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Discussion Starter · #1 ·
last year I was inquiring about a mortality study done during the everbloom tournament trail regular season and the results are in.
here is the link the the website
Illinois Natural History Survey

Submitted by Mike Blake on Tue, 02/24/2009 - 1:40pm.
From April through October 2008, the Illinois Natural History Survey (INHS) and the University of Illinois (U of I) conducted tournament research in coordination with the Ever-Bloom tournament trail at Evergreen and Lakes. The goals of this study were to 1) evaluate delayed mortality (fish that are weighed-in alive but die within 3 days of the tournament) after bass tournaments at Evergreen Lake and 2) evaluate the physiological status (stress) of tournament-caught bass at Lake Bloomington at a seasonal scale. Little attention has been paid to smaller, club-style tournaments (<50 boats) although they are more frequent and localized than larger, tour-style events. Results from this study will not only provide a clear picture of what is going on at tournaments at Evergreen and Bloomington lakes, but will also provide recommendations to tournament organizations throughout the state and country to improve tournament practices and minimize the impact of tournaments on fisheries.

Research Methods

Visited tournaments at Evergreen and Bloomington Lakes in 2008, one tournament per lake per season (seasons defined as early-spring, late-spring/early-summer, mid-summer, fall)

Performed delayed mortality estimates at Evergreen Lake using holding pens

Placed tournament-caught fish into holding pens following the conclusion of the tournaments

Checked for delayed mortality for 3 days, then released remaining fish

3 days is a standard length of time used in other studies-if kept for more than 3 days, any mortality of bass is probably not due to the tournament

Used 9 feet deep soft mesh cages to allow the fish to choose from a variety of depths/temperatures and minimizing the effects of the holding pens

Collected control fish using electrofishing gear to account for cage-induced mortality

Evaluated physiological condition (stress) at Lake Bloomington
Took blood from tournament-caught bass following the conclusion of the tournament

Some whole blood was stored in liquid nitrogen while the remainder was separated into plasma and red blood cells which was then frozen in liquid nitrogen

Analyzed blood and plasma samples at our lab in Urbana for stress indicators

Also collected blood from a "resting" control group of fish to determine seasonal baselines of blood parameters


Evergreen Lake

No delayed mortality during early-spring, late-spring or summer tournaments

1 delayed mortality during fall

Water temperature was as high as 82ºF during the summer

All tournaments combined, there was a total of 1% delayed mortality

5% delayed mortality is considered the standard for "very good" so Ever-Bloom tournaments were even better

Overall, Ever-Bloom tournaments had very minimal impact with respect to mortality at Evergreen Lake

Lake Bloomington

Blood/plasma parameters indicated that summer was most stressful followed by late-spring, early-spring, then fall

Fall fish exhibited very few changes in stress parameters, indicating fish caught in the fall were only slightly affected by tournaments

Summer fish (both resting and tournament-caught) had low levels of hemoglobin which carries oxygen in the blood (similar to humans). This suggests that bass simply don't carry as much oxygen in their blood during the summer

Late-spring fish showed changes in stress parameters even though water temperatures were relatively cool. This is possibly due to stress or recovery from spawning.


Although we saw increased stress parameters during tournaments, we did not observe any significant mortality even though water temperatures were upwards of 82ºF during summer. This is most likely due to the extremely efficient weigh-in procedure during all tournaments. From previous studies, the weigh-in has been identified as the most stressful part of a tournament for bass but the weigh-ins conducted by the Ever-Bloom circuit were quick and efficient. Some notable practices that reduced stress in bass:

Boats were trailered before weigh-ins

This meant that fish spent minimal time in weigh-in bags. Fish only had to spend a small amount of time in weigh-in bags as anglers got their catch from their nearby boats rather than docking boats, putting fish in bags, carrying them to the scale, and then waiting for others to weigh-in.

Livewells are comfortable environments for bass as they are aerated, shaded, and temperatures do not fluctuate severely

Weigh-in bags are uncomfortable for bass as they are un-aerated, exposed to the sun, and have less water than livewells so temperatures can change more quickly and more drastically

Only a few weigh-in bags were allowed out at a time

If many weigh-in bags are allowed out at a time, then fish spend a lot of time in them as anglers wait for others to weigh-in

A lot of times, if there are anglers waiting, they usually rest their weigh-in bags on the hot asphalt/concrete which can be bad for bass

Some organizations like to distribute a lot of weigh-in bags because they think that it will speed up the weigh-in process. At the Ever-Bloom tournaments, even though there were only a few bags let out at a time, weigh-ins were continuous and quick.

1-pound dead fish penalty

This is about 4 times higher than the standard dead fish penalty

This penalty definitely made sure anglers were conscientious of the health of their fish

Anglers ensuring aerators worked and making sure aerators were run during tournaments to avoid such a large penalty definitely reduced the stress and mortality of the fish


This study showed that when run properly, tournaments can have a minimal impact on the fishery

The Ever-Bloom circuit did several things right and provides a good example for other organizations to learn from

I only have 3 suggestions for the circuit to further minimize stress of bass:

Consider using aerated weigh-in bags, especially during summer

Fish carry less oxygen during summer, warmer water holds less oxygen, and weigh-in bags can heat up quickly because there is not much water

Consider conducting weigh-ins in a shaded area to further reduce the temperature changes fish can experience

Keep doing what you're doing! These 2 suggestions are only suggestions-the circuit has shown that mortality is almost negligible using their procedures

Things learned from this study for other organizations to consider

Trailer boats before weigh-ins

Only allow a few weigh-in bags out at a time to minimize the time fish spend in them

Consider using large penalties for dead fish - this makes anglers double check their fish

Fish carry less oxygen in summer so be extra careful to aerate during summer

Consider using aerated weigh-in bags

Consider performing weigh-ins in the shade

Tournaments can have little to no mortality if run correctly and efficiently as shown by the Ever-Bloom Circuit

General comments for everyone

We saw increased stress levels in late-spring even though temperatures were low. Fish spend a lot of energy spawning and may not have fully recovered so take extra care of these fish.

Run aerators continuously, even if you have 1 small keeper in the livewell or a 25 pound limit

Be careful of temperature changes in livewells-you can cold shock fish by adding too much ice

Thanks to all tournament participants and especially Terry Brown and Mike Blake for allowing us to conduct this study! We've learned a lot from this study and hopefully can apply these finding to tournaments throughout the country to minimize the impacts of tournaments everywhere.
Any questions can be sent to Matt at [email protected].

Super Moderator
6,234 Posts
EXCELLENT info MadCraw. I have been wondering where you have been at all winter. Its great to see you back. While we have tossed around numerous ideas for the 2009 WCF trail, the one thing everyone seems to agree on is mandatory aerated livewells. Your setup last year was awesome and my boat will be getting the same for this year. The health of the fish should always be our primary concern.

160 Posts
Discussion Starter · #4 ·
lee wdnr did a study similar to this but with crazy results. there results where something like half mortality but don't quote me on it. matt good to hear from you too dude I have been hibernating and gaining weight all winter. will see ya for some wcf events for sure. :wink:

5,340 Posts
"Livewells are comfortable environments for bass as they are aerated, shaded, and temperatures do not fluctuate severely "

Bingo !!!!!

Tony and I had one at the end of the season and it made a HUGE difference in the health of the fish at weigh-in time... :mrgreen:

825 Posts
That is very encouraging to hear. Thanks for the report. I thought delayed mortality was much higher and now I feel a little better.

I know I have been in 2 clubs and I think that both of their weigh-in procedures need to be tweaked. The recommendation of a few bags out at a time is dead-on. My club has no weigh-in procedure other than "scales are open." I've seen 6 guys in line and each one is getting a big bass weighed. I've recommended weighing in the fish in the same order as take-off but that hasn't really been embraced. I think I'll bring it up again.

Thanks again Madcraw and don't be a stranger around here.

160 Posts
Discussion Starter · #7 ·
hey paul with these bags of fish being weighed in does your club even have a tub of oxyginated water so they can dip there bags of fish in while they wait to get weighed in?
i found this graphic on
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