Winter is coming. The fall cool down just got more serious late this week, with hard frosts forecast nightly in the extended forecast.
Any lake that hadn’t gone through turnover yet was going through turnover this week. Turnover is when the colder water on the surface of the lakes becomes heavier and more dense than the warmer water on the bottom of the lake, so water on the surface starts to sink.
Anglers can see the green layer of dead algae on the surface of the lakes early in the morning, before the wind has had a chance to mix the greenish slime back into the water.
The dead algae comes from the bottom of the lake when the water column turns over. This process re-oxygenates the entire water column, so the lakes go into winter with good oxygen levels from the surface to the deepest part of the lake before winter arrives.
Once the lakes reach 40 degrees Fahrenheit, they are ready to begin freezing. Water is most dense around 40 degrees, so any water colder than 40 degrees floats on top of the 40 degree water and eventually turns to ice.
Small shallow lakes freeze first, followed by large shallow lakes, then the small deep lakes and finally the large deep lakes freeze last. Sometimes we get a night of below zero temperatures early in the season, which can freeze all the lakes in one night if the conditions are right.
Lake Irving and Three Island Lake are good examples of small shallow lakes. Upper Red Lake and Lake Winnibigoshish are good examples of large shallow lakes.
Lake Bemidji and Cass Lake are good examples of deep lakes, with Lake Superior the best example of a large deep lake. Much of Lake Superior stays open all winter, except in the coldest winters.
Once the lakes have gone through turnover, anglers are basically ice fishing from their boats. Anglers should be able to find active fish right up until the lakes freeze.
Many of the docks at the public accesses have already been removed, with any remaining docks likely coming out of the water soon.
tullibees and whitefish are two fall spawning species that live in many of the lakes in the Bemidji area. Muskies and large pike target the soft finned, high fat content tullibees as their prefered forage in most lakes.
tullibees and whitefish spawn in many of the same locations walleyes use to spawn in the spring. This includes current areas in rivers and streams as well as gravel bottomed areas il the lakes that have current or constant wave action.
The presence of spawning tullibees in an area gives anglers a golden opportunity to catch big pike and muskies. Many anglers use larger jerkbaits and crankbaits that imitate the silver/black color pattern of the tullibees.
It is hard for muskie anglers to cast for long periods late in the season because casting muskie baits naturally gets anglers hands wet. Most anglers will cast the productive areas as long as they can stand the cold and then troll while they warm up their hands.
Having more than one pair of gloves in the boat is often a good idea when casting for muskies late in the season.
The large predators often give their locations away from the large boils in the water from chasing after the tullibees in shallow water.
Muskies and big pike are not the only species that can be more concentrated into specific areas late in the season. This means there will be many areas that are almost void of fish, while a few areas will be loaded with fish.
Anglers can speed up the search process by using their electronics before they stop and fish. Many species of fish like walleyes, crappies and sunfish are usually located in deeper water late in the season, which makes it easier to locate the schools of fish with conventional sonar.
Shallow fish like muskies, pike and perch may be easier to locate using the side imaging feature on some high end electronics.