BOSTON (AP) – Fishermen trying to survive ever-tightening restrictions will have access to a new class of fishing days starting today, about a year after an industry group first proposed them.

Pitched as a lifeline to fishermen, the “B days” allow them to catch healthy stocks, such as haddock, while keeping them off struggling stocks like cod.

The “B Days” offer fishermen a route around the traditional way of regulating New England’s complicated seas, where a diverse mix of fish stocks, all of varying health, mingle in the same waters. Regulators have long protected the weaker stocks by restricting fishing on all species in their waters – shutting fishermen off from the plentiful varieties that also live there.

Fisherman have long said that they have the ability to catch the healthy stocks without hurting protected fish. The “B Days” give them an opportunity to do that, said Jackie Odell of the Northeast Seafood Coalition, which proposed the concept last November.

“At least now we have an opportunity … open to all fishermen to use their knowledge, their experience and their ingenuity to target healthy stocks,” she said.

This year, fishermen absorbed a 24 percent cut in the number of regular fishing days, whittling the maximum days for most fishermen down to 53 per year.

The pilot program, scheduled to run through next October, gives the New England fleet 4,000 “B Days” to share, with no more than 1,000 days to be used per quarter.

The program sets daily catch limits on the amount of protected stocks that fishermen haul up when targeting the healthy species. It also shuts down the program for the quarter if a catch limit on a protected stock is reached.

A “flip” provision in the rules forces fishermen on a “B Day” to use a regular fishing day if he catches more than his quota of a restricted species.

In the past, fishermen have been forced to throw the fish away.

The program’s skeptics say the “B Days” won’t work because it’s too difficult to avoid protected species in New England’s crowded seas. Maine fishermen have worried the healthy stocks are too far away for them to benefit.

Odell called the new rules an experiment with conservative limits that needs good communication among fishermen to truly work. But she said the program can work and the added days are way better than nothing.

“This is just something to give fishermen a couple extra days to get over that hump,” she said.