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Acipenser medirostris:   (click for more)

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  • Acipenser (Antaceus) agassizi  Duméril, 1867: 181, Pl.11 (figs. 2, 2a-b).
  • Acipenser (Antaceus) alexandri  Duméril, 1867: 183, Pl.15 (figs.1, 1a-b).
  • Acipenser (Antaceus) oligopeltis  Duméril, 1867: 184, Pl. 15 (figs.2, 2a-b).
    FAO Names
    En - Green sturgeon, Fr - Esturgeon vert, Sp - Esturión verde.
    3Alpha Code: AAM     Taxonomic Code: 1170100115
    Scientific Name with Original Description
    Acipenser medirostris  Ayres, 1854The Pacific vol. 4, nº 1: 2. Near San Francisco, California, USA.
    Diagnostic Features
    Snout in adults blunt and rounded but sharp, longer than postorbital length, and concave on top in young.  Spiracle present. Snout and caudal peduncle subconical. Gill membranes joined to isthmus. Mouth transverse. 4 barbels nearer to mouth than to tip of snout.  18-20 gill rakers, scarcely longer than broad, on the first gill arch.  D: 29-41, A: 18-28 rays. Anal fin longer than dorsal fin. Tip of anal reaching or passing base of lower lobe of caudal fin.  8-12, large, hooked, dorsal scutes. 25-30, not touching, lateral scutes. 7-11 ventral scutes. 1 plate between dorsal fin and caudal fulcrum. 1 plate between anal fin and caudal fulcrum. 3 plates in single row between anus and anal fin.  Head and body at all sizes definite dark green to olive green colour. Lower surfaces paler to whitish green. Lateral scutes paler than body. In life, a longitudinal stripe, olive-green, between lateral and ventral scutes. Fins dusky grey to pale. Viscera pale. 
    Geographical Distribution

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    Pacific coasts of North America from Aleutian Islands and the Gulf of Alaska to Ensenada, Mexico. Usually about the mouths and in the lower reaches of large rivers (Scott & Crossman, 1990).
    Habitat and Biology
    It is always reported as rare in freshwater, preferring the mouths of large rivers where it is seen in August and September.Consists mostly of amphipods and mysid shrimps and bony fish (Ammodytes hexapterus).
    The green sturgeons may cover considerable distances in the ocean (Morrow, 1980). Its capture in nets set for salmon in the late summer and early fall in lower Fraser River would indicate that it is anadromous and moves into fresh water through the fall and winter to spawn in the spring. Spawning has been reported at 1.5 km above Orleans on the Klamath River (Moyle, 1976) and in the upper inland streams of large rivers such as the Sacramento and Klamath rivers (Fry, 1973). Juveniles were collected in San Francisco Bay up to the lower reaches of the Sacramento-San Joaquin rivers and the Delta. The smallest of the fish identified as green sturgeon were 20-22 cm FL and were captured by gillnets and trawls by Radtke (1966). The origin of those juveniles was probably the upper Sacramento River (Fry, 1973). 
    Maximum size: 213 cm TL.
    Interest to Fisheries
    Their flesh has been said to be edible, but dark, with a strong disagreeable taste, and an unpleasant odour (Scott & Crossman, 1990).
    Local Names
    CANADA : Green sturgeon ,  Esturgeon vert .
    FINLAND : Vihersampi .
    FRANCE : Esturgeon vert .
    GERMANY : Grüner Stör .
    MEXICO : EsturiÓn verde .
    POLAND : Jesiotr sachalinski .
    PORTUGAL : Esturjão-verde .
    RUSSIAN FED. : Sterlyad .
    SPAIN : Esturión verde .
    UNITED KINGDOM : Green sturgeon .
    USA : Green sturgeon .
    See Acipenser mikadoi fact sheet.
    Birstein, V.J. - 1993. Sturgeons and paddlefishes: threatened fishes in need of conservation. Conserv. Biol. .  7:773-787..
    Clemens, W.A. & G.V. Wilby. - 1961. Fishes of the Pacific coast of Canada. Fish. Res. Bd. Canada Bull. 2nd ed. .  (68):443 .p.
    Eschmeyer, W.N., E.S. Herald & H. Hammann. - 1983. A field guide to Pacific coast fishes of North America. Houghton Mifflin Company, Boston, U.S.A. .  336 .p.
    Escobar-Fernández, R. & M. Siri. - 1997. Nombres vernáculos y científicos de los peces del Pacífico mexicano. Universidad Autónoma de Baja California, Sociedad Ictiológica Mexicana, A.C. Mexico. . 
    Fry, D. H., Jr. - 1973. Anadromous fishes of California. California Department of Fish and Game. .  111 .pp.
    Hart, J. L. - 1973. Pacific fishes of Canada. Bull. Fish. Res. Board Can. .  180. 740 .pp.
    Miller D. J. & R. N. Lea. - 1972. Guide to the coastal marine fishes of California. California., Department of Fish and Game Bulletin 157. .  249 .pp. (1976).
    Morrow, J.E. - 1980. The freshwater fishes of Alaska. University of. B.C. Animal Resources Ecology Library. .  248.p.
    Moyle, P. B. - 1976. Inland fishes of California. University of California Press, Berkeley. .  405 .pp.
    Page, L.M. & B.M. Burr. - 1991. A field guide to freshwater fishes of North America north of Mexico. Houghton Mifflin Company, Boston. .  432 .p.
    Radtke, L. D. - 1966. Distribution of smelt, juvenile sturgeon, and starry flounder in the Sacramento-San Joaquin Delta with observations on food of sturgeon. In J. L. Turner and D. W. Kelly (comp.) Ecological studies of the Sacramento-San Joaquin Delta. Part II Fishes of the Delta. .  p. 115-129..
    Scott, W. B. & E. J. Crossman. - 1990. Freshwater fishes of Canada. Bull. Fish. Res. Board Can. 184. .  966 .pp.
    Wilimovsky, N.J. - 1964. Inshore fish fauna of the Aleutian archipelago. Proc. Alaska Sci. Conf. .  14: 172-190..
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