Argyropelecus affinis Garman, 1899
Pacific hatchet fish
photo by JAMARC

Family:  Sternoptychidae (Marine hatchetfishes), subfamily: Sternoptychinae
Max. size:  8.4 cm SL (male/unsexed)
Environment:  bathypelagic; marine; depth range 1 - 3872 m, oceanodromous
Distribution:  Eastern Atlantic: occasionally between Azores and Madeira (Ref. 4739), also from Senegal to Gulf of Guinea. Western Atlantic: 30°N-30°S, including the Gulf of Mexico (Ref. 27768). Northwest Atlantic: Canada (Ref. 5951). Indian Ocean: 20°N-20°S. Eastern Pacific: 35°N-35°S. Western Pacific: 30°N-10°S. South China Sea (Ref.74511).
Diagnosis:  Dorsal spines (total): 0-0; Dorsal soft rays (total): 8-9; Anal spines: 0-0; Anal soft rays: 12-14; Vertebrae: 38-41. Scales deciduous; swim bladder well developed, gas-filled, euphysoclistous; branchiostegal rays 10, 3 on epihyal; post-abdominal spines (iliac) short, equal in length; abdominal keels shallow (Ref. 4739).
Biology:  An oceanic and mesopelagic species (Ref. 4739, 58302), mainly at 300-650 m (Ref. 4054), 170-500 m at night and 350-600 m during day (Ref. 58302), commonly 1-600m (Ref. 035838). May make short diel migrations (Ref. 4739). Smaller individuals feed on copepods and ostracods; larger ones feed on euphausiids, salps and chaetognaths (Ref. 4739). Adult complement of photophores acquired at about 14 mm SL (Ref. 4739). Oviparous, with planktonic eggs and larvae (Ref. 35838).
IUCN Red List Status: Least Concern (LC); Date assessed: 15 July 2014 Ref. (130435)
Threat to humans:  harmless


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