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🌊 Marine Critically Endangered 🌡️ Subtropical

Japanese wedgefish

Rhynchobatus mononoke Koeda, Itou, Yamada & Motomura, 2020
Max Length
130 cm
Max Weight
-
Lifespan
-
Trophic Level
3.6
Depth
15–136 m
Climate
Subtropical
Resilience
-
Vulnerability
69.00/100
Typical Length
-
Depth Zone
pelagic

📖 Overview

This species is currently known only from nearshore to offshore waters and have been collected by set net from 15-35 m, but was also reported to have been taken at 135 m by bottom trawl. Based on photos of landed individuals, this species probably attains close to 3 m TL. The captive female individual held for at least 15 years in the Kagoshima City Aquarium reached to 2 m TL. This wedgefish is occasionally landed at fish markets in Kagoshima Prefecture and used for culinary purpose. Reported catches of the species were very rare in the East China Sea and is apparently restricted distribution and increasing rarity indicate that the species should immediately be included in the IUCN Red List CR “Critically Endangered” category, together with other congeners .

Scientific Name
Rhynchobatus mononoke
Authority
Koeda, Itou, Yamada & Motomura, 2020
Habitat
Marine
Climate
Subtropical
IUCN Status
CR
Max Length
130 cm
Depth Range
15–136 m
Trophic Level
3.6
Vulnerability
69.00/100
Salinity
30–40 ppt

🐟 Physical Description

This species is distinguished by the following set of characters: snout obtusely wedge shaped, angle ca. 52-57°; preoral length 17.4-17.9% TL, prespiracular length 19.3-19.5%; interdorsal space 16.7-17.9%; total pectoral-fn radials 54-56; total free vertebral centra 136-144; tooth rows on upper jaw ca. 54-66; no spines on snout; outer fold on posterior margin of spiracle is more pronounced than inner fold; pre-first dorsal-fin length 46.4-48.6%; apex of dorsal fins bluntly rounded; origin of first dorsal fn about level with the pelvic-fin origin; middle of pectoral disc with a spiracle-sized black blotch followed by a single white spot (rarely absent) posterodorsally; distal region of pectoral disc to mid-dorsal area without distinct white spots; a single blotch below the eye is usually absent; anterior half of undersurface covered with a rounded black blotch; near the snout tip, a pair of small distinct black spots .Cross section: flattened.

🌀 Behaviour

Behavioural data for Japanese wedgefish is currently being reviewed.

🦐 Diet

Diet information for Japanese wedgefish is currently being compiled.

🥚 Reproduction

Reproduction data for Japanese wedgefish is currently being compiled.

🌍 Habitat & Distribution

Marine; pelagic-neritic; depth range 15 - 136 m . Subtropical Northwest Pacific: southern Japan.

🌿 Ecology

Zone Preferences
🌊 Marine 🐟 Pelagic
Trophic Level
3.6±0.6

📐 Morphometrics

Length–Weight Relationship: W = 0.00363 × L3.11 (TL)
Max TL
130cm

🌡️ Water Parameters & Tolerance

Salinity Range
30–40ppt

🛡️ Conservation Assessment

IUCN Category
Critically Endangered
Assessment Date
2023

📊 Population Risk & Fisheries

Fishing Vulnerability
69.00/100
High vulnerability
Trophic Level
3.6
Predator
Climate Zone
Subtropical
Described By
Koeda, Itou, Yamada & Motomura, 2020

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