Jersey's offshore reefs have been given new protection against dredging and trawling.
The ban has been introduced in two large areas around Les Minquiers and Les Écréhous, with unanimous support from States members.
The reefs are home to extensive areas of seagrass, maerl and kelp and are recognised by Ramsar for their importance to wildlife, as well as being listed as threatened marine habitats.
More than 60 different seabed habitats and 750 species have been recorded at the sites.
The States has been trying to introduce a ban for almost five years but the process has been difficult due to negotiations with French authorities.
The area is outside of Jersey's three-mile fishing zone, so fishing in the area is managed via a treaty between the Bailiwick and France.
It means the changes needed approval from both governments.
Jersey's Environment Department says the new restrictions are good news for fishermen, as they will increase the stock of marine life in local waters.
Heavy fishing gear, such as trawlers and dredges that are towed along the seabed, can cause damage to some habitats.
The ban means they will not be able to be used in two areas surrounding the reefs, totalling 62km².
The new zones will still allow the use of static fishing gear such as lobster pots and fishing lines, and activities such as diving and boating are unaffected.