Community based citizen science has increased the scope of ecological data collection and monitoring. Despite its growing popularity, citizen science methods are rarely validated. Validation is important to ensure high quality data can be used in scientific studies, monitoring, and management. The Rouge River (Michigan, USA), an Environmental Protection Agency Area of Concern, is considered a highly degraded river, but has benefited from numerous restoration projects. These projects have improved abiotic conditions in the river, but improvements to the biotic communities have not been assessed. Friends of the Rouge, a non-profit, has collected fish assemblage data throughout the river network for 10 years by seining, a sampling method they selected due to concerns including cost, safety, and fit to the organization’s volunteer-based monitoring program.

We aimed to evaluate differences between sampling fish assemblages through seining performed by citizen scientists and the electrofishing method recommended for standardized assessments performed by fisheries professionals. We examined data from 48 sites across the Rouge River watershed where both sampling methods were implemented. We compared: a) species captured, b) the relationship between species richness and effort, c) diversity metrics used for standardized evaluation, and d) assemblage similarity between methods across the watershed.

Our results showed that in the wadeable reaches of this urban river, electrofishing and seining were comparable. The majority of species captured within the reaches were shared across sampling methods, although community similarity was lowest and highest in small branches. Differences in species captured were mostly driven by rare and benthic species. Species accumulation curves were not significantly different at the watershed or subwatershed scales (except when non-wadeable reaches were included).

Total species richness, the richness of species tolerant and intolerant to environmental degradation, and Procedure 51 scores used by Michigan agencies to assess the status of fish communities, sometimes differed among branches, but neither method was more effective overall at capturing fish diversity.

Our work demonstrates how citizen science methods can be validated by comparison with standard methods. Validating citizen science data enhances utility for monitoring, assessment, and management decisions.

We compared two techniques for sampling fish assemblages in the Rouge River: seining and electrofishing. FOTR has been collecting fish assemblages data by seining in the river since 2012 at 10-20 sites yearly between April-September . At each site, and during each sampling event, they seined roughly 20 times trying to cover the variety of habitats present; and then identified, counted, and measured each fish before returning it back to the river. For most sites, they use a four-foot high and twelve-foot length, 1/8th inch mesh seine and have used four-, eight-, twelve- and twenty-foot seines in the past. Seining has been led by a small team that is a mix of FOTR staff and community volunteers well trained in fish identification and sampling protocols. The team frequently collaborates and communicates with the Michigan Department of Natural Resources (MDNR) and the state’s Department of Environment, Great Lakes, and Energy (EGLE). They also confer with the University of Michigan Museum of Zoology on fish identification when questions arise.

From June to August 2022, we resampled 54 sites throughout the watershed by electrofishing. We chose sites based on FOTR priorities and length of time between previous sampling events while maintaining at least two sites per river valley segment, a Michigan river classification system, to assure spatial distribution throughout the river network. A Smith-Root backpack shocker and an ETS Electrofishing barge shocker were used depending on stream size and access. For the boat electrofishing, we partnered with MDNR to sample. We followed Procedure 51 sampling protocols as closely as possible. Personnel, river conditions, and obstructions sometimes resulted in sampling shorter lengths than Procedure 51 recommendations. We always sampled at least one pool-riffle complex per sample reach. As in the FOTR methods, we identified, counted, and measured all the fish collected. Fish sampling was conducted with Scientific Collector’s Permits issued by the Michigan Department of Natural Resources issued to Robert Muller and Karen Alofs and was approved by the University of Michigan Institutional Animal Care and Use Committee under Animal Use Protocol PRO00008585.

This is the raw data of all seining and shocking sites in the Rouge. When we used paired data, we took the electrofishing site and then found the closest seining date (not including seine data from 2022). The non-wadeable section of the Rouge is considered below the Fair Lane/Henry Ford Estate Dam.