Scientists grew concerned that if the declines continued much further, the whales would no longer have a viable gene pool and would soon tumble into an inevitable downward population spiral. By then, scientists had learned that the Southern Residents are genetically isolated, that even though Bigg’s killer whales visit their waters to feed on large sea mammals like seals and sea lions, there is no social interaction or apparent communication between them. Likewise, they do not interact with their fellow Northern Residents at all, nor with offshore killer whales,
