Australian Longnose Skate, Dentiraja confusa Last 2008

Introduction

The Australian Longnose Skate is endemic to southeastern Australia. A recently described species in 2008, it is often confused with the deeper water, Whitespotted skate, Dentiraja cerva (which is more distinctly white spotted and lacks denticles on the underside edge of the body).

Identification

The Australian Longnose Skate is a brownish or yellowish-brown skate, with a pattern of paler and darker spots and reticulations, and a mostly whitish underside with greyish areas over most of the head, on the belly and near the cloaca, and black-edged sensory pores. It has distinctive denticles on the anterior ventral disc margin.

Habitat

The Australian Longnose Skate inhabits soft bottoms on the continental shelf and slope at depths between 20-120m but can be found to 600m.

Distribution

The species is endemic to southeastern Australia, from Sydney, New South Wales, to Portland, Victoria, including around Tasmania.

The map below shows the Australian distribution of the species based on public sightings and specimens in Australian Museums. Source: Atlas of Living Australia.

Feeding and diet

The Australian Longnose Skate feeds on benthic crustaceans benthic invertebrates particularly crabs and shrimp.

Breeding behaviours

The species is oviparous (egg laying), with females depositing egg cases in sandy or muddy flats. Males mature at approximately 47 cm TL, corresponding to an approximate age of 6 years, while females mature at approximately 53 cm TL, corresponding to an approximate age of 7 years. The maximum age recorded is 12 years, resulting in a generation length of 9.5 years. Young hatch out at around 10 cm TL after 96-180 days.

Primary threats

The Australian Longnose Skate is assessed as Critically Endangered (IUCN) and faces a high risk of extinction due to several factors, including habitat loss, overfishing, and environmental changes. The Longnose Skate population has declined by over 80% in the last 30 years, leading to its current critically endangered status. The Longnose Skate faces significant threats from various fishing methods employed in the Southern and Eastern Scalefish and Shark Fishery (SESSF). Heavy fishing pressure in parts of its range, dating back to the 1970s, has led to a notable decline in population.