Studies done to evaluate the stress and mortality levels of striped bass, for example, that were caught and released have shown the mortality rate is probably much higher than most people think. Fish caught during the winter when temperatures were cooler did better following release than those caught during the summer. During the warm weather months when air and water temperatures were high, stress and mortality levels were considerably higher.
Where the fish is hooked, how deep the hook is embedded and how long the fish is played are some of the key factors affecting stress levels. The angler’s fishing abilities and how the fish is handled and released can also significantly affect the level of stress and possible resulting mortality the fish may face.
For fish that will be released, try to keep the fish in the water at all times, handle it as little as possible and try not to disrupt their protective slime coat. If the hook appears to be deep and not easily removed, cut the line and leave the hook in the fish. The less time the fish is on the line, the better its chance for survival. By considering water conditions, air and water temperatures, fishing techniques and how the fish is handled prior to release, anglers can directly influence the well-being of the fish they are catching and releasing, and this goes for all species.
Remember, just because a fish swims away when released, this does not mean damage has not already been done and that the fish won’t still die in the upcoming hours or days from the experience. But, by considering all of these factors and trying to minimizing their stress, the fish will have a better chance of survival to be caught again on another day.