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(Brandt, 1851)

Description
Eye round and large [E.krohni eye & rostrum ]. The ratio of the eye diameter and the carapace length is about 0.21.
Peduncle of first antenna: the first segment has a pectinate lappet with 9 teeth projecting anteriorly over the second segment [E.krohni lappet ]. The lappet's outer tooth is produced into an oblique, thin process which is distally trifurcate. The dorsal margin of the second segment has two short but prominent, forward-projecting spine-like tubercles, one on the outer edge and one on the inner edge. These extend scarcely beyond the distal limit of the segment. The third segment has a keel.
Rostrum long, sharply pointed, reaching the anterior limit of the eyes. The gastric region is domed, with a small high keel at its apex[t] [E.krohni eye & rostrum ].
Carapace with two pairs of lateral denticles [E.krohni carapace denticles].
Abdomen without dorsal spines or specific features [E.krohni-drawing ].
Thoracic legs 8 and 7 are rudimentary, legs 6 to 1 strongly developed and nearly uniform in structure.
Petasma: the terminal process is moderately long and conspicuously widened and rounded towards the end where there is a minute lateral tooth. The proximal process has three irregular, large teeth on the distal third of the inner margin. The end of the proximal process is flattened and rounded [E.krohni petasma ].
Reproduction: breeds at a body length of about 12 mm at one year of age, in spring and summer. E. krohni can become two years of age, breeding for a second time (after Mauchline, 1984).

Size
Adults are 12-19 mm.

Larval stages
E.krohni-A
E.krohni-B
E.krohni-C
E.krohni-D

Ecology
E. krohni aggregates and is the a food source for fish and decapods.

Depth range
At 400-600 m during the day; migrates to 0-200 m at night.

Distribution in the North Sea
Regarding the depth range, E. krohni is unlikely to occur in the shallow North Sea; might be encountered in the N North Sea, in the deeper waters in the vicinity of the Orkney and Shetland Islands, as well as the Norwegian Deep, entered there from the adjacent NE Atlantic waters. E. krohni is recorded from the northern entrance of the North Sea (S. Hay, pers. com.).

World distribution
Temperate and subtropical N Atlantic, N and tropical Atlantic, Mediterranean. Northernmost records are in the Gulf Stream extension around Iceland (65°N), and off Norway (62-63°N). Southernmost records are off the African coast at the equator.

[After Brinton et al., 1999]

Euphausia krohni