Only the nuttiest of muskie nuts would venture out on this opener.

ON THE ST. CROIX – Last Saturday broke clear and warm on this river, which on the first day of the long holiday weekend should have been a yachtsman's playground. Instead, a 5-miles-per-hour speed limit imposed here on boats due to high water kept the mimosa and Bloody Mary set tied fast to their berths, engines stilled.

Anglers on this first day of St. Croix muskie fishing seemed content to stay home as well.

Blame, perhaps, the no-wake restrictions. Also, the high water likely would make muskies even more challenging to locate than they otherwise are, which is challenging enough. Additionally, a generalized lethargy regulates muskie moods and movements in early season, making hookups by anglers at this time of year a rarity.

Thus even the nuttiest of muskie nuts had a trifecta of excuses not to rise early and toss big baits a thousand times over in hopes of landing one of these trophies.

Still, just before dawn, my son Cole, his pal Dominic Schneider, and I backed a boat into this flooded river.

Cole was home for a week after finishing college for the year, his visit timed to include the border water muskie opener as well as the extraction, two days earlier, of four wisdom teeth.

This last explained the bottle of Advil on the boat dashboard.

No man steps into the same river twice, someone once said, because it's not the same river and he's not the same man. This was never truer than on this Saturday, as the rising sun bathed the flushed St. Croix in a reflective pool that spanned the orange spectrum: peach, also melon, cinnabar, bittersweet and persimmon.

"We've got the place to ourselves," Dominic said. And we started casting.

Our hope was that Cole's bucktail, Dominic's jerkbait or my surface bait would somehow intersect the comings and goings of a willing muskie.

Awash as muskies are in mystery, we could only guess as to their whereabouts — upriver or down, deep water or shallow.

A state Department of Natural Resources (DNR) study of St. Croix muskies underscores the challenge of locating these fish.

The effort is part of a larger project undertaken by the DNR and the U.S. Fish and Wildlife Service, among other agencies, to assess fish movements in the St. Croix and Mississippi rivers.

The research was prompted by the appearance years ago of Asian carp in the Mississippi near the Minnesota-Iowa border. To prevent the northward movement of these invasive fish, barrier installations were proposed at various upstream locks and dams.

"At the time, we didn't know much about the movement of native fish in the St. Croix and Mississippi, and needed to understand how these fish would be affected by barriers if they were installed," said Joel Stiras, DNR east-metro fisheries specialist.

Now about 250 fish of various species, including paddlefish and lake sturgeon, are carrying the surgically implanted transmitters, whose pings are picked up by 55 acoustic receivers sunk in the St. Croix and Mississippi rivers.

Information from the transmitters is retrieved and downloaded twice annually.

Key early findings of the study show muskies are capable of traveling long distances upriver and down, in a hurry.

"Two muskies we implanted and released at Prescott, Wis., ran up to Taylors Falls," Stiras said. "One traveled that distance in two weeks. Another muskie we implanted with a transmitter and released at Prescott swam 12 miles upriver in 12 hours."

Five of the eight implanted muskies spent time in the Mississippi River, with one traveling to Pool 4, 17 miles downriver, en route swimming through Lock and Dam 3.

Muskies also move higher and lower in the water column than anglers might think, the research shows, with some of these fish swimming 50 feet down.

So it was that while Cole, Dominic and I cast baits in a relatively small parcel of the St. Croix, in water that at times was 18 feet deep and at other times only a few feet deep, beneath us, essentially, lay an underwater highway on which a lot of fish were swimming.

Next time.

Dennis Anderson • 612-673-4424