Author: (Lütken, 1892)
Hygophum hygomii (Lütken, 1892)
Status in World Register of Marine Species:
Accepted name: Hygophum hygomii (Lütken, 1892) (updated 2009-06-25)
Diagnosis: North Atlantic population: dorsal finrays 14 (13); anal finrays 21 (20-22); pectoral finrays 16 (15, rarely 14 or 17). Gillrakers 5 (rarely 4 or 6) + 1 + 14 (13, rarely 15), total 20 (19, rarely 18 or 21). AO 7 (6, rarely 8) + 6 (5-7), total 13 (12-14). South Atlantic population: dorsal finrays 14 (13-15); anal finrays 21 (20-23); pectoral finrays 15-16 (14-17). Gillrakers 5 (6) + 1 + 14-15 (rarely 13 or 16), total 21 (20-22, rarely 19 or 23). AO 7 (6-8) + 6 (5-7), total 13 (12-14). Males with single supra-caudal luminous gland; females with 2 (1-3) infra-caudal glands, but occasional specimens with supra- and infra-caudal glands. Size: to 68 mm.
Habitat: high-oceanic, mesopelagic; Mediterranean: day at 600- 750 m; nyctoepipelagic at surface and down to 235 m. Canaries: day at 400-700 m (maximum abundance at 500-600 m); night at 10-100 m (maximum abundance at 10-25 m), but a few juveniles at 500-600 m. Bermuda: day at 601-800 m (maximum abundance at 651-700 m); night at 50-300 m (maximum abundance at 50 m). Post-larvae and juveniles non-migratory near Bermuda and juveniles near Canaries. Food: no data. Reproduction: caudal glands develop in males at 35-40 mm and in females at 45-50 mm; sexually mature from about 58 mm. Spawning peak in late summerautumn (Mediterranean) and late autumn-winter (Bermuda). Sexually dimorphic growth rates apparent.
Distribution: Atlantic; subtropical pattern (bisubtropical subpattern), with two recognizable populations, between 38° and 20° N and including the eastern and western Mediterranean basins (eastern sector) and between 26° and 40° S (western sector) and between 13° and 40° S (eastern sector). Elsewhere, southern Indian and Pacific Oceans.
Eggs, larvae and young stages. Tåning, 1918: 51-57, fig. 17 | Sanzo, 1918: 27-31 | Tåning, 1932: pl. 120 (fig. 2) | Tortonese, 1956: 937-939, fig. 812 | Moser and Ahlström, 1974: 397, fig. 4 C.
Otoliths (sagitta). Kotthaus, 1972a: 12, 26, fig. 58.