Catch and Release Fishing: How Many Fish Survive, and How to Do It

Catch and release fishing works, and it works less well than most anglers assume. The largest review of the science, 53 studies across freshwater and saltwater species, found that on average 18 percent of released fish died, with a range from almost none to more than 90 percent; the spread is the useful part, because almost all of it comes down to three things an angler controls: where the hook lands, how long the fish is out of the water, and how warm the water is. Below: the survival numbers by species and hook from the named studies, the factors in order of importance, and a ten-step release that moves a fish from the bad end of the range to the good one.

Across 53 studies, an average of 18 percent of released fish died, from almost none to more than 90 percent. Where the hook lands, how long the fish is out of the water and how warm the water is decide which end of that range you get.

What you need

• Circle hooks for bait fishing, or J-hooks with the barbs crushed flat with pliers.
• A rubber or rubber-coated landing net; knotted nylon mesh strips the slime coat.
• Long-nosed pliers or a dehooker, and cutters for the line.
• A wet hand, a wet cloth, and a camera that is ready before the fish comes out of the water.
• For deep-caught reef fish, a venting needle (no longer than 1½ in, 38 mm) or a descending device.

How many fish survive

What decides it, in order

1. Hook location. Jaw- and mouth-hooked fish survive at 98–99 percent; gut- and gill-hooked fish are where the deaths are. In an FWC snook trial, four of 24 deep-hooked fish died when the hook was removed and none died when the leader was cut and the hook left in.
2. Bait or lure, and the hook. Bait is swallowed; lures are not. Circle hooks jaw-hook tuna and billfish nine times in ten and cut deep hooking in striped bass fourfold, with J-hooks 21 times more likely to cause bleeding.
3. Water temperature. Warm water holds less oxygen and raises the fish’s metabolism; the Oklahoma summer tournaments lost 43 percent, the spring ones 3.
4. Air exposure. Largemouth bass lose equilibrium after 30 seconds out of water at 77 °F (25 °C) and above, and tolerate ten minutes at 54 °F (12 °C); 10–20 seconds harms some species.
5. Handling. Dry hands and surfaces strip the mucus that protects against infection; hanging a big fish by the jaw damages the jaw and the organs behind it.
6. Depth. Fish from 30 ft (10 m) and deeper suffer barotrauma; venting or descending returns most of them.

The ten-step release

1. Fish tackle that ends the fight fast. A bass on 4 lb line played for ten minutes is worse off than one landed in one.
2. Use circle hooks for bait and crush the barbs on lure hooks.
3. Keep the fish in the water while you get the pliers and the camera ready.
4. Net it in rubber, wet the net first, and leave the fish in the net in the water while you unhook it.
5. Wet your hands before touching it, and never lay it on a dry deck, rock or grass.
6. Unhook in the water if you can. With barbless hooks most fish come off with a twist of the pliers.
7. Gut-hooked: cut the line as close to the hook as you can and leave it. The hook rusts or works free; digging for it kills the fish.
8. Photograph in under ten seconds, held horizontally with a wet hand under the belly, never hanging from the jaw.
9. Revive facing the current, or hold it upright in still water until it kicks away on its own; do not push it back and forth.
10. Deep-caught fish: vent behind the pectoral fin with the needle, or send it down on a descending device, before releasing.

History and the law

Lee Wulff wrote in 1936 that “game fish are too valuable to be caught only once”; Michigan adopted catch and release for trout in 1952 to cut hatchery costs; it is mandatory for some species in Canada and on rivers such as Scotland’s Dee for salmon, banned in Germany and Switzerland under animal-welfare law, and was reversed by Yellowstone National Park in 2011, which now requires anglers to kill invasive rainbow and brook trout in some waters. In the United States it is the default for bass, the norm for trout on many rivers, and required by slot and size limits for most saltwater species. The species pages carry each fish’s handling notes; the hooks hub covers circle hooks and the snell knot that makes them work.

Mistakes that kill fish

• Lifting a fish by the gills or hanging a heavy one from the jaw.
• The five-minute photo session with the fish on the deck.
• Ripping out a swallowed hook.
• Fishing bait on J-hooks in summer for fish you mean to release.
• Throwing a fish back instead of putting it back.

When to use something else

When the fish is legal, in season and wanted for the table, keeping it is often the better conservation outcome than releasing a deep-hooked fish to die; the regulations for each state are covered as the states section is built. The basics hub holds the rest of the fundamentals, and the knots hub and the species pages are this page’s neighbors. What a bag limit, a possession limit and a slot limit each mean is under rules, records and conservation in the fishing terms.