The Association of Fish and Wildlife Agencies (AFWA) recently honored Idaho Fish and Game with the Ernest Thompson Seton Award for the agency’s research on the effects of air exposure on caught-and-released fish. The annual award is given to a fish and wildlife agency to recognize outstanding accomplishments using science in wildlife management and effectively communicating that science to the public.
Research and Findings
The research was initiated in response to a growing belief by many anglers that holding fish out of water – even briefly – can negatively impact their survival after they are released. Anglers, being dedicated conservationists at heart, were becoming increasingly concerned that poor catch-and-release practices might be widespread and could hurt fish populations, especially for some of their favorite fishes – trout and steelhead.
Several aspects of catch-and-release angling have been intensively studied, however, in recent years there has been a dramatic increase in interest and studies evaluating survival impacts to caught-and-released fish based on how long it takes to land a fish (aka, fight time) and how long anglers hold a fish out of water while unhooking it or photographing it (aka, air exposure). Numerous studies have shown that angling handling practices can cause a short-term stress response in fish, but actual mortality has only been demonstrated when fish have been exercised to complete exhaustion and held out of water for several minutes or more. Nevertheless, some anglers began to question whether new fishing regulations should be adopted in Idaho to prohibit removing certain fish from water as they are being released. In fact, several states have already adopted such regulations, and some angling magazines prohibit pictures of anglers holding fish out of water.
Idaho Fish and Game staff were concerned that undue momentum was building among anglers that even short intervals of air exposure was detrimental to fish. Working together with the University of Idaho, researchers monitored how much time anglers actually spent landing fish they hooked, and how long they exposed those fish to air before releasing them. Surprisingly, no one had ever studied anglers while they were fishing to understand the scope of the problem. It turns out that for trout, steelhead, bass, crappie, and perch, Idaho anglers generally landed their catch in one minute or less, and held fish out of water for 30 seconds or less. Very few anglers held fish out of water for more than 60 seconds. Researchers also set up field experiments to estimate survival and reproductive success for fish that were fought for normal lengths of time and exposed to either 0, 30, or 60 seconds. They found that air exposure at these more realistic levels (up to 60 seconds) had no impact on fish survival or their reproductive capabilities.
The results of these studies were published in several peer-reviewed journals, presented to numerous angling groups, and shared with other state and federal agencies to spread the message.
If anglers are planning to release a fish, they should minimize the length of time it takes to land the fish and keep air exposure to as little as is needed to admire their catch or take a photo. However, anglers should not feel bad about briefly exposing fish to air during the catch-and-release process. Rather, anglers should feel good that, in general, the fishing community already demonstrates very responsible fish-handling practices when it comes to air exposure of caught-and-released fish.
- Fight and air exposure time for trout caught-and-released by anglers
Lamansky, J. A. Jr., and K. A. Meyer. 2016. North American Journal of Fisheries Management 36:1018-1023.
- Air exposure, fight times, and deep-hooking rates of steelhead caught-and-released by anglers
Chiaramonte, L. V., K. A. Meyer, D. W. Whitney, and J. L. McCormick. 2018. North American Journal of Fisheries Management 38:1114-1121.
- Effects of air exposure in summer on the survival of caught-and-released trout
Roth, C. J., D. J. Schill, M. C. Quist, and B. High. 2018. North American Journal of Fisheries Management 38:886-895.
- Fight and air exposure times of caught-and-released trout on the South Fork Snake River
Roth, C. J., D. J. Schill, and M. C. Quist. 2018. Fisheries Research 201:38-43.
- Effects of air exposure on survival and reproductive fitness of wild Cutthroat Trout
Roth, C. J., D. J. Schill, M. C. Quist, B. High, M. R. Campbell, and N. Vu. 2019. North American Journal of Fisheries Management 39:191-204.
- Effects of fight time and air exposure on pre-spawn survival and reproductive success of adult hatchery steelhead
Whitney, D. W., K. A. Meyer, J. L. McCormick, and B. J. Bowersox. 2019. North American Journal of Fisheries Management 39:372-378.
- Effects of air exposure on survival of wild Cutthroat Trout from a warm water stream
McCarrick, D. K., C. J. Roth, D. J. Schill, B. High, M. C. Quist. In press. Journal of Fish and Wildlife Management.