Gasterochisma melampus Richardson, 1845
Butterfly kingfish
Gasterochisma melampus
photo by Archambault, C.

Family:  Scombridae (Mackerels, tunas, bonitos), subfamily: Gasterochismatinae
Max. size:  164 cm FL (male/unsexed)
Environment:  pelagic-oceanic; marine; depth range - 200 m, oceanodromous
Distribution:  Circumglobal in southern temperate waters.
Diagnosis:  Dorsal spines (total): 17-18; Dorsal soft rays (total): 9-12; Anal spines: 0-0; Anal soft rays: 11-13; Vertebrae: 44-44. Pelvic fins enormous in juveniles, longer than head length. Pelvic fins fitting into a deep ventral groove at all sizes. Interpelvic process tiny and bifid. No anterior corselet. Swim bladder present with two anterior projections that extend into the back of the skull. The morphological adaptations required for maintaining high brain and retinal temperatures are discussed in Ref. 11221.
Biology:  Occurs in deep oceanic waters (Ref. 9563), most abundant in waters of 8° to 10°C. Stomach contents of the specimen from north of the Hawaiian Archipelago include onychoteuthids, ommastrephid squid, vertebrae and fin rays from an unidentified fish, bird feathers and parasitic nematodes (Ref. 11006). Taken as longline by-catch by Japanese fishing for Thunnus maccoyii.
IUCN Red List Status: Least Concern (LC); Date assessed: 01 March 2022 Ref. (130435)
Threat to humans:  harmless


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