Latin name

Hemigaleus microstoma

Other name

Hemigaleus microstoma

Identification

The sicklefin weasel shark has a slender body and a rounded, rather elongated snout. The large oval eyes are horizontally elongated and have flashing membranes. There are tiny spiracles behind the eyes. The gill slits are 0.8-1.3 times the length of the eye. The short mouth is curved into a wide arch. The length of the mouth is 31-43% of its width. The lower jaw is rounded at the symphysis. The corners of the mouth are furrowed. There are no serrations on the edges of the teeth. 

Features of fish fins

Dorsal spines (total): 0; Anal spines: 0. 

The fins are sickle-shaped. The first dorsal fin is rather large, with its base between the bases of the pectoral and ventral fins. The height of the second dorsal fin is 3/5 that of the first. Its base is above the base of the anal fin. The anal fin is considerably smaller than either dorsal fin. There is a ventral notch at the top of the caudal fin. The caudal fin is almost horizontal. 

Fish colouring

The colouration of the Sicklefin Weasel Shark is light grey to bronze. Sometimes there is a dark or pale edge to the fins and white spots on the sides.

Distribution

Found in the Indian Ocean and the northwestern and central western Pacific off the coasts of India, Sri Lanka, Thailand, China, Taiwan, Malaysia, Philippines, Indonesia and possibly the Red Sea. 

Habitat

Tropical marine bottom dweller. It inhabits water depths of 170m or more. In Australian waters, these sharks are harvested at depths of 12 to 167 m, where bottom water temperatures range from 22°C to 27.6°C.

Size

The maximum recorded size of this species is 110 cm. 

Behavior

A small, relatively common coastal and offshore shark found on continental and island shelves.

Food and feeding habits

It feeds mainly on cephalopods, octopus, and crustaceans.

Reproduction

Sicklefin sharks reproduce by placental birth. The embryo also feeds on the yolk. The length of fully developed embryos with the umbilical cord cut is 23.7-25.6 cm. Newborn babies are about 47 cm long. There are 2 to 4 newborns per litter. Males and females reach sexual maturity at 75 and 75-78 cm respectively. Females probably breed twice a year, with gestation lasting about 6 months. 

Fishing

These sharks are caught by artisanal fishermen using bottom-set gillnets and longlines. The International Union for Conservation of Nature has listed this species as Vulnerable.

Relationship with a person

The species is not dangerous to humans. The meat is eaten as food and the waste is used to make fishmeal. The fins are not highly valued due to their small size.