PORTLAND, Maine (AP) — New protections for a species of threatened East Coast shark went into effect this week.

Dusky sharks, which range from Maine to Florida, are down to about 20 percent of their 1970s population off the East Coast and Gulf of Mexico. They were once a common large coastal shark and a target of commercial fishermen, who sought them for their meat, oil and fins.

It’s now illegal to fish for dusky sharks, but they are still sometimes accidentally caught by fishermen of species such as tuna and swordfish. The federal government rolled out new protections for the shark on Monday.

One measure requires longline fishing vessels to take new precautions when they accidentally catch a dusky shark and release it. They have to minimize the amount of fishing gear left behind on a released shark.

Other measures include new educational tools and a new communication system in which vessels must broadcast their locations when they accidentally catch a dusky shark. Other fishermen then have to stay away from the area where the shark was caught.

Another measure requires certain kinds of fishermen to use gear that is less likely to kill dusky sharks. That one will go into effect on Jan. 1, 2018.

The environmental group Oceana is suing the federal government for better protection of the sharks. The group contends the new rules to protect dusky sharks don’t go far enough.