Teleostei (teleosts) >
Scombriformes (Mackerels) >
Gempylidae (Snake mackerels)
Etymology: Rexea: Latin, rex, rego = king.
Eponymy: Dr Izumi Nakamura (1939–2021) was a Japanese ichthyologist at the Kyoto University Aquatic Natural History Museum’s Maizuru Fisheries Research Station and an expert on billfishes. [...] (Ref. 128868), visit book page.
Environment: milieu / climate zone / depth range / distribution range
Ecology
Marine; benthopelagic; depth range 340 - 370 m (Ref. 6181). Deep-water; 34°N - 18°S, 53°E - 154°W (Ref. 6181)
Indo-West Pacific: Nazareth Bank and off Sumatra in the Indian Ocean and Kyushu-Palau Ridge, Japan and off Oahu, Hawaii.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 38.0 cm SL male/unsexed; (Ref. 6181)
Dorsal spines (total): 19 - 20; Dorsal soft rays (total): 15 - 18; Anal spines: 2; Anal soft rays: 12 - 13; Vertebrae: 34. Pectoral fin is represented by a single spine in small specimens or entirely absent in individuals over 25 cm SL. Lateral line branching below the 5th to 6th spine of the first dorsal fin. The upper line reaches to the base of the first dorsal finlet, the lower line runs sub laterally. Most of the body is naked except for a large rectangular stripe of squamation extending forward from the caudal peduncle. Overall color is grayish brown; a black blotch is on membranes between the first and third dorsal-fin spine.
Mesobenthopelagic (Ref. 58302). Matures at about 25 cm standard length (Ref. 6181).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Nakamura, I. and N.V. Parin, 1993. FAO Species Catalogue. Vol. 15. Snake mackerels and cutlassfishes of the world (families Gempylidae and Trichiuridae). An annotated and illustrated catalogue of the snake mackerels, snoeks, escolars, gemfishes, sackfishes, domine, oilfish, cutlassfishes,. scabbardfishes, hairtails, and frostfishes known to date. FAO Fish. Synop. 125(15):136 p. (Ref. 6181)
IUCN Red List Status (Ref. 130435: Version 2024-1)
Threat to humans
Harmless
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Estimates based on models
Preferred temperature (Ref.
123201): 3.9 - 7.2, mean 6 °C (based on 147 cells).
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5078 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00372 (0.00167 - 0.00826), b=3.10 (2.91 - 3.29), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref.
93245).
Trophic level (Ref.
69278): 4.2 ±0.7 se; based on size and trophs of closest relatives
Resilience (Ref.
120179): Medium, minimum population doubling time 1.4 - 4.4 years (Preliminary K or Fecundity.).
Fishing Vulnerability (Ref.
59153): Moderate vulnerability (36 of 100).