Squalus acanthias juvenile from Alaska, Prince William Sound
Date 2000
Source NOAA Photo Library http://www.photolib.noaa.gov/htmls/fish4033.htm
Author David Csepp, NMFS/AKFSC/ABL
Source: https://commons.wikimedia.org/wiki/File:Squalus_acanthias_juvenile.jpg

The spiny dogfish, spurdog, mud shark, or piked dogfish (Squalus acanthias) is one of the best known species of the Squalidae (dogfish) family of sharks, which is part of the Squaliformes order. It is found mostly in shallow waters and further offshore in most parts of the world, especially in temperate waters.