Give bass a better chance to survive in a livewell
It’s the middle of summer, when it’s tough to be on the water all day and when bass retained in a livewell for later release — such as in a tournament — commonly suffer increased mortality. Following are some guidelines for keeping survival of bass held in livewells high and some results from a recent Mississippi State University study that addresses the survival of bass held in livewells and those released immediately.
Simple guidelines for bass survival
For many years, I have worked with Gene Gilliland, my colleague, friend, frequent fishing buddy and B.A.S.S. conservation director, to develop and test simple procedures for maximizing survival of livewell-held bass in summer tournaments. Details are available at https://www.bassmaster.com/sites/default/files/keepingbassalive_guidebook_comp.pdf.
Here’s the short version for summer bass care:
- Fill the livewell early in the day when the surface water is coolest. Set your livewell water-control system to recirculate.
- Use blocks of ice to keep your livewell at 80°F. Half-gallon milk jugs filled with water, capped and frozen, work well.
- Run your aerator continuously if you have more than a few pounds of bass.
- If you have more than 5 pounds of bass in the livewell, pump out half of the livewell water every three hours, then refill with fresh water from areas with good water quality. Add block ice to lower the livewell water temperature to 80°F.
- As always, handle bass quickly and gently; don’t let them flop on the carpet; use a coated or rubber landing net, and minimize air exposure.
Research at Mississippi State has proven that following these recommendations in summer tournaments will reduce mortality by 50 percent compared to no temperature control. You will also find that bass from livewells where the temperature is controlled are more vigorous and have a heavy slime coat, while bass from the warm livewells are lethargic and feel dry and rough.
Research recently completed at Mississippi State University measured the survival of bass released immediately and bass retained in livewells for eight hours and subjected to a typical tournament weigh-in at water temperatures ranging from 63°F to 91°F. The findings:
- Bass subjected to one minute of simulated angling and immediate release had 100-percent survival at all temperatures.
- Bass subjected to one minute of simulated angling and eight hours retention in live wells with five parts per million (ppm) dissolved oxygen had high survival up to 84°F. Mortality was 30 to 40 percent when the water temperature was 91°F and livewell temperature was 91°F or lowered 7°F but was 100 percent if livewell temperature increased 7°F during the livewell retention period.
- Survival of bass subjected to one minute of simulated angling and eight hours retention in livewells was 15- to 20-percent lower in livewells with 2 ppm dissolved oxygen than in livewells with 5 ppm dissolved oxygen at 77°F and 84°F, and only 15 percent of the bass held at 91°F survived when dissolved oxygen was 2 ppm.
- Survival declined significantly when simulated angling was increased from one to three minutes at 84°F for both bass released immediately and those held in livewells and subjected to tournament weigh in procedures.
- Lowering livewell water temperature 7°F improved survival at water temperatures at or above 84°F.
Summer temperatures stress anglers and bass, but survival of fish immediately released or held in livewells can be 100 percent in water temperatures up to 91°F when fish are landed quickly, handled gently, and held in well-aerated, cool-water livewells. Admittedly, the recent Mississippi State study used very controlled conditions, but they demonstrate that high survival is possible for bass caught from the warmest water anglers face in Mississippi.