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.
When referring to skin and flesh color references of Brites, Pails, and Darks are often used. Chum Salmon (Oncorhynchus keta) is the meatiest of the wild Salmon. Chum Salmon is the most wide-ranging of the Pacific Salmon species, as well as the most abundant commercially harvested Salmon species in parts of Alaska.