The spiny dogfish or spurdog Squalus acanthias
is a small member of the dogfish family reaching up to 1.6 m in length. It has a grey to brown dorsal colouring and a much paler belly. It can easily be distinguished from similar species by conspicuous white spots covering the entire body. It has two dorsal fins each with large spines. The caudal fin outline is smooth.One of the most abundant shark species in the world, Squalus acanthias
is a well studied species and has been the subject of many studies focusing on heavy metal pollution and sensitivity to pollution studies (McMillan & Morse, 1999).