It's one of Minnesota's biggest fishing regulation changes in decades. The statewide three-fish possession limit for northern pike, in place since the 1940s, will be replaced this season with limits customized for three different management zones.

"The three-fish bag limit was not designed to meet any specific management objectives," says Gary Barnard, Bemidji area fisheries supervisor. "But these zone regulations are geared toward specific objectives for different population characteristics of each zone."

Lakes in north-central Minnesota are teeming with small northern pike, often disparagingly dubbed "hammer handles," that frustrate anglers with their overabundance. In other parts of the state, the story changes. In the northeast, pike grow large, but they take a long time to get that way. In the south, pike grow fast but overall there are fewer of them.

In the north-central zone, the vexing issue with small pike stems in part from the way people enjoy the area's many lakes. Numerous anglers fish these lakes, and northern pike are notoriously vulnerable to angling. Over the years, the large and medium-size pike went on the stringer and the small ones went back into the lake. As the density of small pike increases, growth slows, so small pike stay small longer. Further compounding the problem is that those larger fish are no longer around to eat the small pike.

When left to overpopulate, the small pike eat a greater share of a lake's available food supply than larger pike relative to their size. In other words, 10 pike weighing 1 pound each will in total eat more than one 10-pound pike. And small pike feast on small fish, including important forage fish, such as perch, which can have wide-ranging effects on other fish populations.

Under the new regulations, nothing changes for anglers who don't want to keep pike. Those who do will need to know what zone they're fishing in and will need to measure fish.

In the north-central zone, anglers will be able to keep up to 10 northern pike, but no more than two pike larger than 26 inches; and all pike from 22 to 26 inches must be released. The objective is to reduce small pike abundance by shifting population size structure back to more medium to large pike.

In the northeast zone, anglers can keep two pike, with one over 40 inches in possession, and all from 30 to 40 inches must be released. This regulation is meant to maintain harvest opportunity while protecting large fish already present.

In the southern zone, anglers can keep two fish, with a minimum size of 24 inches. The regulation here is meant to increase pike abundance and improve the size of fish harvested.

"Anglers will need to measure fish before deciding to harvest, but we've come a long way toward that over the past 20-plus years of special length-based regulations," Barnard says. "Most people are accustomed to measuring fish, and most already have measuring devices stuck on their boats."

Special regulations will still apply for northern pike on some water bodies, fewer than 100 statewide. If the possession or size limit on a special regulation lake or stream is different from the new zone limit, the special regulation limit applies. The new regulations do not apply to waters that border other states or Canada.

Darkhouse spearing will also be affected by zone management but with slightly different regulations. The north-central zone will allow the same expanded 10-fish bag limit for spearing, but will allow one of the two larger fish to be within the protected angling slot of 22 to 26 inches.

Similarly, in the northeast, the same two-fish bag limit will apply for spearing, with one fish over 26 inches allowed. In the southern zone, angling and spearing regulations allow two pike larger than 24 inches.