Friday, January 21, 2000, Lake Sam Rayburn, TX.
Due to the confusion of conflictive reports on proper procedures for live release of largemouth black bass, this report has been compiled to be used as a guideline for those bass anglers and bass clubs who wish to format and support live release programs. Though live release of bass has come under fire by some organizations and individuals who express their concerns for delayed bass mortality, it is "very important"that we promote the positives of active live release formats for the purpose of conserving even the slimmest survival margins, for without it, our bass fishery, as we now know and enjoy it, could become totaly dependant on State hatchery productions.
DEEPWATER & BOUYANCY PROBLEMS;
BASS, like most species of fish, adjust their bouyancy to maintain vertical positions in their water enviornment. This is done through the workings of their gas bladders much like the bouyancy compensating devices (BCD) that scuba divers use. As depth increases, pressure increases, and the gas compresses-(occupies less volumn)- As the compressed gas provides less bouyancy the bass has to release more gas into its bladder to maintain a verticle position. When the bass ascends, the pressure decreases and the volumn within its bladder increases causing bloating and unstable positioning. In order to maintain proper bouyancy the bass has to release the gas from its bladder by using a gas gland which is a slow process. Therefore, if a bass can't release its excess gas from the bladder fast enough it will suffer from the bends which causes painful air bubbles within its system causing bulging eyes, laying on its side, and bloddy fins & tails caused by ruptured blood vessels which can result in death. Bass caught from water deeper than 30' will most always suffer from rapid depressurization and must have their gas bladders relieved of excess pressure in order to return to normal bouyancy. This can be done in two ways, by caging and lowering the bass down to the depth from which it was caught, or by using a hypodermic needle or intravenous needle. Since using submersible cages can be un-realistic for most, the other option will be to use the needle. In this case, the intravenous, or IV-needle, is much prefered over the hypo. An IV-needle of from 18 to 16 gauge sizes of at least 2 inch lengths are reccomended with the 16 gauge needle being best. If you attempt this procedure you must have knowledge of where the gas bladder is and how to access it properly.
See diagram -(A)-(Point of insertion can be located by drawing an imaginary line from between the dorsal fin soft rays and spiny rays down to the lateral line. Insert the needle approximately 3 to 5 scales below the lateral line mark.)
Bass tournament organizations are reccomended to use 55 gallon holding tanks with air, or oxygen generators for this procedure. After placing no more than 10 average sized bass into a holding tank which has been filled with "treated" water, allow the bass to settle in for at least 15 minutes. After 15 minutes the bass which are in need of gas deflation will remain on top swimming on their sides, and the releasable bass will be in normal swim positions. Release the bass which aren't affected. Using a cleared, and clean IV-needle, slip the tip under a scale in the area of the gas bladder, puncture and slide-in "straight down" then submerge the bass and the needle below the waterline, gas bubbles should immediatley start escaping from the needle. As you begin to feel the bass settling in your grasp, pull the needle and let go of the bass. "CAUTION" don't keep the needle in until the gas bubbles stop as this will have the opposite effect on the bass by releasing too much gas which will cause it to lose ballast and lay on the bottom as this could also result in death. If no gas bubbles escape, jiggle the needle, and retry. If still no gas escapes, pull needle and clear it. Redo this procedure -BUT- on the other side of the bass. NEVER re-stick the same side of the bass more than twice as this will only cause hemoraging. After the bass has righted itself, allow another 15 minutes prior to releasing it. If the bass still lays on its side, check to see if the eyes are clear, if they have started to become cloudy, the bass will die no-matter what you do, so place it in a cooler and out of the tank. Be sure to clear the needle each time that it is used. Practicing this procedure will make for more experienced fish recovery operators, so be advised to train several of your bass tournament anglers for smoother and improved live release procedures. When releasing the recovered bass always try to release them in deeper water which is as clear and cool as possible. The bass will usually hold in the release area for a few days before they began moving off back to their preferred structure.
WATER TEMPERATURE SHOCK;
Except for near freezing water conditions, cold water temps have little effect on bass stressing, but studies have found that warm water temps, and fluctuating temp extremes, can become very stressful and lethal to bass. Temperature fluctuations-(rapid temp changes)- can cause shock, stress, and delayed mortality to bass. Livewell systems of bass boats can become "death-caskets" for bass when not operated properly. First, there can be large differences between the water in the live-well and the water from which the bass are caught. During normal conditions, the water temp of the waters surface can have as much as a 5 degree, or more, difference between it and the deeper water, or dense aquatic vegetation areas -(hydrilla mats)-. With surface temps being warmer, and because surface water is pumped into live-wells, this could, and does, create problems as the bass can go into shock just simply by being placed into the warmer live-well water. And as the live-well water begins to heat up even more, the bass could suffer, or even die from sudden water temperature increases of as little as 5 degrees can become very stressful and increases of 8 degrees can become lethal. As rapid decreases of water temps can also cause the same problems, this must be remembered when using ice for cooling the boat live-wells, or tournament holding tanks. Proper control of water temperatures to minimize stress and mortality of bass can be accomplished with the use of ice, or by just flushing out and re-filling your live-wells. Under cool conditions, when the water temps are between 65 and 75 dgrees, just flushing out and re-filling your live-well systems should help, but during the warmer periods, when surface temps can reach into the 80's and 90's, much more must be done to avoid stress and death. Ice is a common cooling tool for most bass anglers as they will have coolers with bags of chunk ice, or plastic jugs of ice, to be used for cooling their live-wells. Rule of thumb for this is to try and keep the live-well water at least 5 degrees cooler than the surface water as a 1/2 gallon of ice can lower the temp of a 10 gallon live-well by 8 degrees. Warmer days may call for several ice packs to be used in order to maintain more survivable conditions. (Bagged ice users must take note that when using bagged ice, and when they melt into your tanks they will release "toxic" chlorine into your live-wells or holding tanks, so the ice which is frozen into plastic jugs is a much preferred cooling additive.)
Compared with the oxygen that we humans breath there is very little oxygen in the water. Water contains between 1ppm and 10ppm's of oxygen-(ppm=parts per million)- (1) ppm is equivalent to (1) lb of oxygen to one million lbs of water. The oxygen in freshwater lakes is produced from the photosynthetic activity of aquatic plants. During the day the healthy plants will produce more oxygen than they can use so the excess is absorbed into the water. At night, these same plants will only consume the oxygen that is in the water. So at night the oxygen levels will decrease, and during the day the oxygen levels will increase. "So, take note that the oxygen levels in the lake will be at its greatest volumn during the afternoon hours and at its lowest level during the dawn hours.
OXYGEN PPM CHART;
60 degrees----sea level-(9.9)----3,000ft-(8.8)----6,000ft-(7.9)
80 degrees----sea level-(8.0)----3,000ft-(7.1)----6,000ft-(6.4)
90 degrees----sea level-(7.3)----3,000ft-(6.5)----6,000ft-(5.8)
Because bass are cold blooded they will consume less oxygen in cold water conditions and more oxygen in warm water conditions. Because of this we must maintain a minimum of 5ppm's of oxygen in our live-wells at all times. As the rate of oxygen consumption in our live-wells increases at higher temps, it is reccommended that we run our aeration systems continually during the hot water months as anything under 5ppm will become stressful and even lethal to our holding bass. This can become an expensive disaster to tournament anglers-(case in point)- at a 1998 BASSMaster's Classic the world championship was lost by a federation angler due to a dead fish which became the difference between a $16,000 payday and a $100,000 windfall. This also holds true to most circuit tournaments that maintain strict conservation formats for protecting their natural resources. Remember, oxygen levels less than 5ppm can stress out the bass and levels of 3ppm will become lethal to your live-welled bass.
BASS WASTE & DELAYED MORTALITY;
The primary waste product of bass is ammonia and carbon dioxide. As these gases become toxic to fish when dissolved in water it is important to remove them from our live-well systems to avoid streesful and lethal conditions. Carbon Dioxide can be removed just by simply aerating our wells, but ammonia buildups can't be removed by aeration and can cause death or delayed mortality when allowed to remain. As the production of ammonia is mostly caused from the simple breathing process of bass, as ammonia is emitted from their gills, it is important to maintain a high alert for anglers who hold multiple bass catches within their live-wells. Ammonia occurs in toxic-(un-ionized)-and non-toxic-(ionized)-forms the toxic forms will increase with increasing water temps and higher PH levels. As toxic levels of ammonia less than 1ppm can kill bass within 24 hours this becomes the major cause of delayed mortality after the bass has been released. When fishing waters of 70 degrees with PH-7 levels, it is advisable to flush out the ammonia saturated water and refill with freshwater. Rule of thumb for this procedure would be for every 1/2 lb of fish per gallon of live-well water at least 10 gallons must be flushed out from the system once every 2 hours. For water temps of 80 degrees and above, this procedure must be more frequent by flushing once every 1/2 hour for more extreme situations.( Please take note that during this process of eliminating the ammonia buildups that the cooling and aeration elements are also maintained.) Some tournament anglers will alleviate this problem by splitting their normal 5 bass tournament limits between their two bass boat live-well tanks.
Although several brands of water treatment additives are available on the open retail market, be forewarned that the FDA-(Food & Drug Administration)-doesn't reccommend the use of these elements due to their chemical formats. -BUT- be alerted to the approved use of common salts, such as sea-salt, rock-salt-, or table-salt, with sea-salt being the better for being used in handling and transportation of fish. Salt insertions will soothe and help to calm the bass much the same as the chemical live release additives do, and is recognized as a safer additive by the FDA. The amounts of salt to add to live-well systems is determined by live-well volumns with 0.5% -or-0.7 ozs of salt per gallon of water.
SALT ADDITION TABLE;
10 gallons of water---------(3.5 ounces of salt)
15 gallons of water---------(10.5 ounces of salt)
20 gallons of water---------(14.0 ounces of salt)
Be advised that when using salts that it must be re-added after each and every time that the live-wells are flushed.
It is unfortunate, but even after diligent care is taken when handling bass, that death can still occur in your live-well. As dead fish give off adverse body fluids and gases, it is most important that you immediatley remove it from your live-well and place it in a cooler for transportation to your cleaning table or for tournament weigh-ins.
With bass fishing, and especially bass tournament fishing, becoming a popular national pastime, the number of bass anglers have increased greatly from that of 10 or 15 years ago. This increase has been noticed by most Wildlife & Fishery Agencies as they have reacted to it with stricter fishing rules and regulations, as well as increased re-stocking programs to assist in protecting this natural resource. But decreased limits and increased bass re-stocking programs just won't be enough without the natural spawns. And if live release methods for bass are condemned and shunned by most anglers simply because of a possible 30% to a 50% delayed mortality rate, then those 70% to 50% of bass which would've survived the release procedures will not have had their opportunity to carry on with the spawning ritual of infusing their natural genetics back into the existing bass populations.This could become an absolute disaster for our bass fishery, as well as for the bass fishing industry, as we would then have to rely on State controlled or Private Enterprised hatchery systems to provide us with what we've learned to enjoy, and have tried to protect for the enjoyments of our children, and for the future of our childrens, children. "So, it's really in the hands of the individual angler, and the tournament live release crews, as to what will happen to the future of our bass fishery. Will it become strictly a put and take fishery, or will it survive as a natural enjoyment. "It's up to "US".
The above article information was based on the printed studies of "Live Release Of Bass" a guideline for Anglers and Tournament Organizers-printed by Texas Tech Press -(Copyright -1988-).For updated printed material on proper live release procedures contact your local area Fish & Game Agencies.