During the past decades, Southern resident killer whale populations in the Pacific Northwest have declined substantially, leading researchers to look for causes of this worrisome trend. Some of the threats that have been identified include fluctuations in salmon prey, exposure to toxic pollutants, and disturbance and noise from ships and other vessels.  Now, by combining modern genomics with decades of field observations, an international team of scientists has found that the small size and isolation of the endangered population of Southern residents in the Pacific Northwest have...