Diagnostic Description
provided by Fishbase
Diagnosis: Body somewhat compressed, fairly deep with depth at pectoral fin more than head length, scutes apparent along belly (Ref. 188, 51442). Upper jaw with a distinct median notch, lower jaw fitting into it; no teeth on palatine and vomer; gillrakers long, thin and numerous, a total of 85 to 155 on first arch, longer than gill filaments (Ref. 188, 6683, 59043). A dark spot posterior to gill opening, but sometimes absent, sometimes followed by several small blotches (Ref. 188, 59043). Alosa alosa resembles Alosa fallax, which has fewer and shorter gillrakers and 7 or 8 black spots along flank (Ref. 188).Description: Body fusiform and laterally compressed (Ref. 122971). Head large, high, and laterally compressed; a median notch on the upper jaw (Ref. 122971). Gillrakers long, thin and numerous, a total of 85 to 155 on first arch; distinctly longer than branchial filaments in specimens longer than 250 mm standard length; 55-85 gillrakers on lower part of anterior arch (Ref. 188, 6683, 11601, 59043). Number of dorsal fin rays 18 to 21; number of anal fin rays 22 to 27; caudal fin is distinctly forked and homocercal (Ref. 11601, 122971). Large, thin scales; 60-90 well-developed, deciduous cycloid scales on a longitudinal line and 22-26 in a transverse series; scaling is irregular on the longitudinal line (Ref. 11601, 51442, 52923; 122971). A ventral keel of scutes is present (Ref. 51442, 122971).Colouration: Dark blue or blue-green back, becoming greenish brown or golden to the sides, sides and ventral side are silvery; a single dusky spot behind the gill opening, sometimes absent, and occasionally 1-6 more dusky spots behind it (Ref. 188, 52923, 59043, 88187, 122971).
- Recorder
- Crispina B. Binohlan
Life Cycle
provided by Fishbase
Adults in the sea begin to move towards the coast in February and congregate near or in estuaries (Ref. 10536). They ascend rivers in April and May when water temperature is 9-12 °C, peaking at 13-16 °C. Adults may migrate up to 700 km from the sea into major rivers and occasionally into the largest tributaries of these rivers to spawn (Ref. 10536). Males migrate upriver at 3-9 years; females first reproduce 1-3 years later than males. Gametogenesis occurs during spawning migration. Males arrive first in the upper reaches and occupy appropriate spawning sites, with females arriving 1-2 weeks later (Ref. 10536). Spawning sites are usually shallow areas (
Migration
provided by Fishbase
Anadromous. Fish that ascend rivers to spawn, as salmon and hilsa do. Sub-division of diadromous. Migrations should be cyclical and predictable and cover more than 100 km.
- Recorder
- Crispina B. Binohlan
Morphology
provided by Fishbase
Dorsal spines (total): 0; Dorsal soft rays (total): 18 - 21; Analspines: 0; Analsoft rays: 20 - 27; Vertebrae: 57 - 58
- Recorder
- Crispina B. Binohlan
Trophic Strategy
provided by Fishbase
In brackish water near estuaries adults prey mainly on planktonic crustaceans (Refs. 40, 89654) and may add small schooling fishes to their diet while at sea (Refs. 188, 10536). Juveniles in freshwater feed on insect larvae, planktonic crustaceans and rotifers (Refs. 10536, 35387) adding herring larvae and planktonic crustaceans to their diet when they move to brackish water near estuaries (Refs. 40, 89654). Feeding appears to cease during migration into rivers (Refs. 10536, 30578).
- Recorder
- Crispina B. Binohlan
Biology
provided by Fishbase
Amphihaline species, schooling and strongly migratory, penetrating far up rivers but not into small tributaries (Refs. 188, 59043). Adults are usually found in open waters along the coast (Ref. 51442). In freshwater, inhabits major rivers but may also enter tributaries, if water temperature is equal to or is warmer than the main river (Ref. 188, 10536). Known lake populations from Morocco and Portugal need access to rivers to spawn (Refs. 10536, 89647, 89648). Larvae and small juveniles inhabit deep slow-flowing areas of rivers (Ref. 89649), some swimming upstream in late summer and autumn (Ref. 10536). Juveniles (up to 1+ years) are usually found near estuaries or river mouths (Refs. 10536, 59043), possibly making vertical diurnal movements synchronized with the tides; they remain in estuaries for over one year (Ref. 89630). Feeds on a wide range of planktonic crustaceans; larger adults feed on small schooling fishes (Ref. 188, 51442, 59043). Juveniles in freshwater prey on insect larvae. Females in European rivers commonly reach 70 cm total length (Ref. 10536). Females grow faster and are always larger than males of the same age (Ref. 10536). Less common than Alosa fallax but both have suffered from pollution and weirs or other obstructions (Ref. 188). It has been suggested that members of the genus Alosa are hearing specialists with the American shad (Alosa sapidissima) having been found to detect and respond to sounds up to at least 180 kHz (Ref. 89631). This may aid in predator avoidance (e.g. cetaceans) (Ref. 89632). Hybridization with the twaite shad (Alosa fallax) has been reported from the Rhine (Ref. 89633) as well as from rivers in France and Algeria (Ref. 10536). Shad hybrids may reproduce (Ref. 27567). Marketed fresh and frozen; eaten sautéed, broiled, fried and baked (Ref. 9988).
- Recorder
- Crispina B. Binohlan
Importance
provided by Fishbase
fisheries: minor commercial; gamefish: yes; price category: low; price reliability: reliable: based on ex-vessel price for this species
- Recorder
- Crispina B. Binohlan
Allis shad
provided by wikipedia EN
The allis shad (Alosa alosa) is a widespread Northeast Atlantic species of fish in the herring family, Clupeidae. 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.
Description
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]
Distribution
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 lifecycle
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
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]
Conservation
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]
References
-
^ 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.
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^ 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.
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^ "Allis shad: Alosa alosa". NatureGate. Retrieved 14 December 2013.
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^ 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.
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^ 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.
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- Wikipedia authors and editors
Allis shad: Brief Summary
provided by wikipedia EN
Allis shad
The allis shad (Alosa alosa) is a widespread Northeast Atlantic species of fish in the herring family, Clupeidae. It is an anadromous fish which migrates into fresh water to spawn. 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.
- license
- cc-by-sa-3.0
- copyright
- Wikipedia authors and editors
Introduction
provided by World Register of Marine Species
This species has been introduced or released in Dutch waters.
2. Fish, J. D. & Fish, S. (1996)
A student's guide to the seashore. Second Edition. Cambridge University Press, Cambridge.
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- WoRMS Editorial Board
Allis shad 
