Japanese spurdog
Template:Short description Template:Speciesbox Script error: No such module "Portal". The Japanese spurdog (Squalus japonicus) is a dogfish, a member of the family Squalidae. It is found in the western Pacific Ocean – southeastern Japan and the East China Sea,[1] including the Republic of Korea, the Philippines, and the Arafura Sea.[2] It occurs in temperate and tropical waters along the continental shelf and slopes[3] and primarily feeds on teleost fish and squid.[1] It is caught as bycatch in commercial fishing, which has caused populations to decline.[4]
Description
Males measure 50 to 70 cm (19.7 to 27.6 in) long in adulthood, while females measure 56 to 80 cm (22 to 31.5 in) long.[4] Females are also higher in weight than males.[1] They have 25 to 27 teeth on their upper jaw and 20 to 24 teeth on their lower jaw.[3]
Distribution and habitat
The Japanese spurdog is found in the Pacific Ocean, in southeast Japan, China, North Korea, South Korea, and Taiwan.[4][3] Additionally, there is one record of S. japonicus being caught in a trawl net in the Arafura Sea, between Australia and Western New Guinea.[2] It is a demersal species, found on the continental shelf and upper slope[3] at depths of 52 to 400 m (170.6 to 1312 ft).[4]
Reproduction
They are viviparous, giving birth to between 2 and 8 pups in each litter.[3] The pups are 19 to 30 cm (7.5 to 11.8 in) long at birth.[3] Gestation is 11 to 12 months[4] and they reproduce annually.[3] A study in the East China Sea found an equal sex ratio of both embryos and adults.[1]
Conservation
The Japanese spurdog is listed on the IUCN Red List as Endangered.[4] Populations in Japan have been stable since 1983, but shark abundance elsewhere in its range has been in decline since the middle of the twentieth century.[4] It is believed that S. japonicus abundance has declined in those areas as well.[4]
Its major threat is commercial fishing. Though not a commercial product itself, it is caught as bycatch in demersal fishing and used for meat or fish meal.[3]
References
<templatestyles src="Reflist/styles.css" />
Script error: No such module "Check for unknown parameters".