New 🐟 Mercury Safety Guide & Omega-3 Rankings Updated for 2026. View Omega-3 Rankings →

🌊 Marine Least Concern 🌡️ Deep-water

Roughtail skate

Bathyraja trachura Gilbert, 1892
Max Length
91 cm
Max Weight
5.0 kg
Lifespan
20 yrs
Trophic Level
4
Depth
213–2550 m
Climate
Deep-water
Resilience
Low
Vulnerability
57.00/100
Typical Length
-
Depth Zone
deep-water

📖 Overview

Inhabits deeper waters than hardnose skates and reported to prefer medium to cold temperatures and low oxygen environments compared to its congeners. It is found over a wide range of substrates, from fine sediment to rocky environments. Feeds mostly on benthic organisms, including annelids, shrimps, crabs, and fishes, with adults preferring fishes, whereas juveniles consume mostly invertebrates . Oviparous. Distinct pairing with embrace. Young may tend to follow large objects, such as their mother . Reported size at maturity for males 74 cm TL and for females 80 cm TL with males growing to at least 90 cm TL and females at least 89 cm TL; with size at birth 9-16 cm TL. Maximum age reported estimated to be 20 years for males and 17 years for females. Egg cases small in size (6.2-7.8 cm TL), colour dark brown and becoming light golden brown on keels, which are smooth and plush-like when touched. Egg cases with long, slender horns at each corner, curving inwardly and slightly overlap at their tips with a distinct crossbar originating midway along the posterior horns in some specimens .

Scientific Name
Bathyraja trachura
Authority
Gilbert, 1892
Habitat
Marine
Climate
Deep-water
IUCN Status
LC
Max Length
91 cm
Max Weight
5 kg
Lifespan
20 years
Depth Range
213–2550 m
Trophic Level
4
Resilience
Low
Vulnerability
57.00/100
Salinity
30–40 ppt

🐟 Physical Description

This moderately sized skates (91.0 cm TL) with disc length (28.7-56.7% TL) are distinguished by the following: pectorals broadly rounded, head length short (15.0-24.1% TL), preorbital length short (9.0-13.5% TL) are also distinguished by having the following: claspers short, tips relatively rounded, with large pseudosiphon and a strong, short pseudorhipidion, not reaching the tip, V-shaped cleft, projection absent; teeth in 27-36 rows on upper jaw and in 26-36 rows on lower jaw; pectoral fin radials 81; pelvics 23; total vertebrae 109; dorsal surface is covered with rough prickles, prickles on tail are larger and more robust; thorns on dorsal surface, mature males with alar thorns, no malar thorns, middorsal thorns weak or absent (0-1); nuchal thorns small or obsolete (0-3); tail thorns moderate (21-30); interdorsal thorns are small to occasionally absent (0-1). Colouration: dorsal dark purple, brown, or grey, spiracles occasionally pale, ventral coloration a lighter grey than dorsal surface, often with white blotching on mouth, gills, cloaca, and scattered across the body .Cross section: flattened.

🌀 Behaviour

Behavioural data for Roughtail skate is currently being reviewed.

🦐 Diet

small fish
crustaceans
cephalopods

🥚 Reproduction

🐣 Oviparous

Oviparous, paired eggs are laid. Embryos feed solely on yolk . Distinct pairing with embrace. Young may tend to follow large objects, such as their mother .

🌍 Habitat & Distribution

Marine; bathydemersal; depth range 213 - 2550 m . Deep-water; 63°N - 22°N, 144°E - 106°W south to gthe Gulf of California, Mexico, and to the west to the Sea of Okhotsk.

🌿 Ecology

Zone Preferences
🌊 Marine 🌑 Deep Water
Trophic Level
4±0.7

📐 Morphometrics

Length–Weight Relationship: W = 0.00447 × L3.05 (TL)
Max TL
91cm
Max Weight
5,000g

🌡️ Water Parameters & Tolerance

Salinity Range
30–40ppt

🛡️ Conservation Assessment

IUCN Category
Least Concern
Assessment Date
2023

📊 Population Risk & Fisheries

Population Resilience
Low
Minimum doubling time
Fishing Vulnerability
57.00/100
High vulnerability
Trophic Level
4
Apex / Top predator
Climate Zone
Deep-water
Described By
Gilbert, 1892

🌐 Names & Taxonomy

Language Common Names
🇬🇧English Black Skate · roughtail skate
🌍CES rejnok santabarbarský
🇫🇷French raie à queue rude
🇯🇵Japanese Yasuda-kasube
🇳🇱Dutch Ruwstaartrog
🇷🇺Russian Грубохвостый скат · Черный скат
🇪🇸Spanish Raya cola arrugada

Scientific Synonyms

Scientific Name Author Year Status
Bathyraja microtrachys Osburn & Nichols 1916 Synonym
Raia trachura Gilbert 1892 Synonym
Raja microtrachys Osburn & Nichols 1916 Synonym
Raja trachura Gilbert 1892 Synonym

🗺️ Global Occurrence Map

Occurrence records from the Global Biodiversity Information Facility (GBIF) - 7 records indexed .

Occurrence density from GBIF View GBIF records ↗

👥 Community & Contribute

Aquareap Community Observations
0 Observations logged on Aquareap

No observations yet - be the first to log one!

View all observations for Roughtail skate ↗
Suggest an Edit

Spotted incorrect or outdated data? Submit a correction and our editorial team will review it. Approved edits go live within 48 hours.

Link to a scientific paper, FishBase, or other authoritative source
Report an Issue

Found a factual error, broken data, or inappropriate content? Let us know and we will investigate promptly.