Fish Surveys - Minnow Traps

Revision History

• Revised on 05/10/26 to address rope type and length, deployment location identification, 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 should obtain a scientific collection permit 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

    • 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

• Identification

  • Traps must have an NFC tag affixed for identification

• 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

      • If a trap is accidentally lost it needs to be retrieved immediately to prevent stress and accidental mortality

      • Ghost traps 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

    • Excess rope should be coiled up and secured 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 retrieval.

      • Tape should be placed within 10-feet of the trap on either side but not right at the trap so as not to draw attention

• 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 deep and shallow water to increase your odds of finding fish

• 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

  • Fish trapped should be identified, measured, and photographed for reference

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