Description:

Dorsal spines: 0; Dorsal rays: 24-27; Anal spines: 0; Anal rays: 22-24.
Body elongate, rounded in cross-section. Upper and lower jaws greatly elongate and lined with small sharp teeth. Anterior part of dorsal fin with a low lobe. Pectoral and 
pelvic fins relatively short. A distinct black lateral keel on caudal peduncle. Caudal fin deeply forked, lower lobe much longer than upper. Juveniles have an elevated 
black lobe in the posterior part of the dorsal fin.
Colour: dark bluish dorsally to silvery white ventrally.
 

Maturity: Lm 56.8cm EFL (Eye-Fork Length) females, 53.3cm EFL males. Range unknown. Max Length: 100cm TL. Commonly to 50cm TL.

Found in offshore and coastal waters (typically more offshore than T. crocodilus) depth 0-1m. Feeds mainly on small fishes. Oviparous.

This species is not protected or subject to fishery regulations. It is caught by trolling and also with nets. It is an uncommon component of the catch.

Collette, B.B. (1984). Belonidae. In W. Fischer and G. Bianchi (eds.) FAO species identification sheets for fishery purposes. Western Indian Ocean (Fishing Area 51), 
Volume 1. FAO, Rome.
Froese, R. & D. Pauly. Eds. (2019). FishBase. https://www.fishbase.se/summary/1317 (14/06/19).
Liao, Y-Y. & Chang Y-H. (2011). Reproductive Biology of the Needlefish Tylosurus acus melanotus in Waters around Hsiao-Liu-Chiu Island, Southwestern Taiwan. 
Zoological Studies 50(3): 296-308 (2011).

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Nevill, J.E.G. (2019). Tylosurus acus melanotus, Keel-jawed needle fish. Seychelles Seatizens. www.seatizens.sc. https://seatizens.sc/species/tylosurus-acus-melanotus-bleeker-1850/  (edited 19/06/22).