Cartoon by Peter Kohlsaat

pHishing at Dawn and Dusk

How many times have you gotten up four hours before normal people to enjoy a dawn topwater bite? Or endured a fishless afternoon and 100 mosquito bites to whack ’em right before dark? Here’s what the wrapped-boat crowd has to say about whether dawn or dusk is best.

Pro W: “I like the morning better because the fish aren’t too active at night if it’s been a really hot day, so they feed early before it gets hot out and they head deep again.”

This guy fishes where the bass have some strange rules: No feeding at night or in deep water if it’s hot.

Pro X: “I’d rather fish early. The water quality is higher in the shallows in the morning because the pH level goes down at night as the plant life become inactive.”

Partly right. The pH decreases through the night and is lowest at dawn because plants—both rooted plants and phytoplankton—are using oxygen and producing carbon dioxide, which lowers pH. Although pH got a lot of attention in the 1980s and bass tolerate only a certain range of it, there’s no hard evidence about the effects of pH on bass feeding. If you believe that high pH is good, sleep in and fish the dusk bite.

Pro Y: “Dawn is a better time to fish during summer because bass feed more actively in the shallows at night, and this usually continues into the first hours of dawn until they head to deeper water.”

Unlike Pro W, this guy’s fish are much less regimented and can feed whenever they want. I’ve always wondered if bass move deep after the topwater bite dies or whether they just hang out and wait for low-light conditions to become more active again. An interesting study in heavily vegetated Lake Seminole on the Florida-Georgia border provides some insights. Adult bass followed a daily onshore-offshore movement pattern. Deep or shallow, bass were always associated with good cover. No loitering in the shallows for that bass bunch.

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Biological Blarney

And you can find a few pearls of wisdom from the ivy-tower crowd, as well: “Reservoirs are artificial lakes.”

Lakes can be formed in almost 100 different ways. Man-made dams are just one. Most lakes in North America were formed by glaciers and sinkholes. I concede that since the dam was not created by nature, the reservoir is man-made; but I can’t call it an artificial lake. Fortunately for anglers, the reservoir is filled with real water and real fish, and you do need a real license to fish there.

“Bigger lures catch bigger bass.”

This study looked at a bunch of small, starving bass striking lures more than half their own length. There’s abundant research suggesting that bass and other piscivorous fish consume forage smaller than the maximum size they can eat. In-Fisherman Editor and fishery scientist Rob Neumann got it right in his article in the June-July 2008 issue on what pike and muskie eat. He described prey size as a wedge—as a predator grows, the largest size prey it eats increases, but it also continues to eat small prey. Bass, like other predators, are opportunists—if it’s close, if they can catch it, and if it fits down their throat, it’s dinner.

Dr. Hal Schramm, Starkeville, Mississippi, is leader of the Mississippi Cooperative Fish and Wildlife Research Unit. He’s also a freelance outdoor writer and avid angler.