Teleostei (teleosts) >
Acanthuriformes (Surgeonfishes) >
Lobotidae (Tripletails)
Etymology: Hapalogenys: Greek, hapalos = soft * Greek, geny, -yos = face (Ref. 45335); sennin: Name from the Japanese mythology, 'sennin' (sen'nin), referring to the face with barbels and solitary habitat.
Environment: milieu / climate zone / depth range / distribution range
Ecology
Marine; pelagic-neritic; depth range ? - 50 m (Ref. 56360). Temperate
Northwest Pacific: Currently known only from southern Japan except in the Ryukyu and Ogasawara isalnds.
Size / Weight / Age
Maturity: Lm ? range ? - ? cm
Max length : 29.6 cm SL (female)
Short description
Identification keys | Morphology | Morphometrics
Dorsal spines (total): 11; Dorsal soft rays (total): 16 - 18. Diagnosis. Distinguished from its congerners by the following: dorsal-fin rays XI, 16-18 (usually XI, 17); scales above lateral line 9-12 (usually 10 or 11), below 15-19 (usually 16 or 17); scales on maxilla absent; 10 pores on and behind chin, including one very smalei pore near each side of symphysis, two moderate sized pores anteroventrally on each dentary, a single large pore ventrally, midway along each dentary (usually obscured by dense papillae), and a single large pore ventrally at articulation of dentary (two posteriormost pores slit-like concave traces); cluster of short and long dense papillae and barbels on fleshy lower lip, its posterior part naked; shape of dorsal- and anal-fin rays strongly angulated, usually angular, anal more strong than dorsal; body uniformly dark brown, sometimes with two indistinct oblique dark bands, the first descending from nape to behind pectoral fin, the second from base of 7th-10th dorsal-fin spines, curving downward above or through lateral line (Ref. 56360).
The species is apparently restricted to river mouths and coastal rocky to sandy bottoms of less than 50 m depth. The smallest specimen (MUFS 22226, 46 mm SL) was collected in a river mouth, while larger specimens were captured by set net or small trawl between 5-50 m depth over rocky or sandy bottoms. Between 1960-1980, the species were observed by Miyazaki SCUBA divers to be solitary and common in small caves, holes, and under overhanging rocks along the Nichinan coast, Miyazaki, southeastern Kyushu Island, from late
summer to winter. However, in recent years (post 1990) the species has been only rarely observed (Ref. 56360).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Iwatsuki, Y. and T. Nakabo, 2005. Redescription of Hapologenys nigripinnis (Schlegel in Temminck and Schlegel, 1843), a senior synonym of H. nitens Richardson, 1844, and a new species from Japan. Copeia 2005(4):854-867. (Ref. 56360)
IUCN Red List Status (Ref. 130435: Version 2024-1)
Threat to humans
Harmless
Human uses
Fisheries: bycatch
Tools
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Internet sources
Estimates based on models
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5078 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01862 (0.00834 - 0.04158), b=3.01 (2.81 - 3.21), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref.
93245).
Trophic level (Ref.
69278): 3.9 ±0.6 se; based on size and trophs of closest relatives
Resilience (Ref.
120179): High, minimum population doubling time less than 15 months (Preliminary K or Fecundity.).
Fishing Vulnerability (Ref.
59153): Low to moderate vulnerability (26 of 100).
