DEER RIVER — A shortage of spottail shiner minnows is causing a ripple effect across north-central Minnesota, frustrating anglers and worrying bait dealers who rely on the fish for a significant portion of their revenue.

Spottail minnows are prized as walleye bait and sell for about twice as much as more common fathead minnows. But there’s a shortage this year due to a late thaw and a ban on harvesting spottails from Lake Winnibigoshish, the region’s most productive source of spottails in the area.

The effect is being felt across the region. Minnow trappers are desperate to catch anything, bait dealers are missing out on big dollar and anglers are grumpy about the lack of supply.

“There’s a following with these shiners and walleyes,” said Jonny Petrowske, a minnow trapper and fishing guide. “(Anglers) truly believe this is all there is. It’s almost a cult following.”

Petrowske said competition has become so intense among trappers that he’s begun putting iron bars and padlocks over his traps so other bait dealers can’t raid them in the middle of the night.

Bill Powell, who owns Fred’s Bait in Deer River, usually harvests 100 gallons — 5,000 to 6,000 dozen — of shiners for Memorial Day weekend. This year he managed to find four gallons, about 200 dozen. He called his fiancée at the shop to put out the word. By the time Powell returned anglers were already rushing inside to form a line.

“We sold four gallons in 15 minutes,” Powell said. “I rationed ’em out.”

Not every lake produces spottails. Lake Winnibigoshish was always the main source, but the state Department of Natural Resources banned minnow harvesting after the larvae of zebra mussels were found over the winter. The DNR was concerned that trappers would inadvertently collect the larvae and move them to more lakes.

The ban made things tough on wholesale bait dealers, including Jim Stone of Stone’s Bait Service in Northome.

“It’s getting worse all the time. Everyone is screaming for shiners,” Stone said. “Everybody’s upset. Bait dealers are upset. Resorts are upset. Fishermen are upset.”

Powell has suggested that the DNR approve a system of flushing water from trapped minnows and letting that water drain away from lakes in a way that could prevent the spread of zebra mussel larvae. But he said he hasn’t heard back from the agency.

It’s unclear whether the spottail harvest will improve this spring. Even if it does, some trappers say, it’ll be too little too late.

Ken Roy, who runs River Rat Bait near Cohasset said shiners represent 40 percent of his annual business for a year

“The amount of money and business we lost is never going to come back,” Roy said.