DSO Feature Article: February 2004

Pike spice up the ice on Castle Rock and Petenwell flowages
By Dan Small

If you go ice fishing on the Petenwell or Castle Rock flowage this year, it's not likely you'll be alone. Compared to a decade ago, when few people ice-fished these central-Wisconsin flowages, today they are buzzing with activity on a typical winter weekend.

"Ten years ago you couldn't find a dozen people ice fishing on the flowages," said DNR fisheries biologist Scot Ironside, who manages these sprawling flowages on the Wisconsin River. "But now there are 'cities' of people out there."

Most anglers come for the walleyes, now that water quality has improved and the notorious "paper-mill" taste has gone from their fillets. But more anglers every year are targeting northern pike. Since 1994, a one-fish-per day, 32-inch limit has been imposed on pike from the Wisconsin Dells dam upstream to the Lake du Bay dam, and the pike have responded well.

In a survey conducted on Petenwell last spring, 18 percent of pike sampled measured more than 32 inches, compared with only 12 percent in a 1994 survey. That's a 50-percent increase in less than a decade. The biggest pike sampled last spring measured 42 inches.

No pike are stocked in either flowage, so the pike rebound is due entirely to natural reproduction and the new size and bag limits.

As more anglers target northerns, however, Ironside is concerned about two things: hooking mortality on undersized pike, and the incidental catch of hybrid muskies, which are easily confused with pike.

Some 2,500 true muskies are stocked every year in each flowage, but Ironside has supplemented that number with tens of thousands of hybrid muskies in an effort to boost the muskie fishery and help control nuisance carp. Growth rates of both pike and muskies are phenomenal, he reports, but he fears anglers may mistake small hybrid muskies for pike and either take them out at 32 inches or injure them by careless handling.

Hybrid muskies were stocked heavily back in the 1980s, but Ironside says they never showed up in surveys. He suspects that many were taken by anglers who mistook them for small pike. In those days, the bag limit on pike was five per day and there was no size limit.

True muskies are lethargic in winter, but hybrids act more like northerns and are readily caught. There are so many variations in the color and markings of hybrids, that even biologists are sometimes fooled.

True muskies have pointed fins and vertical dark markings on a light background that ranges from silvery green to shades of brown. Northern pike have rounded fins and horizontal light markings on a dark, usually green, background.

Hybrid muskies have rounded fins and irregular vertical light markings on a dark background. Variations in color and markings make these indicators unreliable.

Muskies and pike also have different scale patterns on their cheeks and operculums, but this method of distinguishing them is also not always clear.

The best indicator is the number of pores on the lower jaw. Pike have five or fewer pores on each lower jaw. Muskies have six to nine pores on each side.

Hybrids have five to seven pores on each side. If a fish has five pores and questionable markings, assume it is a hybrid muskie and release it.

Ironside hopes to gain support for the proposed 45-inch limit on muskies on the flowages because both have the potential to produce trophy fish.

"These are the biggest, fattest, muskies you've ever seen," he said. "After all the effort and expense to stock them, it would be a shame to remove them at 32 inches when they've got the potential to become huge."

Pike and muskies serve an important role in the ecology of the flowages. They eat lots of carp, which are abundant here.

"Carp here are contaminated and can't be disposed of on land or harvested by commercial fishermen," Ironside said. "The only tool we have is to increase the predator base. That was one of the major reasons we went to the 32-inch, one-per-day limit on pike, to try to increase the number and size of our pike to help them control carp. The same is true, now, of muskies. If we catch all these little hybrids out at 32 inches as pike, they won't be able to contribute much to carp control.

Ironside has no illusions of eliminating the carp altogether, but he says that a strong predator base can only help.

As for hooking mortality, Ironside says anglers can reduce injury to fish they plan to release by not using Swedish hooks, popular for fishing with dead smelt. In a study conducted by DNR fisheries staff on Madison area lakes a number of years ago, Swedish hooks were found to increase mortality on pike caught and released. Other styles of hooks caused far fewer fatal injuries. Ironside thinks the new circle hooks might help save more fish.

Another conclusion of that survey was that a small amount of bleeding from mouth or gills does not mean a fish will die when released.

Backwaters, especially those with tributaries flowing into them, are the best places to ice fish for pike on either flowage. Tip-ups baited with dead smelt or live suckers or golden shiners produce well. Some anglers also use jig rods baited with a golden shiner or sucker.

With a one-fish limit on pike, most ice anglers will probably still concentrate on walleyes or panfish, but set out one tip-up for pike. Nothing spices up a day on the ice like tangling with a big green torpedo, and there's probably no better place in Wisconsin to do it than on these two flowages.

Pike spice up the ice ...
February 2004