Author: (Nilsson, 1855)
Trisopterus esmarki (Nilsson, 1855)
Status in World Register of Marine Species:
Accepted name: Trisopterus esmarkii (Nilsson, 1855) (updated 2009-06-25)
Diagnosis: lower jaw projecting beyond upper one. A barbel on chin one-third to one-half of eye diameter. First anal fin base shorter than preanal distance, its origin behind middle of first dorsal fin base. Anal fins in contact, dorsal fins with short interspaces. Body depth usually less than head length. First dorsal finrays 14-17, second dorsal finrays 22-28, third dorsal finrays 23-29; first anal finrays 26-31, second anal finrays 25-31. Vertebrae 53-55. Gillrakers 33-43. Colour: grey-brown on back, dull silvery on sides, belly more pale. Size: to 26 cm SL, usually 15-20 cm.
Habitat: the more oceanic species of the genus. Open sea, at depths of 80-200 m, over muddy bottoms. Behaviour: gregarious, often in large shoals, no long-distance migrations. Food: small crustaceans (copepods, euphausiids), also amphipods, shrimps and small fishes. Reproduction: from January to July, mainly from March to May, in deep water.
Distribution: European coasts from Bay of Biscay, Skagerrak and Kattegat to Iceland, southwestern Barents Sea and Spitzbergen (rare).
Eggs, larvae and young stages. Schmidt, 1905: 40, fig. 12, 15, pl. III (fig. 1-9) | Ehrenbaum, 1909: 252, fig. 31-32.
Otoliths (sagitta). Scott, 1906: 64, pl. IIA (fig. 25-26) | Schmidt, 1968: 16, pl. 3 (fig. 31), pl. 16.