Is Consistant Tournament Pressure Hurting Lake Havasu's Fishery?

Question
My question regards the consistent tournament pressure of targeting pre-spawn fish during the spawn. I recently was fortunate enough to spend 1 month fishing Lake Havasu in Arizona. These man made impoundments can be great fishing and this one is, however, every week there is a tournament on Lake Havasu. Great for Havasu's economy but tell me if there is a threat to the smallmouth and Largemouth fishery after keeping fish in the live well for sometime 6 hours or more after taking a female from her bed. These fish are all released alive with the exception of those fish that died on route to weigh in.

Currently Lake Havasu encourages tournaments every week end no matter what time of year it is or regardless of the spawn. Since the temperature of the lake determines when the fish spawn, will this constant pressure on the spawning fish during tournaments eventually effect the fishery. Already the Largemouth are being taken over by smallmouth which seem to do better there. The striper fishing is phenomenal, but stressed by the snow birds in the northern U.S. There are no perfect solutions for any fisheries until a proper understanding is developed about that specific body of water.

Sincerely,
John Mariano,
Albany, New York

Answer
Fishing during the spawn is certainly controversial. From a biologist's perspective, I have yet to see any evidence where fishing, and even tournament fishing, during the spring spawning period has any impacts on bass populations. Every water body has a limit to the amount of life it can support...also known as carrying capacity. With anywhere from five to twenty thousand eggs per nest, how many successful nests are required to have a strong year-class? No one knows, and it likely varies each year, and certainly from one body of water to the next. More bass fry are produced each year than will survive to their first birthday. It's not logical to assume that you can protect every nest and every fry produced will survive. There is only so much food, cover and space to go around. If one nest fails, the resources (food/cover/space) that would have gone to members of that nest are now available to some members from another nest...so the second nests survival goes up.

Now this is all theory based on personal, anecdotal evidence, but shared by most other biologists that I know. Generally in the south (where I spent my days in the field), where fishing during the spawn has been popular for the last century, population fluctuations can almost always be correlated with environmental factors (too much water, too little water, extreme temp variations, low nutrients, high nutrients, etc.). There has been some research that demonstrates if you remove the male (female actually doesn't guard the nest...just does her thing and moves on) for a few minutes, egg predation from other fish/aquatic organisms will clean out the nest rather quickly. However, that's not looking at the population level, which no one has been able to document an impact there.Largemouth will likely be dominated by smallmouth in an aging reservoir regardless of fishing pressure. It's simply a shift in the habitat complexity, which favors smallmouth (and generally spotted bass as well). As the amount of woody debris/aquatic vegetation is reduced and becomes more rock/boulder/coble, largemouth are at a competitive disadvantage, and the populations shift naturally. I've seen that in my own data numerous times. It can also go the other way if aquatic vegetation becomes established in relative abundance.

Chris Horton
Bassmaster Magazine