Starspotted Smoothhound Shark.
Body slender. Snout fairly long and pointed. Upper and lower labial furrows similar in length. Small, visible spiracle behind eye. First dorsal fin origin midway between pectoral fin insertion and free rear tip. Second dorsal fin much larger than anal fin. Dorsal fin posterior margins un-frayed. Lower caudal lobe indistinct. Dorsal coloration greyish-brown with bronzy hues. Dorsal surface above lateral line lightly sprinkled with small white spots. A row of tightly spaced small white spots run along the lateral line from level with the first gill opening almost to the tip of the tail. A very short row of small white spots runs posteriorly from the eye, through the spiracle, diagonally downward to the cheek. Fins unmarked.
Maximum length 135cm. Size at birth approximately 30cm.
A temperate/tropical species inhabiting muddy or sandy substrates on the continental shelf from 1-360m.
The starspotted smoothhound shark is found in the northwestern Pacific from China, Japan; Korea, Russia, Taiwan, and Viet Nam. It has also been reported from Kenya but any records from East Africa are almost certainly a different species; probably the whitespot smoothhound (Mustelus palumbes).
Mustelus manazo is a utilised catch of demersal trawl and longline fisheries. Although reported as generally abundant where it occurs, significant declines are reported to have occurred in Taiwanese waters in the past 10-20 years to the point of almost complete disappearance (with the exception of islands off northern Taiwan, Province of China). It was once commercially fished in this area, but is now very difficult to find throughout most of its range off Taiwan. The catch has also reportedly decreased in the western waters of Kyushu, Japan. No information on population trends is currently available from the rest of its range and this is required. M. manazo is currently assessed as Data Deficient globally until further information on population trends and capture in fisheries throughout its range can be collected. There is concern that it may qualify for a threat category in the future and reassessment should be a priority.
Citations and References
Tanaka, S. & participants of the IUCN SSG Asia Northwest Pacific Workshop. 2009. Mustelus manazo. The IUCN Red List of Threatened Species 2009: e.T161633A5469162. https://dx.doi.org/10.2305/IUCN.UK.2009-2.RLTS.T161633A5469162.en. Downloaded on 03 November 2020.
A viviparous species with yolk-sac placenta. 1-22 pups per litter. Gestation is approximately 10-12 months. Reproductive parameters appear to vary geographically, with northern populations growing to a larger size and living for a longer period (Yamaguchi et al. 1998, 2000).
Predates heavily on crustaceans.
Reaction to divers
Very shy due to its small size. Unlikely to approach unless baited.
Rarely seen by divers in most of its range. It may be possible to encounter starspotted smoothhound sharks off the south coast of Honshu where they are often caught by fishermen in the vicinity of Chiba and probably elsewhere along the coast.