Leadhead jigs tipped with artificial minnows are one good way to dupe deep water bass.

A heavy weight interrupted the upward phase of the jigging motion. A second later the pulse of a strong fish was felt. Taking a quick glance at the bow-mounted sonar unit I noted the depth at 37 feet.

The bass gave a good account of itself. When it was within 10 feet or so of the surface its bronze form confirmed what I’d expected: a nice-sized smallmouth.

Soon afterward my partner Dave scooped up the fat fish, one which appeared to be about 19 inches, give or take. Wanting to return the fish to the water quickly, so it could return to the depth from which it had come, we opted not to measure or weight it.

That smallmouth, along with a bunch of others this winter, came from the depths of nearby Keystone Lake this past weekend. The unseasonably mild winter has provided several open water outings on the deep, 1,000 acre impoundment, as ice cover was sporadic.

Be it lake, river or reservoir, cold water fishing often means deep fishing, as gamefish typically congregate in deeper areas of the given body of water. In flowing water deep pools provide the stable sanctuary needed to survive the elements of winter. The same can be said of stillwater settings, which also are somewhat warmer in their depths since water is most dense (i.e. heaviest) at 39 degrees.

Within the next few weeks – sooner if the warm weather persists – there will be a shift in gamefish location from deep to shallow, movements driven by the need to feed and reproduce. But for the time being it’s likely there will still be plenty of fish in the depths, particularly on deeper lakes like Keystone that take a while to warm up. With that in mind here are some tips on deep water fishing:

Plan on going vertical when fishing depths in excess of 15 or 20 feet. This means fishing directly under the boat. As they say, the shortest distance between two points is a straight line. By keeping the distance between yourself and your bait as short as possible you’re better able to distinguish what’s going on down there, in terms of working your lure and detecting hits.

When possible pick windless days, or ones with light winds. Fishing vertically is a bit of an art form, one where the boat’s movements have much to do with how your bait is being presented. Maintaining good boat control – in concert with staying in touch with your bait/lure – is much, much easier when you’re not fighting the wind.

Use lures that fish well when presented vertically. This includes jigging spoons, blade baits, leadhead jigs dressed with minnows or soft-bodied imitations of such, and bucktail jigs. All are compact, provide little water resistance (a plus when fishing deep), upping your ability to keep them deep, all the while staying in contact with what they are doing.

Go heavier. While eighth and quarter ounce jigs are fine for fishing depths of five to 15 feet, plan on going up to three-eighths or half once in the jig department. The same holds true with jigging spoons. I prefer half-ounce blade baits for fishing deeper water.

Watch for the presence of baitfish. Forage fish like emerald shiners and rainbow smelt (both of which are in Keystone) are subject to the same environmental issues that drive gamefish to the depths. So it’s common to find gamefish in the same areas where you seen schools of bait. Note too the depth at which bait seems to be holding. If you’re seeing clouds of bait in the 30 foot zone (both on the bottom and suspended) it’s often wise to key in on that depth, even in areas where bait isn’t showing up on the sonar.

Fish slow. Fish are cold blooded. Their metabolism is slow when the water is icy cold. They need to feed little, if at all. But they will bite if you make it easy to do so. Which is why hanging a jig-style bait in front of them, and doing it for extended periods of time, can produce. It’s not a time of year when you should be covering lots of water.

Understand that at some point the fish will move shallow and the action will pick up. So on days when the water’s warming up it pays to try out some shallow areas too, just to keep them honest. Basically, these shallow water movements are what most folks key in on during their early season outings, which is fine if the fish have moved there. But if not, fishing deep can provide some action on otherwise fishless days.

Jeff Knapp is an outdoors columnist for the Butler Eagle.