Abstract
This study compares the efficacy of environmental DNA (eDNA) sampling to traditional capture-based methods such as seine netting and minnow trapping for monitoring fish assemblages in the Elk River estuary. The Elk River estuary is located in Humboldt County, California and hosts a diverse range of fish species due to its tidal influences and brackish habitat. A restoration is planned for this area, thus it is important to explore the effectiveness of different fish monitoring methods that could be used to evaluate restoration success. For this capstone project, we conducted a pilot study at five sites within the Elk River estuary, where water samples for eDNA analysis of fish species were collected alongside capture-based fish sampling methods (seining and minnow trapping) for comparison. These five sites are potentially inhabited by several species of interest including: coho salmon (Oncorhynchus kisutch), Chinook salmon (Oncorhynchus tshawytscha), steelhead trout (Oncorhynchus mykiss), coastal cutthroat trout (Oncorhynchus clarkii clarkii), tidewater goby (Eucyclogobius newberryi), and longfin smelt (Spirinchus thaleichthys). We then generated a monitoring plan based on our findings from the pilot study with sites for immediate sampling and sites where sampling should be conducted once the restoration project is completed. Included in the monitoring plan are limitations to eDNA sampling with reflections on the strengths of both eDNA and capture-based samplings. Overall, we found that eDNA sampling was less labor intensive and easier to conduct compared to seining and minnow trapping. The results from this pilot study and subsequent monitoring plan are intended to help organizations such as CalTrout to determine the most effective and cost-efficient methods to monitor fish species as part of restoration post-project assessment.
Date
Spring 2024
Department
Environmental Science & Management
Advisor/Professor
Daniel Lipe, Alison O'Dowd