Shortspine thornyhead (Sebastolobus alascanus) are found in the waters off of the West Coast of the United States from northern Baja California to the Bering Sea. They are found from 20 to over 1,500 meters in depth. Shortspine thornyhead do not appear to be distributed evenly across the West Coast, with higher densities (kg/ha) of thornyheads in shallower areas (under 500 meters) off of Oregon and Washington, and higher densities in deeper areas off of California (Piner and Method 2001).

Although their densities vary, shortspine thornyheads are present in almost all trawlable areas below 500 m. They are caught in 91% of the trawl survey hauls below 500 m and 94% of the commercial bottom trawl hauls below 500 m. Trawl landings represent only bottom trawl gear and non-trawl landings include all other gears, the majority of which is longline, with some catch by pot gear. Both trawl and non-trawl landings are divided into North (the waters off Washington and Oregon) and South (the waters off California) fleets although they are assumed to be fishing on the same unit stock (Taylor and Stephens 2013).

Genetic studies of stock structure do not suggest separate stocks along the west coast. Siebenaller (1978) and Stepien (1995) found few genetic differences among shortspine thornyheads along the Pacific coast.