PAUL NELSON COLUMN: Catch should be picking up soon

The roller coaster weather in the Bemidji area continues. Last week had the hottest temperatures so far this summer, with several days of highs in the 90s.
The extended forecast for this weekend and next week predicts highs anywhere from the upper 50s to the low 80s, so the ride continues.
Surface water temperatures in the lakes spiked to more than 75 degrees during the hot weather, but the rain and cooler temperatures have the water temperatures falling again.
Fish struggle to get enough to eat during the hottest part of the summer because their elevated metabolism burns up most of the calories they eat.
Larger fish have a tough time holding their weight over the summer and are rarely able to gain weight when the water temperatures are at their peak.
Most species of fish have their biggest growth spurt of the year during the late summer and fall. The fish are able to increase their feeding activity and put on some weight before the water gets too cold and the fish slow down.
The cold water period usually begins sometime in October and lasts until early May, which means the fish do most of their growing for the year between late August and early October.
Fishing should be picking up for all species in the lakes soon, with anglers having some of the best fishing of the season as the lakes cool down in the fall.
Most fish species prefer water temperatures somewhere between 50 and 70 degrees. The length of time the lakes are between the two temperature ranges in the fall varies, as the lakes cool down differently each year.
The cooling water temperatures have a compound effect on the lakes. One of the first things to happen is the algae blooms slow down, so the water in the lakes begins to clear.
The young-of-the-year hatches of minnows in the lakes have spent the summer in the shallowest parts of the lakes, usually between 1 and 3 feet of water.
The cooling water begins to kill off the algae in the lakes and makes the water much clearer, with a film of dead algae on the surface of the lakes each morning the water temperatures did into the 50s or cooler.
The minnows living in the shallows are suddenly exposed to birds and their food source disappears, which forces them to head for deeper water and search for larger prey.
Most species of fish have to make the switch from zooplankton and tiny insects to larger prey in order to survive their first winter.
The new hatches of minnows from this spring have been too small to be viable forage to this point in the season, but now that they have grown larger and have left the shallows, they suddenly find themselves as the center of attention for feeding walleyes and larger perch.
Anglers fishing in the late summer and fall often see perch and walleyes with stomachs full with literally dozens of small minnows. Somehow, despite their full stomachs, the fish were still hungry enough to bite and get caught.
This illustrates how heavy the fish feed in the fall and the opportunity anglers have to catch most species of fish as the water temperatures cool down late in the open water season.
Just when fishing is starting to improve for most species, part of the angling population will be turning their attention from fishing to hunting or some other activity.
There is less time for everyone in the fall. The days are getting shorter, schools are opening for the year and other fall activities including sports and hunting, so there is less time for fishing.
There are only a couple of weeks left of the summer tourist season, with schools in parts of the country starting sooner than they do in Minnesota.
The first hunting seasons open on September 1st, with bear and dove hunting among the first seasons to open. Most bear hunters are already in the woods baiting and checking trail cameras, to get ready for the opener.
Nelson runs the Bemidji Area Lakes Guide Service. He can be contacted at panelsonbemidji@gmail.com