ESCANABA — ‘Tis the season — spawning should be finished, and in the Upper Peninsula, walleye season opened today. The population is good, but an early ice-off this year meant an early spawn, and anglers will be adjusting their techniques to target their desired catches.

Local regulations — specific to the U.P. Great Lakes, inland waters, and the St. Mary’s River — are unchanged from last year: The daily possession limit is five, with a minimum size of 15 inches, and no more than one walleye over 23 inches may be included in an angler’s daily limit in Little Bay de Noc (defined as being north of the line drawn from the mouth of the Ford River to Stonington’s Peninsula Point Lighthouse).

As a cold-water fish, walleye spawn in the spring, when water temperatures warm to about 42 to 50 degrees. This is often in rivers in April, and then they head back into open water. But several things can affect their habits, and people from scientists to anglers are anticipating variation.

“Spawning was, on average, a little bit earlier (this year), about a week to ten days earlier,” said Fisheries Biologist John Bauman with Michigan DNR’s Northern Lake Michigan Management Unit. “We typically do walleye egg take around April 15 or so, and we did it the week before.”

On an “average” year, he said, the fish are done spawning by May 15, with some still near the spawning grounds and a good number in Little Bay de Noc and the northern end of Green Bay.

“On a year like this, where they spawn a little bit early, we would expect the females to be out of the rivers and moving south quite a bit,” Bauman said, “and some of our data suggests that within two to three weeks after spawning, a large majority of those big females migrate pretty far south just within a few weeks after spawning, so not a lot of big females are going to be hanging around. But males hang around the spawning grounds for … several weeks afterwards.”

He added that some rivers warm up sooner than others, so spawning may have taken place a couple days sooner in the Whitefish and later in the Escanaba and Ford Rivers.

So how will anglers be fishing after the 15th?

“I would be trolling, specifically shad stickbaits in the daytime at about 20 feet of water — if there’s a good walleye chop,” said Ben Wiitala of Marinette, who uses a non-resident license to hunt and fish in the U.P.

Many anglers say walleye are more active when slightly rougher conditions stir up the water and make it appear a little darker.

“A slight chop on the water, not big rollers,” Wiitala clarified.

While the walleye population has been sizable and healthy the past few years, it’s uncertain what the next few may hold. There was a strong year class in 2018, said Fisheries Research Biologist Troy Zorn, which may have been in part due to high water levels. Walleye mature between three and four years old, and as the ones from the 2018 boom would now be six, they’re around but maturing out.

Lots of precipitation and high water can bode well for fish populations, said Bauman, because it helps flush down nutrients which are good for growing algae and plankton that in turn feed larval fish and then game fish — if invasive species don’t get to them first.

“When the quagga mussels came up into our area, we saw water clarity increase, and I went out and did some zooplankton surveys, and found that our zooplankton densities were quite low, very low,” Zorn said.

Bauman pointed out that it might be difficult to predict long-term effects of certain factors, like the weather or population fluctuations, because the environment has changed so much. He compared the rains and walleye boom of 2018 to some conditions in the late ’80s and early ’90s — but pointed out that parallels couldn’t be extrapolated in other areas because that was before these waters had the invasive species that are presenting now.

Regardless, the biology of some won’t change. Anglers will still be out fishing during open season.

“What I like about walleye fishing — one, it connects me to my upbringing,” said Wiitala, who grew up in rural Wisconsin. “Two, it provides food. Three, it’s the challenge. It’s not like you’re gonna have success every day. So it’s rewarding in that sense… You can’t win unless you lose.”

To take part, persons aged 17 and older must obtain valid fishing licenses — good for all species — which may be purchased online though the DNR or from a number of retailers, including bait shops and some grocery stores and gas stations.