Spiny dogfish (Squalus acanthias): The spiny dogfish is found within all of the world's oceans.  This slender bodied shark is dark gray on top with white spots and white on the bottom.  The spiny dogfish received its name from a combination of physical and behavioral characteristics.  With sharp venomous spines in front of each dorsal fin, their name includes the word spiny.  Fishermen gave the title dogfish to these sharks since they travel in packs of hundreds to thousands segregated by size and sex.  Spiny dogfish occupy the depths from the surface of the ocean to 900 m below.  The average lifespan for spiny dogfish is 30 years, but they can live to 100 years.  Spiny dogfish feed on bony fish, jellyfish, crabs, squid, and octopus and are prey themselves to killer whales, seals, sea lions, and other sharks.  Spiny dogfish are caught for a variety of purposes including: fish and chips, shark fin soup, fertilizers, liver oil, pet food, and as a popular vertebrate dissection specimen in high school science classes.  Due to the popularity of the species and its inability to recover from high fishing pressures, the spiny dogfish is listed as "vulnerable" in the International Union for the Conservation of Nature's "Red List" of threatened species.