Fish Surveys - Minnow Traps

Revision History

• Revised on 05/10/26 to address rope type and length, deployment location identification for maintenance and retrieval, and fish handling concerns

Background

Fish surveys are a big part of NFC’s Holistic Stream Assessment/Restoration methodology. This includes NFC sponsored trapping and netting, and agency sponsored electro-fishing where NFC assists. These surveys are usually performed under a Scientific Collection permit issued by a state fish and game agency.

Goals 

Minnow traps are a cheap, non-lethal, effective, and efficient method for surveying fish. Unlike sein and cast nets which have to be actively maintained, minnow traps can be set and left in place for a period of time.

Policy

Below are the rules pertaining to the use of minnow traps:

• Administrative

  • Chapters must obtain a scientific collection permit from the appropriate government agency before setting traps

    • Do not operate under the guise of legal bait trapping as that is not what we are doing

  • Where applicable, landowners should be notified in advance of your intent to trap with a request for permission to do so

    • Municipality owned land

    • State-owned land

      • While this is often covered under a state-issued scientific collection permit, notifying state fish and game lets them know what we are doing where and when

    • Organization owned land

    • Business owned land

    • Private land

• Equipment

  • Standard minnow traps

    • Black traps are recommended as they are harder to detect and less likely to stolen, vandalized, or removed from the water

    • Vinyl dipped traps are preferred as they resist rusting and last a bit longer than painted traps

    • Traps should be equipped with ringed versus barbed entry holes to prevent injury to fish

    • Traps should be equipped with a quick-release clip for fast and easy opening and closing

• Identification

  • Traps must have an NFC ID tag affixed for identification

    • National NFC will provide these upon request

• Deployment

  • Traps should have a 30-foot dull colored, ideally camouflaged, sinking rope attached to them

    • Ropes should be tied off to a tree, root, bush, or tent stake before throwing the trap in the water to prevent loss

    • Excess rope should be coiled up and secured with a twist tie, zip tie, or short length of string or cord so that it does not get in the way or pose a hazard to humans or wildlife

    • Trap locations should be marked with a short piece of surveyors tape with “NFC” on it for easy identification and retrieval.

      • Marking tape should be placed within 5-feet of the trap on either side but not right at the trap so as not to draw attention

  • If a trap is accidentally lost or manages to come unsecured, it needs to be retrieved within 24 hours

    • Ghost traps can kill fish and amphibians due to stress, oxygen depletion, lack of food, etc.

    • If found by someone outside of NFC, this is a poor reflection on the chapter and the organization as a whole and can result in a refusal to allow trap deployment in the future

• Bait

  • Traps can be baited with bread, pet kibble, perforated cans of cat food or tuna, capsules or nets with worms or other insects, fish flesh, poultry or meat, etc.

    • Bait should be adjusted based on the targeted species, or mixed to attract multiple species

• Location

  • Traps should be set away from high traffic areas wherever possible

  • Traps should be set near inlets and outlets

  • Traps should be set in shallow and deep water to increase your odds of finding fish, as well as varying species

• Duration

  • Traps should be set for no more than 24 hours to lessen the chance of stress or mortality

    • Sets of 6-12 hours are preferred and often equally as affective

• Handling

  • Traps containing fish should not be placed on the ground

  • Fish should be removed from the trap by hand and placed in a 5-gallon bucket of fresh water as quickly as possible to lessen stress

    • If fish will be kept in a bucket for more than 5 minutes, a small battery powered aerator should be used

• Miscellaneous

  • Dead, visibly stressed, and diseased fish should be removed from the trap and disposed of properly

  • Nonnative fish should be disposed of rather than released when doing so would have a positive impact

  • Rare or protected native species should be photographed, released immediately and unharmed, and reported to the proper authorities within 24 hours

  • Unusual nonnative species and those not known to be present should be contained and reported to presented to the proper authorities within 24 hours

  • All fish trapped should be identified, measured, cataloged, and photographed for reference

    • Like sized fish of the same species do not need to be photographed more than a couple of times