Gerres oyena (Fabricius, 1775)
Common silver-biddy
Gerres oyena
photo by Ryanskiy, A.

Family:  Gerreidae (Mojarras)
Max. size:  30 cm TL (male/unsexed)
Environment:  reef-associated; brackish; marine; depth range 0 - 20 m
Distribution:  Indo-Pacific: Red Sea to South Africa, east to Marshall and Samoa islands; north to the Ryukyus and south to the Queensland, Australia (Great Barrier Reef) and New Caledonia.
Diagnosis:  Dorsal spines (total): 9-9; Dorsal soft rays (total): 10-10; Anal spines: 3-3; Anal soft rays: 7-7. Body silvery with 6-8 irregular, faint dusky oblique and vertical bands dorsolaterally and ventrolaterally (usually more apparent in young stressed or preserved specimens. U-shaped premaxilla groove mostly without scales (tiny scales anteriorly in specimens over 13 cm SL). Posterior margin of maxillary beyond a vertical through anterior margin of pupil. Supraneural bones 3. Spinous dorsal fin with an indistinct dusky patch (2nd-6th spines) and very narrow dusky distal margins on upper membranes between spines. Scales between 5th dorsal fin spine and lateral line 3-4, usually 3.5. Pelvic fin when fresh is semi-transparent or dull yellow color with an indistinct dusky band and dull white distal margin posteriorly (Ref. 35850); pectoral fins reaches beyond level of anus; caudal fin forked deeply and with long lobes (Ref. 90102).
Biology:  Found along the coast, saltwater lagoons, and estuaries (Ref. 5213). Also in sand bottoms in sheltered waters near reefs (Ref. 90102). Occurs singly or in groups (Ref. 9710). Feeds on small organisms living on sandy bottoms. Utilized as fish meal and duck food. Sold fresh in markets.
IUCN Red List Status: Least Concern (LC); Date assessed: 02 March 2015 Ref. (130435)
Threat to humans:  harmless


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