, but no heads .Then one day bang, all the Flavs popped at once. Best night I've ever had there. Go figure. Tiny sample but that blog post seems pretty authoritative and my experience is consistent with it.

Definitely noticed an increase of water temps and also increases of algae in local streams. Both stonefly and mayfly nymphs numbers seem to be down.
We hosted some of the sites for the World Masters and Ladies Fly Fishing Championships this past summer, but I hear the increased pink salmon run was a bigger factor in the struggles landing trout on the bigger rivers here however.

It's a painful and fluctuating process.....the highly localized & VERY INTENSE fits & starts hits of a changing climate. Sure wish the jetstream could somehow be leveled off to either resume the west-->east character or simulate some weather pattern that encourages a west-to-east jetstream/airflow. I think that's how science is going to have to look to solving the picture...instead of trying to make us all buy new vehicles without a BIGGGG government subsidy....y/n? ..Cause I, for one, don't have the $$ I once did, being 69 now. Cross our fingers for a lot of snow this winter!

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Originally Posted by steved

It's a painful and fluctuating process.....the highly localized & VERY INTENSE fits & starts hits of a changing climate. Sure wish the jetstream could somehow be leveled off to either resume the west-->east character or simulate some weather pattern that encourages a west-to-east jetstream/airflow. I think that's how science is going to have to look to solving the picture...instead of trying to make us all buy new vehicles without a BIGGGG government subsidy....y/n? ..Cause I, for one, don't have the $$ I once did, being 69 now. Cross our fingers for a lot of snow this winter!

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I don't know if water levels can explain what's happening. Mayflies are usually able to rebound after a drought cycle. There is a sustained decline occurring. It's a trend that's continued across good and bad water years. Its going on in different geographical areas with dissimilar elevations and ecosystems. And its happening across different genera of mayflies. Free swimmers, clingers, burrowers are all in decline.

So, imho, it will take more than a few good snow years to fix this.

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Originally Posted by neckdeep

I don't know if water levels can explain what's happening. Mayflies are usually able to rebound after a drought cycle. There is a sustained decline occurring. It's a trend that's continued across good and bad water years. Its going on in different geographical areas with dissimilar elevations and ecosystems. And its happening across different genera of mayflies. Free swimmers, clingers, burrowers are all in decline.

So, imho, it will take more than a few good snow years to fix this.

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Agreed.....