NPAFC
Doc. 486
Rev. _
Results of the 2000 Salmon Research Cruises of the Hokusei maru
by
Toshimi Meguro, Yoshihiko Kamei, Naoto Kobayashi, Takashi Yoshida, and Osamu Kimura
Hokusei maru,
Faculty of Fisheries, Hokkaido University
3-1-1 Minato-cho, Hakodate 041-8611, Japan
Submitted to the
NORTH PACIFIC ANADROMOUS FISH COMMISSION
by the
JAPAN NATIONAL SECTION
October 2000
THIS PAPER MAY BE CITED IN THE FOLLOWING MANNER:
Meguro, T., Kamei, Y, Kobayashi, N., and Yoshida, T. 2000. Results of the 2000 Salmon
Research Cruise of the Hokusei maru. (NPAFC Doc. 486) lOp. Faculty of Fisheries,
Hokkaido University, 3-1-1 Minato-cho, Hakodate 041-8611, Japan.
0
Three research cruise of the Hokusei maru were conducted along 155 E from 44 N to 35
0
0
N between 1 June and 11 August, 2000. The primary object of the cruises was to collect
oceanographic and biological data.
In the 1st Cruise, the Subarctic Boundary crossed at 40° 30'N, and the Subarctic Front (or
Polar Front) crossed at 43° N. In the 2nd Cruise, the Subarctic Boundary crossed at 40° 30'N,
and the Subarctic Front crossed at 43° 30'N. In the 3rdCruise, the Subarctic Boundary crossed
at 40° N, and the Subarctic Front crossed at 43° 30'N. Sea surface temperatures were highest
during the 3rd cruise. But sea surface salinity was the lowest.
Drift gillnet research was conducted at 13 stations. The almost all salmonids caught in the
1st cruise were pink salmon (Oncorhynchus gorbuscha). In the 2nd cruise, CPUE value of
pink salmon was lower than that in the 1st cruise, but CPUE values of chum salmon
(Oncorhynchus keta) and coho salmon (Oncorhynchus kisutch) were higher than in the 2nd
cruise. No salmonids were caught during the 3rd cruise when sea surface temperatures were
0
high, and at stations south of 42.5 N, there were many organisms that inhabit the subtropic
region. The fork length frequencies of chum salmon were not different among stations on the
1st cruise or on the 2nd cruise. 97% of the collected chum salmon were mature. The mean and
median of the pink salmon fork lengths at 44 N were higher 25mm on the 2nd cruise than on
0
the 1st cruise. On the 1st cruise, the proportions of chum salmon and pink salmon males were
higher in northern stations than that at southern stations. At 44 N on the 2nd cruise, the
0
proportions of chum salmon and pink salmon males were lower than at 44 ON on the 1st cruise.
Flying squid (Ommastrephes bartramii) caught at 39.5 Nand 41 N on the 1st cruise were
0
0
only large immature females. On the 2nd cruise, large immature males were collected with
large immature females at 39.5 ON, and one fully matured male were collected with five small
immature males and females at 35 ° N. On the 3rd cruise, maturing or fully matured males and
0
females were distributed with small immature males and females between 39.5 Nand 44 N.
Pacific saury (Cololabis saira) collected on the first two cruises was under 260mmBL, and
0
most samples collected on the 3rd cruise were over 260mmBL. The distribution, composition,
and biological characteristics of species caught in the 3rd cruise were much different in the 1st
and 2nd cruise.
INTRODUCTION
The Hokusei maru and Oshoro maru have conducted salmon research and have studied the
oceanic structure and marine biology in the North Pacific Ocean, Bering Sea and/or Chukchi
Sea every summer since 1953. Data collected during each cruise have been published by
Hokkaido University in "DATA RECORD OF OCEANOGRAPHIC OBSERVATIONS AND
EXPLORATORY FISHING' since 1957. In March 2000, the 43rd annual volume of this report
was published. In addition, many studies of salmonids using data collected during these
cruises have been published in the "Bulletin of the Faculty of Fisheries, Hokkaido
University" since 1950 and other scientific journals.
Since 1978, several transects have been repeatedly sampled to study long-term changes in
0
0
0
the North Pacific ecosystem. These transects include 155 E, 170 E, and 175 30'E by the
Hokusei maru, and 180
0
by the Oshoro maru. In 2000, three cruises were conducted on the
0
Hokusei maru along 155 E. The primary object of the Hokusei maru cruises was to continue
0
collecting oceanographic and biological data along 155 E.
We now coordinate our efforts with other research ships. In 2000, the Wakatake maru
sampled salmonids along 180
0
and the Bering Sea, the Shoyo maru sampled salmonids along
165 E and the Oshoro maru sampled salmonids along 165 Wand 145 • W, while the Hokusei
0
0
0
maru sampled salmonids along 155 E. All of these surveys by Japanese research vessels
include fishing of salmonids using non-selective research giIlnet and oceanographic
observation.
This document reports the preliminary results of the 2000 research cruises of the TIS
Hokusei maru along 155 E .
0
METHODS
t.Survey Area and Cruise Schedule
In 2000, three hydrographic and salmonids research cruises were conducted along the
155° E from 35° N to 44° N. (Fig. 1, Table 1 and 2)
The period of the 1st cruise was from 1 June to 15 June.
The period of the 2nd cruise was from 21 June to 5 July.
the period of the 3rdcruise was from 28 July to 11 August.
2.0ceanographic Observation
0
Oceanographic stations were occupied along 155 E at intervals of 45 nautical miles from
0
0
35 N to 44 N in all three cruises (Table 1). Data collected by CTD and XB T were used to
plot the temperature, salinity and density sections, and T-S diagram.
3.Drift Gillnet Sampling
A drift gillnet was used to catch salmonids and the other organisms at 13 stations (Table 2).
The net consisted of 30 tans of C-Gear gillnet (non-selective varied research mesh, Takagi,
1975; 48,55,63, 72, 82,93, 106, 121, 138 and 157 mm mesh size; 3 tans of each mesh size; 1
tan is 50 m long), 12 tans of A-Gear gillnet (commercial mesh; 112 and 118 mm mesh size; 6
tans of each mesh size) and 7 tans ofF-Gear gillnet (special mesh; 19,22, 25, 29, 33, 37 and
42 mm mesh size; 1 tan of each mesh size). The drift gillnet was set at 18:00 (Ship's Time)
and retrieved at 04:00 or 04:30 (Ship's Time) on the following morning.
The numbers of organisms caught by drift gillnet were counted by species and mesh size.
Catch per unit of effort (CPUE) was calculated as the number of fish caught by 17 tans of
drift gillnet (each 1 ofC-Gear and F-Gear gillnet). In the 2nd cruise, drift gillnet was set twice
0
at 44 N, therefore the CPUE at this station was based on the average of the two catches. Fork
length, body weight, and gonad weight of a maximum 60 fish for each salmon species were
measured. Scales were collected from the INPFC preferred body area. Chum salmon
(Oncorhynchus keta) was distinguished between mature and immature by gonad weight
(Takagi, 1961). For Pacific saury, body length and total weight of maximum 150 fish by mesh
size were measured. For flying squid, mantle length, body weight, sex and maturity of
maximum 30 squid by mesh size were measured.
RESULTS AND DISCUSSION
Final oceanographic data and biological data on salmonids collected during the cruise will
be published in the "DATA RECORD OF OCEANOGRAPHIC OBSERVATIONS At""ID
EXPLORATORY FISHING NO. 44" ofHokkaido University no later than early March 2001.
1.0ceanographic Conditions
The survey area is divided into 3 regions: the Subarctic Gyre in the north, the North Pacific
Current in the south, and the Transition Domain between the two current systems. In this area,
generally, low-temperature, low-salinity and high-density water is distributed in the north, and
high-temperature, high-salinity and low-density water is distributed in the south. There is a
permanent thermocline at 400 - 600 m depth in the North Pacific Current, and it converges
along the Subarctic Boundary. At about 100m depth, there is a maximum salinity layer. The
minimum salinity layer corresponds to the depth of the thermocline. In the Subarctic Gyre, the
permanent thermocline and minimum salinity layer do not occur. The position of the
Subarctic Boundary was determined by the vertical isohaline of34.00 psu at 100 m depth, as
defined by Favorite et al. (1976). The position of the Subarctic Front (or Polar Front) was
determined by the vertical isotherm of 4 °c at 100 m depth (Dodimead et aI., 1963;Favorite
et aI., I 976).The T-S curve at deep layer of this area converges at at = 27.5.
[The I st Cruise]
Temperature, salinity and density sections, (O-IOOOm) and a T-S diagram are shown in
Figure 2. The Subarctic Boundary position occurred at 40° 30'N. The Subarctic Front
occurred at 43°N. A seasonal thermocline was observed at 30 m depth between 4'0° 30'N and
44° N. The depth of isotherms under the seasonal thermocline was undulating steeply from
0
43 N to 41" N. This may have been caused by a meso-scale eddy. This eddy is thought to
more than 1000 m depth. A seasonal pycnocline was observed at 30 - 40 m depth.
This area was divided as follows:
the Subarctic Gyre, from 44° N to 43° N;
the Transition Domain, from 43° N to 40° 30'N;
and the North Pacific Current, from 40° 30'N to 3So N.
[The 2nd Cruise]
Temperature, salinity and density sections (O-IOOOm), and a T-S diagram are shown in
Figure 3. The Subarctic Boundary position occurred at 40° 30'N. The Subarctic Front
occurred at 43° 30'N. A seasonal thermocline and a seasonal pycnocline were observed at 30 SOm depth; both appeared more clearly than in the 1st cruise.
This area was divided as follows:
the Subarctic Gyre, from 44° N to 43° 30'N;
the Transition Domain, from 43° 30'N to 40° 30'N;
and the North Pacific Current, From 40° 30'N to 35° N.
[The 3rd Cruise]
Temperature, salinity and density sections (O-1000m), and a T-S diagram are shown in
Figure 4. The Subarctic Boundary occurred at 40° N. The Subarctic Front position occurred at
43° 30'N. Sea surface temperatures on the 3rdcruise were higher than the 1st and 2nd cruises.
The seasonal thermocline and the seasonal pycnocline were the clearest of the three cruises,
but under the seasonal pycnocline, the isopycnic lines were similar those in the 2nd cruise. A
seasonal halocline was observed.
This area was divided as follows:
the subarctic Gyre, from 44° N to 43° 30'N;
the Transition Domain, from 43° 30'N to 40° N;
0
the North Pacific Current, from 40° N to 35 N.
Next vertical profiles of temperature and salinity are shown in Figure 5 and 6. Vertical
profiles of the 1st and 2nd cruises were similar. Most variation in the vertical profiles among
the three cruises occurred from the sea surface to 50 m depth. Temperature and salinity varied
little between 0-50m depths in the first two cruises, but varied much in the 3rd cruise. In the
3rd cruise, the seasonal thermocline was very strong, and temperatures from the sea surface to
50 m depth varied about lOoC. At 44° N, temperatures between 0 and 50m varied more than
10°C. The low variation I the first two cruises was presumably due to convection.
Surface salinity values in the 1st and 2nd cruises were higher than in the 3rd cruise.
2.Distribution and abundance of organisms caught by drift giIlnet
The numbers of fishes caught by the drift gillnet at each station are shown in Table 3. The
CPUE values and species composition at each station are showed in Figure 7.
[The 1st Cruise]
Salmonids were caught north of 41 N and the CPUE values at northern stations were larger
0
than that at southern stations. Almost all salmonids caught in the 1st cruise were pink salmon
(Oncorhynchus gorbuscha); the other salmonid species were chum and coho salmon
(Oncorhynchus kisutch). Non-salmonid organisms caught in 44 • N and 42.5 • N were boreal
clubhook squid (Onychoteuthis borealijaponica), lantern fishes (Myctophidae), and smalleye
squaretail (Tetragonurus cuvieri), which inhabit the subarctic region. Organisms caught at 41
0
Nand 39.5 • N included those that migrate north from the subtropic region for feeding in
summer: Japanese common squid (Todarodes pacificus), flying squid (Ommastrephes
bartramii), Pacific saury (Cololabis saira), and Pacific pomfret (Bramajaponica). (Naito et
aI., 1977, Murakamietal., 1981, Takagi and Onishi, 1996, Takagietal., 1997)
[The 2nd Cruise]
Salmonids were caught only at 44· N. CPUE values were smaller than in the 1st cruise. In
the 2nd cruise, Catches of pink: salmon decreased, but catches of chum salmon and coho
0
salmon increased. The most abundant fish species at 39.5 N was Pacific pomfret. At 35 N,
0
Japanese scaled sardine (Sardinops melanostictus), flyingfishes (Exocoetidae), and Japanese
anchovy (Engraulis japonicus) were caught in high ratios. In addition, a small number of
many organisms that inhabit the subtropic region were caught at 35 N.
0
[The 3rd Cruise]
Surface temperatures increased to 16.7 e as for North as 44· N. The high temperatures
c
were presumably the reason why no salmonids were caught. At 44 N, boreal clubhook squid
0
and pacific saury were caught in high numbers. Surface temperatures were over 20 e at
0
stations south of 42.5· N, so there were many organisms that inhabit the subtropic region.
0
Flying squid were distributed between 39.5 N and 44 N.
0
3.Biological characteristics of salmonids, flying squid, and Pacific saury
[Chum salmon (Oncorhynchus keta)]
Figure 8-( 1) shows the fork length frequency distribution, male ratio, and adult ratio of chum
salmon caught by the drift gillnet at each station. There were no differences in fork length
frequency among stations on the 1st cruise or on the 2nd cruise. 97% of the collected chum
salmon that might be born in Asia or Russia (Myers et al., 1993) were mature. On the 1st
cruise, the proportion of males was high at 44 oN of 1st cruise (71.4%), but under 50% at
0
42.5 Nand 41 N. At 44 N on the 2nd cruise, the proportion of males decreased to 52.9%.
0
0
[Pink: salmon (Oncorhynchus gorbuscha)]
Figure 8-(2) shows the fork length frequency distribution and male ratio of pink: salmon
caught by the drift gill net at each station. There were no differences in fork length frequency
distribution among stations on the 1st cruise. But at 44 N on the 2nd cruise, the mean and the
0
median of the fork length were higher 25mm than those on the 1st cruise. The proportions of
0
males were 52.5% at 44 Nand 54.1% at 42.5 N on the 1st cruise. At 41 N on the 1st cruise
0
0
and at 44 N on the 2nd cruise, proportions of males were under 50%.
0
[Coho salmon (Oncorhynchus kisutch)]
Figure 8-(2) shows the fork length frequency distribution and male ratio of coho salmon
caught by drift gillnet at 44 oN on the 2nd cruise. The Range of fork lengths was 500-680mm,
and proportion of males was 67.6%.
[Flying squid (Ommastrephes bartramii)]
Figure 8-(3) shows the mantle length frequency distribution and maturity of flying squid
caught by drift gillnet at each station. All samples caught on the 1st cruise were large
immature females that were presumably born in last autumn (Murakami et at., 1981, Yatsu et
0
at. 1996). On the 2nd cruise, large immature males and females were caught at 39.5 N, and
one mature male (298mmML) and five small (l60-200m~1L) immature males and females
were caught at 35 • N. On the 3rd cruise, small immature males and females were caught from
0
39.5 N northward and these mantle lengths increased with increasing with latitude. Maturing
females were caught at 44 • Nand 42.5 . N, maturing males were caught at 42.5 N, and fully
0
0
matured male were caught at 39.5 N on the 3rd cruise. Those small immature males and
females collected on the 2nd and the 3rd cruises were born in winter or spring (Yatsu et at.
1996).
[pacific saury (Cololabis saira)]
Figure 8-(4) shows the body length frequency distribution of Pacific saury caught by drift
gillnet at each station. Almost all samples caught on the first two cruises were under
260mmBL. During the 3rd cruise, Pacific saury were caught only at 44 • N, and most samples
at this station were over 260mmBL.
ACKNOWLEDGMENTS
The Oshoro Maru and the Hokusei Maru, which belong to the Ministry of Education,
Science, Sports and Culture, Government of Japan, are the training vessels for students,
cadets and fisheries technicians. We thank the INPFC, NPAFC and their affiliated scientists
who are helping us to conduct salmon-research in the North Pacific Ocean for many years.
Your cooperation has helped us to train and teach many scientists and leaders in the fishing
industry through our salmon research program.
The other officers, crew, graduate students, and cadets of the Hokusei Maru acknowledge
their outstanding assistance and cooperation, in sampling and data collection under sometimes
severe conditions. We also thank Prof. Hideo Miyake, Prof. Tsutomu Ikeda, Prof. Kouji Iida,
Associate Prof. Naonobu Shiga, Associate Prof. Isao Kudo, Associate Prof. Yasunori
Sakurai, Associate Prof. Syuuichi Watanabe, and Assistant Prof. Hiroji Ohnishi, about their
help.
REFERENCES
Data Record of Oceanographic and Exploratory Fishing Numbers 1-43 (1956-2000). Faculty
of Fisheries, Hokkaido University, Hakodate.
Dodimead, A.1., F. Favorite, T. Hirano. 1963.: Salmon of the North Pacific Ocean. Part II.
Review of oceanography of the subarctic Pacific region. Int. North Pacific Fish. Comm.
Bull. 13: 1-195.
Favorite, F., A.1. Dodimead, and K Nasu. 1976.: Oceanography of the Subarctic Pacific
region. Int. North Pacific Fish. Comm Bull. 33: 1-187.
Myers K W., C. K Harris, Ishida, Y, L. Margolis, and Ogura, M. 1993.: Review of the
Japanese landbased driftnet salmon fishery in the western North Pacific Ocean and the
continent of origin of salmonids in this area. Int. North Pacific Fish. Comm. BulL :52-86.
Murakami, K, Watanabe, Y and Nakata, 1. 1981.: Growth, Distribution and Migration of
Flying Squid (Ommastrephes bartrami) in the North Pacific. Contribution No. 136 from
the Research Institute of North Pacific Fisheries, Faculty of Fisheries, Hokkaido
University. :161-179.
Naito, M., Murakami, K, Kobayashi, T., Nakayama, N. and Ogasawara, 1. 1977.: Distribution
(Ommastrephes bartrami, Onychoteuthis
Borealijaponicus, Berryteuthis Magister and Gonatopsis Borealis) in the western
and
Migration
of
oceanic
squids
subarctic Pacific region. Contribution No. 90 from the Research Institute of North
Pacific Fisheries, Faculty of Fish eries, Hokkaido University. :321-337.
Takagi, K 1961.: The seasonal change of gonad weight of sockeye and chum salmon in the
North Pacific Ocean, especially with reference to mature and immature fish. Bull.
HokkaidoReg. Fish. Res. Lab. 23:17-34.
Takagi, K. 1975.: A non-selective salmon gillnet for research operation. Int. North Pacific
Fish. Comm. Bull. 32: 13-41.
Takagi, S. and Onishi, H. 1996.: Interannual variability in distribution and abundance of
pelagic nekton and oceanographic conditions in the central North Pacific in early
summer, 1979-1995. Prc. Salmon Workshop.
Takagi, S., Sakurai, Y, Kamei, Y, Miyoi, T., Sakaoka, K. and Shiga, N. 1997.: Oceanographic
conditions and distribution of pelagic ocean during the summer and fall in 1995 and
1996. Bulletin of the Faculty of Fisheries, Hokkaido University, Vol. 48, No. 112,: 13-28.
Yatsu, A., Midorikawa, S., Shimada, T. and Uozumi, Y 1996.: Age and growth of the flying
squid (Ommastrephes bartrami),
(1997): 250-270.
In
the North Pacific Ocean. Fisheries research 29
Table I List of oceanographic stations
(contained water color and transparency ofthe sea)
Station
Lat.(N)' I Long.(E)"!
S.MT(TZ.+lO) COL*2 TR."3 Remark
Date
H000014 35-00.0
\55-00.0 June 4
1402
X.BT
HOOOOl5 35-45.0
155-00.0
5
1223
X.BT
H000016 36-30.0
155-00.0
5
1703
X.BT
X.BT
HOOOOl7 37-15.0
155-00.0
5
2300
H000018 38-00.5
154-59.3
6
0437
4
16
CTo.
H000019 38-44.9
155-00.2
6
1220
3
10
CTD.
H000020 39-31.7
155-02.3
6
1904
4
13
CTD.
H000021 40-14.9
155-01.7
7
0927
5
15
C.TD.
H000022 40-59.9
155-00.0
7
1502
4
15
C.TD.
H000023 41-45.1
155-00.0
8
0905
4
14
CTD.
H000024 42-30.1
155-00.0
8
1452
4
11
CTD.
H000025 43-14.9
155-00.1
9
0840
5
10
CTD.
H000026 44-00.0
155-00.0
9
1336
5
8
CTD.
25
0726
CTD.
C.To.
C.To.
H000028 43-58.8
154-59.2
H000029 43-15.2
155-00.4
26
0926
4
12
H000030 42-30.0
155-00.0
26
1455
4
13
H000031 41-44.8
154-59.5
26
2128
CTo.
H000032 41-00.0
155-00.0
27
0416
4
11
C.TD.
H000033 40-15.0
155-00.0
27
1005
3
13
C.TD.
H000034 39-30.2
154-59.8
27
1501
3
11
CTD.
H000035 38-45.1
154-59.8
28
0917
4
17
CTD.
H000036 37-59.9
155-00.0
28
1430
3
23
CTD.
H000037 37-15.4
154-59.9
28
2037
C.TD.
H000038 36-30.0
155-00.0
29
0323
C.TD.
H000039 35-44.9
155-00.0
29
0920
3
24
CTD.·
H000040 34-57.5
154-58.0
29
1820
3
27
CTD.
H000074 44-00.0
155-00.0
July 31
1234
4
6
CTD.
3
II
H000075 43-15.0
155-00.0 Aug. 1
1040
H000076 42-30.9
155-05.0
2
0004
H000077 41-45.0
155-00.0
2
1010
H000078 41-00.0
155-00.0
3
0141
C.TD.
CTD.
3
IS
CTD.
CTD.
H000079 40-15.0
155-00.0
3
0950
3
19
CTD.
H000080 39-26.9
155-05.7
4
0024
3
21
C.TD.
H000081 38-45.0
155-00.0
4
0848
3
32
CTD.
H000082 38-00.2
155-00.0
4
1442
3
28
CTD.
H000083 37-15.0
155-00.0
4
2250
H000084 36-30.0
155-00.1
5
1215
2
28
CTD.
H000085 35-15.0
155-00.0
6
0824
2
30
CTD.
H000086 35-00.0
155-00.0
6
1358
2
24
CTD.
* I: Fixed position by Global Positioning System
*2: COL.
*3 : TR..
=
=
Water color in Forel-Vle scale
Transparency in meters with Secchi disk
X.B.T. : X.B.T. cast
C.T.D. : C.T.D. cast
C.TD.
Table 2 Position and research conditions of drift gillnet research at each station for all three cruises
No. of
Date and Time (T.Z.: +lOh)
Position
D.D.
research
Net set
Net haul
Lat(N)
Long.(W)
Bottom
depth(m)
Wr
Wind
ST
Tr
(C)
HOGOOOI
June 6
1828-1846
June 7
0431-0517
39-30.2
154-59.7
045
5597
c
SE
-4
15.7
13
HOGOO02
7
1750-1805
8
0431-0511
41-00.2
154-59.2
000
5490
c
SSE -4
12.2
15
HOGOO03
8
1753-1817
9
0403-0449
42-30.5
155-00.5
220
5192
bc
West -4
11.9
II
HOGOOO4
IO
1746-1808
II
0358-0442
43-59.8
154-59.9
215
5304
0
NW
-4
7.2
8
HOGOOO5
24
1748-1806
25
0420-0513
44-00.1
154-59.8
225
5299
0
North -3
9.2
10
HOGOO06
25
1747-1807
26
0352-0454
44-00.7
155-00.7
225
5322
0
NNW -3
9.3
12
HOGOOO7
27
1749-1807
28
0426-0519
39-30.2
154-59.1
290
5619
ENE -5
17.1
II
HOGOOO8
29
1748-1812
30
0418-0500
34-59.7
154-59.7
210
5628
bc
South -3
23.4
II
HOGOO09
July 31
1758-1817
August I
0433-0526
43-59.7
154-59.4
070
5293
f
SW
-3
16.7
6
HOGOOIO
August I
1752-1809
2
0421-0516
42-30.3
155-01.3
IIO
5192
c
SSE -5
19.9
15
HOGOOII
2
1753-1810
3
0425-0506
41-00.3
154-59.6
045
5515
0
West -5
22.4
14
HOG{)012
3
1757-1812
4
0438-0518
39-30.1
155-00.1
080
5625
c
West -3
25.4
21
HOGOOl3
5
1751-1807
6
0442-0515
36-29.6
I 55-00.!
150
5704
0
South -4
29.4
28
D.D : Direction of Drift toward
ST : Surface temperature
Wr. : Weather
Tr : Transparency
Table 3 Data on number of organisms caugut by drift gillnet
during the HOKUSEI MARU cruise in 2000
Species
HOGOOOI 0002 0003 0004 0005 0006 0007 0008 0009 0010 0011 0012 0013 Total
Japanese common squid
Boreal clubhook squid
6
85
41
2
16
Eight-armed squid
Flymg squid
16
II
33
39
322
496
6
36
3
389
4
5
3
7
19
12
Luminous flying squid
Blue shark
2
6
200
103
1
19
44
8
99
10
182
Atlantic mako shark
I
Salmon shark
2
Cigar shark
Japanese scaled sardine
12
Japanese anchovy
3
2
40
2
20
Pink salmon
65
Coho salmon
116 405
4
Chum salmon
19
20
3
62
53
32
II
106
244
43
26
936
76
134
114
349
Chinook salmon
I
Lantern fishes
6
Pacific lancetfish
1
Pacific saury
5
17
2
3
145
2
315
FIyingfishes
4
463
66
5
7
33
III
Carangidae
Pilotfish
5
YelJo\,tail
62
7
2
72
3
2
2
25
24
4
2
2
78
936
Striped jack
Pompano dolphin
Dolphinfish
18
882
12
8
8
2
7
19
2
7
2
2
2
Amberjack
Pacific pomfret
I
Taractes sp.
Striped marlin
2
I
ShortbilJ spearfish
Swordfish
2
Chub mackerel
3
5
4
2
7
Auxis sp.
Skipjack tuna
Albacore
381
9
2
48
60
6
Figured scriptus
Dall's porpoise
2
19
2
2
163
18
10
Unicorn filefish
Tufted puffm
21
2
Japanese butlerfish
Homed puffin
28
15
2
lcichthys !ockingtoni
Short-tailed shearwater
9
7
Snake mackerel
Smalleye squaretail
405
2
13
2
24
2
54
107
14
47
47
2
3
5
145
0
150
0
155"E
Fig. 1-1 The 1st cruise (June 1'"'-'June 15)
June 21 departure
July 5 return
: @ : Oceanographic station and
Drift gillnet station
150
0
155°E
Fig. 1-2 The 2nd cruise (June 21 '"'-'July 5)
145
0
155°E
Fig. 1-3 The 3rd cruise (July 28'"'-'August 11)
Fig. 1 Locations of oceanographic stations and drift gillnet stations during each cruise
1st Cruise, from June 1 to 15 (Fig. 1-1);
2nd Cruise, from June 21 to July 5 (Fig. 1-2);
and 3rd Cruise, from July 28 to August 11 (Fig. 1-3)
Latitude ( oN )
o
44
43
42
41
40
39
Latitude ( oN )
38
37
36
35
44
43
42
41
40
38
37
36
200
200
400
400
~
~
n
~
~
~
C~
C~
800
800
1000
No Data
~Hff/)¥~
h
0"
I
1000
Temperature
Salinity
Latitude ( oN )
44
43
42
41
40
39
400~~\V/2
. . '\~~
~./
-5
'\
IiOO
_
38
37
36
35
~~~~.
'""
c3
39
0
\2
'\
\ '"
~
'7f..YfJffJJfffJj'"
No Data
~
Mol . ~
IOool~,
Density
(
C)
, ~ ~:; '
::1
OJ
~
~
15
~
~ ': f// ""ooo'~J
0
33
34
(PRU)
SALINITY
0
Fig. 2 Temperature, salinity and density from surface to 1000m depth along the 155 E transect in the 1st cruise
35
Latitude CN )
43
42
41
40
39
Latitude ( oN )
38
37
36
43
35
200
41
40
38
39
37
36
35
200
400
400
..c:
..c:
0.
QJ
Q
42
0.
QJ
Q
600
600
800
800
1000
1000
,],....~
Salinity
Temperature
Latitude ( ON )
44
43
42
41
40
39
CC)
38
37
36
..
35
0
jjDotllHO
25
II(lDOO38
flob~037
"-11000<>3
1I0qoo;,e ~-,
200
1I04no35-';;;
"'il\>00034
20
IIOOO~{;~~003
W
""
<:
"w
400
[-
0.
::1
W
600
[-
15
__
ItOOJ)lY.3"6
..
1109DO 31
1o;:029
..-A1
10
~---.--
,
."H000028
800
1000
.""
o
Density
L----.-L-~---L-~~U)
34
33
SALINITY
Fig. 3 Temperature, salinity and density from surface to lOOOm depth along the 155°E transect in the 2nd cruise
0
Fig. 4 Temperature, salinity and density from surface to lOOOm depth along the 155 E transect in the 3rd cruise
o
4
2
6
8
Dell
o
8
ti
2
4
6
8
Il
~
II
ti
I!
:D
O~I~-L~~-W~~~I~I~I
~~~Wl~~~~_ _~~
The 1st cruise
The 15t cruise
J
J
o
2
4
6
8
Dell
B
ti
02468D~lItiB:D
The 2nd cruise
(
02468D12l1tiB:D2I21:D
~-'-'-w...l-'--'-'-'-'-~'-'-'-~T~h'-'e~2..LnW~ cruise
j>f-I
J
~
j
o
2
4
6
8
Dell
ti
B
o
2
1
'-----1
The 3rd cruise
4
6
8
D
1I
rl
Ii
8
:D
';~!
/.-'
/
o
2 4 6 8 Drlllti8:D2I21:D
!
j
!
!
!
!
)
I
I
The 3rd cruise
The 3rd cruise
Fig. 5 Vertical profiles of water temperature along the 155°E transect in 2000 .
44°30'N
44°N
3D
3lS
:00
315
310
315
Jill
3D
3lS
3D
315
01
I..,...
Jill
,
:00
315
310
315
Jill
3D
315
Jill
The 1st cruise
~
J
3lS
310
I
~
3D
315
~
I
J
ID
i
The 1st cruise
1
~
3lS
:--------~~
J
aJ
,
3D
01
I
J
The 1st cru ise
315
310
39°30'N
J
31.5
:00
315
310
315
Jill
3D
31.5
:00
315
310
315
Jill
01
The 2nd cruise
The 2nd cruise
:I
\
I
I
mj
The 2nd cruise
I
I
~
~
I
.(l)j
J
J
i The 3rd cruise
I
J
0
Fig. 6 Vertical profiles of water salinity along the 155 E transect in 2000
The 1st cruise
The 3rd cruise
The 2nd cruise
squid 0.3%
Chum
6.3%
P
44N
Others
Pink
54.8%
Chum
/2.2%
13.,. _ _ _
42.5N
Cohcl1
0.7%
Pink
837%
.
N=45
Flying squid
32.9%
41N
N= 106
squid
Japanese anchovy
10.3%
29.9%
Yellow tail
20.7%
Flying squid
45.7%
N= 42
Dolphinfish
16.5%
N= 375
Dolphinfish
12.6%
36.5N
N= 118
Japanese scale sardine
35N
r
Japanese anchovy
17.0%
Unicorn filefish
24.1%
N= 64
Flyingfishes
27.2%
Fig. 7 Latitudinal variability of CPUE and species composition caught by non-selective drift
gillnet during each cruise. Area of circles corresponds to CPUE value. N=CPUE
Chum salmon
The 1st cruise
The 2nd cruise
50.0
50.0
::; 40.0
100% mature
N=25
Male:71 .4%
::; 40.0
'-"
'-"
....
30.0
(i)
....(i) 30.0
8::l 20.0
Z
44N ~
Z
..0
10.0
N=104
M:52.9%
98.1 %mature
20.0
10.0
0.0
480 500 520 540 560 580 600 620 640
0.0 '--==
480 500 520 540 560 580 600 620 640
Fork Length (mm)
Fork Length (mm)
50.0
::; 40.0
'-"
N=3
Male:66.7%
66.7% mature
42.SN
~ 30.0
8:::l 20.0
Z
10.0
0.0
480 500 520 540 560 580 600 620 640
Fork Length (mm)
50.0
::; 40.0
'-"
is
8
..0
N=7
Male:40.0%
96% mature
30.0
Z 20.0
41N
10.0
0.0
480 500 520 540 560 580 600 620 640
Fork Length (mm)
Fig. 8-(1) Fork length frequency distribution, male ratio, and adult ratio of chum salmon
caught by non-selective drift giIInet at each station during each cruise.
The 1st cruise
50.0
Pink salmon
50.0
;j 40.0
The 2nd cruise
;j40.0
'-'
N=221
Male:52.5%
~
.E
~
'-'
N=230
Male:36.1%
~30.0
§J
44N. Z
120.0
10.0
300320340360380400420440460480500520540560580
0.0''----"'---'---'----.:
300320340360380400420440460480500520540560580
Fork Length (mm)
,-.,
Fork Length (mm)
N=111
Male:54.1%
";f.
'-'
~
il)
I
Coho salmon
42.SN
0.0'
=
rj1!!!i!j!!J"'-'-)¥
300320340360380400420440460480500520540560580
Fork Length (mm)
50.0
'-'
~ 30.0
.D
~
~
20.0
1z
10.0
41N
ZE 20.0
0.0
10.
0.0 1
N=37
Male:67.6%
";'
il)
N=55
Male:32.7%
;j 40.0
30.0
500 520 540 560 580 600 620 640 660 680 700
rj1!!!i!j!!J
fI'!S!'!
Fork Length (mm)
300320340360380400420440460480500520540560580
Fork Length (mm)
Fig. 8-(2) Fork length frequency distribution and male ratio of pink and coho salmon caught by non-selective drift gillnet at each station
during each cruise.
Flying squid
The 2nd cruise
The 1st cruise
,-.... 50
~
40
15
30
§
20
....
44N
Z
The 3rd cruise
N=4
one maturing
female
10
o
~~~====~~--~-
,-.... 50
~
....
42.5N
40 P---+----.,.--J
15
30
§
20
Z
10
o
50
all immature female
,-.... 50
~
~ 40
,-....
~ 40
'-'
N=14
~ 30
41N
..0
§ 20
Z
....
15
8::l
Z
30
20
10
10
o '--~
o
260 300 340 380 420 460 500
Mantle Length (nun)
~
Only two
immature female
(374&392mm M.L.)
'#.
'-'
50
39.5N
40
N=5
j ::
60
~ 50
';:;' 40
<U
..0 30
8
Z 20
10
10
o .I..-._-!-_ _
o
140 180 220 260 300 340 380 420 460 500
Mantle Length (mm)
,-.... 50
~
40
~
30
1
N=6
J
20
10
o
140 180 220 260 300 340 380 420
Mantle Length (nun)
Fig. 8-(3) Mantle length frequency distribution and maturity of flying squid caught
by non-selective drift giI1net at each station during each cruise.
Pacific saury
The 1st cruise
The 2nd cruise
The 3rd cruise
35
,-, 30
~
]44N]
'-' 25
~
..0
~
N=122
20
15
10
5
o
100
140
180
220
260
300
340
Body Length (mm)
I Only one (190mm B.L.) I
] 42.5N ]
35
,-,
~
'-'
.....
v
..0
S
::l
Z
30
I
-
N=210
I 39.5N ]
I
180
220
260
300
340
I
380
Only two (220 &
250mm B.L.)
Body Length (mm)
Fig. 8-(4) Body length frequency distribution of pacific saury caught by non-selective drift giBnet at each station during each cruise.
380