GRAND RAPIDS -- It was a once-in-a-lifetime catch for a man fishing below the Fourth Street dam -- a 5-foot lake sturgeon. By law, he was supposed to let it go.

He didn't.

Now, the Michigan Department of Natural Resources is looking for him and is offering a $1,000 reward as bait.Tuesday, DNR law enforcement officials began circulating a photo a bystander took of the man. Two weeks of watching the site in hopes of his return proved fruitless. Witnesses said he drove a newer model silver-gray GMC pickup with a white tool box behind the cab.

"We've been looking for his truck but haven't gotten anywhere," said Dave Rodgers, a conservation officer with the DNR.

Lake sturgeon are a protected species in Michigan due to their scarcity. They are listed as threatened.

It is illegal to keep them on most Michigan waters. Limited seasons are open only on Black Lake in Cheboygan County, Michigan-Wisconsin boundary waters, Otsego Lake in Otsego County and on Lake St. Clair and the St. Clair River. Otherwise, anglers who hook them are required to release them.

Keeping one is punishable with jail time from 30 to 180 days, fines from $500 to $2,000, court costs and $1,500 restitution to the state.

"He's going to show off his fish and, hopefully, someone will realize the importance of this and turn him in," Rodgers said.

The May 17 incident was reported to the state's Report All Poaching Hotline by an acquaintance of the bystander who shot the photo being circulated.

Onlookers reported the angler snagged the fish in the tail and fought to bring it in. He was fishing on the east side of the Grand River just downstream from the dam.

Once he landed the fish, they encouraged him to return it to the river. Despite the catcalls and scorn from onlookers, he put the sturgeon in his truck, Rodgers said.

The state is working to restore the native lake sturgeon population. They can live 100 years but are slow to reproduce. Males take 15 to 20 years to reach sexual maturity. Females take 20 to 25 years. They spawn every four years.

Rodgers said anglers report sturgeon getting hooked on the Grand each year, typically in spring when the big fish come up to spawn. Those who catch them typically release them.

"Given its size, it would have to be a fairly old fish," Rodgers said. "So losing even one can have an impact on the sturgeon population."

Anyone with information about its capture can contact the state Report All Poaching Hotline at 800-292-7800.

E-mail Howard Meyerson: hmeyerson@grpress.com