To Keep or Release?

By Andrew Branson | February 1, 2025
From Missouri Conservationist: February 2025
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To Keep or Release?
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Once you catch a fish, you have a decision to make — are you going to keep it or release it? Whether you decide to keep or release it, proper fish handling comes into play, and it is all about safety — your safety as well as the safety and health of the fish. 

When releasing a fish, it is important to take steps to reduce stress on the fish, maintain the health of the fish, and lessen catch-and-release mortality.

Sometimes there is not a decision to be made. Some fish simply must be released after they are caught. Seasons, length limits, and daily limits are just a few regulations that may require a fish to be released immediately. Part of being a responsible angler is staying mindful of the regulations that dictate methods for fish harvest and returning a fish to the water alive when required.

Choosing Equipment

Choosing the right equipment when fishing is important. Fish that strike artificial baits have a higher survival rate because they are less likely to be hooked deep enough to damage vital organs, so it’s best to use artificial lures instead of live bait, especially for catch-and-release fishing. 

Squeeze hook barbs flat with pliers or file them off. Barbless hooks reduce the risk of causing serious wounds.

Use a landing net large enough to handle your fish safely. Nets made of soft, woven, knotless nylon or rubber are preferred.

Measuring Your Catch

Learn to measure and identify the fish you catch so that you can abide by Missouri’s fishing seasons, daily limits, length limits, and other regulations. When in doubt about a fish’s legal length, play it safe and immediately return the fish to the water unharmed.

To measure a fish:

  • Place the fish on a ruler. Make sure the fish is laid flat on its side.
  • Close the fish’s mouth.
  • Squeeze the lobes of the fish’s tail fin together.
  • Measure a straight line from the tip of the snout to the tip of the tail lobes. 

While this technique works for most game fish, some fish are measured differently. For example, paddlefish are measured from the eye to the fork of the tail. Sturgeon are measured from the tip of the snout to the fork of the tail.

Any fish below the legal minimum length must be returned to the water unharmed immediately after being caught. 

Reducing Fish Stress

Don’t let your leisure activity become a source of stress for the fish you are pursuing. 

If you’re using live bait, set the hook at the first sign of a bite so the fish is less likely to swallow the bait. On rod and reel, don’t play a fish any longer than necessary.

Check setlines frequently to improve survival of released fish. In the summer, keep setlines positioned above the thermocline — or the transition zone between surface water and deep water. Never set them in deeper water where the oxygen concentrations are lower.

Reviving a Tired Fish

An exhausted fish may have little energy to swim away when released. There are some things you can do to potentially revive a fish before releasing it.

Hold it upright in the water by grasping its tail with one hand while supporting its belly with the other.

Gently move the fish back and forth below the water’s surface. This allows oxygenated water to flow over the gills.

When the fish is revived, release your grip and allow it to swim away.

Handling Fish Carefully

If you plan to release your catch, continuous moisture is key. Wet your hands and any other dry surface a fish may touch. This will protect the fish’s slime coat, which guards it from infection and improves its survival. Keep the fish in the water as much as possible while removing the hook. 

Hold large fish by the lower jaw with one hand and cradle the heavy body with the other. It may be best to have another person remove the hook. Always carry a hook disgorger or needle-nosed pliers. Back the hooks out if possible.

Cut the line as close to the hook as possible if the fish is hooked deeply in the gills or stomach. The hook will fall out after a time, with minimal harm to the fish.

Avoid teeth by grasping fish over the gill covers. Never put your fingers in the eye sockets or gills and do not lift the fish by the gill covers.

Always be gentle. Squeezing the fish can cause damage to vital organs.

Minimizing Exposure to Air

A good rule-of-thumb is to keep the fish out of water no longer than you can hold your own breath. Be especially mindful during freezing temperatures, which can be damaging to the gills, eyes, and other sensitive areas of a fish. If you are 
going to take a picture with your catch, do so quickly.

Finally, always release endangered fish unharmed immediately. Pallid sturgeon and lake sturgeon are the endangered fish species that anglers are most likely to catch.

Navigating Buoyancy Problems

Most fish have an internal swim bladder that is used to maintain buoyancy. Bringing fish up quickly from depths greater than 30 feet can cause barotrauma and increase fish mortality.

Due to physiological differences, some fish species, such as trout, gar, and catfish, can prevent barotrauma. Other fish species cannot and exhibit symptoms of barotrauma such as bulging eyes, bloody fins due to ruptured blood vessels, protruding stomach from the mouth, or remaining “belly-up” at the water’s surface.

To help reduce the likelihood of barotrauma, fish waters no deeper than 30 feet and reel fish in slowly, giving them time to depressurize.

Identifying Endangered Species

Missouri is home to three species of sturgeon — lake, pallid, and shovelnose. Pallid sturgeon and lake sturgeon are endangered fish species that anglers must release unharmed immediately. This guide will help sort out the three species.

Lake sturgeon (endangered)

  • Sides and back range from dark slate to light brown or yellowish olive; white belly
  • Found throughout the Missouri and Mississippi rivers and its tributaries
  • May reach 8 feet and more than 300 pounds

Pallid sturgeon (endangered)

  • Grayish white
  • Found in the Missouri River and in the Mississippi River downstream from the mouth of the Illinois River and its tributaries
  • May exceed 30 inches and reach 10 pounds or more

Shovelnose sturgeon

  • Reddish brown or buff
  • Found throughout Missouri and Mississippi rivers and their tributaries
  • Rarely exceed 30 inches or 5 pounds

Recommendations for Tournaments

Tournaments can mean long days on the water. Keep fish in livewells until all participants leave their boats. At weigh-in, use only three to five organizer-provided weigh-in baskets. A series of light colored, clean, 50-gallon plastic garbage cans of lake water should be spaced every 10 feet up to the scales so that baskets of fish can be kept in water until the actual weigh-in. The water in these cans must be kept cool, fresh, and aerated.

Provide proper water conditions in the post weigh-in holding tank by using continuous aeration and maintaining recommended temperature and salt concentrations.

Assign people to coordinate fish release. Choose release sites with relatively cool, clear, deep water. At the time of release, fish should be classified as releasable or non-releasable. Dead, weak, or injured fish should be considered non-releasable.

Three to five days after the release, check every release area and remove any dead fish. The tournament should not be considered over until this has been done.

Consider refereed or geo-referenced photographic tournament formats. Nearly immediate release after recording increases fish survival.

A complete guidebook for tournament anglers and organizers can be found at:

  • B.A.S.S.: short.mdc.mo.gov/4YY
  • Shimano: short.mdc.mo.gov/4Yr

Maintaining Optimal Conditions in Holding Tanks and Livewells

A long day of fishing may require a place to store your fish, especially if you are planning to keep them or if you are participating in a tournament. Holding tanks and livewells can fill that need.

Don’t put too many fish in a livewell. You should hold no more than 3/4 pounds of fish per gallon of water.

Provide continuous aeration, cool the water with ice when the livewell water temperature is over 80 degrees, maintain a 0.5 percent salt solution (1/3 cup non-iodized salt per 5 gallons of water), and replace half of the livewell water at least every two hours.

Don’t allow water to drain from a livewell when motoring around the lake.

For more information on fish handling and release guidelines, visit short.mdc.mo.gov/Zws. 

Andrew Branson has been with MDC since 2005 and now works out of the headquarters in Jefferson City. He knows Missouri is a great place to fish and enjoys spending his free time doing just that.

The source material for this article comes from MDC’s publication, Handling and Releasing Fish: A guide for the angler to lessen fish stress and catch-and-release mortality, available for free to order or download at short.mdc.mo.gov/4Hx.

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This Issue's Staff

Magazine Manager – Stephanie Thurber
Editor – Angie Daly Morfeld
Associate Editor – Larry Archer
Photography Editor – Ben Nickelson
Staff Writer – Kristie Hilgedick
Staff Writer – Joe Jerek
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Photographer – Noppadol Paothong
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