For many Maine lobster fishermen, a looming federal decision on what kind of equipment they’ll be allowed to use on their gear is giving them a sinking feeling.

They’re worried that the National Marine Fisheries Service will require them to use a type of rope that supposedly will reduce the threat of entanglement to whales, especially the federally protected North Atlantic right whale. Trouble is, lobstermen say, this type of rope is more expensive and is apt to get more of their gear stuck in rocky areas off the coast – and to put a significant financial dent in an industry that netted $290 million worth of lobster in Maine last year.

Fishermen who set traps in areas with a rocky bottom most often use a type of rope called “float” rope, which is used between traps that are tied together in a single line. The sections of rope float up toward the surface between each trap, creating vertical arcs that scientists say pose a threat to diving whales.

The option that many fishermen fear will become a requirement is “sink” rope, which sinks to the bottom. Sink rope may be less likely to get snagged by diving whales, but fishermen say it will eat into their economic bottom line.

Not only will it run up their equipment purchase costs, they claim, but it also will result in an increased amount of gear that gets snagged on the rocky bottom and lost, and it will force fishermen to spend more time and maintenance on keeping their gear in good repair.

And, according to David Cousens, a South Thomaston fisherman and president of Maine Lobstermen’s Association, there’s no indication that requiring such a switch in equipment will do right whales any good.

“I’ve never seen one,” Cousens said Wednesday about the animals. “You’ve got a better chance of seeing a UFO around here than a right whale.”

Cousens said lobstermen have been receptive to trying out gear modifications aimed at helping whales, such as breakaway lines on buoys and sink rope on traps set far offshore and in other areas with muddy bottom. Of the handful of right whales seen in Maine waters in recent years, he added, the only one found wrapped with Maine lobster fishing gear was successfully freed with the help of fishermen.

To tell fishermen not to use float rope close to shore is “crazy,” he said, especially in eastern Maine where the bottom is rocky, currents are strong and whales are rarely, if ever, seen.

“We have to use float rope,” Cousens said. “We can’t give up float rope for our groundlines.”

Estimates for the number of right whales, which nearly were hunted to extinction in the 18th century, run between 300 and 400. Most of them have rope scars from getting entangled in fishing gear, according to scientists.

Cutler lobsterman Kristan Porter said Wednesday that if fishermen are forced to convert to sink rope, each one would face between $12,000 and $15,000 in additional operating expenses each year. He said the federal government is applying a “one-size-fits-all” philosophy to all types of fishermen on the East Coast, even though the practices, equipment and physical terrain differ from state to state, and sometimes within a state.

“I don’t know if we can survive this one,” Porter said. “This isn’t going to help anything. I haven’t bought any rope for next year because I don’t know what they’ll do.”

Or when they are going to do it. Federal regulators had been expected to release the final environmental impact statement on the issue sometime this week but now have put it off indefinitely.

“It’s still in the review process,” Teri Frady, regional spokeswoman for the National Oceanic and Atmospheric Administration’s National Fisheries Service said Tuesday.

Frady said the federal government has to wait at least 30 days after it releases the statement before it can adopt the recommendations as a rule.

While the NMFS is considering what to do, Sen. Susan Collins has urged the agency to minimize the effect the rule would have on Maine’s lobster industry. She indicated in a statement released Wednesday that the state industry would absorb $12.8 million of the annual $14.2 million cost of the proposed rule.

“[M]ore than 75 percent of the projected cost of the rule is expected to be incurred by lobstermen operating in the inshore and near-shore areas of Maine,” Collins said in the release.

According to Frady, there could be exceptions to the expected federal ruling, but the service is considering banning all use of float rope throughout the Northeast.

“Yes,” Frady said when asked if this was the case. “That’s the short answer.”

If the rule is adopted, exceptions are what fishermen are hoping for. Cousens said most whales swim through the Gulf of Maine on a fairly straight line between Cape Cod and the Bay of Fundy and not within a few miles of shore, where 90 percent of Maine lobstermen set their traps.

An exception zone three miles out from all shore frontage, including islands, or a general zone extending roughly 15 miles out from the mainland would allow fishermen to keep operating as they do now and would target the area where right whales are most likely to travel, Cousens said.

“We’d just like a common-sense curve,” he said.

One thing fishermen will get if the rule is enacted is help buying new rope. The Gulf of Maine Lobster Foundation has been given $1.4 million by Congress to use in a rope exchange program called the Bottom Line Project.

Laura Ludwig, coordinator for the program, said Monday that fishermen would be given vouchers for float rope they turn in to the foundation. Fishermen will be able to use the vouchers to help them buy sink rope, she said.

The $1.4 million should cover only about 1 million pounds of float rope that is exchanged, according to Ludwig. How much total float rope actually is being used by the approximately 6,800 licensed lobstermen in Maine is unknown, she said, but there could be as much as 9 million pounds that has to be replaced.

“That’s a total ballpark estimate,” Ludwig said. “Nobody has any better idea than anybody else.”

Because sink rope tends to be more expensive than float rope, she said, fishermen likely will have to pay more than what they get through the voucher program to end up with the same total length of rope that they started out with.

Regardless of the funding limitation, not all fishermen are likely to participate in the rope exchange program. To protest the anticipated rule, the board of directors for the Down East Lobstermen’s Association earlier this month voted unanimously to recommend that the group’s 300 or so members not participate in the exchange.

Clive Farrin, a Boothbay Harbor fisherman and president of DELA, said Wednesday that banning float rope may well put many eastern Maine lobstermen out of business. For many of them, he said, there isn’t much else they can turn to.

“What will these guys do that have done nothing but go fishing since they were in diapers almost?” Farrin asked. “It just seems like every time we do something in good faith, we’re smacked with another regulation.”