News and Reports

VICTORIA — The discovery of a dead female orca calf near Vancouver Island in American waters continues to raise questions among researchers.

Michael Weiss, research director with the American-based Center for Whale Research, said in emailed statement that it is not clear whether the calf was stillborn or died shortly after birth.

Weiss said researchers cannot assign any individual death to a particular factor in the ecosystem.

But Weiss said that "low reproductive success in this population" is tied to high levels of pollutants — particularly industrial chemicals known as PCBs — that inhibit immune and reproductive function and a lack of prey, especially Chinook salmon, which are orcas' preferred prey.