The Japanese red stingray (Hemitrygon akajei; historically Dasyatis akajei) is a coastaldasyatid common in the northwestern Pacific. It has a reddish‑brown dorsum and a long tail armed withone or two venomous spines. It feeds on benthic invertebrates and small fishes and reproduces viaaplacental viviparity with histotroph (“uterine milk”).
Ecology & Biology
Diet: bivalves, crabs/shrimps, polychaetes and small demersal fishes.
Reproduction: aplacental viviparous; litters of about 2–10 pups depending on region.
Behaviour: often partly buried by day and forages at night on sandy/muddy bottoms of coasts and estuaries.
Identification
Disc sub‑rhomboid, leading edge relatively straight; dorsum reddish‑brown, venter pale.
Slender tail with 1–2 serrated, venomous spines; ventral/dorsal skin folds present posteriorly.
Crushing dentition adapted to hard‑shelled prey; males with claspers.
Size & Longevity
Disc width: typically 40–60 cm, maximum around ~100 cm.
Life: estimated 15–20 years (population/sex dependent).
Range & Habitat
NW Pacific: Japan, Korean Peninsula, China (Yellow/Bohai/East China Seas) and Taiwan. Shallow coastal and estuarinesandy/muddy habitats, usually 5–100 m (records deeper as well).
Conservation & Interactions
Threats: targeted catch and bycatch in trawls/set gear, habitat degradation and coastal pollution.
Measures: size (disc‑width) limits, seasonal closures, essential‑habitat protection and gear modifications.
Safety: the tail spine is venomous; wear protective footwear and avoid handling. Seek medical care after injuries (educational note).
IUCN: often cited as Vulnerable (VU) with regional declines; refer to the latest assessment for updates.
