The weather has taken a turn toward fall and, eventually, toward winter. There is already snow in the mountains of Montana and probably frost on the pumpkins if you have some outside.

Surface water temperatures in the lakes have dropped back out of the 60s after the September warm up, with most lakes now having surface water temperatures in the mid- to upper 50s.

The thermocline is disappearing from lakes where it still exists. Turnover is the next thing on the calendar, when surface water temperatures become significantly colder and more dense than water on the bottom.

Once this happens, the more dense surface water begins to sink and displace the less dense warmer water on the bottom, which forces it to the surface.

Turnover is the process where lakes become fully oxygenated before winter and the water column becomes one temperature from the surface to the bottom.

Water is most dense at between 39 and 40 degrees, which is the temperature of the water under the ice. Water colder than 39 degrees floats on top of the water column and begins to form ice when it hits 32 degrees.

If ice didn’t float, the lakes would freeze solid during the winter and everything would die and ice fishing wouldn’t be a thing.

Actually, ice fishing is huge and getting bigger, not only in Minnesota, but across Canada and the rest of the Ice Belt.

The ice fishing sector of the fishing industry is consistently the fastest growing part of the sector, with many new product lines coming out each year focused solely on ice fishing.

The Winter Sports and Ice Fishing Show in early December at the RiverCenter in St. Paul is where most ice fishing companies roll out their new products. It’s worth checking out if you love ice fishing and want to see virtually all the products in one location.

Meanwhile, there is still open water fishing to do, with October a good month for catching big fish of all species and doing homework for the ice fishing season.

Stable weather is one of the biggest factors in anglers’ success rates during the fall. Many anglers become weather dependant in October.

They will continue to fish if the weather stays nice, with most anglers, other than muskie anglers, “cherry picking” the days with good weather to go fishing.

Walleyes have been in a wide range of depths recently, depending on the conditions, the lake and where the forage the walleyes are feeding on is located.

Shallow rocks and the remaining green weeds can be like magnets to walleyes under the right conditions. Schools of walleyes will move in and out of these areas when they alternate between feeding in shallower water and resting in deeper water.

Schools of perch are on the shoreline flats and on top of humps in the right depth range, feeding on crayfish and minnows.

There are also walleyes in deep water in many lakes, feeding on shiners, suckers, small perch, crayfish and other types of baitfish.

Crappie and sunfish anglers are seeing the fish abandon the last areas with green weeds and heading toward areas with mud bottom, so they can feed on insect larvae, zooplankton and minnows.

Sunfish tend to like shallower mud flats in the 20 foot range, while crappies often go deeper and like to feed around the perimeter of the deep holes.

Crappies and sunfish may be located in the same areas in smaller lakes that don’t have as many choices for habitat as the larger lakes.

Fish utilize what is available to them in the lakes, so each lake can be slightly different, based on what types of structures exist in the lake.

Fish are very adaptable and able to thrive in many different scenarios. As long as the fish have enough food to eat, good spawning habitat and suitable oxygen and temperature levels at all times of the year, fish can thrive in many different situations.

Paul A. Nelson runs the Bemidji Area Lakes Guide Service. Guided fishing trips for 2020 and the rest of 2019 can be booked by phone or text at 218-760-7751 or by email at panelsonbemidji@gmail.com.