The pale referred to in the idiom is usually taken to mean the English Pale, the part of Ireland under English rule, and therefore, as perceived by its rulers, within the bounds of civilization. pale see: beyond the pale
For the food, see Salmon as food. The chum salmon (Oncorhynchus keta) is a species of anadromous fish in the salmon family. It is a Pacific salmon, and may also be known as dog salmon or keta salmon, and is often marketed under the name silverbrite salmon.
Scientific Name: Oncorhynchus Keta. Market Names: Chum, Keta, Silverbrite Vernacular Names: Dog Salmon, Calico Salmon, Chub, Keta Salmon. Keta Salmon have greenish-blue backs with silver splashes in the tail. It looks very similar to a Sockeye salmon when ocean fresh. Keta salmon range from 6-17 pounds and are mature at 3-6 years old.