According to the Center for Whale Research, who took the photos above, the calf was first spotted on Saturday, October 24:

The calf was first seen in Haro Strait early in the day and later photographed by CWR staff in the Strait of Juan de Fuca. The new calf was seen closely traveling with a 38 year old female, J17, who is the presumed mother. J17 has previously had three offspring: two daughters, J28 and J35 now adult, with two grand offspring J46 and J47 respectively, and a son J44, born in 2009. The new calf is designated by the Center for Whale Research as J53. The previous sighting of J17 without the calf was on the 15th of October, meaning that the calf was no more than 10 days old at the time it was first seen on Saturday.

The Center for Whale Research has been studying southern resident killer whales since 1976. They keep track of them—and can tell the difference between them—through photographs alone: The dorsal fins and saddlepatches (that white marking you can see behind the dorsal fin) are unique.

In 1995, there were 98 southern resident killer whales in the wild; by 2001, there were only 81. That sudden population drop couldn't be explained by any single factor, leading the federal government to place southern resident killer whales on the Endangered Species List in 2005. (Earlier this year, the captive southern resident Lolita was added to the list.) As of the July 2015 census, there were still 81 in the wild. NOAA is currently studying three possible factors to explain the low population figures: salmon scarcity, pollution, and stress caused by vessel noise.

According to Center for Whale Research:

The greatest number of calves born in a year was 9 in 1977, and there were none born that survived in 2013 or 2014. We hope this year’s "baby-boom" represents a turn-around in what has been a negative population trend in recent years.

This is the sixth southern resident calf born in the last 11 months, the Seattle Times pointed out yesterday. Michael Harris of the Pacific Whale Watch Association told them he hopes J53 turns out to be a girl because "only one of the other five baby whales born this year is female." I'm with Harris; male southern residents are high-maintenance, powerless, brooding losers compared with the female southern residents.

About half of orca calves born in the wild die within the first year.

Think good thoughts for J53.