B.C.'s orcas keep on booming with 8th calf

After years of population decline, the orca baby boom on the West Coast just won't stop, it appears.

On Wednesday, the Centre for Whale Research confirmed the birth of the eighth calf this year in the endangered southern residents, boosting the population to 84.

"1977 is the only previous year in the past 40 years in which as many baby killer whales were born into this community of whales, and there were nine in that year," said Michael Harris, the director of the Pacific Whale Watch Association in a statement.

The calf was first spotted on Dec. 1 near San Juan Island in Washington state, but it wasn't until Wednesdaythat researchers were able to snap a photo in Haro Strait and confirm it was not one of the other calves born this year.

The sex of the calf has not been determined, but it has been named J54. The mother is J28, a 22-year-old femalewhich is also the mother of a female born in 2009, named J46, whichstill survives.

Back to normal, but for how long?

The latest birth actually puts the population back within its normal birth rate, according to Harris.

"From calculations accounting for all reproductive age females, we estimate that typically up to nine babies could be produced each year, but there is usually a high rate of neonatal and perinatal mortality, and we have seen only three babies annually on average."

Part of the decline in births in the past year has been blamed on dwindling salmon stocks, which make up most of the diet of the resident orcas.

"In the years immediately following poor salmon years, we see fewer babies and higher mortality of all age cohorts," said Harris.

Despite this year's population recovery, researchers still have concerns about their long term survival, in part because of global warming.

"Warmer ocean waters are less productive, and rivers without continual water from snow melt (rains run off too quickly) and with warmer water are lethal to salmon," notes Harris.

"Survival of all of the new calves and their mothers and relatives depends upon a future with plentiful salmon, especially Chinook salmon, in the eastern North Pacific Ocean ecosystem."

Here's our photogallery from earlier this year