Tourney Impacts to Bass Populations

Trips: 29     Hours: 66.5     Bass: 373     No. > 5#: 0

This is a topic that gets a lot of attention whenever the subject of bass tournaments comes up. There is a general perception in the angling public's eye that tourneys negatively affect overall fishing quality. A 1998 study by Wilde et al. found 51% of Texas anglers held this belief, while Ditton and Hunt (article by Ralph Manns) found around 40% of anglers viewed tourneys negatively. Two of the biggest concerns are the possible issue of fish relocation and concentration around selectively few release sites, and mortality due to accumulated stressors from tourney related activities (livewell confinement, weigh in procedures, etc.).

Several studies have documented limited dispersal from release sites (Lantz and Carver 1976; Gilliland 2001; Stang et al. 1996). Additionally, several studies including WIlde (1998) have documented various levels of tournament level mortality at various times of the year. What largely hasn't been addressed is the actual degree to which mortality directly affects the overall bass population in a given lake. The newest issue of the North American Journal of Fisheries Management has the most recent study to date which tries to answer this question. Entitled "Impact of Tournaments on the Largemouth Bass Population at Sam Rayburn Reservoir, Texas", this study utilized over 6,000 tagged largemouth bass scattered throughout the entire reservoir to document catch rates of legal largemouth bass from both tourney and non-tourney anglers. It then applied known (simulated) mortality rates to the actual numbers documented and accounted for miscellaneous uncertainties such as nonreporting or tag loss.

Their final conclusions:

• "At what we believe is our most realistic simulation (tournament mortality rate of 30% at our estimate of exploitation [6%]), tournament mortality only resulted in a 2% reduction of legal-length fish and contributed just 16% of angling mortality and 4% of total annual mortality."
• "We conclude that the tournament-related impacts on the largemouth bass population at Sam Rayburn Reservoir were low. Despite more than 300 tournaments and approximately 150,000 total tournament angling-hours during our study period (Texas Parks and Wildlife Department, unpublished data), tournament-retained fish and tournament mortality only comprised 5% and 2% of the harvestable population, respectively. Annual tournament mortality was 75% lower than exploitation and 20% lower than catch-and-release mortality."
• "Our results agree with those of other studies finding negligible effects tournament-related mortality. Northern studies with cooler water temperatures found lower tournament-related mortality than we did and even less impact on bass populations (Kwak and Henry 1995; Edwards et al. 2004)."

It is important to note that the authors do caution about the potential greater impact that could occur on significantly smaller bodies of water that receive heavy pressure. Their findings also supported the work of Allen et al. (2004) that a simple ratio of tournament harvest to nontournament harvest (TH/NH) could act as a guideline to fishery managers as to when bass tournaments may pose an issue to certain bodies of water. If this ratio is less than 1.0 (0.80 in this Sam Rayburn study), there is likely negligible impact. If this ratio is 3.0 or greater, then the likelihood of tournies affecting the overall population or size structure of bass is increased.

For all you Indiana guys out there, here is a good article by Jed Pearson, District 3 Indiana Fisheries Biologist (Bass Fishing at Lake Wawasee) that touches on some of these same issues in our state (scroll down to page 4 of link).

Comments

[Richard Ziert]

Maybe you don't , won't think much of it, but I don't know how you keep so abreast of the comings and goings of the outdoor world. Yours is a special soul! A gift. If you ever stop doing what you are doing, the world will be less one absolutely great conveyance, not to mention the essence of your spirit.

Thank you Brian for all that you do here and elsewhere.

"Sincerely",

Rich Ziert