Opisthonema oglinum

Common Name

Atlantic Thread Herring

Year Described

Lesueur, 1818

Identification

Dorsal Fin: 17-21
Anal Fin: 20-25
Pectoral Fin: 15-17
Pelvic Fin: 7 branched
Vertebrae: 45-48
Lateral Line Scales: 43-50
Ventral Scutes: 32-36
Gill Rakers: 28-46 (first arch)

Body elongate, compressed and quite deep bodied. Head moderate. Mouth small, barely extending to orbit. Upper jaw not notched. Hypomaxilla absent. Teeth absent. Rear of gill cover with two fleshy lobes. Gill rakers numerous.
Dorsal fin centered at midbody with a concave margin. Dorsal fin with prominent filament on last ray (compare Dorosoma as only other genus in area with this). Anal fin small with origin well behind last dorsal ray. Pelvic fin under dorsal fin, with a straight posterior margin. Pectoral fin inserted low on body. Tail forked. Body fully scaled. Keeled ventral scutes present.

Color

Body silvery with a blue-gray back. A dark blotch behind upper gill cover is faint or prominent. Longitudinal lines follow scale rows on dorsum. Additional spots rarely present on upper side. Dorsal fin dusky. Caudal fin dusky with prominent dark tips on each lobe. Rest of fins clear.

Size

Maximum size 38cm SL, but common >20cm SL.

Habitat

Inshore coastal pelagic in full seawater. Forms large schools.

Range

Gulf of Maine to southern Brazil, including the Gulf of Mexico and Caribbean Sea. Also Bermuda.

References

McEachran, J.D. & J.D. Fechhelm. 1998. Fishes of the Gulf of Mexico. Volume 1: Myxiniformes to Gasterosteiformes. University of Texas Press, Austin. i-viii + 1-1112.

Munroe, T.A. & M.S. Nizinski. 2002. Clupeidaeidae (pp 804-830). In: Carpenter. 2002. The living marine resources of the Western Central Atlantic. Vol. 2: Bony fishes part 1 (Acipenseridae-Grammatidae). FAO Species Identification Guides for Fisheries Purposes. American Society of Ichthyologists and Herpetologists Special Publication No. 5.