From the second they’re hooked to the moment of release, fish experience some level of injury and stress (in scientific terms: physiological disturbance) during fishing. Even if a fish vigorously swims away when you release it, impacts associated with catch-and-release can cause negative consequences such as diminished ability to avoid predators, reduced reproductive success, and mortality due to increased susceptibility to disease.
Keep Fish Wet Principles address the elements of the angling event that are most in an angler’s control. Our three Principles are universal and can be used for a wide range of species and settings, and are backed by scientific evidence.
Watch best practices in action here.
PRINCIPLE 1: Minimize air Exposure
Just like humans, fish need oxygen to support essential bodily functions and keep them alive. What’s different is that fish get their oxygen from the water (it is dissolved), not the air. Fish respiration (“breathing”) involves moving water into their mouth and over their gills, whether by pumping it or when swimming with their mouths open.
Also like humans, fish need to respire more during and after exercise, including when they are fighting on the end of a fishing line, as well as after they are landed. Maximizing the ability for fish to get oxygen when they are recovering from the stress of angling is essential for a speedy recovery.
Holding a fish out of the water prevents recovery and can lead to death if done for too long. Even short durations of air exposure (as little as 10-20 seconds for some species) can harm fish.
You can reduce negative impacts by keeping a fish’s mouth and gills fully submerged in water as much as possible. It’s simple – #keepfishwet
PRINCIPLE 2: ELIMINATE CONTACT WITH DRY SURFACES
Fish have a layer of protective mucus (slime) and scales that protects them from disease. Contact with dry, hard, or rough surfaces (such as hands, rocks, sand, and boat bottoms) can remove slime and scales making fish more susceptible to diseases, especially fungal infections. Keeping fish in or over the water, and holding them with clean, wet hands or a soft rubber net will help keep their slime layer and scales intact and the fish disease free.
PRINCIPLE 3: REDUCE HANDLING time
Fish are wild animals and handling is stressful for them, whether they are in your hands or in a net. Most fish that are brought to hand are still amped up based on the release of glucose to fuel their ‘fight or flight’ response to being caught. It can take hours for a fish to physiologically return to normal once it is released. The longer you handle a fish, the more stressful it is for them, which compounds the stress associated with capture.
Don’t confuse seeing a fish ‘swim away just fine’ as a sign that it has completely recovered. See the Tip on reviving fish for more information. If you are not going to take a photo of your catch, consider releasing the fish without touching or netting them. Run your hand down the line and remove the hook – something made even easier if the hook is barbless.