MINNEAPOLIS — Federal officials promised an aggressive crackdown on fish poaching from lakes in northern Minnesota but the court cases have languished, raising concerns that unchecked poaching could ruin the catch for law-abiding anglers.

U.S. prosecutors reportedly announced 10 federal indictments last year, but four cases were dismissed, four more were overturned at a judge’s discretion and two remain on hold.

The 10 men were accused of illegally catching and selling hundreds of thousands of dollars’ worth of walleyes and other fish from the Red Lake and Leech Lake Indian reservations. Other people were charged in state and tribal courts.

The federal cases haven’t gone well, though. Prosecutors themselves requested dropping four cases because the language of the indictments was flawed.

U.S. District Judge John Tunheim overturned four others, citing a 177-year-old Indian treaty that he said trumped the case brought by federal prosecutors. That ruling has led to an appeal, and the remaining two cases have been placed on hold pending the outcome of the appeal.

Tom Heffelfinger, a former federal prosecutor, said it was unfortunate that the cases weren’t resulting in people being held accountable.

“These fish on these waterways are tremendous resources for these tribes,” he said. “Without having prosecution as an effective tool to protect the waterways and the resources, it really undermines the ability of the tribes to protect tribal resources.”

The state cases have fared better for prosecutors, with 38 charges leading to 30 convictions.

In some cases, though, the tribes say they’d prefer that federal officials stay out of the enforcement process. They say tribal conservation officers can do a better job of handling the situation, in part because they’re more in tune with nuances of the situation.

George Goggleye, who chaired the Leech Lake tribal government from 2004 to 2008, said the 10 indictments appeared to be politically motivated. He said the men involved should have been issued tickets instead.

“A lot of these people were my friends who were indicted, and provided fish to families who could not go out to fish themselves,” he said.

Even though the federal cases haven’t led to prosecutions, the state Department of Natural Resources said it will enforce state laws just as it always has. Ken Soring, a DNR conservation officer, said improved compliance helps tribal anglers as well as non-tribal ones by ensuring that fish populations remain healthy.