Viper Dogfish

About the Viper Dogfish

The Viper Dogfish was first identified in 1986. They are rare deep sea sharks and have been found in the Pacific Ocean off the coasts of Japan, Taiwan and Hawaii.   

They migrate vertically in the ocean. At night, viper dogfish swim at between 300 m to 400 m/984–1,312 f underwater and during the day they will swim closer to the surface at 150 m/492 ft. 

Biology and Behaviour

There is very little known about viper dogfish since they are rarely seen.

Viper dogfish have a large number of photophores on their underside and a smaller number around their bodies which allows them to glow. Their dermal denticles, which are v-shaped scales, make their skin tough and allow them to swim away quickly and quietly. 

Viper dogfish capture their prey by extending their jaws and have needle-like teeth. They mainly feed on bony fish, but can consume prey half their size. Scientists revealed the stomach contents of these sharks where they most likely swallow their prey whole. 

Male viper dogfish can grow to 47 cm/1.54 ft, while female viper dogfish reach 53 cm/1.74 ft from head to tail.

Reproduction and Lifespan

Viper dogfish are ovoviviparous. Ovoviviparous animals reproduce by developing eggs inside the mother’s body, where the embryos hatch internally and are born as live young, nourished by the egg yolk rather than a placenta.

Conservation and Tourism

The species is a bycatch of demersal trawl and purse seine fisheries and is retained, at least in Taiwan, for fish meal. The small size of the species may reduce its catchability in some fishing gears. It is considered rare in Japan and Hawaii, and uncommon in Taiwan. The deep-water trawl fishery in Taiwan has moved deeper over the past 30 years to depths of 300–700 m. During the monsoon season, the conditions preclude deep-water trawling and some trawlers operate in the shallower depths of 100–300 m, which would provide the species seasonal refuge from fishing pressure. In Japan, bottom trawl fishing effort decreased markedly over the last three decades and is continuing to decline. The species has refuge at depth from bottom trawling as it occurs beyond the maximum depth of trawls and has rarely been reported in purse seine fisheries. Due to its partially epipelagic habitat and refuge at depth from fishing pressure, there is no evidence of population decline and since the Viper Dogfish is not suspected to be close to reaching the population reduction threshold, it is assessed as Least Concern.

No specific measures are in place. Since 1999, all demersal trawling in Taiwan is prohibited within 3 nautical miles (nm) of the coast and within 12 nm for trawlers larger than 50 Gross Registered Tonnage (Fisheries Agency 2019, Liao et al. 2019). In Japan, management measures have been implemented since the mid-1990s to control fishing effort that include total allowable catches, seasonal closures, and gear restrictions (White Paper 2015). Research is needed on population size and life history, and catch rates should be monitored.

Do you have images or videos of Viper Dogfishs?
Submit them to [email protected].

Viper Dogfish Gallery