Preserving Hawaii's False Killer Whales
Action is being taken to preserve a rare Hawaiian creature.
False killer whales are no typical marine mammal. They are fast, able to swim from Kauai to the Big Island in four days. They create long-lasting friendships and can stay with partners for more than 20 years. They have a unique way of feeding, which may reveal how they communicate trust: When a false killer whale catches a fish, it passes it to every individual in its group—imagine a game of Frisbee—who eventually returns the fish intact.
Over the past 20 years, Hawaii’s population of false killer whales, or Pseudorcas, has dwindled from roughly 470 to about 150. This population stays within 70 miles of the main Hawaiian Islands year-round, and is genetically different from open-ocean false killer whales.
One factor in their decline is the gear used by the long-line fishing industry. False killer whales are known to take hooked fish off fishing lines, which can cause them to get snagged and drown, or ingest the hook, which can lead to serious injury.
In July, a team of scientists, fishermen and conservationists turned in a plan on how to reduce the bycatch of false killer whales. The group had been assembled by the National Marine Fisheries Service (NMFS), the federal agency responsible for fisheries management. (Sidenote: Earthjustice, a nonprofit environmental law firm, sued NMFS in 2009 for not forming the group sooner.)
“Within U.S. waters around Hawaii, the average bycatch, which mean serious injury or mortality, has been around eight false killer whales per year for the last five years,” says Robin Baird, a research biologist and a member of the team.
The group recommended that fishermen use weaker circle hooks, instead of Japanese-style tuna hooks.
Another recommendation calls for the permanent closure of an area open to the fishery four months out of the year. “This is an area about 50 to 75 miles away from the Islands where both the resident and pelagic population overlap,” says Baird.
Additional threats to false killer whales include a reduction in the fish they eat, both in size and abundance, as well as chemical contaminants, such as pesticides, found in the fish they consume.
NMFS has until Sept. 20 to review the group’s recommendations and make proposed regulations open for public comment. By Oct. 1, it will also decide whether the resident population should be protected under the Federal Endangered Species Act.