Nature has many sensory indicators of seasonal change. Most indicators are visual. A few, like the music of migrating birds, are auditory. Smell and taste are more difficult to assess. But, the smell and taste of spring and fall are undeniable.
Tactile issues are toughest to decipher, especially when trying to figure out behavioral patterns in cold-blooded creatures, like fish. This is one instance where the surface temperature gauge on marine electronics is perhaps the most-critical component of this recreational shiny object.
A lifetime of chasing fish has revealed the magic of 55 degrees. In the spring, bass “turn on” when the “double nickel” shows up on sonar screens. Not only do bass begin aggressively chasing baits, small-mouth bass and flathead catfish begin to migrate into areas where they will spend the warmer months.
A reverse migration is happening now with surface temperatures on the Mississippi River mainstem tickling 55 degrees on Oct. 14 – for the first time since spring. Bass and other warm-water species will seek out the warmest water available, bunching tightly and feeding aggressively until their entire environment has an ambient temperature below 43 degrees.
Northern pike, walleye and panfish feeding activity kicks into high gear when temperatures drop to 43 degrees, remaining quite active until the slide to honest winter begins with temps in the upper 30s.
In the spring, walleyes, saugers and perch are done spawning when water temps warm to 55 degrees. These popular species spawn at 45-48 degrees, with northern pike getting the urge to procreate at about 45 degrees, often when ice still covers the shallow, weedy areas where these big green toothers drop their eggs.
When water temperatures drop to 55 degrees in the fall, walleyes are casually beginning their migration toward “wintering holes” in deeper water. From late April until about Nov. 1, many aggressively-feeding walleyes are cruising in four to 12 feet of water on the Mississippi and its myriad backwaters.
These “marble eyes” begin to slide deeper in the water column as water temperatures dip below 45 degrees, often concentrating in tremendous numbers in water 24-40 feet deep, with saugers – the walleye’s smaller cousin with a desert-camo color scheme – holding in even deeper water until waters begin to warm into the upper 30s again in the spring.
Until rain showed up Oct. 12, the water column in the river mainstem was the clearest I’ve seen it in early October in over 20 years – visibility over four feet! To a great extent this clarity is due to filter-feeders like mussels, especially dominating and detrimental species like zebra and quagga mussels which colonize about desirable native mussels like the Higgin’s eye.
Desirable weed growth across open areas in shallower water cuts down on turbidity caused by “wind fetch” while also creating wonderful habitat for countless prey species. Vast mats of eel grass which has died, floating downstream in tennis court sized mats in the fall has been a pernicious problem for fishers since Shep was a pup. So far this fall it has been possible to find fishable areas away from this rogue lawn on steroids – most of the time.
The mighty Mississippi River is a force of nature in the truest sense. The two biggest factors in realizing consistent success catching many of the estimated 130 species of fish which swim here are learning to work with the river instead of fighting it and spending as much time on the water as possible.