U.S. fisheries managers on Monday embraced limits on the number of endangered whales and turtles that can be captured inadvertently in drift gillnets used to catch swordfish off California’s coast in a move praised by environmentalists.

The measure approved by the Pacific Fishery Management Council would cap at two over a two-year period the number of creatures such as sperm whales and loggerhead turtles that could be injured or killed after becoming entangled in gillnets, said Kit Dahl, staff officer with the council.

The plan is expected to receive final approval from the U.S. National Marine Fisheries Service before going into effect as early as next August, Dahl said.

It is the latest effort to address hazards posed by the nets, mile-long (1.6 km) strands of nylon mesh attached to floats, to other sea life that can be snared as “bycatch” and drown.

The measure is designed to protect declining populations of four types of whales (fin, humpback, sperm and short-finned pilot), four kinds of turtles (leatherback, loggerhead, olive ridley and green sea turtle) and one dolphin species (bottlenose).

The measure was lauded by environmentalists who have waged a years-long battle with gillnet fishermen who harvest swordfish mostly in Pacific waters off San Diego and Los Angeles.

“We want to see the drift gillnets banned and we’re hoping this is a significant step in that direction,” said Ben Enticknap, senior scientist with the environmental group Oceana.

Earlier this year, federal fisheries managers imposed a temporary gillnet ban off Southern California to protect loggerheads lured to the area by the ocean-warming pattern known as El Nino.

Under the new restrictions, swordfish gillnet fishing off California would be suspended for the rest of the season after the capture of two of any of three types of endangered whales, or two of any of the four types of protected turtles.

The snaring of four short-finned pilot whales or four common bottle nose dolphins also would trigger a suspension.

It was unclear how often fishermen capture endangered species in the gillnets. But the entanglement in 2010 of two sperm whales in waters off San Diego’s coast spurred calls for action, Enticknap said.

One whale died, and the other was so badly injured that federal marine biologists predicted it likely would die too after being released.

Several commercial fishermen who use the nets off Southern California, as well as groups representing the industry, did not immediately respond to requests for comment on Monday.