State: Oklahoma Grant Number: F-50-R

Grant Title: Fish Research for Oklahoma Waters

Project Number: 8

Project Title: Evaluation of Procedures to Reduce Delayed Mortality of Black Bass Following Summer Tournaments.

Period covered: March 1, 1996 - February 28, 1997

I. Project Objectives:

To evaluate black bass handling and tournament weigh-in procedures recommended in the ODWC Weigh-in Kit program by estimating initial and delayed (6-day) mortality of fish released after summer tournaments using controlled methods.

II. Background:

Mortality of black bass, Micropterus spp., released after tournaments has been studied since the early 1970's (May 1973, Wellborn and Barkley 1974, Archer and Loyacano 1975, Plumb et al. 1975, Seidensticker 1975). Findings showed total mortalities as high as 60%. By the late 1980's, fish care and weigh-in procedures had been refined to a point where mortality rates were less than 20% in some tournaments (Chapman and Fish 1985; Schramm et al. 1987; Plumb et al. 1988). Schramm et al. (1985) suggested this decrease in mortality was due to changes in angler attitude and an increased knowledge of how to keep fish alive. Professional tournaments run by the Bass Anglers Sportsmans Society (B.A.S.S.) had an excellent record with mortality rates generally less than 10% due to strict fish handling guidelines and state-of-the-art weigh-in procedures (Bryan 1988). An important factor in the low mortality associated with professional tournaments was their being held in cooler months of the year when lower water temperatures were less stressful on tournament-caught bass (Holbrook 1975).

Recently however, published reports of high delayed mortalities following summer tournaments (Steeger et al. 1994; Weathers and Newman 1997), evidence that larger bass suffered higher mortality rates (Meals and Miranda 1994) and increasing numbers of events (Schramm et al. 1991; Gilliland 1997) raised new questions about tournament impacts on bass populations.

The Oklahoma Department of Wildlife Conservation (ODWC) receives numerous complaints each year from both anglers and non-anglers about tournament-related bass mortality. In response to the concerns of the public and concern among biologists about the health of the resource, Oklahoma Fishery Research Laboratory (OFRL) personnel developed the Black Bass Tournament Weigh-in Kit (WIK). These portable kits contain everything a bass club or event organizer needs to conduct a tournament weigh-in except scales for weighing fish. After prototype kits were field tested and refined, Oklahoma fishing tackle manufacturers funded the construction of six kits that were placed at fishing tackle and marine dealers across the state. A loaner program was establish to make the kits available to tournament organizations free-of-charge. This program received national attention through articles in fishing publications such as BassMaster and In-Fisherman magazines and tabloids such as BassTimes.

Each kit consists of two 380-l Rubbermaid1 plastic stock tanks with bilge-pump aerators; a plastic laundry sink with an aluminum fish measuring board; a table for the weigh-in scales; an

1 Use of company or product names, logos or trademarks does not imply endorsement by the Oklahoma Department of Wildlife Conservation or the U.S. Fish and Wildlife Service Division of Federal Aid.

aerated laundry sink filled with a salt-water solution (3% w/w non-iodized NaCl) for a prophylactic "salt-dip" before the bass are returned to the lake; and various baskets, hoses, cords and buckets for handling fish, filling and draining tanks, and running aerator pumps (Figure 1). Reinforced heavy plastic tournament weigh-in bags are also provided. These bags are perforated to allow water exchange when anglers dip their bag of fish into the aerated waiting line tanks. When tournament water temperatures are above 21C, waiting line tanks are cooled 5C with ice. Each group borrowing the equipment is provided with salt, written and video-taped instructions and a complete schematic and parts list so they can build their own kit.

The materials and equipment supplied with each kit and the suggested procedures resemble those used in B.A.S.S. weigh-ins but on a smaller scale. Recommendations on fish care and weigh-in procedures made by authors of previous mortality studies (Carmichael et al. 1984; Schramm et al. 1985, 1987; Plumb et al. 1988), guidelines set up by the California Department of Fish and Game (1991) and the booklet Live Release of Bass, A Guide for Anglers and Tournament Organizers (Schramm and Heidinger 1988) were incorporated into the WIK system.

In a simulated tournament setting, Plumb et al. (1988) examined the influences of water temperature and the use of commercial water conditioners (such as Professional Sporting Goods' Catch and Release). However, there had been no field evaluations of different protocols for care of fish in live wells, or of the ODWC-recommended weigh-in procedures. Experiments using anglers in actual tournaments to test different procedures would tell us if the recommendations made in the WIK program were not only effective but also practical enough that they would be used regularly. Results of such a study would allow tournament anglers and organizers that followed the recommendations to feel confident that they were doing all they could to protect the resource and project a positive public image.

III. Procedures:

1995 Preliminary Studies

Oklahoma bass tournament organizations were contacted in spring 1995 to find participants for a pilot study of tournament-related mortality. The objective of this phase of the research was to determine the extent and seasonal nature of tournament mortality and to develop techniques for evaluating live-well aeration and weigh-in procedures. Five team-tournaments (two anglers per boat) were chosen based on their willingness to assist with the study, manageable numbers of participants (<50 boats) and compatible locations (weigh-ins at or near cooperating marinas). Marinas participated by loaning covered boat slips for a week following the event where holding nets were secured. Boat slips were in a minimum of 4.0 m deep water and protected from wind and waves.

Three spring (April and May) and two summer tournaments (August and September) were selected on reservoirs in southern (lakes Murray and Texoma), central (Lake Eufalua) and northeastern Oklahoma (lakes Ft.Gibson and Grand). Participants were not given any special instructions on fish care or live-well aerator operation, however, tournament organizers were asked to follow ODWC-recommended weigh-in procedures and use WIK equipment.

Following weigh-in, fish were taken by anglers or volunteer workers to the holding nets. Holding nets were constructed of 6 mm mesh soft nylon netting wrapped around two PVC pipe hoops to form a 1.8 m diameter cylinder, 3 m deep, with a closed bottom. Net lids were made from 1.8 m diameter PVC pipe hoops covered with the same netting. Lids were secured with plastic ties.

Each team's fish were salt-dipped then randomly placed into holding nets (27 fish per net maximum). Three control bass (>356 mm) were collected by electrofishing outside the release area and placed into each net. Control fish were marked with both caudal and pelvic fin hole punches. At least one-third of the teams at each tournament were interviewed as they came to weigh-in. Water temperature (C) and dissolved oxygen (D.O. in mg/l) in boat live wells were recorded as were total number of fish brought in and the number dead, aerator operating procedures (manual or timer-controlled, flow-through or recirculating) and use of live-well water conditioners. Temperature and D.O. measurements were also made at the surface and bottom of the holding nets, and at the maximum depth under the nets at the beginning of each experiment, after three and six days.

Nets were checked after three and lifted after six days. Dead fish were counted, examined for hole punches, measured and removed. Notes were made of abrasions, infections, or hemorrhaging, etc on each fish. All live fish were measured, salt-dipped and released.

Initial mortality was recorded as fish brought to weigh-in dead by contestants (percent of total tournament catch). Estimates of delayed mortality were calculated from percentages of fish retained in holding nets that died within six days. Delayed mortality estimates were adjusted (reduced) by deaths among control fish. Total mortality was calculated as initial mortality plus delayed mortality.

Water quality measurements and aerator operating procedures only, were recorded at a fall tournament on Lake Ft.Gibson. This event featured a drive-through weigh-in held approximately 30 km from the tournament lake. Each team's fish were transported in their boat's live well as it was trailered to the weigh-in. No fish were retained from this event for mortality estimates.

1996 Summer Tournaments

Live-well treatments rather than weigh-in procedures were tested in summer 1996 to determine what anglers must do to keep fish healthy. Participating tournament organizations agreed to conduct their weigh-ins following ODWC recommendations and use WIK equipment. Tournament teams were assigned to one of three treatment groups and given an identifying ribbon for their boat (Figure 2). Group A received live-well aerator operation instructions only; Group B received special fish care instructions and supplies. These included: addition of ice to the live well three times per day, addition of non-iodized salt to live-well water to maintain a 0.5% w/w solution, recirculation of live-well water rather than pumping of warmer fresh water during the day, and water exchange twice per day to flush ammonia and carbon dioxide.

All boaters in Groups A and B were instructed to run live-well aerators continuously (Schramm and Heidinger 1988). If the aeration system was controlled by an automatic timer, contestants were instructed to set them to run as often as possible. Anglers in control groups (C) were not given any instructions on aerator operation or fish care but they did used the same weigh-in procedures and equipment as other groups.

Group assignments were not random. Boats with live well systems designed only to pump fresh water rather than recirculate had to be assigned to Group A. As a result, the number of teams in each group were unequal.

Prior to the first tournament, a test was done to determine the quantity of ice (3.63 kg blocks) necessary to reduce water temperatures in an average bass boat live well 5C below ambient surface water temperature. A cooler environment is thought to slow metabolic processes including oxygen demand (Horton 1956) and osmoregulatory dysfunction caused by stress (Carmichael 1984). Trial #1 used a block at the beginning of the test only. In Trial #2 an additional block of ice was added after four hours. In Trial #3 blocks were added at approximately three hour intervals to maintain the temperature during the eight-hour tournament simulation. In each trial, before additional ice was added, half of the live-well volume was replaced with fresh water at 29.0C to flush ammonia and carbon dioxide waste products. A total of 7.26 kg of fish (held in 29.0C water) were added over the day to simulate the addition of an angler's catch. Information from this test was used in determining quantities of ice to provide to teams in Group B.

Teams within each treatment group weighed in at specified times to prevent overlap and crowding in weigh-in lines. Water quality parameters were measured in at least one-third of the boat live wells as they came to weigh-in. Contestants were asked specifics on their live-well aerator operation as a check to see if they followed instructions for their group.

Following weigh-in, tournament-caught and control fish were treated and placed in holding nets as in 1995. Water quality parameters were also measured in and around the nets. After three and six days, dead fish were counted and (adjusted) delayed mortality was estimated as described above. All live fish were salt-dipped and released.

IV. Results

1995 Tournament Mortality

Initial mortality in both spring and summer tournaments was relatively low (Table 1). Only 11 of 533 tournament-caught fish were dead when brought to weigh-in. Contestants brought in an average of only 1.3 dead fish per event (1.6%) in spring tournaments but this value increased to 3.5 fish (4.1%) in summer events. Among the three spring tournaments, total mortality averaged 2.9% with a maximum of only 5.1%. No control fish died during the spring, therefor delayed mortality estimates were not adjusted. However, summer tournaments averaged 33.6% total mortality with a maximum of 43.3%. Control fish experienced a high degree of delayed mortality (58.3%) in one summer event. High mortality among tournament-caught fish and rapid decomposition at 28C in the nets may have caused localized D.O. deficiencies that stressed other captive fish and increased mortality. However, D.O. in and around the nets at the beginning of the trial, at three and at six days was always above 5.0 mg/l. There were no significant differences in mean length of fish that survived confinement versus those that died within the six-day holding period in either spring or summer trials.

At the final 1995 summer tournament (Ft. Gibson), fish were separated into two groups based on D.O. levels in teams' live wells at weigh-in. Fish from live wells with less than 6.0 mg/l D.O. were classified as "Low" group. The mean live-well D.O. for this group was 4.3 mg/l. Fish from live wells with D.O. > 6.0 mg/l were placed in the "High" group. This group had a significantly higher mean D.O. (7.0 mg/l; P<0.01). Adjusted total mortality of fish in the Low group was 51% while fish in the High group suffered a mortality rate of only 35%. Live-well water temperature, mean length and number of fish per live well were not significantly different between groups. A difference was seen in the percentage of boaters that ran live-well aerators continuously versus allowing automatic timers to cycle the pumps on and off. Only 28% of the Low group boats used continuous aeration while 42% of the High group did.

Fall 1995 Drive-through Weigh-in

While no mortality estimates were generated from this tournament, the results of the live-well water quality measurements and aerator operation survey at the fall tournament's drive-through weigh-in yielded valuable information on the capabilities of many boat aeration systems and how knowledgeable anglers were about the oxygen requirements of confined bass. This information helped in developing the procedures tested during the 1996 tournaments.

The weigh-in took place in the parking lot of a large suburban shopping mall approximately 30 km from the tournament site. Two sets of scales were used to weigh fish. However, with 212 boats weighing two-at-a-time, it took over two hours to weigh all the fish. Twenty percent of the boats did not have, or were not using recirculating aeration systems that could aerate the water while the boat was being trailered. Dissolved oxygen levels in live wells with recirculation systems were significantly higher (6.7 mg/l, P<0.01) than those without recirculation systems (3.9 mg/l). To see if oxygen demand in the live wells could have influenced D.O. levels, the mean number of fish per boat was tested but there was no difference (3.3 fish/boat vs. 3.2 fish/boat among teams with, and without recirculating systems, respectively.)

Live Well Cooling Test

In testing to determine the quantity of ice needed for summer tournament experiments, a single 3.63 kg block of ice put into the live well at the start of the day reduced water temperature in the test boat's live well from 29.1C to 23.7C in approximately 1 h (Figure 2). However, temperatures climbed steadily through the eight-hour trial. Using one additional block of ice during the day helped slightly in maintaining more even water temperature in the live well. Using two additional blocks, one each at three hour intervals, kept temperatures closer to the target of 5C below ambient. Continuous recirculation and aeration of the water increased D.O. from 5.0 mg/l at the start of each trial to a maximum of 7.7 mg/l. Oxygen levels remained at or above 6.0 mg/l in each trial.

1996 Summer Tournaments

Initial mortality was low at all 1996 tournaments (Table 2). Only two bass were judged as dead by tournament officials at weigh-in. During each tournament several other fish of questionable health were placed into the holding nets. They were categorized as "live" however, because we wanted to simulate what tournament anglers and directors would do when releasing fish.

The first two events at Lake Texoma in July and August and the final tournament in September at Grand Lake had a total mortality of 17.9%, 13.4% and 14.5%, respectively. Total mortality at the Lake Eufaula tournament in August was 38.0%. While this was much higher than the previous two events, it may not have been an accurate representation of the effects of the treatments. Three nets were vandalized at the marina and an additional 36 tournament-caught and nine control fish were taken from the nets so the effective sample size for the trial was cut in half.

At Lake Tenkiller, a large charity fund-raising tournament had agreed to participate in the study. However, at weigh-in, the organizers did not follow all of the ODWC weigh-in procedures or use WIK equipment as suggested. Long waits to weigh fish and poor water quality in waiting-line tanks resulted in severely stressed fish from all treatment groups being taken to the holding nets. Total mortality was 65.0%. Because of the differences in weigh-in procedures and equipment used in this tournament, the Tenkiller results were not used in further comparisons between treatments.

A total of 238 bass were held for observation (excluding the fish stolen at Lake Eufaula and all fish from the Tenkiller event). Only one of 64 control fish electrofished and held in the nets died during the six-day observation periods. Many of the tournament-caught and control fish had raw or worn fins from net abrasion. Few of the surviving control fish had any external evidence of bacterial or fungal infections (1.7%) whereas more of the surviving tournament-caught bass (10.8%) had moderate to severe infections. Fifty-three percent of the dead fish were found at the bottoms of the nets rather than floating, indicating they had recently died. Dead fish bloated and floated to the surface after four or five days but it is likely that in actual tournament situations where the fish are released at a marina, boat ramp or dock, turtles or other scavengers would eat many of the dead or weak fish before they could float and become a visible indicator of delayed mortality.

The control groups (Group C) that received no instructions or supplies had, on average, the harshest live-well conditions among the three treatments (Table 3). Live-well water temperatures in Group C averaged 28.8C. Oxygen levels ranged from 1.7 to 7.6 mg/l with a mean of 4.7 mg/l. Total mortality among Group C fish averaged 32.3%. Group A which used continuous flow-through aeration but no additives had slightly cooler live-well water temperature of 27.4C. Oxygen levels ranged from 1.9 to 8.3 mg/l and averaged 6.1 mg/l. Total mortality among fish from Group A was 21.6%. Group B had average live-well water temperature of 25.7C, which was 2C below mean surface water temperature. Dissolved oxygen in Group B live wells averaged 5.9 mg/l. The D.O. range among boats in Group B was from 3.0 to 8.0 mg/l. Total mortality was 18.0%.

Live-well water temperatures were significantly lower for Group B (P=0.03) as were oxygen concentration for control Group C (P=0.04). Group B had fewer boats with excessively warm temperatures (>32C) or lethal oxygen levels (<3 mg/l). Maximum live-well water temperatures among Group B boats was 32.1C and the minimum D.O. was 3.0 mg/l, whereas Groups A and C had maximum temperatures of 34.0C and 34.4C, respectively and minimum D.O. levels of 1.7 mg/l.

V. Conclusions and Recommendations

Actual mortality from 1995 tournaments may not have been as high as estimated because fish released back into the wild may have a lower mortality than fish confined in cages (Hegan et al. 1982). While anglers and tournament organizers argued that released bass would have fared better if allowed to swim to deeper, cooler water while recovering, water quality measurements did not support this idea. Mean water temperatures were only slightly cooler (0.7C) at maximum depth but mean D.O. also dropped to lethal levels (<3.0 mg/l). Since tournament-caught fish are known to travel very little immediately after release (Blake 1981; Klindt and Schiavone 1991) it is unlikely that they would have traveled hundreds of meters to find more favorable water quality.

Despite the possibility of mortality estimates being biased, the magnitude of the differences observed between spring and summer tournaments in 1995 was a very real concern. These differences were apparent even though all tournaments followed recommended weigh-in procedures and used the same WIK equipment. Near-lethal dissolved oxygen concentrations and stressful live-well water temperatures were common findings at each summer contest. It was obvious that our "first-aid" at weigh-in would not save fish that were mistreated and stressed in live wells.

Many of the boats had recirculating systems but they were not being used. This suggested that many anglers were simply ignorant of the oxygen needs of confined bass. Most of those teams that were not using, or did not have a recirculating system assumed that a full live well was sufficient to keep their catch healthy. Many were surprised to find that D.O. levels in their live wells were as low as 0.8 mg/l. These anglers often argued that continuous use of aerators drained boat batteries or caused excessive noise that scared fish in shallow water.

Anglers typically assumed that modern bass boats have built-in aeration systems that are adequate to keep fish healthy. While some systems did appear to be designed well, many anglers did not take advantage of the systems they had. In 1995 we found that 71% of the boaters relied on automatic timers to cycle aeration pumps on and off. These timers were frequently set to minimum times that did not run the aerator frequently enough to supply the oxygen needed by a large catch of bass (Schramm and Heidinger 1988).

To the fishery science community, the mortality estimates from the 1995 tournaments simply reinforced findings of similar magnitude and seasonality in other states (May 1973, Wellborn and Barkley 1974, Archer and Loyacano 1975, Plumb et al. 1975, Seidensticker 1975; Schramm et al. 1985, 1987; Plumb et al. 1988; Weathers and Newman 1997). As was the case in most of these studies, initial mortality in both 1995 and 1996 had little relationship to delayed or total mortality. Participants and contest organizers would have seldom seen dead bass to give them indications that tournament-related mortality was occurring. As a result, most Oklahoma tournament anglers and organizers did not believe that delayed mortality was an issue until it was demonstrated "right here at home", with those same Oklahoma anglers as participants in the study. The media attention that was given to the first year results opened many tournament anglers' eyes to an issue that they did not know (or would not admit) existed.

Given the negative publicity that tournaments received because of the results of the 1995 study, we had no problem recruiting volunteer organizations for 1996. Tournament anglers and organizers were eager to participate in research that would not only show them how to take better care of their fish but would also show the public that tournaments were taking an active part in trying to find solutions to the problem and protect the resource.

During the summer 1996 tournaments we focused on testing live well and aerator operation recommendations. In choosing procedures to incorporate into our tests, we picked those that we felt would be effective (based on the recommendations of Schramm et al. 1987; Schramm and Heidinger 1988; Weathers and Newman 1997) but that would also be practical from the tournament angler's viewpoint. The best procedures will do no good if they are not used. Our final suite of recommendations are based on both year's experiences with 11 tournaments and over 1000 anglers.

Managers should recommend that anglers, at a minimum, run flow-through live-well aerator pumps continuously when water temperatures are above 21C. This technique provided the highest volume of fresh water to the live well and maintained higher average oxygen levels. Continuous flow-through aeration appeared to reduce mortality below levels that were seen with intermittent water exchange and aeration using timer-controlled pumps.

Anglers that were willing to be more conscientious and take the time to add proper amounts of ice and salt and recirculate rather than pump in hot surface water could maintain cooler temperatures and more favorable electrolyte balances in the live well. These methods appeared to reduce mortality slightly more than continuous pumping of aerated fresh water alone. Non-iodized salt is very inexpensive and can be carried in pre-measured zip-lock plastic bags for easy addition to the live well. One drawback to this protocol is that anglers must have storage in the boat for sufficient ice to accomplish live-well temperature control.

Boat manufacturers should be encouraged to provide aerator pump controls that allow continuous operation as well as intermittent timer-control. They should also be encouraged to provide angler-controlled recirculating aerator systems on all live wells and use the largest pumps available to maximize re-aeration capabilities (Marzofka 1995). Cooling systems such as those incorporated into some Charger Bass Boats should be utilized by more manufacturers to provide more control over live well temperatures. Commercially available oxygen delivery systems for boats and live-bait tanks (Dearman 1995) should be investigated to determine if they can supply necessary oxygen safely without supersaturation of live-well water and its associated physiological problems. Systems that incorporate recently developed solid-state oxygen monitors (O2 Marine, Mt. Airy, Maryland) coupled to aeration pumps or oxygen delivery devices that automatically turn on when D.O. drops below a threshold level could be developed to make live-well aeration more fool-proof.

We also saw that all the benefits gained during the day by using proper temperature control and continuous aeration could be lost with poor weigh-in procedures. Tournament organizers must be aware of the increased stress that warm summer water temperatures place on the bass both in contestants live wells and during weigh-ins. Following procedures recommended by Schramm et al. (1985) and Weathers and Newman (1997) and those described in the ODWC Weigh-in Kit documentation can also reduce delayed mortality. Tournaments that use such weigh-in equipment, either as stand-alone kits or part of a mobile weigh-in trailer, also project a more positive image to the non-tournament angling public. This image is one of a group that cares about the future of the resource and is willing to spend time and money on equipment and follow special procedures to ensure the health of released bass.

One component of some weigh-in systems that was not evaluated in this study was the use of a recovery or "hospital" tank. This is a aerated tank into which fish are placed after weighing. This tank is filled with lake water and dosed heavily with commercial water conditioners. After a few minutes in this tank, fish that appear healthy are released back into the lake. It has been our experience with tournaments that use these tanks that they allow retention of fish that were judged alive at weigh-in but are probably too weak to survive. However, they also allowed temporary revival of weak fish that were then released because they looked healthy to untrained tournament workers when in fact the fish were severely stressed and probably died within a few days.

Summer tournaments (June through September) make up only about 25% of Oklahoma tournaments permitted by agencies such as the Corps of Engineers, Grand River Dam Authority or Oklahoma State Parks (Gilliland 1997). However, mortality may be an order of magnitude higher in summer than in spring or fall events. As many other authors have suggested, tournament organizations should try to schedule events during cooler months. But with over 1600 tournaments per year, it would be unrealistic to expect all organizations to avoid summer contests. Instead, alternatives to conventional tournament weigh-ins should be utilized. Long holding periods in live wells may increase mortality (Seidensticker 1975) so shorter fishing hours in summer or allowing anglers to weigh-in several times during the day to reduce live-well retention time may help. "Paper tournaments" where anglers simply measure and release fish immediately are an even better solution (Schramm and Heidinger 1988).


We thank Falcon Graphite Rods, Inc. and Gene Larew Tackle, Inc. for funding the ODWC Weigh-in Kit program and Golden Rule Measuring Boards, Rex-Air Aeration Systems, Inc., Rubbermaid. Inc., York Metals, Inc. and Reef Industries, Inc. for providing components for the kits. We also thank the anglers and directors of the following Oklahoma tournament organizations for volunteering their time and energy during this study: Always Bassin' Team Tournaments (J. Alan Daniels), Anglers Choice Couples Tournaments-Oklahoma Division (Rick Hawkins), Anglers Choice Team Tournaments-Oklahoma North Division (Jim Nunnaly), Bass'n Badges-Oklahoma Division (Roy Roper), Fellowship of Christian Anglers Society-Lake Tenkiller Chapter (Jimmy Houston), Lake Country BassMasters (Eddie Lankford), Oklahoma State Team Championship (Carl Woods), Okiebass Team Tournaments (Jimmy Hawkins), Oklahoma B.A.S.S. Federation (Robert Cartlidge), and Oklahoma Municipal Bass Anglers (Ernie Summeral).

VI. Prepared by:

Gene Gilliland, Biologist III

VII. Date:


VII. Approved by:

Dr. Harold Namminga, Federal Aid Coordinator

Literature Cited

Archer, D. L. and H. A. Loyacano. 1975. Initial and delayed mortalities of largemouth bass captured in the 1973 National Keowee B.A.S.S. Tournament. Proceedings of the Annual Conference of Southeastern Association of Game and Fish Commissioners 28(1974):90-96.

Blake, L. M. 1981. Movement of tournament-caught and released bass. New York Fish and Game Journal 28(1):115-117.

Bryan, H. 1988. Conserving the resource: an evaluation of B.A.S.S.'s catch-and-release program. Bass Anglers Sportsmen Society, Montgomery, Alabama.

California Department of Fish and Game. 1991. Issuance of permits for offering prizes for the taking of game fish. California Code of Regulations, Title 14, Section 230.

Carmichael, G. J., J. R. Tomasso, B. A. Simco and K. B. Davis. 1984. Characterization and alleviation of stress associated with hauling largemouth bass. Transactions of the American Fisheries Society. 113:778-785.

Chapman, P. and W. Fish. 1985. Largemouth bass tournament catch results in Florida. Proceedings of the Annual Conference of Southeastern Association of Fish and Wildlife Agencies 37(1983):495-505.

Dearman, R. Oxygenation versus aeration. 1995. Texas Outdoors 1995(8):10-11.

Gilliland, E. R. 1997. Oklahoma bass tournaments, 1997 annual report. Oklahoma Department of Wildlife Conservation Special Publication. Oklahoma City, Oklahoma.

Hegan, H. E., G. C. Matlock and A. W. Green. 1982. Handling and tagging survival of hook-caught spotted seatrout held in cages. Annual Proceedings of the Texas Chapter, American Fisheries Society 5:39-53.

Holbrook, J. A. II. 1975. Bass fishing tournaments. Pages 408-415 in H. Clepper, ed. Black bass biology and management. Sport Fishing Institute, Washington D.C.

Horton, H.F. 1956. An evaluation of some physical and mechanical factors important in reducing delayed mortality of hatchery-reared rainbow trout. Progressive Fish-Culturist 18:3-14.

Klindt, R. M. and Al. Schiavone, Jr. 1991. Post-release mortality and movements of tournament-caught largemouth and smallmouth bass in the St. Lawrence River. Bureau of Fisheries, New York Department of Environmental Conservation. Watertown, New York.

Marzofka, T. 1995. Live well handbook: increasing tournament release rates. Cross Country Research, Rhinelander, Wisconsin.

May, B. E. 1973. Evaluation of large-scale release programs with special reference to bass fishing tournaments. Proceedings of the Annual Conference of Southeastern Association of Game and Fish Commissioners 26(1972):325-334.

Meals, K. O. and L. E. Miranda. 1994. Size related mortality of tournament-caught largemouth bass. North American Journal of Fisheries Management 14:460-463.

Plumb, J. A., J. L. Gaines, and M. Gennings. 1975. Experimental use of antibiotics in preventing delayed mortality in a bass tournament on Lake Seminole, Georgia. Proceedings of the Annual Conference of Southeastern Association of Game and Fish Commissioners 28(1974):87-90.

Plumb, J. A., J. M. Grizzle, and W. A. Rogers. 1988 Survival of caught and released largemouth bass after confinement in live wells. North American Journal of Fisheries Management 8:325-328.

Schramm, H. L. Jr., P. J. Haydt, and N. A. Bruno. 1985. Survival of tournament-caught largemouth bass in two Florida lakes. North American Journal of Fisheries Management 5:606-611.

Schramm, H. L. Jr., P. J. Haydt, and K. M. Potier. 1987. Evaluation of prerelease, postrelease, and total mortality of largemouth bass caught during tournaments in two Florida lakes. North American Journal of Fisheries Management 7:394-402.

Schramm, H. L. Jr. and R. C. Heidinger. 1988 Live release of bass, a guide for anglers and tournament organizers. Bass Research Foundation. Chattanooga, Tennessee. 16 pp.

Schramm, H. L. Jr., and nine coauthors. 1991. Sociological, economic, and biological aspects of competitive fishing. Fisheries 16(3):13-21.

Seidensticker, E. P. 1975. Mortality of largemouth bass for two tournaments utilizing a "don't kill your catch" program. Proceedings of the Annual Conference of Southeastern Association of Game and Fish Commissioners 28(1974):83-86.

Steeger, T. M., J. M. Grizzle, K. Weathers, and M. Newman. 1994. Bacterial diseases and mortality of angler caught largemouth bass released after tournaments on Walter F. George Reservoir, Alabama-Georgia. North American Journal of Fisheries Management 14:435-441.

Weathers, K. C. and M. J. Newman. 1997. Effects of organizational procedures on mortality of largemouth bass during summer tournaments. North American Journal of Fisheries Management 17:131-135.

Wellborn, T. L. and J. H. Barkley. 1974. Study on the survival of tournament released bass on Ross R. Barnett Reservoir, April 1973. Proceedings of the Annual Conference of Southeastern Association of Game and Fish Commissioners 27(1977):512-519.


Table 1. Mortality of black bass in 1995 following five Oklahoma black bass tournaments. Tournament site and date; surface water temperature and dissolved oxygen content (D.O.); mean boat live-well water temperature and D.O.1; number of tournament-caught fish and controls retained in holding nets; initial mortality ; delayed mortality after six days; total mortality adjusted for control mortality.




No. Tourn.


Delayed Mortality


(Date) C

Temp. in C

Fish / Controls


Tourn. Fish/Controls

Mortality 2

D.O. in mg/l

No. / %

No. / %

No. / %




19.9 (0.70)

162 / 18

0 / 0.0

3 / 1.9

0 / 0




7.1 (1.53)



16.7 (0.71)

117 / 18

1 / 0.9

1 / 0.9

0 / 0




7.4 (2.26)



17.0 (0.23)

79 / 15

3 / 3.8

1 / 1.3

0 / 0




7.4 (1.42)

Spring Means


17.9 (0.55)

119 / 17

1 / 1.6

2 / 1.4

0 / 0



7.3 (1.74)



29.4 (0.72)

83 / 12

5 / 6.0

64 / 82.1

7 / 58.3




6.7 (1.73)



24.5 (0.27)

92 / 18

2 / 2.2

44 / 48.9

1 / 5.6




5.6 (1.63)

Summer Means


26.9 (0.50)

88 / 15

3.5 / 4.1

4 / 32.0

54 / 65.5



6.2 (1.68)

1 Standard deviations in parentheses. 2 Delayed Mortality estimate reduced by percent mortality of control fish.

Table 2. Mortality of black bass in 1996 following five Oklahoma black bass tournaments. Tournament site and date; surface water temperature and dissolved oxygen content (D.O.); mean boat live-well water temperature and D.O.1; number of tournament-caught fish and controls retained in holding nets; initial mortality ; delayed mortality after six days; total mortality adjusted for control mortality.




No. Tourn.


Delayed Mortality



Temp. in C

Temp. in C

Fish / Controls


Tourn. Fish/Controls

Mortality 2

D.O. in mg/l

No. / %

No. / %

No. / %




31.6 (1.32)

56 / 12

0 / 0

10 / 17.9

0 / 0




5.3 (1.75)



27.9 (1.55)

52 / 12

1 / 1.9

6 / 11.5

0 / 0




7.1 (0.75)



29.6 (1.82)

61 / 9

1 / 1.6

29 / 47.5

1 / 11.1




5.1 (1.28)

Tenkiller 3


23.8 (2.29)

60 / 9

0 / 0

39 / 65.0

0 / 0




5.3 (1.67)



23.2 (1.65)

69 / 12

0 / 0

10 / 14.5

0 / 0




7.1 (0.73)

1 Standard deviations in parentheses.

2 Delayed Mortality estimate reduced by percent mortality of control fish.

3 Tournament organizers did not follow ODWC weigh-in procedures or use WIK equipment.

Table 3. Mortality of black bass in 1996 following four 1 Oklahoma black bass tournaments grouped by treatment. Mean boat live-well water temperature and dissolved oxygen content (D.O.) 2; number of tournament-caught fish and controls retained in holding nets; initial mortality ; delayed mortality after six days; total mortality adjusted for control mortality.



No. Tourn.


Delayed Mortality



Temp. in C

Fish / Controls


Tourn. Fish/Controls

Mortality 3

D.O. in mg/l

No. / %

No. / %

No. / %


A (flow-through aeration)

27.4 (3.23)

134 / 21

1 / 0.7

28 / 20.9

0 / 0


6.1 (1.54)

B (ice, salt, recirculation)

25.7 (4.20)

73 / 15

1 / 1.4

17 / 23.3

1 / 6.7


5.9 (1.50)

C (no instructions)

28.8 (4.66)

31 / 9

0 / 0

10 / 32.3

0 / 0


4.7 (1.68)

1 Tenkiller (9/14/96) not included because tournament organizers did not follow ODWC weigh-in procedures or use WIK equipment.

2 Standard deviations in parentheses.

3 Delayed Mortality estimate reduced by percent mortality of control fish.

Figure 1. Diagram of ODWC Black Bass Tournament Weigh-in Kit equipment showing kit components and steps taken in weighing angler's catch.

Figure 2. Effects of adding ice on live-well water temperature during a simulated eight-hour tournament. Test boat was a 1996 Champion with a 102 l live well. Boat was in full sun all day and air temperature was from 33 to 37C. Fish were added to simulate angler catch.

Figure 3. Diagram of tournament weigh-in showing methods used in 1996 study to evaluate live well treatments. Group "A" used only flow-through aeration, Group "B" used ice and salt in the live wells and recirculated water, Group "C" received no instructions on fish care.

Appendix 1. Recommended fish care and tournament weigh-in procedures. Measurements are in English units for ease of understanding by anglers and tournament organizers.

Anglers should:

1. Fill live well as soon as you reach your first fishing spot. Use water from open lake, not in a cove or marina area. Turn on recirculating aerators to begin building oxygen levels.

2. Run recirculating aerator continuously. If aerator must run on a timer, run it as frequently as possible. Open live-well lids occasionally to provide fresh air to live-well compartment.

3. Add non-iodized salt to the live well to reduce stress. Add 3.5 ozs. (1/3 cup) of salt per five gallons of water. This is non-iodized stock salt from a livestock feed supplier.

4. Monitor lake surface water temperatures. When water temperatures are above 70F add ice to keep live-well temperatures 10F cooler than the lake. Recirculate water rather than pumping in hot surface water. Eight-pound blocks melt slowly and provide more even gradual temperature. One eight-pound block will usually cool the average-sized live well (25-30 gallons) for two to three hours. For smaller, or dual compartment live wells, break ice into four-pound blocks as needed.

5. Change one-half of the live-well water every three to four hours to remove ammonia. Add more ice to cool the water back to the desired temperature and add one-half dose of salt.

6. At the weigh-in, fill your bag with cool live-well water first. When standing in weigh-in line, keep your bag submerged in aerated tanks and frequently dip fresh water into the bag. Bags with holes punched into them allow circulation of fresh water through the bag.

Tournament organizers:

1. Have contestants demonstrate that boat live well aeration systems are functional before teams are permitted to leave for the day's fishing.

2. Boats should remain in the water with aerators running if they don't have recirculating live wells, until they receive a weigh-in bag. Do not allow boats to participate in drive-through weigh-ins unless they have recirculating aerator systems.

3. Contestants place their catch into a water filled weigh-in bag. Bags are perforated so water will leak out. Regulate the pace of the weigh-in by passing out no more than five bags per 20 contestants. Never give out more than 15 bags unless there are multiple sets of scales.

4. Contestants place their bags in the holding tank(s) while waiting in line. Most of the live-well water will have run out of the bag by the time the contestant reaches the weigh-in line. Instruct them to dip their bags into the tank to refresh the fish. Monitor tank water temperatures and add ice as needed to keep them 10F cooler than lake water.

Add one holding tank for each 20 additional contestants. Staggered weigh-in times in flights are strongly suggested for large groups to prevent long weigh-in lines.

5. One contestant at a time takes their fish out of the holding tank, and pours them out of the bag into a plastic laundry basket in the weigh-in sink. Quickly measure fish if necessary, place the cover on the fish, lift the basket, drain excess water, and place it on the scales. Weigh big bass separately if necessary but do not keep fish out of water any longer than you can hold your breath!

6. Remove the cover, lift the basket off of the scales and place basket and fish into the salt-dip sink. Salt solution is made by adding 3.5 pounds of non-iodized salt to 15 gallons of water in the aerated dip-sink. The fish may splash for a few seconds then will become calm and start to loose their equilibrium. As soon as they roll over on their backs, lift the basket of fish out of the salt water. Do not leave the fish in the salt water for more than 15 seconds regardless of how they react.

Dip no more than 50 fish then drain the sink and make a fresh salt solution. Have buckets of water and pre-weighed salt ready to mix so you don't slow down the weigh-in process. Attach a drain hose to the sink bottom to drain the salt water taking care not to drain onto grass or plants.

7. Remove the basket of fish from the salt-dip sink and quickly carry it to the release site. Slide the fish gently out of the basket, releasing them into deeper water if possible (off the deep end of a dock or pier or slide them through a large diameter PVC pipe tube that is wetted inside with a continuous stream of water). It is normal for the fish to take a few seconds to recover from the salt-dip treatment.

8. Fish that have been caught from deep water or that have been stressed by confinement in a live well may experience air bladder over-inflation. See p.4 of the booklet Live Release of Bass, a Guide for angler and Tournament Organizers for advice on how to remedy this.

9. Remain in the release area for at least one hour after the last fish are released. Pick up any fish that are floating or are unable to swim - they will probably not survive and need to be removed from the area to avoid public relations problems.

After weigh-in, thoroughly clean the weigh-in equipment. Use a small squirt bottle filled with a weak solution of chlorine bleach and fresh water. Spray the baskets, tanks, and sinks to disinfect them then scrub away any slime, scales, foam, or water treatment product residue. Rinse all components thoroughly with fresh water. Flush aerator tubes, hoses, and pumps and allow to dry. Rinse each weigh-in bag and hang to dry.

Appendix 2. Numerical values of water temperature over time when cooling live well water with 3.63 kg blocks of ice (see Figure 1).

Live-well Temperature (C)

Time One Block Ice at 0700 Blocks at 0700 & 1100 Blocks at 0700, 1000&1300

0700 29.4 29.4 29.2

0730 27.8 27.5 27.8

0800 23.7 24.9 23.7

0830 23.7 24.7 23.7

0900 23.6 24.5 22.6

0930 24.5 24.6 24.5

1000 26.8 24.6 25.8

1030 26.8 25.8 25.0

1100 27.2 26.2 24.1

1130 27.3 28.5 23.8

1200 27.8 27.8 24.0

1230 28.5 25.5 24.3

1300 28.7 24.8 25.9

1330 28.9 23.9 25.4

1400 29.5 23.5 24.1

1430 29.8 23.6 23.5

1500 29.8 24.5 22.8