EPA-OW: NRSA Fish 2009 (Wade):  Fish sample collection in small wadeable streams

  • Summary
  • Analytes
  • Revision
  • Data and Sites
Official Method Name
Section 6.5: Wadeable streams-Fish (of National Rivers and Streams Assessment: Field Operations Manual (2009))
Current Revision
April 2009
WATER  (Waterbody type - Wadeable stream)
Electrofishing Unit
Method Subcategory
Method Source
  National Rivers and Streams Assessment: Field Operations Manual (2009)
EPA-841-B-07-009 - National Rivers and Streams Assessment: Field Operations Manual (2009)
Brief Method Summary
The fish sampling method is designed to provide a representative sample of the fish community, collecting all but the rarest fish taxa inhabiting the site. It is assumed to accurately represent species richness, species guilds, relative abundance, and anomalies. The goal is to collect fish community data that will allow the calculation of an Index of Biotic Integrity (IBI) and Observed/Expected (O/E) models. Backpack or barge electrofishing is the preferred method. If electrofishing is not possible due to safety concerns, high turbidity, or extremes in conductivity, complete the “Not Fished” section of the field form and comment why. Streams with mean wetted widths less than 12.5 m will be electrofished in their entirety, covering all available habitats. However, the time and effort necessary to sample reaches greater than or equal to 12.5 m wide is prohibitive in the context of the survey, thus subsampling is required. Sub-sampling is defined by 5-10 sampling zones, each starting at a transect. In all instances electrofishing in wadeable systems should proceed in an upstream direction using a single anode. Identification and processing of fish should occur at the completion of each subreach.
Scope and Application
This method describes the procedure for collecting fish in wadeable streams that are sampled as part of the U.S. EPA's National Rivers and Streams Assessment.
Applicable Concentration Range
Very low or very high conductivity can decrease the effectiveness of electrofishing equipment. If no fish can be collected or electrofishing is ineffective due to high conductivity or extreme turbidity, refer to a seining protocol.
Quality Control Requirements
Sample Handling
Fish retained for laboratory identification or as vouchers should be preserved in the field following the precautions outlined in the MSDS. All personnel handling 10% buffered formalin must read the MSDS (Appendix D). Formalin is a potential carcinogen and should be used with extreme caution.

Processing of fish must be completed at the end of each transect; however, if fish show signs of stress (e.g., loss of righting response, gaping, gulping air, excessive mucus), change water or stop fishing and initiate processing.
Maximum Holding Time
Relative Cost
3 - 6 hrs. per site/sample
Sample Preparation Methods