Newborn killer whale J-46 swims with its mother in the Strait of Juan de Fuca. (Mark Malleson)

A second newborn killer whale has been spotted in the waters off Washington state's San Juan Islands and near Victoria.

The calf, given the scientific designation J-46, is the newest member of what marine scientists call J-Pod, part of a larger group of endangered killer whales called the southern residents.

The presumed mother is a 16-year-old known as J-28, or Polaris, according to the Orca Network, a non-profit whale monitoring organization.

This was the second killer whale birth in the area in recent weeks, after a new calf was spotted in another pod last month and brings the southern resident population to 87, said Susan Berta, co-founder of the network.

J-46 has a distinguishing peach-coloured eye patch. (Mark Malleson)Whale photographer Mark Malleson of Victoria hurried to the area when he got word of the discovery.

"It's amazing to see them any size, but it's a great sight to see … a young one travelling right alongside its mom," Malleson said.

The young whale's prospects are daunting, according to some research, which has found that many of the marine mammals don't survive their first year.

"It's quite a high mortality rate, like 50 percent," Malleson said.

Food supply favourable

The southern residents' numbers have been dwindling for decades, possibly because of ocean pollution and conflicts with the fishing industry, according to marine scientists at the University of British Columbia.

In the calf's favour, however, is the southern residents' diet of chinook salmon. An unusually high volume of chinook returned to the area in the summer, Berta said.

This might mean the mother will be able to bulk up and nurse the calf. Young orcas nurse for up to two years but can start including meat in their diets after their first year.

The first test for the calf will be to survive the winter.

"I look forward to the next encounter with J-Pod and hopefully we'll see that calf again," Malleson said.

With files from The Associated Press