For some Arctic streams, the only nutrients available come from the decaying carcasses of spawned-out kokanee and salmon. The absence of these kokanee creates a productivity deficit which then cascades into a decline in food availability. The decline and eventual collapse of the kokanee population in the Kootenai River tributaries have resulted in a net loss of productivity for the tributaries due to the disappearance of returning spawning kokanee.
Returning kokanee that spawn and eventually die in the tributaries are a significant source of nitrogen, phosphorus, carbon, and other micronutrients. Collapse of this fishery has negatively affected productivity in both the tributaries and the mainstem Kootenai River. Kokanee are considered a keystone species and are prey for burbot, white sturgeon, and bull trout. We propose adding nutrients to experimentally offset the nutrient deficit from the decline and/or disappearance decaying kokanee. The goal is to stimulate productivity and potentially increase food availability at critical times in both the tributary and the mainstem Kootenai River. Results from this study are expected to inform future scientific decisions regarding stream nutrient management in the Kootenai River tributaries.
This experimental study is designed to investigate the effectiveness of adding limiting nutrients to Kootenai River tributaries with the goal of increasing productivity in tributaries that historically supported kokanee populations.