LOS ANGELES (September 30, 2009) – The Natural Resources Defense Council today called on the federal government to list the Hawaiian population of false killer whales as an endangered species and designate critical habitat to ensure its recovery under the Endangered Species Act. The Hawaiian false killer whale population is a small and ecologically unique population of 120 animals that has suffered a significant decline over the last 25 years.
“Given the extremely small size of this population, the loss of even a few mature adults could have serious and long-term reproductive consequences,” said Sylvia Fallon, wildlife biologist with NRDC. “Toxic chemicals, reduced food sources and interactions with fishing vessels are the biggest threats to this unique mammal.”
Hawaiian false killer whales (Pseudorca crassidens) are large members of the dolphin family. Females can grow up to 15 feet and males can reach 20 feet. In adulthood, false killer whales can weigh up to 1,500 pounds. They are pelagic deep, open water animals, and the Hawaiian inshore population is the only one of its entire species known to make its home near land. This indicates not only the uniqueness of the population, but also the biological importance of Hawaiian waters as an oasis for marine mammals.
“The Hawaiian Islands are the most remote chain of islands in the world, creating a marine environment that supports a unique array of whale and dolphin populations found nowhere else in the world,” said Liz Alter, marine mammal scientist with NRDC. “The extreme isolation of the Hawaiian ecology has created specific breeding and foraging habitat for a number of evolutionarily distinct, island-associated marine mammal populations.”
The population faces a number of threats including interactions with local fisheries, reduced food sources and exposure to toxic chemicals. False killer whales are likely affected both by long-line and unregulated near-shore and “short” long-line fisheries. A recent study showed that disfigurement from fishing gear in this population was four times higher than for other dolphin and toothed whale species, suggesting high rates of interactions with fisheries. These fisheries may also be contributing to a decline in the size or number of the primary food source for false killer whales, which are large deep water fish including mahi mahi and yellowfin tuna.
Recent research confirms the presence of PCBs (a toxic substance found in plastics), DDT and flame retardants in tissue samples taken from the Hawaiian false killer whales. Pollution levels found in one-third of the samples are known to cause serious health problems in marine mammals.
The cumulative effects of these risks combined with the depleted population qualify the Hawaiian false killer whale as an endangered species under the federal Endangered Species Act. If listed, the population would become the first of Hawaii's resident toothed whale species to be listed under ESA. Today’s petition was sent to the Secretary of Commerce through the National Marine Fisheries Service.