Pacific Spiny Dogfish

Habitat:  The Pacific spiny dogfish can be found from the Bering sea down to Baja California.  They can be found in waters as deep as 4050 ft (1234m) but are commonly found in shallow inland waters and bays.  Males are generally found in shallower waters than females unless the females are giving birth.  They are comfortable in temperatures of 6 – 11C (43-52 F).

Prey:  Spiny dogfish love to eat bony fish such as salmon as well as cartilaginous fish such as other smaller sharks. They have a very diverse diet that can include cephalopods, gastropods, crustaceans, sea cucumbers, ctenophores, hydrozoans, jelly fish, squid, octopus and herring. They travel and hunt in packs and the pack size can range from hundreds to thousands. The pack is sometimes segregated by gender.

Predators:  Some of the predators of Pacific spiny dogfish include large fish (such as cod and hake), sharks, including larger Pacific spiny dogfish, seals and killer whales. They use their spines on the dorsal fins to defend themselves but despite having venom in the spines many animals still prey on them.

Life Cycle:  Males mature at 11 years and females become mature at about 18 to 21 years. They typically mate during the winter. Mating is ovoviviparous. Mating usually takes place in offshore waters and it is internal fertilization. Once the eggs are fertilized, the mother produces a thin, horny, transparent shell around them called a candle, and here they develop within her body feeding off the egg yolk. The litter can range anywhere from 2 to 11 pups and are approximately 20-30cm at birth.  The gestation period of the Spiny Dogfish is 18 to 24 months, one of the longest of any vertebrates.  They live for at least 44 years but can live for as long as 100 years. The population has decreased drastically over the years due to the fact that it takes them a long time to mature and they have such a lengthy gestation period.  They are fished to be used as pet food, fish and chips, fertilizers, oils, and a cheaper version of shark fin’s soup.

References:

Benz, G. (2004). Squaliformes (Dogfish Sharks). In M. Hutchins, R. W. Garrison, V. Geist, P. V. Loiselle, N. Schlager, M. C. McDade, et al. (Eds.), Grzimek’s Animal Life Encyclopedia (2nd ed., Vol. 4: Fishes I, p. 158). Detroit: Gale. Retrieved November 28, 2014, from http://go.galegroup.com/ps/i.do?id=GALE|CX3406700245&v=2.1&u=61vhss&it=r&p=GVRL&sw=w&asid=27e00f1840ff2a583d5b18810cae46b1

Bester, C. (n.d.). FLMNH Ichthyology Department: Spiny Dogfish. Retrieved November 6, 2014, from http://www.flmnh.ufl.edu/fish/Gallery/Descript/Spinydogfish/SpinyDogfish.html

Hart, J. (1973). Pacific Fishes of Canada (p. 44). Ottawa, Ontario: Minister of Supply and Services Canada.

Maddalena, A. D., Preti, A., & Polansky, T. (2007). Sharks of the Pacific Northwest: Including Oregon, Washington, British Columbia and Alaska. Madeira Park, BC: Harbour Pub.

Pacific Spiny Dogfish | NOAA Fisheries. (n.d.). NOAA Fisheries. Retrieved August 24, 2024, from https://www.fisheries.noaa.gov/species/pacific-spiny-dogfish

Parker, S. (2008). The Encyclopedia of Sharks (2nd ed.). Buffalo, New York: Firefly Books.

Street, R. (2002). Squalus acanthias. Retrieved November 26, 2014, from http://animaldiversity.ummz.umich.edu/accounts/Squalus_acanthias/

Col, J. (1999). SPINY DOGFISH SHARK – Zoom Sharks. Retrieved December 3, 2014, from http://www.enchantedlearning.com/subjects/sharks/species/Dogfish.shtml

Spiny Dogfish. (2014, January 23). Retrieved December 3, 2014, from http://www.bio.gc.ca/sharks/maritime/squalusacanthias-eng.php