What if I told you that most everything we as bass anglers have been instructed to do to help keep our fish alive during tourneys is wrong?
A new study on livewell treatments for bass, currently in press, has come to some interesting conclusions that are somewhat contrary to what most bass anglers have been instructed to do for years.
In this particular study*, they tested 3 different livewell treatment scenarios in 3 different situations – a field study, a laboratory study and a pond study.
The field study took place with the help of bass tourney organizations over on Shelbyville Lake in Illinois. The three tourneys used in the field were held in June (surface temp = 77), July (surface temp = 94) and August (surface temp = 87). The parameters tested were based around livewell additives, and were randomly assigned to boats in each tourney.
Treatments included:
- Non-iodized salt only treatment (~3.8 oz. per 5 gal. = 5%; twice daily)
- Ice only treatment (1 gal. block to cool water ~9 deg., every 2h as needed)
- Combined ice + salt treatment (as stated above)
- Controls (no treatments, just lake water additions and recirculation)
No other additives (Rejuvenade, Please Release Me, etc.) were allowed to be used by boats in the study. These exact same conditions were also replicated during the laboratory and pond studies to compare against more controlled holding and treatment conditions.
Results in the field experiments showed that initial mortality across all months and treatments was low at 1.9 +/- 1.2%. Delayed mortality (5-day) varied among months, with July having the highest rate (55.8 +/- 8.36%), August was next (29.9 +/- 9.75%) and June having the lowest (12.4 +/- 5.22%).
By treatment type, ‘salt only’ had the highest average mortality at (52.4 +/- 11.6%), followed by ‘ice only’ (32.4 +/- 14.7%), ‘combined’ treatment (31.6 +/- 10.7%) and controls (25.5 +/- 7.5%).
After analyzing the laboratory and pond data, researchers were able to come to the following conclusions:
- The use of livewell water additives such as salt and ice or their combination does not significantly reduce tournament-related mortality.
- Fish size and ambient water temperature may have a greater influence on delayed mortality observed during competitive angling events than specific livewell additives.
- Smaller-sized fish appear to be more resilient to tournament related stressors that result in mortality as compared to larger fishes regardless of ambient water temperature or livewell additive – because they experience less physiological disturbances since they are often played for shorter periods of time and endure shorter periods of air exposure during weigh-in procedures.
- “Collectively, these results suggest that the addition of livewell additives does not enhance fish survival following competitive angling events. As a result, we encourage anglers to practice proper fish handling practices as well as maintain good water quality within lilvewells as opposed to altering water quality with additives.”
_____
Pretty interesting data that supports some previous research, but also conflict with others. It certainly isn’t the final word, as there are still several questions around commercial treatments that would be interesting to see tested, as well as factors related to oxygen (hydrogen peroxide, in particular, along with the various pure oxygen infused systems) that I’d like to see data on.
It does suggest that tourneys during the warmest months of the year are likely the most detrimental from an overall mortality standpoint, as well as having a more negative effect on the largest fish caught during an event. But that’s a conclusion that has been largely derived and accepted in most, if not all, studies I’ve seen to date.
* Kenneth G. Ostrand, Michael J. Siepker and David H. Wahl (2011) Effectiveness of Livewell Additives on Largemouth Bass Survival. Journal of Fish and Wildlife Management In-Press
BryanT
May 23, 2011 at 2:49 pm
On a side note from looking at BFL results, looks like catch rates go way down in the summer. So the impact is still limited even though the percentages look high. I have always used two 1000gph pumps on constantly pumping in fresh water in the Legend’s 42 gal well and have had little issues with fish kill. I don’t like ice and additives. Bagged ice contains Cl when mixed with NaCl and H2O, you end up with a reaction making a Cl2 or extra chlorine ions swimming around in the tank with your prized catch. Not good, and even though it is a small amount, it is enough to increase mortality.
Rich Arnold
May 23, 2011 at 3:43 pm
Interesting post for sure. I think that water temp is important and also agree with Jay that I would like to see some other tests done with the oxygen levels and that new Kool Well system. I don’t lose fish very often, but July and August are the bad months for me. I normally catch them deeper during those months and notice the fish seem to suffer more from the pressure change as I generally regulate the water temp pretty good (5 degrees cooler than the lake). I am not sure that “fizzing” helps that much and you really need to know what you are doing or you can make the whole ordeal worse. To ice or not to ice, to fizz or not to fizz…is that really the question?
Chad Keogh
May 23, 2011 at 5:14 pm
I’ve never fished an event before where the water temp was high enough to require ice be added to the livewell, plus I usually fill my livewell as soon as I launch so it’s full of lake water at it’s coolest.
As for the salt usage, I use Rejuvenade and will continue to do so since I’ve used it in the past and my bass stay very feisty until it’s time to take them out.
Alex Voog
May 25, 2011 at 11:02 am
Rejuvenade has proven itself over and over to me. Never mind it’s proven tournament results, I once kept several dozen large fathead minnows (ice fishing) alive for 2 weeks in a 5 gallon bucket, in the basement, only adding 25 percent fresh water every other day and a piece of bread, and a teaspoon of Rejuvenade. Only one minnow died before they were Pike bait again….over half of them were released live back into the lake after I landed a 28″ pike on a 6 lb test dropshot rig (works awesome!). I figured the survivors deserved their freedom….
Alex Voog
May 25, 2011 at 11:05 am
Oh, there was no aerator either. REJUVENADE.
AaronW
May 25, 2011 at 9:05 pm
Interesting information for sure; however, before using this information as gospel that “ice + salt = not nice” you should really understand what the information that you are publishing is saying. Statistical analysis is an interesting science that scientists use to try to make sense of data that they collect. Often these results can be skewed.
“By treatment type, ‘salt only’ had the highest average mortality at (52.4 +/- 11.6%), followed by ‘ice only’ (32.4 +/- 14.7%), ‘combined’ treatment (31.6 +/- 10.7%) and controls (25.5 +/- 7.5%).” is very misleading because you don’t know whether these statistics are a product of the data across the entire study when water temperatures were lower and less likely a strong factor in both delayed and/or initial mortality. I would be more interested in seeing statistics of the effect of these treatments taken from the subset of their data in July and August when mortality was at its highest. Interestingly, this is also the time of year that scientists encourage fishermen to use these treatments.