Armed with that suggestion, I then turned to the Internet and started looking for articles that might provide some helpful guidance. It didn't take long to find one that looked interesting. After calling and talking to one of the two authors, I was convinced it would be a good choice. The two authors are Gene Gilliland (the gentleman I spoke to), who is with the Oklahoma Fishery Research Laboratory, Oklahoma Department of Wildlife Conservation, in Norman, Oklahoma, and Hal Schramm, who is with the U.S. Geological Survey, Mississippi Cooperative Fish and Wildlife Research Unit, Mississippi State University, Mississippi State, Mississippi. With their permission to reprint it, here's a somewhat condensed version of the article that I found.
Bass tournament anglers long have been dedicated to the conservation of black-bass resources. The practice of catch and release has reached outside their ranks into the practices of bass anglers everywhere, and this has done much to conserve or recycle bass resources on many water bodies throughout the United States. Released bass have been shown to survive very well when released immediately after capture, but recent data demonstrates that survival may not be as high for fish released after tournament events. This has become a source of concern to many anglers and fishery managers who have witnessed large increases in bass-tournament participation.
Over the past decade, several studies have addressed delayed mortality of bass weighed in at fishing tournaments. Although not all tournaments had high mortality, the high-end ranges that follow were observed during summer events:
Range in Delayed Mortality for Tournaments
* 1-50% (Alabama summer 1991-92)
* 11-52% (Alabama/Georgia summer 1991)
* 1-44% (Oklahoma summer 1995-96)
* 0-93% (Tennessee summer 1988-89)
* 38% (Lake Fork, Texas in October 1999)
What Causes Mortality?
* Physical Injury
* Oxygen Deprivation
* High Ammonia or Carbon Dioxide
* High Water Temperature
What Causes Delayed Mortality?
* Oxygen Debt
* Toxins in the Bloodstream
* Infections
Other studies have shown that smallmouth bass had significantly higher mortality than largemouth bass after being released.
By using holding pens to observe mortality on fish released after weigh-ins, researchers were able to determine that substantial numbers of fish died after release, even when they appeared healthy following weigh-in. Approximately 50 percent of the fish released sank after dying--a phenomenon that has led many tournament participants to underestimate the amount of mortality caused by their events.
Here are some pointers on how to hold "fish friendly" tournaments:* Fill your livewell at your first fishing spot, using water from open areas.
* Turn on your recirculating pump immediately and leave it on all day (set pump switch to manual for continuous operation). If the aerator must run on a timer, run as often as possible because oxygen depletion occurs quickly when the pump is off. Make sure the aeration system provides proper aeration until the fish are weighed in and released. If you don't have a recirculating system, add one.
* Only pump in fresh water when the surface-water temperature is below 75 degrees.
* When the surface-water temperature is above 75 degrees, recirculate livewell water continuously, but don't pump in hot water. Use ice to cool the water and slow fish metabolism (block ice melts slower), and try to maintain the livewell water 10 degrees cooler than the temperature of the water you're fishing. Don't overcool the water, which also can be stressful to fish. Use only non-chlorinated block or bagged ice.
* Use non-iodized salt (available at feed stores) to maintain electrolyte balance and reduce effects of stress. Salt should be added at 1/3 cup per 5 gallons of water. Premeasure and store in ziplock bags. Commercial livewell additives also may be added as directed, but don't oversalt if using both.
* Drain half of the livewell water every three hours to remove toxic waste products (carbon dioxide and ammonia), then refill with fresh water from areas with good water quality. Avoid adding water from stagnant backwaters or shallow areas that may be extremely warm and low in oxygen. Add one-half the amount of ice, salt and commercial livewell additive each time.
* Keep fish in rear livewells, evenly distributed between compartments. Fish in forward livewells are more likely to be injured from bouncing on rough water.
* Land fish with knotless or rubber nets. Land them quickly and avoid damage to their slime coating. Grasp fish by lower jaw only, holding them vertically. Support large fish with a wet hand under the belly. Do not allow fish to touch boat or carpet and rub off protective slime.
* Remove hooks quickly with as little tissue damage as possible. Remove deep hooks carefully with pliers or hemostats. When attempts fail, cut the line five or six inches above the hook.
* Do not keep fish out of water longer than you can hold your breath. This includes fish in bags headed for weigh-in and fish being displayed. Depletion of oxygen in bags can occur in as little as two minutes.
* Remove dead fish from boat livewells immediately to prevent further mortality. Dead fish may spread fungus and disease to other bass.
* Do not use livewells when you are not competing. Practice catch and immediate release or selective harvest by keeping smaller fish (for the kitchen on ice) and immediately releasing large fish.
* Install an oxygen-delivery system, which delivers oxygen directly into livewells from a pressurized tank through air stones or a hose. The system must have a regulator or pressure valve, and the tank must be securely mounted. This system is better than simple aeration (air is only 21 percent oxygen) and solves oxygen-demand problems. Although less need for water-temperature adjustments is usually required, flushing with freshwater every 2-3 hours still is essential.
* If available, use a pre-release recovery tank (75-to-100-gallon capacity) after weigh-in. Water should be aerated and cooled 10 degrees below the body of water temperature with block ice. Tank should contain 1 pound of uniodized salt per 25 gallons of water. An oxygen tank with air stone or bubble hose should be set up to supply pure oxygen to the fish. Weak fish should be treated longer in the recovery tank. After 20 to 30 minutes, weak fish should be recovered sufficiently and then prepared for release. Active fish should be recaptured immediately and prepared for release.
* Use a release boat if available (another option would be to use all or some of the tournament boats). In any event, move and redistribute bass out of high-traffic and/or weigh-in areas. Studies have shown that many released fish stay in the weigh-in area, making them highly vulnerable to harvest after the tournament is over.
This chart shows the average delayed mortality of bass after summer tournaments, using different aeration methods.
For a more detailed article on preserving tournament bass to be caught again, check out this link: http://www.bassmaster.com/sites/default/files/imce/KeepingBassAlive_guidebook%20comp.pdf.
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