Elongate Silver Biddy

Scales between 5th dorsal fin spine base and lateral line, 4-4.5. Upper jaw extending almost to the level of anterior margin of dermal eye opening. Second dorsal fin spine longest, 19-26% of SL (mean 23%). Caudal fin dusky (rarely with dark distal margin); lower edge of lower caudal fin hyaline. Dusky stripes absent or very indistinct along scale rows above lateral line (sometimes 4-9 slightly oblique dusky bands in specimens less than about 10 cm SL); 4-9 slightly oblique dusky bands or columns of ovoid dark spots (rarely brownish) immediately below lateral line, but more obvious in preserved or stressed live specimens (Ref. 41108). Adult body plain silver; may have faint dusky bars especially juveniles. Body elongate, depth max 2.8-3.3 in SL. Preopercle lower flange scaleless. Caudal fin forked deeply and with long lobes; pectoral fins do not reach beyond level of anus. (Ref. 90102)

Dorsal spines (total): 9; Dorsal soft rays (total): 10; Analspines: 3; Analsoft rays: 7

Occurs inshore (Ref. 75154). Prefers coralline areas (Ref. 30573); forms schools (Ref. 12915, 75154). Migrates to specific sandy areas near outer reef edge to spawn in late afternoons during full moon. Feeds on small benthic organisms living on sandy bottoms (Ref. 3409, 12915).

Prefers coralline areas (Ref. 30573). Migrates to specific sandy areas near outer reef edge to spawn in late afternoons during full moon. Feeds on small benthic organisms living on sandy bottoms (Ref. 3409, 48635). In Palau, migrates to specific sandy spots near the outer reef edge to spawn in late afternoons around full moon (Ref. 37816). Forms schools. Feeds on small invertebrates found in the sand. Marketed fresh (Ref. 12915).

fisheries: commercial

分布於印度-西太平洋區，西起紅海、非洲東岸，西至所羅門群島，北達琉球群島，南迄新加勒多尼亞。台灣南部、西部、北部沿海及澎湖海域均見。

一般以底拖網或流刺綱採獲，魚體小者，常作下雜魚處理，供養殖飼料之用，體型大者市場偶可見到。可生鮮或醃漬處理，適宜煎、炸食用。

體細而側扁，標準體長約為體高的3.1-3.4倍，體背於背鰭起點處略為彎曲，與水平方向軸約呈30度角。口小唇薄，能伸縮自如，伸出時向下垂。眼大，吻尖。上下頜齒細長，呈絨毛狀；鋤骨、腭骨及舌面皆無齒。體被薄圓鱗，易脫落；背鰭及臀鰭基底具鱗鞘；側線完全，呈弧狀，至尾鰭基底之側線鱗數44-45，尾鰭基底之有孔鱗4或5；側線上鱗列數4.5-5.5(側線至背鰭第V棘間，且不含側線鱗)。背鰭單一，硬棘部IX，第II棘最長而略呈絲狀，略長於或等於頭長；臀鰭第II棘細尖狀，臀鰭基底長約為其2倍長；胸鰭長，幼魚時，末端達及肛門後緣，隨著成長，末端可達臀鰭第I棘的上方；尾鰭深叉形，最長鰭條長約與胸鰭等長。體色呈銀白色，體背淡褐色；背鰭具黑緣；各鰭淡色。

棲息在沿岸沙泥地，生殖季時可發現於珊瑚礁區周圍之沙地，以沙泥地中的無脊椎動物為食。

The slender silver-biddy (Gerres oblongus) is a species of mojarra native to marine and brackish waters of coastal waters of the Indian Ocean and the western Pacific Ocean, far towards Vanuatu. It inhabits estuaries, coastal waters and lagoons. They inhabit at depths from 0 to 10 m (0 to 33 ft). This species can reach a length of 30 cm (12 in), with the average of 15 cm (5.9 in). This species is important to local commercial fisheries in many tropical countries.

Migrates to specific sandy areas near outer reef edge to spawn in late afternoons to spawn during full moon. Feeds on small benthic organisms living on sandy bottoms (Ref. 3409).