418
W. NELLEN:
of catches from a single station may give quite another picture. Qualitative differences
resulting from 3 kinds of tows at one station and within one night hour are shown in
Fig. 2. No single sample included all 47 species found at this station. The RT which went
down to only 70 m caught most species, namely 28, followed by the HLN tow from
200 to 0 m, which caught 27 species, only 20 species being caught by the HLN towed
from 100 to 0 m. Besides the difference in the number of species, there is a difference
RT
HLN I
HLN II
70-0m
200-0m
laO-Om
species
l ime . 23 .00
22.50
22.40
I
mmn
[JI]!ffi
number of sp"ci"s in
rrnm
m
mmo 011 hauls 9 spec.
mmo only RT
16 spec.
10
I
only HLN I
9 spec.
DIDID
mnm only HLN II 3spec.
m
mnm only RT.
I
HLN t
2sp"c.
I
mnm
only RT.
HLN II
1 spec .
20
I
only HLN I.
HLN II 7 spec.
mrm
•
25
mrm
30
IllIIIJ
I I
mmn
35
I •
UIDID
mnm
4
IIIIIID
D
onnn
47
mmn
IIIIIll
station Na.175 : 47 species. RT
: 28 sp"ci"s
HLN 1 . 27 species
HLN II : 20 5P"cies
Fig. 2. Species number and kind of haul at one station
in species composition in the 3 hauls. Each net caught several species exclusively; in the
RT those numbered 16, in the HLN 200-0 m 9, and in the HLN 100-0 m 3. Not
more than 9 species from the total of 47 were found in all nets, and these 9 species did
not even rank first in abundance in the samples. Only 5 of them appeared more than once
among the 5 most abundant species in any of the 3 samples. The total number of larvae
per m 2 sea surface was 10 in the RT, 35 in the HLN 100-0 m, and 39 in the HLN
200-0m.