Thought it seems winter never will release its icy grip, within a month or so lakes will be opening up.

One of the first open venues of the year will be Pymatuning Lake, where the walleye population is on the rebound with solid year classes established the past four years.

For the first couple of weeks of open water, before the fish move into the shallows to spawn, it’s often necessary to fish the depths to enjoy success.

One of the best ways of precisely presenting lures in deeper water is with leadcore line.

With leadcore line, a nylon sheath protects a thin strand of lead. The strength of the line is determined by the thickness of the outer sheath. The inner lead strand remains the same size regardless of pound test, thus the sinking characteristics of differing strength lines remains similar. A 18-pound test is common in walleye fishing.

Leadcore line is color coded, changing colors every 10 yards. This allows anglers to determine how much line is out, allowing them to duplicate it when the correct distance is found.

Some lines, such as Cabela’s Nylon Leadcore Line, come with a handy sticker that lists the order of the line color metering. The sticker is affixed to the reel and provides a good means of keeping track of line colors.

A 100-yard spool of line that features colors is adequate for fishing inland waters. Leadcore line is bulky and must be teamed with level wind-trolling reels that feature a large line capacity.

Reels with line counters add to the level of accuracy of line let-out. Rods should be fairly stiff. Major outfitters offer trolling combos at reasonable prices.

Leadcore line functions as a sinker, pulling the lure deeper as more line is unreeled. The style of crankbait has minimal influence on how deep the lure will run. Shallow runner can be fished at depths of 30 feet with no trouble.

Leadcore line is speed sensitive. Slow trolling allows the line to sink and the lure to be fished deeper. As boat speed is increased, the line lifts up, pulling the lure with it.

In the cold water of early spring, common walleye trolling speeds are on the slow side, between 1 and 2 mph. At that speed it takes about four colors of leadcore for a Rapala to reach 25 feet of depth.

GPS units, even attractively priced hand-held units, register accurate boat speeds that assist in early season trolling.

One of the advantages of trolling with leadcore line is the accuracy that can be achieved. Say you want to start the day targeting a flat located in 22 feet of water. Get the boat moving at the speed you desire, then allow enough line back to where the lure is hitting the bottom. Crank it in until it stops ticking the bottom. The lure will be running just off the bottom.

If stumps are present and you want to lift the lure up a bit, bring it in a few more feet. Typically, taking in 5 feet of line will lift the lure about a foot.

If the boat comes up on a shallow point, one that rises to, say, 18 feet, increasing the boat speed often will lift the lures enough to keep them from hanging up. When the boat has passed the point and is in deeper water, the boat speed can be reduced, allowing the lures to sink to the original depth.

When searching for the productive depth of the day, it’s best to fish one zone at a time. In other words, perhaps start off by hitting areas 15 to 17 feet deep. If nothing happens, then begin working out to 18 to 20 feet, making the necessary line-out adjustments.

Continue until you find the depth the fish are hitting in. Don’t try to fish a variety of depths in the same trolling pass.

Rig the terminal end of the leadcore line by tying in a leader of fluorocarbon or monofilament line. In addition to getting the bulky line away from the lure, the leader also acts as a shock absorber of sorts, since the leadcore line has no stretch. A small swivel can be used to make the connection.