For the human species, autumn traditionally has meant a time of plenty. Today, with contemporary (and still-improving) food storage techniques, we enjoy the fruits of modern food production year-round.
But we’ve all seen what it’s like for creatures that rely on the charity of Mother Nature to produce their food. Winter is a difficult time, with natural food becoming increasingly hard to find as the season progresses.
For ice anglers that equates to big starving predator fish under the ice eager to demolish any organic matter we toss their way, right?
Uh, not quite that simple, is it?
No, if fish were suicidal hungry by mid-winter, no one would need to develop new, unusual, or otherwise interesting ways to catch fish through the hard water. The Ice Team would be out of business.
In fact, the very opposite situation exists. Ice anglers, often watching fish in real time with an underwater camera, sometimes see healthy, albeit bored, walleyes and perch barely sniffing the freshest bait money can buy. When guys like Dave Genz speak, they fill seminar halls with wild-eyed ice anglers looking for information on how to tempt these so-called desperate fish into biting.
What’s going on?
A couple things. First, as many readers probably already know, fish are ectotherms, the proper term for what too many people call “cold-blooded.” It means that whatever the environmental temperature, that’s the body temperature of the fish. (“Cold-blooded” is at best misleading. If a catfish is happily living in 85-degree water, its body temperature is 85 degrees. That’s not cold, right?
Nonetheless, as water temperatures drop, so does the body temperature and metabolism of the fish. Bottom line, unlike their mammal friends above the water struggling to maintain core body temperatures in freezing weather, fish can survive in winter on relatively few calories. They’re not as active or hungry.
The second factor: There’s more food out there than you realize. It may be sub-zero above the water, but under the ice, the water hovers just above the freezing mark. That’s warm enough for some food sources to continue emerging. Creatures like bloodworms, the larval stage of midges, are available, and other insects are moving through molting stages and hatches.
A lot of hatches occur under the ice, such as insect eggs hatching into larval or nymph stages or larval stages undergoing multiple transformations, like shedding skins, before becoming an adult and flying away in the spring. These changes don’t completely end when ice covers a lake.
For a little broader perspective, let’s consider the food web that exists underwater year-round. This is important, because as anglers we’re always trying to “match the hatch.” Understanding what’s happening at the microscopic level can mean better results way up the food chain when chasing big fish. In the majority of fishing situations, we need to be where fish are feeding and mimic what they’re eating.
Starting at the microscopic level, small minnows consume zooplankton and small creatures, including one you’ve probably heard about: daphnia. Daphnia are an important food source for many larger aquatic creatures like small fish and the immature, aquatic stages of insects like dragonflies and damselflies. They’re small, almost plankton-like critters that I sometimes hear people incorrectly refer to as water fleas. Fleas are insects, so they also fall under the same group of animals (called arthropods), but daphnia are crustaceans, not insects.
Those larval stages of big, juicy insects like mayflies and dragonflies (often feeding on daphnia) are really important to anglers. Though the adult stage of mayflies is pretty short, the underwater nymph stage can last a year, which means many fish rely upon this food source.
Working down to the base of the water column, all sorts of different organisms, especially invertebrates, spend part of their life in the mud. Most are insects that spend at least part of their life cycle, typically the larval stage, under water. They’re pretty small critters, so the fish feeding on them are small, too.
Where these invertebrates hang in the water column will determine which species feed upon them. Bluegills and crappies will feed on invertebrates closer to the surface, but perch have no problem behaving like pigs and rooting through the mud for fresh meat. (That shouldn’t surprise any angler who’s caught a perch with mud on its nose.)
The tiny ice jigs we use during the dead of winter mimic some of that smaller food that panfish (or larger species like whitefish) feed upon naturally. We ultimately can never mimic zooplankton, but the color and flash of tiny ice-jigs can catch a fish’s eye.
Eurolarvae probably are as close as we can get to naturally presenting something slow-moving winter panfish may target.
Other tiny food sources include creatures like leeches or freshwater shrimp. Devils Lake, N.D., is a well-known example where freshwater shrimp drive the food chain, especially in the winter. Though this ample natural food source can frustrate anglers, it’s also a primary reason why Devils Lake contains so much healthy jumbos! Like daphnia, freshwater shrimp are a sign of a healthy waterway.
From there, it’s just like we learned in elementary school. Big fish eat smaller fish and so on until, we get to the big ones we’re looking to fry up. As with any ecosystem, small organisms are eating a broader range of food sources, and any system ultimately can support relatively few predators, i.e., the big ones.
From an angling perspective, let’s look at a specific species, say northern pike. Think like their food this time of year. On many bodies of water as the hard water season approaches, pike are thinking ciscoes. Right up to ice-up, those ciscoes are spawning. That means I’ll begin my pike search where ciscoes spawn, then work toward the main lake as those post-spawn ciscoes (like so many fish) head for deeper water to recuperate post-spawn. In specific, practical terms, I start on sand and gravel flats, plus reefs or sunken islands.
With walleyes I’m looking for forage sources like perch, shiner minnows, suckers, or on some waterways, even chubs. We’ve already discussed what those “baitfish” are eating. (Starting to get it, folks?)
Tackling and understanding the food chain will improve your fishing year-round. No, they’re not starving under the ice, but they still need calories in winter.
Use that knowledge to your advantage when the hard water arrives.
Adam Johnson is an Aquatic Biologist and a Power Stick on the Ice Team.By: Adam Johnson
