Summary #
Electrofishing (fish shocking) is a sampling method used to survey fish populations in streams. This page explains the technique, equipment requirements, safety considerations, licensing requirements, and when fish shocking is appropriate for watershed assessment.
It is debatable which reflects long term pollution trends better – fish or insects. A combination of both surveys can be very valuable and enlightening.
Fish shocking is used to gather a fair representation of the diversity of the fish population. In this method, electrical current is run through the water, momentarily stunning the fish which are then swept up in nets. the photograph on the overview page illustrates a group employing fish shocking.
The electrodes are attached to a large backpack which holds an electrical generator. The current follows through the water between the two hand-held electrodes. The number of people required to conduct a successful fish-shocking is determined by the size of the waterway. The must be enough people to follow along behind the electrodes to capture the shocked fish in nets as well as people carrying water-filled buckets. The buckets are used to deposit fish into while the fish shocking takes place. Most fish recover quickly from the shock and can be returned to the stream after counting with no ill effects.
The distance covered as well as the length of time should be recorded during a fish shocking. It is important to have trained professionals conduct or assist in this type of assessment to make sure that the equipment is operated safely and correctly with no harm coming to either fish or humans.
Sources/Links (as provided in the source text):
KB Article 8: Biological monitoring – Fish shocking #
It is debatable which reflects long term pollution trends better – fish or insects. A combination of both surveys can be very valuable and enlightening.
Fish shocking is used to gather a fair representation of the diversity of the fish population. In this method, electrical current is run through the water, momentarily stunning the fish which are then swept up in nets. the photograph on the overview page illustrates a group employing fish shocking.
The electrodes are attached to a large backpack which holds an electrical generator. The current follows through the water between the two hand-held electrodes. The number of people required to conduct a successful fish-shocking is determined by the size of the waterway. The must be enough people to follow along behind the electrodes to capture the shocked fish in nets as well as people carrying water-filled buckets. The buckets are used to deposit fish into while the fish shocking takes place. Most fish recover quickly from the shock and can be returned to the stream after counting with no ill effects.
The distance covered as well as the length of time should be recorded during a fish shocking. It is important to have trained professionals conduct or assist in this type of assessment to make sure that the equipment is operated safely and correctly with no harm coming to either fish or humans.
Common fish guide (pics needed)
The following pictures are examples of fish commonly found in streams and creeks in Pennsylvania. Fish shocking is a good way to capture and examine the fish in the watershed.
Black-nosed Dace
Sunfish #
Sunfish come in many sizes and colors, but basically the same shape. Many common sunfish, such as the Bluegill and Pumpkin seed have brightly colored earflaps beside their gills. Most sunfish inhabit quiet, weedy ponds or mud-bottom streams. Some are also found in rocky bottom streams.
Sucker #
Suckers are
Brook Trout #
Brook trout like cool, clear waters in lakes and large streams. Normally, these fish are found in more turbulent areas, such as riffles.
Johnny Darter #
The Johnny darter belongs to the perch family of fishes. They are commonly found on the bottom of streams. They settle to the bottom and dart forward occasionally. Darters are extremely sensitive to pollution and will only inhabit clean water.
The above information taken from A Guide to Common Freshwater Animals part of the Environmental Education Leaflet Series #6 published by the Commonwealth of Pennsylvania, Department of Environmental Resources, Office of Resource Management and Bureau of State Parks.
Descriptions of the fish can be found in Reader’s Digest North American Wildlife.
The Pennsylvania Fish and Boat Commission hosts an online guide to Pennsylvania Fishes. http://sites.state.pa.us/PA_Exec/Fish_Boat/pafish/gal1.htm l
Sources/Links (as provided in the source text):
- http://sites.state.pa.us/PA_Exec/Fish_Boat/pafish/gal1.htm
Related Pages #
- Developing a Monitoring Plan
- Water Quality — What biological monitoring tells us
- Collection Methods — How to collect biological samples
- Macroinvertebrate Guide — Identifying stream organisms
Source and Last Reviewed #
Source: AMR Clearinghouse (amrclearinghouse.org). Migrated to AML-Connect. Last Reviewed: 2026-03-13.
[Admin note: Some external links in this article may be outdated. Verify before relying on them. Flag dead links for removal or replacement.]
Tags: monitoring, sampling, practitioner, safety
