Activity and Food Go Hand in Hand
During early winter, the lakes have turned over, the water holds plenty of oxygen, food has been stirred up and fish are active. Even though the water doesn’t drop below freezing, as winter progresses food becomes more scarce, the waters are still, light penetration drops off and oxygen levels begin to drop too. Fish have learned to adapt to survive.
“To conserve their energy and lower their needs for food and oxygen, most fish decrease their activity during the winter months,” says Minnesota’s DNR Fisheries Supervisor Terry Margenau.
During winter, anglers can see some of those changes. For instance, anglers are more likely to find food in the stomachs of the fish they catch compared to other times of the year.
“When water temperatures are around 75 degrees F in the summer, it may only take a fish 24 hours to digest its prey,” Margenau says. “But in winter, the same food item may take an entire week to digest.”
“When it comes to the winter, different fish choose different activity levels, just like people,” laughs Margenau. “Some stay somewhat active, some get more sluggish, and others just hunker down.”
Walleye, northern pike and panfish also adapt well to cooler water and keep feeding at the onset of winter. In fact, they feed heartily during first ice as protective weed cover for their prey dies back and small prey fish head for the shallower, relatively warmer waters. Other species, like bass and muskies become more sluggish and only feed to meet base maintenance needs in winter. When it comes to food in winter, most fish are fairly opportunistic according to Margenau.
“Take northern pike. Panfish are not a preferred prey food for pike during most of the year because they are tough to swallow, are a big size, and are very effective at using weed beds for cover. Yet, when you’re cleaning pike that are caught in the winter, you will often find they have eaten bluegill as a mainstay of their diet,” Margenau says. Consider that during summer months when aquatic plant growth is at its maximum, panfish have lots of places to hide. When the seasonal vegetation dies back in late fall, this hiding cover is greatly reduced. It’s a perfect advantage for a pike. They’re not picky during the cold months.”
Most fish won’t expend too much energy to find food in winter. They can’t afford to spend much time or effort chasing down other fish to fill their bellies. The trade-off is that since food resources are limited, growth rates during the cold months slow way down. If food supplies are really low, this poor diet can result in stunting where the fishes’ normal growth rates are retarded.
Oh, and in the spring, with warmer waters and more active prey, Pike are on the hunt. They have a lot of making up to do from the winter shortage of food.