Fisheries Inventory at Rocky Mountain National Park

Kanno Y and Preston D. Fisheries Inventory at Rocky Mountain National Park. 2021-2022. National Park Service

The Cameron Peak Fire and East Troublesome Fire of 2020 were the two largest wildfires in Colorado history. They burned approximately 9% of the Rocky Mountain National Park, raising a concern for trout populations that currently support recreational fishing and success of on-going and future efforts to conserve native trout populations. We inventoried habitat characteristics and biological communities at 19 sites in summer of 2021 and a subset of 11 sites in summer of 2022 to characterize wildfire impacts on aquatic resources, with the focus on characterizing trout population responses. There was much site-to-site variation in the trout population responses, but when averaged across sites using Bayesian hierarchical models, trout abundance significantly decreased in 2021 relative to pre-fire abundance, and the decrease was more evident in smaller trout (75-125 mm total length) than in larger trout (> 125 mm). From 2021 to 2022, trout abundance generally increased, although the increase was statistically significant only in small trout. Although pre-fire data were lacking for benthic macroinvertebrates, their abundance and composition was comparable between burned sites and those outside the fire perimeter, indicating that prey availability to trout was not limited. Our results show that trout abundance decreased post-fire, but trout populations were not eradicated and are likely in a recovery phase. These data cannot be used to argue for stocking trout to sustain recreational fisheries or discontinuing native trout conservation actions including the Poudre Headwaters Project.

Type
Project
Authors
Kanno, Yoichiro; Preston, Dan
Publisher
National Park Service
Units
ROMO
Keywords
fish, IMD, macroinvertebrate, National Park Service, NPS, NPS Inventory and Monitoring Division, NPS Species Inventory Program, post-fire, Poudre Headwaters Project, recreational fishing, trout, wildfire
Subjects
Ecological Framework: Biological Integrity | Focal Species or Communities | Freshwater Communities , Ecological Framework: Biological Integrity | Focal Species or Communities | Freshwater Invertebrates , Ecological Framework: Biological Integrity | Focal Species or Communities | Fishes , Ecological Framework: Biological Integrity | At-risk Biota | T&E Species and Communities

Program

Products

Collections

Browse the catalog