Spotless Catshark

About the Spotless Catshark

The Spotless Catshark (Bythaelurus immaculatus) is a rare deep-sea catshark in the family Pentanchidae. It is one of the largest species in the genus Bythaelurus and is known from only a handful of specimens collected in the South China Sea, making it one of the least-studied sharks in the western Pacific. 

The Spotless Catshark is a bathydemersal (deep bottom-dwelling) shark.

Depth range: 534–1,020 m/1,752–3,346 ft, max length: 71-76cm/2.33 ft-2.49 ft. 

It inhabits:

• upper and middle continental slopes
• muddy and soft-bottom deep-sea habitats
• cold, low-light environments

Appearance

The Spotless Catshark is named for its uniform coloration.

Characteristics include:

• plain dark yellowish-brown to brown body
• no spots or stripes
• broad rounded head
• relatively stocky body
• two small dorsal fins set well back on the body
• cat-like eyes typical of deepwater catsharks

They are Ovoviviparous meaning they 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.

The species is possibly a bycatch of Taiwanese deep-water trawl fisheries in the South China Sea that operate to a depth of 700 m, however to date it is only known from three specimens caught by research surveys. This suggests that interactions with commercial fisheries are limited and the species also has refuge at depth. There is nothing to infer or suspect population reduction at this time and the Spotless Catshark is assessed as Least Concern. No information is available on use and trade; if used, it would likely be for human consumption or fish meal.

No specific measures are in place. Research is required to better define the species’ distribution, habitat, life history, and population size and trend, and catch rates should be monitored, particularly if fisheries expand to greater depths in the region.

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