The newest member of the Southern Resident Killer Whale population is what researchers are calling a "very welcome addition." 

Over the weekend, the Center for Whale Research confirmed a new calf swimming with J Pod. The baby orca, designated J56, was born to 24-year-old J31. 

It is J56's first known, successful birth in the past decade, according to Center for Whale Research. J31 had a failed pregnancy in January 2016.

Just to maintain the population, there should be two births per-year, said Howard Garrett, the co-founder of Orca Network. 

The calf boosts the population up to 76 Southern Resident orcas and will potentially add to the number of reproductive females in the future. 

Just a year ago, one researcher noted that whales around the world were struggling. Female whales of reproductive age appeared to be struggling the most. The long gestation (between 15–18 months) and nursing (nearly two years) periods come at a huge cost to the mothers. 

The Southern Resident population continues to struggle, however. Scientists have identified dams, pollution and vessel noise as some of the main causes of their decline. Dwindling salmon returns have forced the orcas to look elsewhere

Mothers often can't carry pregnancies to full term due to the lack of food, Garret said. About 70  percent of pregnancies end in miscarriages. 

It's believed that a recent, extended absence of the Southern Resident orcas stemmed from a lack of Chinook salmon - their primary source of food.