World Library  
Flag as Inappropriate
Email this Article

Spiny dogfish

Article Id: WHEBN0001425524
Reproduction Date:

Title: Spiny dogfish  
Author: World Heritage Encyclopedia
Language: English
Subject: Shark, Squalidae, Squaliformes, Buccinum undatum, Tempura
Collection: Fish of Europe, Fish of New Zealand, Fish of the Black Sea, Fish of the Mediterranean Sea, Seafood Red List, Squalidae
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Spiny dogfish

Spiny dogfish
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Squaliformes
Family: Squalidae
Genus: Squalus
Species: S. acanthias
Binomial name
Squalus acanthias
Linnaeus, 1758
Range of the spiny dogfish (in blue)

The spiny dogfish, spurdog, mud shark, or piked dogfish, Squalus acanthias, is one of the best known species of the Squalidae (dogfish) family of sharks, which is part of the Squaliformes order. While these common names may apply to several species, Squalus acanthias is distinguished by having two spines (one anterior to each dorsal fin) and lacks an anal fin. It is found mostly in shallow waters and further offshore in most parts of the world, especially in temperate waters.

Contents

  • Morphology and behavior 1
  • Commercial use 2
  • Conservation status and management 3
  • Gallery 4
  • See also 5
  • References 6
  • External links 7

Morphology and behavior

Close-up of the head.

The spiny dogfish has dorsal spines, no anal fin, and white spots along its back. The caudal fin has asymmetrical lobes, forming a heterocercal tail. The species name acanthias refers to the shark's two spines. These are used defensively. If captured, the shark can arch its back to pierce its captor. Glands at the base of the spines secrete a mild venom.

Males mature at around 11 years of age, growing to 80–100 cm (2.6–3.3 ft) in length; females mature in 18–21 years and are slightly larger than males, reaching 98.5–159 cm (3.23–5.22 ft).[2] Both sexes are greyish brown in color and are

Reproduction is aplacental viviparous, which was before called ovoviviparity. Fertilization is internal. The male inserts one clasper into the female oviduct orifice and injects sperm along a groove on the clasper's dorsal section. Immediately following fertilization, the eggs are surrounded by thin shells called "candles" with one candle usually surrounding several eggs. Mating takes place in the winter months with gestation lasting 22–24 months. Litters range between 2 and 11 but average 6 or 7.

Spiny dogfish are bottom-dwellers They are commonly found at depths of around 50-149m, but have been found deeper than 700m.[3]

Life span is estimated to be more than 100 years and their gestation period is 18 to 24 months, which may be the longest of any known animal.[4]

Commercial use

Spiny dogfish are fished for food in Europe, the United States, Canada, New Zealand and Chile. The meat is primarily consumed in England, France, the Benelux countries and Germany. The fins and tails are processed into fin needles and are used in less expensive versions of shark fin soup in Chinese cuisine. In England this and other dogfish are sold in fish and chip shops as "rock salmon" or "huss", in France it is sold as "small salmon" (saumonette) and in Belgium and Germany it is sold as "sea eel" (zeepaling and Seeaal, respectively). It is also used as fertilizer, liver oil, and pet food, and, because of its availability, cartilaginous skull, and manageable size, as a popular vertebrate dissection specimen, in both high schools and universities. Reported catches in 2000–2009 varied between 13,800 (2008) and 31,700 (2000) tonnes.[5]

Bottom trawlers and sink gillnets are the primary equipment used to harvest spiny dogfish. In Mid-Atlantic and Southern New England fisheries, they are often caught when harvesting larger groundfish, classified as bycatch, and discarded. Recreational fishing accounts for an insignificant portion of the spiny dogfish harvest.[6]

Conservation status and management

A large catch of spiny dogfish

Once the most abundant shark species in the world, populations of Squalus acanthias have declined significantly. They are classified in the IUCN Red List of threatened species as Vulnerable globally and Critically endangered in the Northeast Atlantic, meaning stocks around Europe have decreased by at least 95%. This is a direct result of overfishing to supply northern Europe's taste for rock salmon, saumonette or zeepaling. Despite these alarming figures, very few management or conservation measures are in place for Squalus acanthias.[1] In EU waters, a Total Allowable Catch (TAC) has been in place since 1999, but until 2007 it only applied to ICES Areas IIa and IV. It was also set well above the actual weight of fish being caught until 2005, rendering it meaningless. Since 2009 a maximum landing size of 100 cm has been imposed in order to protect the most valuable mature females. The TAC for 2011 was set at 0t, ending targeted fishing for the species in EU waters. It remains to be seen if populations will be able to recover.[7]

In the recent past the European market for spiny dogfish has increased dramatically, which led to the overfishing and decline of the species. This drastic increase led to the creation and implementation of many fishery management policies placing restrictions on the fishing of spiny dogfish. However, since the species is a late maturing fish, it takes a while to rebuild the population.

In 2010, Greenpeace International added the spiny dogfish to its seafood red list. "The Greenpeace International seafood red list is a list of fish that are commonly sold in supermarkets around the world, and which have a very high risk of being sourced from unsustainable fisheries."[8] In the same year, the Convention on Migratory Species (CMS; also known as the Bonn Convention) listed the species (Northern Hemisphere populations) under Annex I of its Migratory Shark Memorandum of Understanding.[9]

In recent years however, the US has implemented fishing controls and opened up the fishery. The current proposed quota for 2011 is 35.5m lbs. with a trip limit of 4000 lbs. This is a gain over past years in which the quota has ranged from 5m lbs. to 20m lbs. with trip limits from 2000 to 3000 lbs.[10] In 2010, NOAA announced the Eastern US Atlantic spiny dogfish stocks to be rebuilt[11] and in 2011 concerns about dogfish posing a serious predatory threat to other stocks resulted in an emergency amendment of the quota with nearly 15 million pounds being added.[12]

Gallery

See also

References

  1. ^ a b Fordham, S., Fowler, S.L., Coelho, R., Goldman, K.J. & Francis, M. (2006). "Squalus acanthias".  
  2. ^ Kindersley, Dorling (2001). Animal. New York City: DK Publishing.  
  3. ^ Jose Castro, Diane Peeble (2011). ''The Sharks of North America.'' pg 58. Books.google.be. 2011-07-28. Retrieved 2013-11-06. 
  4. ^ Spiny dogfish. Memorandum of Understanding on the Conservation of Migratory Sharks.
  5. ^ FAO (Food and Agriculture Organization of the United Nations) (2011). Yearbook of fishery and aquaculture statistics 2009. Capture production (PDF). Rome:  
  6. ^ Katherine Sosebee, Paul Rago (December 2006). "Status of Fishery Resources off the Northeastern US: Spiny dogfish (Squalus acanthias)". NEFSC – Resource Evaluation and Assessment Division. 
  7. ^ "Spurdog in the Northeast Atlantic" (PDF). Advice September 2011.  
  8. ^ Greenpeace International Seafood Red list
  9. ^ Cms.int
  10. ^ "Mid- Atlantic Council on Dogfish". 
  11. ^ "NOAA Announces Spiny Dogfish Stocks to be Rebuilt". NOAA. 
  12. ^ "Spiny Dogfish Threaten Other Fish Stocks". 

External links

  • Spiny dogfish at Animal Diversity Web
  • "Squalus acanthias".  
  • Froese, Rainer and Pauly, Daniel, eds. (2005). "Squalus acanthias in FishBase. 10 2005 version.
  • Canadian Shark Research Laboratory
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.