New Research Finds that Long Stays in Live Wells are the Single Greatest Cause of Bass Mortality Post Tournament

Facts at a glance

  • Many factors combine to increase post-release mortality among bass
  • According to the Pennsylvania Fish and Boat Commission, catch-and-release mortality rates were as high as 20%
  • But new research suggests no significant effect of terminal tackle on fish mortality
  • Instead, it was the length of time in the live well that was correlated with post-release mortality
  • Those caught and released immediately had 1.3% mortality; bass caught, held and culled had 14.9% mortality; and fish brought to weigh-in had 39.1% mortality

Bass fishing is one of America’s favorite sports, and pretty much everyone - from tournament-trail pros to weekend anglers - knows that live bait is forbidden in these competitions.

You’ve probably heard a few reasons for this.

Since a tournament is a competition, we want to judge the skill of each angler, and the best way to do that is to skip the live bait in preference for the artificial. That way, it’s not just a matter of luck, but instead demands skillful choice and application.

You’ve probably also heard that lure companies are big sponsors, and thus have a vested interest in promoting their products. They’re not going to fork out big bucks if shiners are the go-to option.

And many of you are aware that the restrictions on live bait are an attempt by regulatory authorities and tournament organizers to reduce post-tournament fish mortality. 

Many bass anglers are at least occasional tournament competitors, and plenty more aspire to be. As a result, live bait isn’t something you’re likely to see very often in bass fishing, and even weekend anglers tend to shun minnows when fishing bass.

I think all of us can see the logic behind that first reason, and I’ll bet the second one rings true, as well. 

But what about the third? 

Is live bait more dangerous to bass than worms, chatterbaits, spinners, crankbaits, and the like? What are the causes of catch-and-release mortality in largemouth bass?

Live bait and fishing mortality: the early research

crawfish bait for bass

Studies from the 1980s and 1990s demonstrated quite a bit of variance in fish mortality depending on the type of terminal tackle that was used to catch them, in addition to other factors like hooking depth, the length of the fight, and water temperature.

These early studies, conducted in salmonids like trout, revealed much higher mortality rates when live bait was used. Indeed, Muoneke and Childress found that live bait resulted in more hooks to the gut, gills, eyes, and other potentially lethal areas.

That makes a lot of sense, and when wildlife biologists studied largemouth bass, they found similar patterns. 

According to the Pennsylvania Fish and Boat Commission, for instance, catch-and-release mortality rates were as high as 20%, with hard fights, rough handling, and deep hooks being a particularly lethal combination. And while not perfectly applicable to largemouth, smallmouth bass that were caught on minnows suffered 11% mortality, compared to zero on spinners.

Settled science? Not quite…

But these results are contentious, and more recent experiments suggest that live bait may not be a threat to fish populations in catch-and-release angling.

A 2021 paper that studied post-catch mortality of trout over three successive years revealed surprising findings, namely, “low mortality of trout that were caught primarily with bait and subjected to more handling stress than they would normally experience in catch-and-release waters.”

The researchers worked with tournament anglers, carefully measuring factors like holding time, hook size, hook type, bait type, water temperature, and other critical variables like the presence of blood in live wells.

trout hook size for worms

As they summarize:

We did not find any significant effect of terminal tackle on trout mortality, which was due in part to a rather small number (1.3%) of anglers that used flies. In our study, the mortality rate for trout that were caught with bait was similar to that for those that were caught on artificial lures, which is contrary to most other studies. Neither hook style (J hook versus treble) nor barb type was related to hooking mortality, which is consistent with other studies.

Now no study is perfect, nor does any one paper end the discussion. And you might be thinking, “Well, trout aren’t largemouth bass.”

And you’re absolutely right.

But researchers from Texas’s Parks and Wildlife ran a similar experiment with bass.

On Lake Umphrey, four teams of two anglers fished twice using a different bait type each time: “treble hook lures, plastic worms fished ‘Carolina rigged,’ live carp under a cork, and live carp on the bottom. Each team fished until it had 30 bass over 14 inches long.”

The results were surprising:

The death rate was no higher for fish caught on live bait than for those caught on artificial baits. On the first trip, mortality was 13% for live bait-caught fish, compared to 23% for artificial baits. On the second trip, it was 28% and 23%. The mortality rate was related to where the fish were hooked, however. It was 48% for fish hooked in the throat, 17% for fish hooked in the gill, and 20% for mouth-hooked fish. The percentage of throat-hooked fish was highest with plastic worms.

Bass Mortality Rates by Bait Type and Hook Location

Bait isn’t the problem: stress is the catch-and-release killer

That provides some food for thought.

The argument against live bait in terms of catch-and-release mortality is that bass are more likely to swallow minnows and other live bait, yielding deep hooks that quickly kill released fish. 

But in this study, plastic worms were more likely to be the culprit for hook injuries, and overall, post-release mortality was effectively equal for live bait and its artificial alternative.

A follow-up study by the same team looked carefully at post-tournament mortality on Lake Fork.

They discovered that “Those caught and released immediately had 1.3% mortality, bass caught, held and culled had 14.9% mortality, and fish brought to weigh-in had 39.1% mortality. The researcher in charge stated that bass mortality due to tournaments can be much higher than many fishermen believe.”

Bass Mortality Post-Tournament

That’s startling.

Taken as a whole, this evidence suggests

 that live bait isn’t a significant problem for largemouth bass populations, while rougher handling and longer times in live wells is the real killer. 

Other things to consider are barometric trauma and water temperature: landing fish from deeper water can lead to higher mortality, and bass caught and released in water over 77 degrees experience high levels of stress, leading to more deaths.

What you can do to keep bass alive

Minimizing catch-and-release bass death rates is in everyone’s interest, and there are things you can do that are supported by the science.

Use tackle that encourages mouth hooking.

While not conclusive by any means, we’re just not seeing the science to suppose that live bait is more dangerous than artificial lures.

But even with that in mind, if you do choose to use live bait when bass fishing, we recommend circle or octopus style hooks that reduce swallowed baits.

Minimize stress and injury to bass by handling them carefully - and as little as possible.

Proper bass handling is critical.

Always handle fish with wet hands - never towels or other materials that may remove their slime or injure their scales.

Other things to avoid include:

  • Using a net with knots (it’s best to use rubber mesh nets)
  • Holding the fish between your knees to get it to stop moving
  • Sliding it up the bank or over the rail of your boat

When you lip bass, which is a good way to hold them without stripping slime or tearing delicate scales, always keep the tail directly below the head.

proper way to hold a bass

If you can’t manage it with one hand, you can gently support the belly of the bass with the other.

proper way to hold a bass with both hands

What you should never do is hold a bass by the jaw with its tail elevated.

That places tremendous stress on its jaw, possibly injuring it and leaving it unable to feed. It’ll swim away, only to starve to death in due time.

wrong way to hold a fish

This is wrong!

Check out this video:

In tournaments, be sure to keep your live well cool and well-aerated.

Higher water temperatures yield lower dissolved oxygen rates, stressing bass both with heat and suffocation. 

But as wildlife biologists with Pennsylvania’s Fish and Boat Commission warn, “While cooler water in live wells helps increase the amount of dissolved oxygen, large water temperature differences can lead to mortality. Water temperature differences should never exceed 10 degrees F.”

Instead, they insist that it’s better to “maximi[ze] the exchange of lake or river water with the water in your live well,” as this reduces a wide range of stressors from pH to water temperature and dissolved oxygen levels.

 

References: 

  • See Mongillo, P. E. 1984. A summary of salmonid hooking mortality. Washington Department of Game, Olympia; Taylor, M. J., and K. R. White. 1992. A meta-analysis of hooking mortality of nonanadromous trout. North American Journal Fisheries Management 12:760–767; and Muoneke, M. I., and W. M. Childress. 1994. Hooking mortality: a review for recreational fisheries. Reviews in Fisheries Science 2:123–156.
  • Muoneke and Childress. “Hooking mortality.”
  • Pennsylvania Fish and Boat Commission Staff, “Catch & Release Fishing: Effects on Bass Populations.” https://www.fishandboat.com/Fish/Fisheries/Documents/cr_mortality.pdf Accessed 7 September 2023.
  • Carline, Robert F, et.al. “Hooking and Handling Mortality of Trout Captured in the Bald Eagle
    Creek Trout Tournament, Pennsylvania.” North American Journal of Fisheries Management 41:1465–1472, 2021.
  • Horst, Jerald. “Catch & Release Living to Fight Again.” LSU Ag Center, 2003.
  • Pennsylvania Fish and Boat Commission Staff, “Catch & Release Fishing.”
 
About The Author
Pete Danylewycz