The allis shad (Alosa alosa) is a widespread Northeast Atlantic species of fish in the Alosidae family. It is an anadromous fish which migrates into fresh water to spawn.[2][3] It is found in the eastern Atlantic Ocean, the western Baltic Sea and the western Mediterranean Sea. In appearance it resembles an Atlantic herring but has a distinctive dark spot behind the gill cover and sometimes a row of up to six spots behind this. It sometimes hybridises with the twait shad (A. fallax). This fish becomes mature when three or more years old and migrates to estuaries, later swimming up rivers to spawn. Populations of this fish have declined due to overfishing, pollution and habitat destruction. Conservation of this species is covered by Appendix III of the Bern Convention and Appendix II and V of the European Community Habitats Directive.
The allis shad is a typical herring-type fish. It has no lateral line and a somewhat rounded belly. The gill cover is ridged and the scales large. The back is a bluish-green colour and the head brownish with a golden tinge on the operculum. The flanks are silvery, sometimes with a bronzy tinge, and a distinctive large dark spot occurs just behind the gill cover, and occasionally one to six smaller spots behind that. The adult length is typically 30 to 60 cm (12 to 24 in).[4][2]
Distributionedit
The allis shad is found in the eastern Atlantic in waters bordering most of Europe and northwestern Africa, and it enters to the western Baltic and western Mediterranean Seas, but it is rare outside France.[2][1]
Biology and lifecycleedit
Biology and lifecycle of Alosa alosa.
Alosa alosa has a similar lifecycle to that of the twait shadA. fallax. They are known to live in sympatry,[5] and the two species can hybridize.[6] They are anadromous species like many other species in the genus Alosa.[6] However, some record of them being landlocked suggests an ability to adapt well to their environment.[6] They primarily live at sea on feeding grounds and migrate to their spawning grounds between April and June once they are sexually mature.[6] Maturity usually ranges from 3–7 years of age.[6]A. alosa can usually only reproduce once in their lifetimes.[6] Juveniles appear in estuaries and brackish water around July to August.[5] The salinity of brackish water may pose problems to the juveniles migrating from fresh water.[5]
Population reductionedit
Populations have been reduced primarily by overfishing, pollution, and habitat destruction.[6] The estuarine phase, or the time that they are in the estuaries migrating from spawning grounds to sea, is estimated to have a duration in A. alosa of up to six months.[5] The estimate, however, does not take into account individual variation and/or survival of juveniles in the estuarine phase.[5]
Conservationedit
Four special areas of conservation have been designated in Ireland where Alosa species have been known to spawn.[6]Alosa alosa "has been placed in Appendix III of the Bern Convention (1979) that lists protected fauna species as well as in Appendix II and V of the European Community Habitats Directive (1992) that list, respectively, species whose conservation requires the designation of special areas of conservation and that are subject to management measures."[5] However, A. alosa is currently under a moratorium (2008) in numerous French watersheds.[5]
Referencesedit
^ abFreyhof, J.; Kottelat, M. (2008). "Alosa alosa". IUCN Red List of Threatened Species. 2008: e.T903A13091343. doi:10.2305/IUCN.UK.2008.RLTS.T903A13091343.en. Retrieved 15 November 2021.
^ abcFroese, Rainer; Pauly, Daniel (eds.) (2015). "Alosa alosa" in FishBase. April 2015 version.
^Freyhof, J.; Kottelat, M. (2008). "Alosa alosa". IUCN Red List of Threatened Species. 2008: e.T903A13091343. doi:10.2305/IUCN.UK.2008.RLTS.T903A13091343.en. Retrieved 18 November 2021.
^"Allis shad: Alosa alosa". NatureGate. Retrieved 14 December 2013.
^ abcdefgLochet, A., S. Boutry, and E. Rochard. Estuarine Phase during Seaward Migration for Allis Shad Alosa Alosa and Twaite Shad Alosa Fallax Future Spawners. Ecology of Freshwater Fish 18 (2009): 323-35.
^ abcdefghCoscia, I., V. Rountree, J. J. King, W. K. Roche, and S. Mariani. A Highly Permeable Species Boundary between Two Anadromous Fishes. Journal of Fish Biology doi:10.1111/j.1095-8649.2010.02768.x 77.5 (2010): 1137-149.
External linksedit
Data related to Alosa alosa at Wikispecies
EU LIFE-Project: The re-introduction of allis shad (Alosa alosa) in the Rhine system
Wikimedia Commons has media related to Alosa alosa.
January 01, 1970
allis, shad, allis, shad, alosa, alosa, widespread, northeast, atlantic, species, fish, alosidae, family, anadromous, fish, which, migrates, into, fresh, water, spawn, found, eastern, atlantic, ocean, western, baltic, western, mediterranean, appearance, resemb. The allis shad Alosa alosa is a widespread Northeast Atlantic species of fish in the Alosidae family It is an anadromous fish which migrates into fresh water to spawn 2 3 It is found in the eastern Atlantic Ocean the western Baltic Sea and the western Mediterranean Sea In appearance it resembles an Atlantic herring but has a distinctive dark spot behind the gill cover and sometimes a row of up to six spots behind this It sometimes hybridises with the twait shad A fallax This fish becomes mature when three or more years old and migrates to estuaries later swimming up rivers to spawn Populations of this fish have declined due to overfishing pollution and habitat destruction Conservation of this species is covered by Appendix III of the Bern Convention and Appendix II and V of the European Community Habitats Directive Allis shad Conservation status Least Concern IUCN 3 1 1 Scientific classification Domain Eukaryota Kingdom Animalia Phylum Chordata Class Actinopterygii Order Clupeiformes Family Alosidae Genus Alosa Species A alosa Binomial name Alosa alosa Linnaeus 1758 Allis shad Contents 1 Description 2 Distribution 3 Biology and lifecycle 4 Population reduction 5 Conservation 6 References 7 External linksDescription editThe allis shad is a typical herring type fish It has no lateral line and a somewhat rounded belly The gill cover is ridged and the scales large The back is a bluish green colour and the head brownish with a golden tinge on the operculum The flanks are silvery sometimes with a bronzy tinge and a distinctive large dark spot occurs just behind the gill cover and occasionally one to six smaller spots behind that The adult length is typically 30 to 60 cm 12 to 24 in 4 2 Distribution editThe allis shad is found in the eastern Atlantic in waters bordering most of Europe and northwestern Africa and it enters to the western Baltic and western Mediterranean Seas but it is rare outside France 2 1 Biology and lifecycle edit nbsp Biology and lifecycle of Alosa alosa Alosa alosa has a similar lifecycle to that of the twait shad A fallax They are known to live in sympatry 5 and the two species can hybridize 6 They are anadromous species like many other species in the genus Alosa 6 However some record of them being landlocked suggests an ability to adapt well to their environment 6 They primarily live at sea on feeding grounds and migrate to their spawning grounds between April and June once they are sexually mature 6 Maturity usually ranges from 3 7 years of age 6 A alosa can usually only reproduce once in their lifetimes 6 Juveniles appear in estuaries and brackish water around July to August 5 The salinity of brackish water may pose problems to the juveniles migrating from fresh water 5 Population reduction editPopulations have been reduced primarily by overfishing pollution and habitat destruction 6 The estuarine phase or the time that they are in the estuaries migrating from spawning grounds to sea is estimated to have a duration in A alosa of up to six months 5 The estimate however does not take into account individual variation and or survival of juveniles in the estuarine phase 5 Conservation editFour special areas of conservation have been designated in Ireland where Alosa species have been known to spawn 6 Alosa alosa has been placed in Appendix III of the Bern Convention 1979 that lists protected fauna species as well as in Appendix II and V of the European Community Habitats Directive 1992 that list respectively species whose conservation requires the designation of special areas of conservation and that are subject to management measures 5 However A alosa is currently under a moratorium 2008 in numerous French watersheds 5 References edit a b Freyhof J Kottelat M 2008 Alosa alosa IUCN Red List of Threatened Species 2008 e T903A13091343 doi 10 2305 IUCN UK 2008 RLTS T903A13091343 en Retrieved 15 November 2021 a b c Froese Rainer Pauly Daniel eds 2015 Alosa alosa in FishBase April 2015 version Freyhof J Kottelat M 2008 Alosa alosa IUCN Red List of Threatened Species 2008 e T903A13091343 doi 10 2305 IUCN UK 2008 RLTS T903A13091343 en Retrieved 18 November 2021 Allis shad Alosa alosa NatureGate Retrieved 14 December 2013 a b c d e f g Lochet A S Boutry and E Rochard Estuarine Phase during Seaward Migration for Allis Shad Alosa Alosa and Twaite Shad Alosa Fallax Future Spawners Ecology of Freshwater Fish 18 2009 323 35 a b c d e f g h Coscia I V Rountree J J King W K Roche and S Mariani A Highly Permeable Species Boundary between Two Anadromous Fishes Journal of Fish Biology doi 10 1111 j 1095 8649 2010 02768 x 77 5 2010 1137 149 External links edit nbsp Data related to Alosa alosa at Wikispecies EU LIFE Project The re introduction of allis shad Alosa alosa in the Rhine system Allice New International Encyclopedia 1905 nbsp Wikimedia Commons has media related to Alosa alosa Retrieved from https en wikipedia org w index php title Allis shad amp oldid 1222426649, wikipedia, wiki, book, 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