Two of the Puget Sound's endangered killer whales died this year and there have been no new births since 2012.
The population of whales in the region's J, K, and L pods has dropped to 78, which is the lowest seen since 1985, the Associated Press reported. In these past these pods would come together during the summer to feed and socialize, but have remained isolated for the past several years.
"What we're seeing with this weird association pattern is two or three members of one pod with two or three from another pod," Balcomb said. "It's a fragmentation of the formal social structure, and you can see that fragmentation going further. They are often staying miles and miles apart and not interacting," Ken Balcomb of the Center for Whale Research told the AP.
"If we were trying to name the pods now, we couldn't do it," he said. "They aren't associating in those patterns anymore."
The researcher believes lack of food in the primary factor in the whales' decline; which typically dine on chinook salmon. Populations of these fish are also on the decline.
During the 1960s and 1970s the Puget Sound's orca population was greatly depleted by captures by marine parks and aquariums. After that practice was stopped the numbers were at 98 by 1995; it had dropped to 80 by 2001, and has fluctuated ever since. In the past orca mothers usually had a calf once every five years.
"If everybody crosses their fingers and hopes for a return to that pattern, we could have eight babies next year," Balcomb said. "But the chances of that happening are pretty slim."
"Transient" orcas that travel and feed on sea mammals appear to be increasing. These whales typically traveled in small groups, but these groups are growing. Since these orcas don't eat fish they are not in competition with the local population.
"Transients change direction when Southern Residents are around, and there is no evidence of combat," Balcomb said.
