A 75% decline over 27 years in flying insect biomass

From the abstract:
“This yet unrecognized loss of insect biomass must be taken into account in evaluating declines in abundance of species depending on insects as a food source”

Available here:


At the tenkara bugout in Oregon last summer I was awestruck by how many flying insects there were. It’s was like nothing I had ever experienced. To me, a cloud of insects means mosquitoes or little biting flies. Instead I was treated to a mozaic of beautiful critters each with it’s own tiny appointments, paying me no attention. I would accidentally bonk the occasional butterfly with my rod, or become an emergency landing pad for a clumsy beatle, but for the most part, me and the bugs lived in parallel.

No doubt this contributed to the excellent fishing. I wonder how many other places I’ve fished that we’re once like this.

Guenther, thank you so very much for posting this article. It documents the declines in fish food I have been observing over time here in the western US - primarily California - but had no official data to back up my observations of declining aquatic insect populations in both streams and lakes for the fish to eat. And with the decline of the aquatics, the rising importance of terrestrial insects as an important source of food for most trout to consume that most anglers tend to ignore, especially Tenkara Anglers. You have done us all a Good Service in making this information available. Climate Change is affecting all anglers and the fish we love to catch, especially in fresh water…Karl.


Guenther, Thank you very much. Anytime you have these type of research articles please share. I geek out on this stuff big time.

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