Farmers in California want the killer whales that ply the waters between British Columbia and the U.S. to be removed from the endangered-species list because the mammal’s status is indirectly creating an economic burden for the agricultural industry.

The farmers’ legal representative, the Pacific Legal Foundation, claims regulations to protect salmon that the killer whales eat are forcing cutbacks in farmland irrigation to protect the fish, making it difficult to expand agricultural operations because of the lack of water.

The foundation has persuaded the U.S. National Oceanic and Atmospheric Administration (NOAA) to review whether southern resident killer whales should be delisted.

NOAA said a petition filed on behalf of two farms and the Center for Environmental Science Accuracy and Reliability presents new information from scientific journals that claim the whales are genetically linked to a much larger population and therefore are not in danger of extinction.

Damien Schiff, a lawyer for the legal foundation, said southern resident killer whales are no different from orcas around the world but U.S. government regulators invented a new sub-category of orca in the Pacific Northwest in order to label them endangered.

‘Single worldwide species’

Scientists believe there are about 86 southern resident killer whales, which were listed as endangered by the U.S. in 2005 when there were 89 of them, according to NOAA.

"The federal government should continue to look at the killer whale as a single worldwide species," Schiff said.

Southern resident killer whales spend much of the year in the Strait of Georgia, the Strait of Juan de Fuca and Puget Sound in Washington and also feed on salmon in California rivers in winter.

Schiff said that while there are biological and behavioural differences in whales such as hunting practices and vocalizations, the southern resident killer whales should not be protected as an "alleged subspecies of North Pacific killer whales."

"It's not about pitting whales against human beings," he said of the petition. "Rather, it's about a balanced environmental regulation because even if the killer whale is removed from the endangered species list, it will continue to be protected under other federal laws."

The Marine Mammal Protection Act, for example, makes it illegal to harm, capture or kill whales.

Water issues have long history

Michael Healey, a retired marine biologist and professor emeritus at the University of British Columbia, said the petition appears to be part of the long history of limited water supply issues in California.

"About 75 per cent of the available supply is used for agriculture and there are continual and never-ending battles about who's going to get the water," he said.

"There have been numerous law cases concerning the protection of aquatic species and in recent years, decisions by the courts to demand that more water be left in rivers for fish and other aquatic organisms. So this is a much bigger issue, particularly in California, than it is [in B.C.]."

Canada listed the southern resident killer whale as endangered under the Species At Risk Act in 2003.