TRAVERSE CITY, Mich.—After nearly four decades as a fishing guide on the Great Lakes, Pat Chrysler has seen enough damage from invasive species to fear what giant, ravenous Asian carp could do to the nation’s largest bodies of freshwater.

“It’s like introducing piranhas to the Great Lakes,” Chrysler said from South Bass Island in Lake Erie, which teems with walleye, perch and other fish that draw anglers from near and far.

Federal and state officials are mounting a desperate, last-ditch effort to prevent the marauding carp from breaching an electrical barrier and slipping into the Great Lakes from the Mississippi River. Michigan is drawing up a lawsuit demanding the closing of shipping locks on a waterway that links the lakes with the Mississippi. And last week, Illinois officials poisoned a six-mile stretch of a canal to wipe out any of the carp.

The prospect of a carp invasion alarms environmentalists and people whose livelihoods depend on a strong fishing and tourism economy, from charter boat skippers to those who sell bait and tackle, rent personal watercraft and operate lakefront restaurants and motels. The Great Lakes fishing industry alone is valued at $7 billion a year.

“I’m afraid they can wipe us out in a hurry,” said Jim Conder, a charter boat operator on Michigan’s St. Joseph River, which flows into Lake Michigan. “We need to spend all we can to keep them out.”

Over the years, parasitic sea lampreys, zebra mussels and other invasive species have killed trout and birds, left prized salmon and whitefish skinnier, and done other damage to the lakes.

Now, many fear that the despised Asian carp, which can reach 4 feet long and weigh up to 100 pounds, will wreak havoc, too — not by attacking native fish, but starving them out by gobbling up plankton.

The carp were imported from Asia to cleanse fish ponds and sewage lagoons in the Deep South but escaped into the Mississippi and have been working their way north since the 1970s.

Much is unknown about what will happen — and how quickly — if they conquer the Great Lakes. But the carp’s ability to take over is evident in places like the Illinois River, where it has caused native fish such as gizzard shad and big-mouth buffalo to go hungry.

They are also spooked by the sound of motors and have a nasty habit of leaping from the water like missiles and colliding with boaters with bone-breaking force.

Steve Munton of Fulton County, Ill., said Asian carp tore his nets, and one jumper knocked his pet Labrador out cold. “They’re nuts,” he said.

Tavern manager Betty De- Ford of Bath, Ill., recalled a battle with soaring carp during an excursion on a 16-foot craft about five years ago. “They just about swamped us. They were like flying torpedoes,” she said. “We were hitting them with a broom, boat oars, anything.”

Afterward, DeFord’s family established the Redneck Fishing Tournament “to get those carp out so we can take back the river.” But their population explosion continues.

Fishing for Asian carp isn’t an attractive option for many anglers. Salmon are fighters and fun to pursue, while the carp have small mouths and aren’t inclined to bite at baited hooks. Also, most Americans would much rather eat salmon, walleye or whitefish. While Asian carp’s defenders say their meat is tasty, they are quite bony.