A new regulation prohibiting the use of wire leaders in longline fisheries is expected to increase the survival of hooked oceanic whitetip sharks by up to 30%.

The regulation takes effect on May 31 this year and will replace wire leaders — short lengths of wire that stop fish from biting themselves free from hooks — with nylon alternatives. Plastic leaders give sharks a better chance of survival because they can bite themselves free, or fishermen can cut them loose with greater ease.

The National Oceanic and Atmospheric Administration regulation comes after the Western Pacific Regional Fishery Management Council and Hawaii Longline Association started addressing the issue in 2020.

Oceanic whitetip sharks, once one of the most abundant sharks in the ocean, are threatened after years of being caught by longline fisheries as bycatch.

Wespac last year recommended NOAA implement the regulation after a working group supported the measure.

In late 2020, the Hawaii Longline Association’s members started voluntarily phasing out wire leaders.

HLA Executive Director Eric Kingma has estimated that the group’s approximately 140 vessels unwittingly hooked about 1,500 oceanic whitetips a year.

The rule also recommends that fishers in the Western Pacific longline fisheries remove as much fishing gear from the threatened sharks as possible before release.