The concept of "catch and release" has become an increasingly popular voluntary practice among fresh water and salt water sport anglers. Fisheries management agencies have also stimulated the catch and release trend by requiring anglers on some waters to release all or nearly all of the fish they catch as a means of improving fishing quality by harvesting fewer fish. Catch and release regulations are also being employed to protect rare and endangered species of fish while still allowing anglers the privilege of fishing for these species.

We won't get the maximum conservation benefits of releasing fish more often -- whether voluntarily or required by law -- unless anglers properly release their catch. Good intentions must be followed up with informed beneficial playing, handling, and release behavior.

Although Wisconsin Trout Unlimited's CPR steps are specifically targeted to help fishers do what is right to maximize trout survival, the five recommended steps are equally valid for anglers catching and releasing many other species.

Scientific studies to evaluate why and how to release trout unharmed date back at least 75 years. Dozens of such studies have been published, including two carried out by biologists employed by the Wisconsin Dept. of Natural Resources (Mason and Hunt, 1967; DuBois, 1994). It is not the intent to include in this addendum a lengthy list of other published reports, but three of them are also cited in the ending citations as noteworthy summary reports of the technical literature (Richardson and Hamre, 1984; Behnke, 1989; and Trotter, 1995).

Let's review now the commonsense biological rationale for consistently following CPR's five simple steps.

1. Don't play fish to exhaustion. Use a landing net.

One of the joys of catching trout on light tackle is the fun of feeling the fish fight back -- feeling that "live wire connection" that runs up your line, down your rod, and up your arm. But it's important not to overdo that connection pleasure. Stress-induced physiological changes, especially increased acidosis of the blood, can reduce post-release survival. The more exhausted a fish is when you release it, the longer it will take for it to return to normal social and feeding behavior. This recovery period could last for a day or two. During this delay to normal behavior, a trout will be at an increased risk from predators.

Anglers need to be especially cautious about causing harmful stress when the water temperature exceeds 65 degrees F. The amount of dissolved oxygen in water declines as temperature increases. With less oxygen to breathe, exhaustion occurs more quickly, so don't play your catch quite as long before releasing it in warm water. Use of a landing net is recommended because a hooked trout can be more easily handled when you are ready to release it and while the fish still has some stamina to swim away normally.

Here are two helpful tips to improve your use of a net. If you plan to keep the fish you just caught, net it head first to reduce the possibility of an escape from your net. But if you plan to release that trout, net it tail first -- this action exposes the head of the fish so you can more quickly remove the hook. Keeping a fish's head exposed also reduces the danger of damaging its bulging eyes from net-induced abrasions. Reducing sub-lethal injuries is also an important component of proper release.

In response to the increased popularity of releasing hooked trout, special catch and release nets are now on the market to facilitate easier releases. They have shallow bags, softer mesh, and a finer weave so hooks are less likely to get caught in the mesh and slow down the removal process. Some of these net models even have a measuring tape built into the mesh bag, another practical improvement to reduce handling time.

2. Handle fish in the net. Grasp across the back and head.

Trout are slippery critters when wet, especially brook trout. Use the net's mesh to help you hold them firmly but gently while you remove hooks. Avoid damage to trout's internal organs by not squeezing their bellies. Instead, grip trout along the back while they are still in your net, and use the mesh to help your grip.

3. Turn the fish belly up while removing hooks.

The upside down position seems to temporarily disorient trout. Fish in this position usually stop wiggling, which makes it easier to remove the hook quickly. When a fish doesn't wiggle so much, you also don't have to hold it quite so hard.

4. Don't remove swallowed hooks. Just cut the line.

This step is the most important one to consistently carry out to increase survival of trout you release. Where a trout is hooked is much more important to its post-release survival than what is on the hook.

Most hooks embedded in the mouth or jaw can be easily removed without causing permanent injuries or death. Trout that have been deeply hooked, however, are very vulnerable to mortal injuries. Nearly all such trout will soon die if swallowed hooks are removed. So, do not remove swallowed hooks if you plan to release your catch. Just cut your line or leader close to the mouth. On average, two of three trout will survive and continue to grow normally if swallowed hooks are allowed to dissolve away in place.

If you are using natural bait, try to strike more quickly, before the bait is swallowed. Your catching success will probably decline a bit, but you will be able to more frequently release trout unharmed -- a conservation and sportsmanship gain worth the tradeoff.

5. Don't keep fish out of water more than 10-15 seconds.

Keeping a trout out of the water is like you holding your head under water -- both actions cause suffocation from lack of absorbed oxygen. Reducing the time you keep your catch out of the water takes on added importance when the air temperature is near or below freezing. Oxygen extraction occurs through the outermost layer of a fish's gills. That layer is only one cell thick, so it is easily damaged when exposed to freezing air temperatures. Minimize that exposure time. Better yet, keep the fish in the water while removing your hook. A few seconds of cold fingers is better than running the risk of damaging a fish's gills.

If you plan to photograph your catch, prepare to do it quickly, and take photos after the hook has been removed. Use a buddy system photographer if that is an option. Either way, cradle the hook-free catch in your net or hands in the water. As mentioned previously, don't use a belly grip. Instead hold fish using both hands, if you can -- one behind the head and the other just ahead of the tail.

Consider Proper Release -- it's working!

Literature Citations

Behnke, R. J. 1989. We're putting them back alive. In TROUT magazine, Autumn: pp. 17-19 and 50-61.

DuBois, R. 1994. Sublethal damage and hooking mortality of small salmonids caught on artificial spinners with barbed single hooks or barbed treble hooks. Wisconsin Dept. of Nat. Resources. Correspondence/Memorandum.

Mason, J.W. and R.L. Hunt. 1967. Mortality rates of deeply hooked rainbow trout. Prog. Fish Cult. 29. Pp. 87-91.

Richardson, F. and R.H. Hamre, editors. Catch and release: panacea, myth, or management tool. In Wild Trout III Symposium. pp. 90-121.

Trotter, P. 1995. Hooking mortality of trout. In FLY FISHERMAN magazine. Vol.26, Issue 3. pp. 16-27.