Life of Sea | Spiny Dogfish (Squalus acanthias) | The Spiny dogfish, Spurdog, Mud shark, or Piked dogfish, is one of the best known ofthedogfish, which aremembersof the familySqualidaeare in the orderSqualiformes. Though these commonnamesapply todifferentspecies,Spiny dogfish is distinguishedby havingtwospines(one anteriorto eachdorsal fin) and lacksan analfin.It occurs mainlyin shallowwaters andfurther offshorein most partsof theworld, especially intemperate waters. This sharkis present in allthe world'stemperate oceansIt rangesin the coastalwatersof the Atlanticand Pacific. ThedogfishisaseasonalmigrantintoCanadian waters.
Species: S. acanthias
TheSpiny dogfish isashark thatsmalldark graywith somewhite spots, the bellyis off-white. It hadtwodorsal fins, each precededbyaslightlypoisonous spider. Ithasashort snout, large eyes andno analfin. TheSpiny dogfishis a small schoolgroupsof hundredsor thousandsof same-sexshapesand sizes. This sharkis gray orbrownishon top andlight grayor white onitsventral sidewith irregularwhitespots onthetop or sideof the body.The seconddorsal finis smallerthan thefirstand bothfinshavespines ontheir origin. The caudal finis asymmetricalwith the upperlobeis larger. The smoothedgesshort andobliqueteethare similarin both theupper andlower jaw. Thespiny dogfishhasan estimated life of25 to 30years.
The Spiny dogfishisanopportunisticfeedereat whateverpreyis abundant. In general, their dietconsists of small fishsuch ascapelin, cod, haddock, hake, herring, menhadenandratfish. Theyalso eatinvertebrates such askrill, crabs, polychaeteworms, jellyfish, ctenophores, amphipods, squidand octopus.
Spiny dogfishare not considereddangerous,but somedamage canbedonethroughtheir teethandtheirpoisonousdorsalspineslight. Spiny dogfish aregregarious(social) and travel inschoolsof hundreds tothousands of individuals. These schoolsare sometimesseparatedby genderand age. Theyare calleddogfishbecausethey travelandhuntin packs. Theymigratein schools, aftercool water.
Spiny dogfishare caughtfor food inEurope, theUnitedStates, Canada, NewZealandand Chile. The meatis mainlyin England, France, BeneluxandGermany.The finsandtailfinareprocessed intoneedlesand are usedin less expensiveversions ofshark finsoupin Chinesecuisine. In Englandtheseare sold indogfishandotherfish and chipshops as"rock salmon"or "Huss", in Franceit issold as"littlesalmon" in Belgium and Germanyandis sold as"sea eel". Itis also used asfertilizer, liver, andpet food, and because of theavailability, cartilageskull, andthemanageable size, asapopularvertebratedissectionspecimen, in both high schoolsand universities.