Speckled Swellshark

About the Speckled Swellshark

The speckled swellshark is a species of deepwater catshark found off the coast of Northwestern Australia. Like all catsharks, they’re bottom feeders, have elongated cat-like eyes, and two small dorsal fins set far back. They’re mostly nocturnal and often sleep in groups during the day. Their diet consists of bony fishes and bottom-dwelling crustacean and cephalopods.

Very little is known of their biology. They’re presumably oviparous and can grow up to 68 cm/ 2.23 ft. They’re usually found in the outer continental shelf and upper slope at depths of 150–455 m/492–1,493 f.

Their name comes from their coloring and their ability to inflate their bodies with air or water to appear larger to predators.

The Speckled Catshark is likely caught incidentally by deepwater trawl fisheries, including the Australian Commonwealth Northwest Slope Trawl Fishery and the Western Deepwater Trawl Fishery which operate across the spatial and depth range of the species. It is possibly encountered in the Western Australian West Coast Deep Sea Crustacean Managed Fishery.  However, effort in these fisheries is low (2–6 vessels). The species also receive refuge in the Australian Commonwealth Marine Reserve network, including North-west Marine Parks Network. Population trends are not known but are suspected to be stable because interactions with fisheries are limited. There is no evidence of population decline and the species is not suspected to be close to reaching the population reduction threshold, and the Speckled Catshark is assessed as Least Concern.

There are no species-specific conservation measures in place for the Speckled Swellshark. Sharks and rays have been prohibited from retention in most Western Australian commercial fisheries since 2006 (Watt et al. 2021). The species would receive refuge in the Australian Commonwealth Marine Reserve network that came info effect in 2018 and is protected by zoning and gear restrictions (Parks Australia 2025). The North-west Marine Park network includes several parks that likely overlap with the range of the species including the Ashmore Reef Marine Park (Parks Australia 2025). In 2021, the national Red List status of this species was Data Deficient and in 2023, the stock was assessed as Negligible meaning it is rarely, if ever, encountered by fisheries (Kyne et al. 2021, Simpfendorfer and Rigby 2023). Further research is needed on its population size and trends, and life history, and catch rates should be monitored.

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Speckled Swellshark Gallery