80
THE BIOLOGY OF EUPHAUSIIDS
Thysanoessa inermis Hansen, 1911: 8-13; 1915: 93-96, pl. ii, figs. 2, a-d;
Einarsson, 1945: 30-34, 46-50, figs. 12, 18, 19; Banner, 1950: 24-27, pl. iii, fig.
23, a-b; Boden et al., 1955: 354-356, fig. 35.
T. inerrnis occurs in both the North Pacific and the North Atlantic
(Fig. 26). Atlantic : found off West Greenland to about 70"N and down
the American coastline to the Gulf of Maine ; present off East Greenland
as far north as 75" to 80"N but does not breed north of 65" to 70"N,
except in the Norwegian Sea and Barents Sea where breeding can take
place just north of 70"N. Southern limit in the eastern Atlantic is at
about 50"N. Pacific : it has been found to 63ON in the Bering Sea and
southwards to 43"N in the North Pacific ; recorded northeast of Point
Barrow but it is not known whether there is any communication between
the Atlantic and Pacific populations. Probably usually occurs between
100 m and 300 m depth during the day, moving towards the surface at
night. Length : Atlantic, up to 32 mm ; Pacific, up to 25 mm. (Hansen,
1908a, 1915 ; Schmitt, 1919 ; Stephensen, 1933, 1943 ; Leavitt, 1935,
1938 ; Ruud, 1936 ; Bigelow and Sears, 1939 ; Einarsson, 1945 ; Marshall,
1948 ; Whiteley, 1948 ; Kielhorn, 1952 ; Wiborg, 1954, 1955 ; 0stvedt,
1955; Brunel, 1959; Brinton, 1962a; Grainger, 1962; Grice and Hart,
1962; Nemoto, 1962a; Drobysheva, 1963, 1964; Holmquist, 1963;
Ponomareva, 1963 ; Dunbar, 1964.)
Thysanoessa bngicaudata ( K r ~ y e r ,
1846)
Thysanopodu longicuudata Krcayer, 1846 : pl. viii, fig. 1. Thysanoessa tenera
G. 0. Sam, 1883a: 53, tab. 1, figs. 19-20. T . Zongicaudata Hunsen, 1887a: 54;
1911 : 41-42, fig. 13 ; Zimmer, 1904: 424, figs. 18-21 ; Holt and Tattersall, 1906a:
107-108, pl. xv. ?Thysanopoda raschii Vanhoffen, 1897 : pl. 1, fig. 1.
This species is restricted to the North Atlantic between the Gulf of
Maine (35"N to 40"N) to West Greenland a t about 70"N in the west
while in the east it is found from the offshore area of the Bay of Biscay
(40"N to 45"N) to 83"N off northeast GreenIand (Fig. 26). It is most
common, however, between 55"N and 70"N and occurs in offshore
areas. North and south of these latitudes it occurs in smaller numbers,
although notable populations are present in the Barents Sea. The
depth a t which it lives is not clear, some records being from the surface
layers, others from deep water. Grows to 16 mm in length. (Holt and
Tattersall, 1905b ; Tattersall, 1911 ; Stephensen, 1913, 1933, 1943;
Hansen, 1915 ; Leavitt, 1935, 1938 ; Ruud, 1936 ; Bigelow and Sears,
1939 ; Einarsson, 1945 ; Kielhorn, 1952 ; Moore, 1952 ; Wiborg, 1954;
0stvedt, 1955; Fraser, 1956, 1961; Zelikman, 1958a; Grice and Hart,
1962; Drobysheva, 1963; Dunbar, 1964.)
THE BIOLOGY OF EUPHAUSIIDS
Thysanoessa inermis Hansen, 1911: 8-13; 1915: 93-96, pl. ii, figs. 2, a-d;
Einarsson, 1945: 30-34, 46-50, figs. 12, 18, 19; Banner, 1950: 24-27, pl. iii, fig.
23, a-b; Boden et al., 1955: 354-356, fig. 35.
T. inerrnis occurs in both the North Pacific and the North Atlantic
(Fig. 26). Atlantic : found off West Greenland to about 70"N and down
the American coastline to the Gulf of Maine ; present off East Greenland
as far north as 75" to 80"N but does not breed north of 65" to 70"N,
except in the Norwegian Sea and Barents Sea where breeding can take
place just north of 70"N. Southern limit in the eastern Atlantic is at
about 50"N. Pacific : it has been found to 63ON in the Bering Sea and
southwards to 43"N in the North Pacific ; recorded northeast of Point
Barrow but it is not known whether there is any communication between
the Atlantic and Pacific populations. Probably usually occurs between
100 m and 300 m depth during the day, moving towards the surface at
night. Length : Atlantic, up to 32 mm ; Pacific, up to 25 mm. (Hansen,
1908a, 1915 ; Schmitt, 1919 ; Stephensen, 1933, 1943 ; Leavitt, 1935,
1938 ; Ruud, 1936 ; Bigelow and Sears, 1939 ; Einarsson, 1945 ; Marshall,
1948 ; Whiteley, 1948 ; Kielhorn, 1952 ; Wiborg, 1954, 1955 ; 0stvedt,
1955; Brunel, 1959; Brinton, 1962a; Grainger, 1962; Grice and Hart,
1962; Nemoto, 1962a; Drobysheva, 1963, 1964; Holmquist, 1963;
Ponomareva, 1963 ; Dunbar, 1964.)
Thysanoessa bngicaudata ( K r ~ y e r ,
1846)
Thysanopodu longicuudata Krcayer, 1846 : pl. viii, fig. 1. Thysanoessa tenera
G. 0. Sam, 1883a: 53, tab. 1, figs. 19-20. T . Zongicaudata Hunsen, 1887a: 54;
1911 : 41-42, fig. 13 ; Zimmer, 1904: 424, figs. 18-21 ; Holt and Tattersall, 1906a:
107-108, pl. xv. ?Thysanopoda raschii Vanhoffen, 1897 : pl. 1, fig. 1.
This species is restricted to the North Atlantic between the Gulf of
Maine (35"N to 40"N) to West Greenland a t about 70"N in the west
while in the east it is found from the offshore area of the Bay of Biscay
(40"N to 45"N) to 83"N off northeast GreenIand (Fig. 26). It is most
common, however, between 55"N and 70"N and occurs in offshore
areas. North and south of these latitudes it occurs in smaller numbers,
although notable populations are present in the Barents Sea. The
depth a t which it lives is not clear, some records being from the surface
layers, others from deep water. Grows to 16 mm in length. (Holt and
Tattersall, 1905b ; Tattersall, 1911 ; Stephensen, 1913, 1933, 1943;
Hansen, 1915 ; Leavitt, 1935, 1938 ; Ruud, 1936 ; Bigelow and Sears,
1939 ; Einarsson, 1945 ; Kielhorn, 1952 ; Moore, 1952 ; Wiborg, 1954;
0stvedt, 1955; Fraser, 1956, 1961; Zelikman, 1958a; Grice and Hart,
1962; Drobysheva, 1963; Dunbar, 1964.)