Klamath Basin Fish Populations

As readers of this blog know, I have an affinity for the Klamath Basin.  The trout fishing there is very good and it is relatively uncrowded.  Over the past couple of years I have been a donor to the Klamath Lake Land Trust which is working on habitat acquisition and restoration in the upper Klamath Basin which could make a good thing even better.

I was at a KLLT donor event last Thursday and on Friday I was able to spend time with a biologist in the local ODFW office to get an update on upper basin trout populations.  Klamath Lake redband trout are renowned for their size.  I regularly catch 24”+ fish in the 5 lb range.  Bigger fish are to be had as well.  These fish spend a significant part of the year in Klamath Lake where there is an amazing amount of food, hence their growth to impressive size.  They move up into rivers like the Williamson to spawn and escape the heat if the lake gets too warm.

Fish and redd counts are regularly taken in the various spawning rivers and streams and, unfortunately, their numbers are down for the second year in a row.  At the same time, phosphorous levels in the lake have risen dramatically.  Like in the Deschutes Basin, phosphorous levels are naturally high due to its presence in volcanic soils and local fish populations are adapted to it.  After after a certain level, however, it creates poor water quality by promoting algae growth, increases disease and infection rates, and lowers resistance to parasites.  This is especially true in lakes.

Phosphorus is bound up in soils but can be released when disturbed from activities like farming, road building, and logging.  The speculation is that the floods of 2017 washed large amounts of soil into various waterways, releasing phosphorous, which was then carried into Klamath Lake.  Additionally, with the subsequent drought, cattle in upper Klamath Basin ranches have spent significantly more time in riparian areas in search of food.  This disturbs banks and stream bottoms releasing phosphorus that had otherwise been bound up, not to mention increasing cattle droppings directly into waterways.

It’s a tough problem.  Human activities disturb soil and floods happen.  I’m sure the ranchers would rather keep their cows out of riparian areas, but if there is not enough forage growing elsewhere due to drought, and the tribes are calling water rights so ranchers cannot irrigate, then the cows are going to get in streams.  Ironically, by maintaining flows in the river for the benefit of fish the tribes may actually be damaging them.

I don’t think we’re all going to become vegans soon, so this problem is going to be with us for a while.