The federal government is releasing new rules designed to protect threatened dusky sharks from being accidentally killed by fishermen.

Dusky sharks are large sharks that are down to about 20 percent of their 1970s population off the East Coast and Gulf of Mexico.

The sharks are in decline in part because of years of harvesting them for their meat, oil and fins. It’s already illegal to fish for them off the U.S., but they sometimes get caught as bycatch.

The federal proposal would require some fishermen to use gear that is less likely to kill the sharks.

The environmental group Oceana says the proposed new rules might help but they don’t go far enough.

Dusky sharks range from Maine to Florida.