Use single hook artificial lures if you are planning to catch & release.
Scientific support: Hooking location – This factor demonstrates the largest source of variation in mortality observed in the studies and experiments reviewed. It is consistently shown that deep-hooking (hooking in the gills or gullet) causes relatively high mortality, up to 35% when accompanied by bleeding, whereas normal hooking (lips or jaw area) consistently causes minimal mortality, which is consistently less than 5% and often less than 1%. The Maryland Department of Natural Resources, in its Recreational Catch and Release Mortality research program concludes that the location of the hook wound is the single most important factor influencing catch and release mortality (4). If the hook wound affects a vital organ, mortality, is high. The location of the wound site has been demonstrated to be a function of hook size, type, the use of natural bait versus artificial lures and additional situational factors. Studies show that when fish are hooked in the lips or jaw area (shallow hooked), mortality is negligible, typically less than 1% (4,5). Conversely, mortality is at its highest when fish are hooked in the esophagus or gills (deep hooked) (5,11). Necropsies performed on gut hooked fish in a study by (5) Grover, et al, found that the majority had sustained major internal damage to the heart, stomach or liver. Grover demonstrates that hooking location effectively correlates to mortality rate.
Use barbless hooks to aid in quick releases and reduce mortality.
Scientific Support: The barbed hooks appreared to produce a significantly higher rate of mortality than barbless.
Use circle hooks when bait fishing to reduce striped bass mortality.
Scientific Support: In the 1999 Study, we determined that 9.1% of the fish caught on conventional hooks died, but only 0.8% of the fish caught on circles hooks died. This dramatic difference in mortality should encourage anglers and fishery resource managers to strive to reduce deep hooking rates. Non-offset circle hooks not only reduce frequency of deep hooking, but deep hooking mortality is lower with non-offset circle hooks than conventional bait hooks.
Keep fish in the water during the release process.
Scientific Support: Studies show that the longer the length of time that fish are removed from the water, the greater the measurable effects in the fish’s short-term biochemical profile. Increases are seen in the physiological indicators of stress (increased blood cortisol and lactate concentration) and the direct gas exchange measurements (carbon dioxide retention and lowered oxygen tension). Smaller fish have been shown to have significantly lower anaerobic resiliency than larger fish (12). These results demonstrate that minimizing time spent out of water, minimizes the risk of mortality, especially in smaller fish.
Avoid nets when possible. If you decide to use a net, make sure it has a plastic coating.
Scientific Support: Fishermen have traditionally used various types of nets to “land” or secure a fish at the boat and to finalize the “catch”. Nets can cause a variety of injuries and tend to greatly increase the time required to release a caught fish. Depending on the type of material, nets can inflict varying degrees of damage to a fish’s sensitive fins, gills, slime coat and scales. Exposed hooks tend to snag in nets often exacerbating the time needed to remove hooks and release fish.
Limit touching the fish to reduce slime loss.
Scientific Support: Simple observation as well as experimental results indicate that minimized handling will reduce the probability of additional post-catch stress, the likelihood of physical injury to fish due to struggling and loss of body slime. The use of purpose-designed unhooking devices and handling tools that are designed to hold fish without physical damage and enable quick release, such as the Boga-grip dramatically reduces the amount of handling necessary prior to release.
Properly revive larger striped bass prior to release.
Scientific Support: Prior to release, fish displaying any signs of exhaustion or stress can be effectively resuscitated by holding the fish with its head pointing into the current. If no current is present, fish may be moved in a figure-8 pattern. Fish can be observed rapidly recovering from the effects of exercise and stress. Upon demonstrating stable equilibrium and strong swimming ability, fish are released. Safe, low stress recovery areas (minimal current and protection against predation) further afford released fish adequate time to recover their strength without requiring further exercise against adverse water conditions while simultaneously isolating fish from potential predators.
Never remove fish you do not plan to keep from the water when air temperatures are very warm
Scientific Support: When environmental conditions are stressful for released fish (high temperature, both air and water, and low salinity) anglers should minimize catch-and-release fishing. When angling during periods of extreme air temperatures (>95 F) keep the fish in the water when releasing. In 1999 we had also intended to evaluate release mortality at two significantly different salinity levels. Drought conditions this summer prevented mortality trials from being conducted at low salinity sites. An identical study will be done in the summer of 2000 to evaluate striped bass catch-and-release mortality under a low salinity environment.