Is Catch and Release Over Hyped. If you're a catch and release fisherman and want to know more, here is some really cool info that I have collected from various sources on the subject of practicing catch and release and why mortalities occur and how to help prevent them.
Fish that are caught and released may die for several reasons, but the two primary causes are stress and wounding. Stress results from the fish fighting after being hooked. Internally, the physical exertion causes an oxygen deficit in the tissues, forcing the muscles to function anaerobically (without oxygen). This causes lactic acid to build up in the muscle tissue, and then to diffuse into the blood. Lactic acid acts as an acid in the blood, causing the pH of the blood to drop. Even slight changes in pH can cause major disruptions of the metabolic processes, ultimately killing the fish. If the fish is quickly released, its blood pH usually returns to normal and the fish will be unaffected. Some fish, after a long tow, may appear to live once released, but the imbalance in the blood chemistry may kill them as late as three days after being caught. In most cases, the means of preventing this type of mortality is to not keep the fish in action for a long period of time, unless the intent is to keep it.
The other primary cause of mortality is wounding by the hook. Injuries caused by hooks can range from very minor to lethal. The degree of injury is dependent on the location of the hook wound. Higher mortalities will occur in fish that are hooked in the gill or stomach areas, while lower mortality's occur in fish that are hooked in the lip, jaw, or cheek areas. Baited hooks are more likely to result in a gill or stomach hooking that artificial lures. Treble hooks, for obvious reasons, will result in more puncture wounds and subsequently higher mortalities. Barbless hooks facilitate release and decrease "out-of-water" time, but for reasons yet unclear, may not significantly reduce mortality, especially when used with bait.
There are other kinds of physiological stress that can lead to higher mortality's in released fish. Fish may not be able to adjust to changes in pressure or to higher surface water temperatures. Also, when a fish is handled or comes in contact with dry surfaces, such as landing nets or dry hands, its mucous layers – commonly called slime layers – may be partially removed, presenting an opportunity for bacteria or pathogens to invade the skin.
How to prevent fish mortalities
- handle fish as little as possible and release them quickly - do not fight fish to exhaustion
- minimize or eliminate the time fish are out of the water - as little as 30 seconds of air exposure causes delayed mortality of released trout
- consider using only artificial lures - their use is mandatory on some waters
- use barbless hooks if you plan to release most of the fish you catch
- when a fish is deeply hooked, do not try to remove the hook - clip the leader instead
- during the warm summer months when stream temperatures are elevated, do not fish for trout if you plan to release them - these fish are already stressed and additional handling may kill them
- likewise, do not fish for trout in spring holes when water temperatures are in the mid 70s or higher (especially if you plan to release them)
I hope this sheds some light on the subject and helps you out.
See you on the trail,