Spiny Dogfish Shark Pictures

By Scott Boyd

One of my favorite local pests, the Spiny dogfish shark (Squalus acanthias), has a sharp, mildly venomous spine in front of each dorsal fin. These sharks are well known to local divers and are often the bane of local fishermen, as they are so abundant; they commonly interrupt several large commercial fisheries in both oceans. As with most sharks, they have bodies which are dark gray above and white below, with white spots on the sides.
 
Dogfish is typically marketed as "rock shark", "rock cod" or "rock salmon" and is often eaten as European fish and chips. Dogfish are commercially harvested off our Coast, with about 6000 tons taken annually off of British Columbia. The name dogfish refers to the gregarious nature of this species, which travel in large packs. Divers will typically encounter these small sharks in the late summer months from July to September, when they are fond of “buzzing” divers, which can be unnerving when you don’t see them coming.

 
Dogfish often occur in schools segregated by size and sex. In the Pacific Ocean the age of maturity for female spiny dogfish ranges from 20-35 years (about 3 feet in length). Dogfish are believed to live to almost 100 years of age. The females are larger than the males, producing an average of 7 live pups that are about 10 inches long. The gestation period is the longest of any vertebrate, at almost 24 months. This species can grow to around 5 feet and weigh as much as 20 pounds, although sharks that size are uncommon.
 
The spiny dogfish is a voracious predator that feeds primarily on the smaller fishes. They are known to prey heavily on schools of spawning herring, and packs of dogfish are often linked with the return of herring to our coastal waters.  Researchers have found many different species of vertebrates and invertebrates in the stomachs of these pesky predators, so it would appear that they are not that picky when they feed.
 
The spiny dogfish is believed to be the worlds' most abundant shark and is the predominant shark species in the Pacific Northwest. Dogfish occur at depths from the surface down to 3000 feet. They occur worldwide, migrating to stay within a temperature range between 45° and 59°F as they follow their food.  They are also capable of very long migrations, and one shark tagged off of the Washington Coast was captured 7 years later near Honshu, Japan (4000 miles away), where I’m sure they made it into soup.