The no-high-grading-of-walleye regulation means anglers must make their decision to keep or release a fish as soon at it is landed. This page discusses important considerations to help you make this choice, based on a fish’s chance of survival.

Whether you’re a person or a fish, stress is a bad thing, and the more things that stress you out, the longer it takes to recover. When fish are caught, a number of factors contribute to how much stress they experience. Effects of stressors on fish add up quickly. The more stress they experience, the lower the chance they will survive, if released. Just because a fish swims away doesn’t mean it will survive.

Minimal Impact:

• Fishing a jig and minnow in shallow water, in the spring
• Casting jigs, spoons or lures with single hooks

Moderate Impact:

• bobbers with a single hook and worm, in the summer
• Fishing a jig and minnow in deep water, in the fall
• Using bottom bouncers and night-crawlers in shallow water, in the spring
• Long-line trolling diving plugs in shallow water, in the summer

Substantial Impact:

• Using bottom bouncers and night-crawlers in deep water, in the summer
• Deep-trolling diving plugs, in the summer
• Vertical jigging in deep water, in the summer
• Ice fishing in deep water

Many fish that have been badly stressed die a few days after release. Some of the major sources of stress on fish that we catch include:

Major Sources of Stress:

Time to Land:  The longer it takes to land a fish, the more stress it experiences. Just like people, fish build up lactic acid in their muscles when they use them. Lactic acid is what makes our muscles sore the day after we work really hard. It takes at least a few days for a walleye to break down the lactic acid that builds up from being caught and released. Playing, landing and releasing a fish quickly, results in less stress for the fish.

Lure Type:  Hooks or lures that generally hook fish in the front of the mouth have high rates of survival of fish released. Hooks or lures that are often swallowed or hang up on the gill arches of a fish generally result in lower rates of survival. Jigs, and diving plugs with treble hooks, are not usually swallowed but diving plugs with a number of hooks on them can easily become tangled in a fish’s gill covers. Single hooks tipped with live bait are more likely to be swallowed by a fish than artificial lures. Also, it usually takes more time to remove treble hooks from a fish than single hooks and barbless hooks, of any style, provide the quickest release of fish.

Changes in Water Temperature:  Warm water temperatures increase the amount of stress on a fish that has been hooked and landed. The cooler the water, the better the chance a fish released will live. Bringing a walleye from deep, cool water up to warm surface water, is especially stressful.

Changes in Depth: Fish have a gas bladder that enables them to adjust their buoyancy and depth, much like a submarine does. However, the gas bladder in walleye is not attached to the throat. Therefore, walleye can’t burp out extra gas in their bladder to quickly change buoyancy or depth. Pressure increases as water depth increases. At 30 ft deep, the pressure on a walleye is twice as great as at the surface. When walleye are brought to the surface from a depth of 30 ft, the gas in the bladder expands quickly, doubling in volume and putting severe pressure on internal organs. When travelling to the surface from 60-ft deep, the pressure change is so great that the gas bladder may stick out of the fish’s mouth, its eyes may bulge and gas bubbles may form in the blood vessels and gills. The percent of fish eventually dying after being caught in 60 ft of water may exceed 50%. The shallower the water, the better the chance a fish will live if released.

Answers to Commonly Asked Questions:

• Does letting gas out of the gas bladder with a needle, or "fizzing" a fish, improve a fish’s chances of surviving?

A fish that is unable to remain upright in the water because it is severely stressed and/or has an over-inflated gas bladder, stands a poor chance of surviving, if released. "Fizzing" is a process where gas is released from the gas bladder of a fish by inserting a needle in the side of the fish and puncturing the gas bladder. While helping a fish regain it’s ability to return to the bottom of the lake, many fish that are "fizzed" end up dying within a few days of release, from the stress of being caught and handled. There is also the likelihood that when you insert the needle into the side of a fish you will damage internal organs such as the kidney or intestines. Just because a fish swims towards the bottom doesn’t mean it will survive. 

• Should I reel in fish hooked in deep water quickly or slowly?

Fast! Contrary to popular belief, slowly reeling in a fish from deep water DOES NOT give a fish enough time to compensate for the change in pressure. Between 20 and 30 minutes may be needed for a fish to compensate for pressure differences between a depth of 30 ft and the surface. Instead, prolonging the time it takes to land and release a fish, increases its stress level. The tissues around the gas bladder are often capable of preventing the gas bladder from increasing in size for up to 5 minutes after the pressure outside of the fish decreases. Once a fish is in the boat, release it as quickly as possible to maximize its chance of surviving.

• What if a fish is bleeding when I bring it into the boat? Will it survive if I release it?

The best you can do is try to assess the extent of the damage to the fish. If a gill was simply nicked by the hook, a fish might stand an excellent chance of surviving if released. However, if the hook has been swallowed deeply or a gill arch has been ripped, you should probably keep the fish, if it is legal to do so. Single hooks on live bait rigs only cost a few cents. If you want to release a fish that has swallowed the hook, simply cut the line rather than ripping the hook out. Also consider effects of other sources of stress on a fish’s chance of surviving, if released.