DNR searches for answers to slow steelhead fishing.

It’s been a strange spawning run for North Shore steelhead.

The Lester River and Knife River each have had a couple of good days when water temperatures rose into the 40s, but cold water has made fishing generally slow.

A Department of Natural Resources angling survey clerk talked to 10 anglers on the Knife River who had caught fish on Tuesday. That same day, DNR fisheries workers found 14 steelhead waiting for them in the Knife River trap, where fish are detained on their way upstream.

“The streams started flowing March 18, and we didn’t see water temps above 40 until April 20 at the Duluth end of the lake,” said Matt Ward, DNR anadromous fisheries specialist for the Lake Superior area fisheries office. “It’s very unique that we’d have streams flowing for about a month and be too cold for fish to migrate in from the lake.”

The biggest run on the Knife occurred April 24, when 81 fish (including 10 stocked Kamloops rainbow trout) were sampled at the trap. Through April 30, 261 adult steelhead have been sampled at the trap.

Ward can tell you exactly how many fish have been moving up the Knife River. He and other fisheries employees check the Knife River trap every morning. They gather information on adult steelhead headed upstream to spawn.

Trap provides some answers

The trap was installed in 1996 so that DNR officials could get better information about the steelhead population, which had declined steadily since the 1970s.

By capturing upbound spawners and downbound juvenile steelhead, the agency hopes to better understand population dynamics of the species.

Over the past 13 years, the number of returning adult steelhead has ranged from about 200 to 700. Some of those fish are naturally reproduced from wild steelhead, and some spent their first year in the French River Hatchery before being stocked.

The DNR, at the urging of the Lake Superior Steelhead Association, has tried stocking the yearling steelhead both far upstream and nearer the lake. The thinking was that those stocked farther upstream would have a chance to acclimate better to the wild than those stocked closer to the lake.

“Right now, that’s turning out to be a wash,” Ward said.

Those stocked upstream and downstream have returned at about the same rate. Overall, about 1 to 2 percent of the hatchery-reared fish return to spawn, compared to about 10 to 12 percent of naturally reproduced fish, he said.

Sampling steelhead

Shortly after 8:30 a.m. on Tuesday, Ward and fisheries technician Beck Reiche begin sampling fish in the trap. Reiche weighs and measures them. Fish No. 11 for the day is a beautiful female.

“Two-point-eight-nine. Seven-oh-two,” Reiche hollers from the depths of the trap.

That’s metric for a steelhead nearly 28 inches long and weighing more than 6 pounds.

“Big fish of the day,” Ward says.

The fish will spend three and a half minutes out of the river, but only a few seconds out of water. The steelhead spend most of their time in a net in a tub of flowing river water. Ward and Reiche determine that this steelhead is “green” — not yet ready to drop her eggs.

She carried a dorsal fin tag, meaning she had been up the river to spawn in a previous year. One fin was clipped, meaning she had spent her first year in the hatchery and a short time in the river before migrating down to Lake Superior.

When Ward is through processing the fish, he carries it upstream of the trap and lets it swim back into the river to continue its journey.

Data from the trap will help the DNR answer some specific questions. Among them:

# Will the stocking of 40,000 hatchery-reared yearling steelhead annually from 2003 to 2007 pay dividends in higher returns of adult fish over the next 10 years?

# Will removal of beavers and beaver dams on the upper Knife and its tributaries allow more fish to reach good spawning water and increase returns in the future? The DNR, with support of the Steelhead Association, has made a concerted effort to remove beaver dams in recent years.

# Does it matter whether stocked steelhead were released far upstream of the Knife River trap or below the trap?

# What effect might a warming climate have on steelhead, and will naturally produced fish survive better than stocked fish in warmer waters?