AUGUSTA – Fishermen squared off against fishermen Tuesday over a proposal to ban several types of live bait that some anglers say could harm Maine’s brook trout and other sport fish populations.

Typically, talk of invasive fish in Maine focuses on Northern pike, muskellunge and other large game fish popular with anglers. But in recent weeks, a proposal to ban a group of 2-inch-long minnows from use as bait has divided Maine’s diverse community of fishing enthusiasts.

The bill would prohibit fishermen from using as live bait the emerald, spottail and blackchin shiners as well as the Eastern silvery minnows because they are not native to the state. The fish are among 23 types explicitly allowed for use as live bait under state fishing regulations.

The bill’s sponsor, Rep. Thomas Watson, D-Bath, and his supporters argue that the four types of fish could pose a threat to native species, especially brook trout and other members of the salmonid family, because they eat fish eggs and compete for other food.

“Very few importations of alien species turn out to be a good idea,” Watson told members of the Legislature’s Inland Fisheries and Wildlife Committee.

Supporters of the bill, LD 163, also contend the non-native shiners and minnows imported illegally into Maine could become a vector for a “fish plague” responsible for killing large numbers of sport fish in the Great Lakes.

Banning the fish, they argued, is just another common-sense step to protecting the precious natural resources that support Maine’s enormous sport fishing industry.

“Failure to pass this bill could, and I believe will, have a far greater negative impact on Maine’s economy than passing it will,” said Bob Mallard, owner and general manager of Kennebec River Outfitters in Madison. “Simply put, we do not know nearly enough about these non-native fish to allow them to be used on Maine waters.”

Mallard and his cadre of ban proponents were severely outnumbered on Tuesday, however.

The committee room was standing room only as dozens of ice fishermen, bait shop owners and representatives of the aquaculture industry showed up to oppose the measure. The Department of Inland Fisheries and Wildlife also came out against the bill.

Speakers offered lawmakers a variety of reasons to reject the bill, including potential economic harm to Maine’s small bait dealers and the prospect of creating an enforcement nightmare for the state’s already thinly stretched game wardens.

Different varieties of the minnows are so difficult to tell apart that wardens would need extensive training. Meanwhile, well-intentioned anglers could break the law by inadvertently trapping and then using non-native bait, critics said.

But the opposing crowd’s predominant theme was this: Why ban bait fish that have been used extensively in Maine for years and that may, in fact, benefit the local ecology.

Several bait shop owners, including Steve Staples from central Maine, said that they have trapped emerald shiners in Maine waters for decades now. Staples estimated that he has caught hundreds of thousands of emeralds in Maine waters over the past 25 years for sale in his shop.

Known as “the poor man’s smelt,” emerald shiners make outstanding live bait because they are hardy, keep well in tanks and travel well, Staples said. Rather than ban the emerald, Maine should consider stocking the shiner as forage for larger fish, he said.

“I mean, it’s here and it’s here to stay,” Staples said. “If you take it out of our hands, we’re going to be left with nothing.”

John Nickerson, owner of the Misty Morning Bait and Tackle shop in Dover-Foxcroft, pointed out that Maine law already prohibits fishermen from dumping their remaining live bait into a waterway at the end of a fishing day.

Nickerson said afterward that he believes the bill is just a steppingstone toward a total ban on fish as live bait.

Such comments are evidence of the antagonism that has grown between different communities of fishermen as a result of the proposal.

In several online forums, ice anglers have charged that fly fishermen are proposing the bill in an attempt to chip away at their right to use any live bait as well as their access to waterways. Bait fishermen have also accused their fly-tying colleagues of elitism.

Bill supporters, not all of whom are fly fishermen, say they are only trying to protect Maine’s native fish.

The situation got so bad that DIFW Deputy Commissioner Paul Jacques said bill supporters asked him to send wardens to an earlier meeting on the issue in case the crowd became rowdy. Jacques, who declined the request, said he was saddened to see fishermen fighting with fishermen.

Tuesday’s hearing was entirely civil, although speakers on both sides accused the other of distorting the facts.

The committee will likely discuss LD 163 during a work session scheduled for next week.