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Alosa

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Alosa
Temporal range:55–0Ma
Eoceneto present[1]
Twaite shad,Alosa fallax
Scientific classificationEdit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Clupeiformes
Family: Alosidae
Genus: Alosa
H. F. Linck,1790
Species

See text.

Synonyms

Caspialosa
Pomolobus

Alosa[2]is a genus offish,theriver herrings,in thefamilyAlosidae.Along with other genera in the subfamilyAlosinae,they are generally known asshads.[3][4]They are distinct from other herrings by having a deeper body and spawning in rivers. Several species can be found on both sides of theAtlantic Oceanand theMediterranean Sea.Also, several taxa occur in the brackish-waterCaspian Seaand theBlack Seabasin.[5]Many are found in fresh water during spawning and some are only found in landlocked fresh water.

Fossil record[edit]

These fishes lived from theEocenetoQuaternary(from 55 million years ago to now). Fossils have been found in Canada, the United States, Greece, Kazakhstan, Azerbaijan, Hungary, Romania, and Italy.[6]

Fossil ofAlosa elongata

Appearance[edit]

Alosaspecies are generally dark on the back and top of the head, with blue, violet, or greenish tints.[5]Some can be identified as having a grey or green back.[5]Spots are commonly found behind the head, and the fins may vary from species to species or individually.[5]Most species ofAlosaweigh 300 g (11 oz) or less, withA. ponticaandA. fallaxweighing up to 2 kg, andA. alosacan exceed 3–4 kg.[5]

Biology[edit]

Shads are thought to be unique among the fishes in having evolved an ability to detectultrasound(at frequencies above 20 kHz, which is the limit of human hearing).[7]This was first discovered by fisheries biologists studying a type of shad known asblueback herring,and was later verified in laboratory studies of hearing in American shad. This ability is thought to help them avoiddolphinsthat find prey using echolocation.Alosaspecies are generallypelagic.[8]They are mostlyanadromousor semianadromous with the exception of strictly freshwater landlocked species.[8]Alosaspecies are generally migratory and schooling fish.[8]Males usually mature about a year before females; they spawn in the late spring to summer.[9][10]Most individuals die shortly after spawning.[9][10]Alosaspecies seemingly can change readily to adapt to their environments, as species are found in a wide range of temperatures and waters.[10]

Lifecycle and reproduction[edit]

AsAlosaspecies are generally anadromous, they face various obstacles to survival.[11]They may have to pass through numerous barriers and waters to get to either their spawning grounds or normal habitats (the sea in most cases).[11]Estuaries are a major factor in numerousAlosaspecies' migrations.[11]Estuaries can be highly variable and complex environments contributing to fluctuating biological interactions,[11]with shifts in osmolarity, food sources, predators, etc.[11]Since many adultAlosaspecies die after spawning, only the young generally migrate to the sea from the spawning grounds.[11]Duration of migration varies among fish, but can greatly affect survival.[11]

Reproduction varies by species.[5]Studies done onAlosain Iranian waters have shown that spawning varies in time, place, and temperature of the waters they inhabit.[5]Fecundity may also vary.[5]Species are known to spawn as early as April or as late as August.[5]Temperatures range from about 11 to 27 °C.[5]Fecundity can range from 20,000 to 312,000 eggs.[5]Eggs are pelagic.[5]Geography and temperature are important environmental factors in egg and young-of-year development.[12]

The lifespan ofAlosaspecies can be up to 10 years, but this is generally uncommon, as many die after spawning.[5]

Systematics[edit]

This article is part of a series on
Commercial fish
Large pelagic
Forage
Demersal
Mixed

The systematics and distribution ofAlosashads are complex. The genus inhabits a wide range ofhabitats,and manytaxaaremigratory.A few forms are landlocked, including one fromKillarneyinIreland,two from lakes in northern Italy, and two inGreece.Several species are native to the Black and Caspian Seas.Alosaspecies of the Caspian are systemically characterized by the number ofrakers on the first gill arch.[13]They are classified as being "multirakered", "medium-rakered", or "oligorakered".[13]The multirakered are primarily plankton feeders, the oligorakered have large rakers and are predators, and the medium-rakered generally consume a mixed diet.[13]Most current species of the genusAlosain North America can be found in Florida, whereas the distribution of most of them is broader.[14]

Morphologyis notoriously liable toadaptto changing food availability in these fish. Several taxa seem to haveevolvedquite recently, making molecular analyses difficult. In addition,hybridizationmay be a factor in shadphylogeny.[15]Nonetheless, some trends are emerging. The North American species except theAmerican shadA. sapidissimacan probably be separated in asubgenusPomolobus.Conversely, the proposed genus (or subgenus)Caspialosafor theCaspian Seaforms is rejected due toparaphyly.[15]

Species by geographical origin[edit]

North America[edit]

Western Europe and the Mediterranean[edit]

Caspian Sea, Black Sea, the Balkans[edit]

Recreational fishing[edit]

Main article:Shad fishing

Commercial fishing[edit]

Commercialcapture production ofwildshad in tonnes.[16][17]
1999 2000 2001 2002 2003 2004 2005 2008 2010 2011 2012 2013 2014
788,770 860,346 665,284 589,692 524,800 569,160 605,548 588,978 645,977 611,371 604,842 628,622 636,678

Management[edit]

Shad populations have been in decline for years due to spawning areas blocked by dams, habitat destruction, pollution, andoverfishing.Management of shad has called for more conservative regulations, and policies to help the species have lower fishing mortality.[18]

Political significance[edit]

Shad serve a peculiar symbolic role inVirginiastate politics. On the year of every gubernatorial election, would-be candidates, lobbyists, campaign workers, and reporters gather in the town ofWakefield, Virginia,forshad planking.American shad served as the focal point ofJohn McPhee's bookThe Founding Fish.[19]

Culinary use[edit]

Shad roe

Theroe,or more properly the entire engorged uterus of theAmerican shad—filled with ripening eggs, sautéed in clarified butter and garnished with parsley and a slice of lemon—is considered a great delicacy, and commands high prices when available.[20]

See also[edit]

References[edit]

  1. ^Sepkoski, Jack (2002)."A compendium of fossil marine animal genera".Bulletins of American Paleontology.364:560. Archived fromthe originalon 2011-07-23.Retrieved2007-12-31.
  2. ^AlosaLinck, 1790ITIS
  3. ^AlosinaeITIS
  4. ^Subfamily Alosinae[permanent dead link]FAO Fisheries Bulletin
  5. ^abcdefghijklmCoad, Brian (1997)."Shad in Iranian Waters"(PDF).Shad Journal.2(4): 4–7.ISSN1094-4990.Archived fromthe original(PDF)on 2013-09-10.Retrieved31 January2014.
  6. ^Paleobiology Database
  7. ^Mann, D. A.; Higgs, D. M.; Tavolga, W. N.; Souza, M. J.; and Popper, A. N. (2001). Ultrasound detection by clupeiform fishes.Journal of the Acoustical Society of America109:3048–3054
  8. ^abcD. C. Bobori, E. T. Koutrakis and P. S. Economidis (2001)."Shad Species In Greek Waters – An Historical Overview And Present Status".Bulletin Français de la Pêche et de la Pisciculture.362–363 (362–363): 1101–1108.doi:10.1051/kmae:2001039.
  9. ^abIngram, Travis, R. (2007).Age, growth and fecundity of Alabama shad (Alosa alabamae) in the Apalachicola River, Florida(M.Sc.). Clemson University.Retrieved31 January2014.{{cite thesis}}:CS1 maint: multiple names: authors list (link)
  10. ^abcBianco, P. G. (2002)."The Status of the Twaite Shad, Alosa agone, in Italy and the Western Balkans".Marine Ecology.23, Supplement 1: 51–64.Bibcode:2002MarEc..23S..51B.doi:10.1111/j.1439-0485.2002.tb00007.x.
  11. ^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.
  12. ^Alexander, Samantha B.; Schlick, CJ Carroll; de Mutsert, Kim (October 2020)."Growth models and growing degree-days: assessment of young-of-year Alewife and Blueback Herring in Potomac River tributaries".Environmental Biology of Fishes.103(10): 1179–1195.Bibcode:2020EnvBF.103.1179A.doi:10.1007/s10641-020-01012-4.ISSN0378-1909.S2CID220948739.
  13. ^abcMalkin, E. M., and S. B. Andrianova.Biology and Traits of the Formation of Stock of Big-eyed Shad Alosa Saposchnikowii.Journal of Ichthyology 48.6 (2008): 443-51.
  14. ^Richard S. McBride (2000).Florida's Shad and River Herrings (Alosaspecies): A Review of Population and Fishery Characteristics.Florida MAR8INE Research Institute Technical Reports: Technical Report TR-5, Florida Fish and Wildlife Conservation Commission. St. Petersburg, Florida.
  15. ^abFaria, R.; Weiss, S.; and Alexandrino, P. (2006).A molecular phylogenetic perspective on the evolutionary history ofAlosaspp. (Clupeidae).Molecular Phylogenetics and Evolution40(1): 298–304.doi:10.1016/j.ympev.2006.02.008(HTML abstract).
  16. ^FAO(2006)Yearbooks of Fishery Statistics Summary Tables[permanent dead link]
  17. ^FAO(2014)Yearbook - Fishery and Aquaculture Statistics,no. 24.
  18. ^"Atlantic States Marine Fisheries Commission: Shad".Archived fromthe originalon 2013-04-14.Retrieved2009-06-30.
  19. ^"American Shad - Fish Reference Library - RedOrbit." RedOrbit - Science, Space, Technology, Health News and Information. 3 Apr. 2007. Web. 27 Nov. 2011. <http://www.redorbit.com/education/reference_library/science_1/fish/2579052/american_shad/index.html>.
  20. ^singlegirldin (2012-02-29)."The Beauty of Shad Roe".Honest Cooking.Retrieved2022-07-25.

External links[edit]

Wikispecieshas information related toAlosa.
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