Marine Species Identification Portal : Japanese topeshark

Author: (Müller and Henle, 1839)

Field Marks:
A houndshark with a moderately long parabolic snout, broadly arched mouth, eyesnarrow, slitlike and dorso lateral,subocular ridges prominent, external nictitating lower eyelids present, nostrils with short, truncatedanterior nasal flaps, internarialspace over 2.5 times the nostrilwidth, compressed teeth withoblique cusps and distal cusplets inboth jaws, first dorsal somewhat longer than second but much shorter than caudal, first dorsal origin usually behind pectoral reartips (except in newborn individuals), anal fin much smaller than first dorsal, fins with conspicuous white edges.

Diagnostic Features:
Eyes slitlike and narrowly elongated. Fins moderately falcate; first dorsal origin about over or posterior to free rear tips of pectoral; distance from pectoral free rear tips to pelvic origins greater than first dorsal length from origin to free rear tip. Total vertebral counts 154 to 165, monospondylous precaudal counts 39 to 43.

Geographical Distribution:
Western Pacific: China, including Taiwan Island, the Koreas and Japan, and with some doubt from Amboina (Indonesia) and New Caledonia.

Habitat and Biology:
A common continental temperate to subtropical shark in the western North Pacific, occurring close inshore and offshore down to at least 100 m depth.

Ovoviviparous, without a yolk-sac placenta. Number of young per litter 8 to 22 (mean 10), with about equal numbers per uterus and with the number increasing with size of female. In aggregates the sex ratio of embryos is 1:1, but individuals may have more of one sex than the other inleft and right uteri and between one another. In the East China Sea mating takes place from June to September (mostly June to August) and birth season from June to August (mainly in June), with a gestation period of 10 months.

Presumably eats small fishes, cephalopods and crustaceans.

Size:
Maximum size about 120 cm, males maturing at about 85 cm and reaching 110 cm, females maturing between 81 and 102 cm and reaching at least 120 cm; size at birth about 20 to 21 cm.

Interest to Fisheries:
A common catch in Japanese, Korean, Taiwanese and probably Chinese. waters. Caught with gillnets, bottom longlines, bottom trawls and set nets; meat used for human consumption.

Type material:
Holotype: In Rijksmuseum van Natuurlijke Historie, Leiden? Type Locality: Japan.

Status in World Register of Marine Species

Accepted name: Hemitriakis japanica (M�ller & Henle, 1839)

Scientific synonyms and common names

Hemitriakis japanica (Müller and Henle, 1839)

Galeus japanicus Müller and Henle, 1839, Syst.Beschr.Plagiost., pt. 2:58, pl. 22.

Synonymy: None.

FAO Names:
Japanese topeshark [English]
Requin-hâ dochizame [French]
Cazón japonés [Spanish]
TRIAK Hem 1 [FAO Code]

Japanese topeshark (Hemitriakis japanica)