Translation Series No. 533
/ c,_
ti.-- FISHERIES RESEARCH BOARD OE cumg NANAIMO, B.
FISHERIES RESEARCH BOARD CE CANADA r Translation Series No. 533
Migration of the iSurumet squid, Ommastrephes sloani pacificus (Steenstrup),
------in -the -coastal waters of Japan
By Junsuke Soeda
From: Scientific Papers of the Hokkaido Experimental Fisheries Institute No. 4, pp. 1-30, 1950.
- Translated by*Expme-s,s-Ttanslatian_Service-,_ -4-01- +Il e Bureau for Translations, Foreign Language Division, Department of the Secretary of State of Canada
Fisheries Research Board of Canada Biological Station, Nanaimo, B. C. 1965 GP/5 44 DEPARTMENT OF THE SECRETARY OF STATE SECRÉTARIAT D'ÉTAT BUREAU FOR TRANSLATIONS BUREAU DES TRADUCTIONS FOREIGN LANGUAGES DIVISION DES LANGUES DIVISION ÉTRANGÈRES
TRANSLATED FROM - TRADUCTION DE INTO - JAPANESE ENGLISH
SUBJECT - SUJET MIGRATION OF THE SQUID ISUR1flME 1
AUTHOR - AUTEUR SOEDA, JUNSUKE
TITLE IN ENGLISH - TITRE ANGLAIS MIGRATION OF TEE (SiTUI-4-11SURUIel) CeLASTREPHES SLOAN' PACIFICUS (STEENSTRUP) IN THE COASTAL WATERS OF •,fAPAN
TITLE IN FoREIGN LANGUAGE - TITRE EN LANGUE ETRANGERE
Ommastrephes sloani pacificus (STEENSTRUP) ;5:e1-. tàs
REFERENCE - RgFdREN,CE (NAME OF BOOK OR PUBLICATION - NOM DU LIVRE OU PUBLICATION) , )% CAZ-1/4:C eUgg.Irjtjr--( Wre tu-4> _,GM-T-ME EXPERIMENTAL FISHERIES INSTITUTE ) No.4, 'Mtn-CH-1-9,C /--3 û /Îrà •
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CITY - VILLE DATE PAGES 1950 1 - 23
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MIGRATION OF THE SQUID ISURUMEt,
OMMASTREPHES SLOANI PACIFICUS (STEENSTRUP)
IN THE COASTAL WATERS OF JAPAN
JUNSUKE SOEDA
Report from the Experimental Fisheries Institute
of Hokkaido, No. 4
March 1950
Experimental Fisheries Institute of Hokkaido 4
OF THE Sun MIGRATION , SURUMEI OLTIASTREPIIES SLOANI P.1 PACIFICUS (STEENSTRUP), IN THE COASTAL WATERS OF jApAN
Junsuke Soeda
INTRODUCTION
The squid, Surume, Ommastrephes sloani pacificus, is very common and is found in all coastal waters of Japan, although there are some seasonal variations in its distribution. From the point of view of the quantity fished, it is one of the most important natural resources of the sea in Japan. In Hokkaido, especially, larger quantities of squid are caught than of any other sea product, about 60% of the total catch being made in South Hokkaido. Hence the economy of the South Hokkaido region depends to a large extent on the fishing of squid.
From 1910 onwards, the fishing of squid can be divided into three periods with respect to the quantity caught in Hokkaido.
The first period lasted until the early Taisho era. The boats used had no engine, and the fishing was carried out when the boats were at anchor. This period, therefore, may be described as the rowing boat period.
The second period lasted until about 1935. Some engine- powered boats were now used; the fishing was still carried out at anchor, but the fishing area was considerably increased.
The third period began in 1935 and reaches up to the present time. No advances or changes in the types of fishing boats have been made, but the number of engine-powered boats has greatly grown.
The boats are not anchored, and the fishing position is changed continuously so that the fishing area has increased still further.
The quantity fished annually during these three periods increased from about 18,750 to 37,500 tons in the first period, 2
to about 56,000 tons in the second period and to about 94,000 tons
in the third period. There were however considerable differences
in every period, depending on the year (see Fig. 1).
An investigation into the causes of the fluctuations in the
annual quantities fished is required, so that fluctuations can be
predicted and thus help to stabilise the squid fishing industry.
In the case of the squid, however, there is no method airailable at present for investigating their group formation and age distributior„ which are known in the cases of other fish. Hence fundamental eco-
logical studies must be undertaken, and any investigations should •
be based on the results of such ecological studies. Complete ecolo-
gical studies of one species cannot however be carried out in a
short period. Studies of this kind are now in progress, but parallel
investigations of the migration routes, which are directly related
to the fishing, are also needed. D.2
.••■■
,•
Fig. 1: Annual total catch in Hokkaido (kan) (1 kan - 3.75 kg.) 3
History of the investigetions of migration
The Hokkaido Fisheries Institute made an investigation in
1889 of the directions from which the squid came every season.
According to their records, along the Pacific coast of South
Hokkaido the squid travel from shallow water to deep water, in the
Tsugaru Channel the squid come from the west and move to the east, in the Hinokiyama district the squid come from the south-east and travel to the west, and in the Goshi district they come from the
South and travel to the north. According to an investigation carried out by the Ministry of Agriculture and Commerce in 1912, squid arrive in Sado Island the from the Noto coast and then P.3 gradually move further out from the shore at the beginning of winter. Sasaki (1921) has published a report on the differences in the fishing season in various parts of the coastal waters of the Japan Sea, but failed to find any evidence that the squid migrate all the way from Kyushu to Hokkaido. He did not reach a conclusion on the problem of the Surume species, i.e. whethar all the Surume-squid in the coastal waters of Japan belong to the same species or not e and after comparing the development and the rate of maturing of the reproductive organs of squid found in Hokkaido with those of the squid found in Kyushu he concluded that it was improbable that the squid would travel such a great distance.
Ishii (1932) has reported, from the results of ecological investi» gations carried out at Oki Island in Shimane prefecture, that there are two different species of squid. Isahaya and Kawana carried out investigations on the squid in Hokkaido and North East Japan over a period of 6 years (1927 - 1932), and classified the Surume- squid found in the Japan Sea into two main types, the Northern type and the Southern type, which they classified further into sub- groups, as shown in Table 1. They also reported (1932) that the Surume-squid generally travel in a north-westerly direction. 4
Table 1: The classification due to Isahaya, and the distribution
North Distribution -district Pacific east of the Hidaka and Pacific Group: Uraga Coasts. species South Distribution - the Iwate Northern Pacific prefecture Group: coasts Type Japan SeaSe Distribution - around Esashi Surume- species : and Hakodate, and as far as -{ East Muroran Squid Southern Pacific Distribution - district south of species : the Iwate prefecture coasts Type Japan SeeSea Distribution - districts further species : south than Rishiri and Rebun I Islands
Tauchi and Sanyoshi (1940) have suggested, from a consideration of the relationship between the fishing season and locality, differences
in the annual catch, etc., that there are two different groups of
squid, one of which travels long distances, like the common sardine
Sardina Melanosticta (T. et S.), while the other group stays within a local area. The present author (1945) has discussed the possibility of predicting the annual fishing conditions for the Surume-squid and has described briefly the two types suggested by Ishii and Isahaya and the relationship between the distribution and fishing season.
After considering the changes in sea temperature, the feeding habits of the squid, their change in size (mantle length) and the seasonal changes in the fishing grounds, obtained from the results of inves- tigations at fishing grounds where the statistics of the amount caught the previous year were known, thp present author reported
(1946) that the Surume-squid in the coastal waters of Japan all belong to a single species which travel between Saharein (Karafuto) in the North and Kyushu in the South. In order to prove this, marking and releasing tests were carried out in the autumn of the same year in the Tsugaru Strait. Some of the results were published
5
in Part 1 (1947) and additional results have been reported since.
The results obtained to date (1948) are summarised in this report.
The Movement of the Fishing Season and the Change in Mantle Length
The Surume-squid can be caught anywhere along the coasts of
Japan, both on the Japan Sea coasts and the Pacific coasts. The
most important fishing grounds are, however, the coasts along which
the Tsushima Current flows, and the Tsugaru Strait. According to
Sasaki (1921), who has described squid fishing in the Japan Sea,
the fishing season commences at Uryo Island in early spring and
after ten days or so the first catches are made at Oki Island;
about 2 weeks after this fishing begins on the north-west coast of
the Noto Peninsula. The fishing season at the Noto Peninsula com-
mences in early May and by the middle of the month fishing begins
on the west coast of Sado Island, and, at the end of the month, on
the east coast of the island. The fishing season in the Tsugaru Strait begins a few days later.
The change in mantle length of the squid caught at many p.4
'places during their fishing season is described. The change in
manfle length of squid caught by angling in the Tsugaru Strait is
shown in Table 2. Apart from these, some squid of mantle length
20 - 40 mm are caught in fixed nets from early spring to May.
The fishing season in the Tsugaru Strait normally begins
in early June, although the date varies slightly from the beginning
of May to the Middle or end of June. The busiest fishing time for tsummer squid', a colloquial term for the squid caught before
1st September, is July. In midsummer, in August and September,
when the temperature of the water rises, fishing becomes less pro-
ductive and this period is known colloquially as the t summer restt;
in some years the squid disappear entirely. In the autumn, as
6
■■■■
h-ngth in dorsal Nos. measured • .Date Average Large* Smallee mm mm , mm ; indv.• 189.72 210 170 50. . 9I AugE ., 241 184 - 1, Sept-, -1/ 202.08
. .182 . 12, re re 205.34 247 226 182 22, - ed. // 204.78 100 // 2, - Oct., /l. 215.46 218 200 30, ee ee. 223.58 247 s' 210 9, Nov., " 230.50 262 90, ee 227.18 245 210 138 2S, May, '46 167.36 198 186 13, Sept., 201 -.94 • 222 245 19G 19, Oct., " 228.84 200 l/ . 5, Nov., " 229.84 - 261 148. 109 // 6, June,. '19 130.50 148 /I • 24, July, " 164.52 189
Table 2: The change in the mantle length during the fishing season, of the squid caught on Hakodate coast
the water temperature falls, the fishing season begins for
'autumn squid', a colloquial term for the squid caught between
1st September and the end of the season. The fishing is fairly
heavy from the middle or end of September, becomes heavier in
October, and the busiest season is in November. The season ends
in January, or, in someyears in.early February. The changes in
the mantle lengths of the squid caught during the fishing seasons
are explained below. In early spring, before the fishing season
begins, squid of mantle length e'qual to 30-40 up to 70-80 mm are
caught infixed nets. In the early part of the fishing season
squid having a mantle length of about 100 - 170 mm are caught.
At this time a few of the colloquially called !female squid', which
are preparing to spawn and have a mantle length of about 270-300 mm,
are caught together with the ordinary squid. A study on 'female n.5 squid' will be published separately. These female squid can be 7 caught in the Tsugaru Strait at any time between early spring and late autumn if the places where they are gathered can be found.
As the fishing season Proceeds, the mantle length gradually increases to about 230 mm for thetautumn squid', and to about 300 mm at the busiest time in November and December. In the January of the follow- ing year the mantle size falls slightly to about 270 mm, and at the end of the fishing season squid with a mantle length of about 250 mm are being caught. This decrease in the mantle length in squid caught towards the end of the fishing season can be explained as follows. At this time of year the fishing grounds are limited to areas close to the shore, because of the strong seasonal north-west winds and the roughness of the sea, while the larger squid are found some distance from the coast, where no fishing is in progress at this time of year. For example, the present author went fishing on December 4, 1947, about 10 nautical miles south-west of Esan, and caught a large number of squid. Their average mantle length was 277 mm, the largest being 287 mm and the smallest 267 mm. The majority of them were impregnated females, but a long time before their eggs would be mature. The ordinary fishing boats, on the other hand, which were fishing much closer to the shore, were catch- ing squid with a mantle length of 250 - 270 mm. This problem of the decrease in size must be studied further. In the Tsugaru Strait, the fishing season in early spring commences first at the entrance to the Japan Sea and then later fishing starts on the north and east coasts of the Strait. At the end of the Wishing season, on the other hand, fishing ceases first east of the Esan Limit and then gradually the fishing season moves west through Matsumae, Oshima, and Kojima, and thus the season ends. Similar tendencies in the movement of the fishing season are seen in all the main fishing areas. The relationship between the fishing season and the mantle length of the Surume for various fishing areas are shown in Fig. 2. Explanations of the figures for individual fishing areas are given below.
8
by Mantle leng,th Ca nun' , m Y •.= •-:.>.. i : :-.71 ,c 7( ›: ;./, _. _.,. Conk- of i i 5 200 --
. 1 I 300; Tsugarn-ç,trait WIO-300 I I 300; Yamr_gc.tr. Prf. .••••• — 40 –100 ' 270-300 i 711-Irmr.guchi P.r.f. — 270.--.300 Prf. 1—i— - -- 10 ,-40 270...300 Clan P•f. I—!— 27O300 Iwte Prf- I 30-7 150 270-200 I I
Fig. 2: The fishing season and the mantle lend-th- of squid for various representative fishing coasts
1.. Sakhalin and Rakmacka area (Karufuto and Rakumakka)
At Mamiya Strait and the Rakmacka coasts the fishing usually
starts at the end of July and the busiest season is in August and p.6 September. In October the squid disappear. The mantle length of
the squid caught in the early part of the season is about 200 mm
increasing to about 230 mm as the season progresses, and finally
reaching about 250 mm by the end of the fishing season in this area.
2. The Hinokiyama Coast of Hokkaido
These areas are located at the west entrance of the Tsugaru
Strait, and therefore the fishing season bagins between the middle
or end of May - and the beginning of June. The Season for 'summer
squid' .is in July and August e and between August and September
the fishing becomes less productive. The fishing season for 'autumn
squid' starts from the end of SePtember to October and, in years
when the seasonal north-west wind is weak, the fishing is most pro-
ductive in November and December and continues till January and
February of the following year. In ordinary years, however, the
seasonal north-west wind characteristic of this district blows 9 strongly, and the weather is frequently too rough to permit fishing; the catch is thus usually smaller at this time. The mantle lengths of the squid caught in this area are no different from those of the
Tsugaru Strait. The first fishing is carried out in the southern part of the area, and the fishing season ends first in the northern part.
3. Yamagata and Ishikawa Prefecture on the Japan Sea
Fishing starts in these districts in early May 9 and the squid caught including ones with a mantle length of 100 mm, small ones of
20-30 mm, spawning females, large ones with immature eggs etc. There is a break in the fishing season in July, or at the latest in August, but after midsummer, when the temperature of the sea water falls, the fishing season starts again following on the season in the West
Tsugaru Strait and the Tsugaru district of the Aomori Prefecture.
The mantle length of the squid fished in this winter season is about
250 - 280 mm. The season ends in January or February of the following year.
4. The Yamaguchi Prefecture Coast
The season starts between October and November, the squid caught having a mantle length of about 270 mm, and lasts till about
March of the following year. The majority of the squid caught throughout the season have a mantle size of about 250 mm and include a mixture of mature and immature squid. There is only one (winter) fishing season.
5. The Tokushima Prefecture Coast
In the spring, in March and April, squid of mantle length
20-30 mm are caught in fixed nets. No squid are found in the summer.
In the autumn, in November, most of the squid caught have a mantle length of about 270 mm but large ones (300 mm) are also caught. The fishing season ends in February of the following year. 10
6. The Chiba Prefecture coasts
In the spring, from April to May, squids of mantle length
10-40 mm are caught in fixed nets or in drag nets and in the summer the squid disappear. In the autumn, from the end of October to
November, squid having a mantle length between 200 and 270 mm are
caught. The season ends in February of the following year. In this
district, therefore, there are two fishing seasons: one in early
spring and one lasting from autIlmn to winter.
7. The Iwate Prefecture coasts
The fishing season in this district begins in the spring,
from April to May, when squid of mantle length about 30 mm are
caught. May and June are the busiest times for catching these
small squid. The mantle length gradually increases and in August, D ,7 when the fishing season ends, it is 100 - 180 mm. The autumn fishing season is from the end of September to October, a few weeks later than the season on the Shimokita-gun coast of Aomori Prefec- ture. The mantle length of the squid is abàut 250 - 270 mm. The fishing season lasts till January or February of the following year.
In this district the spring fishing season begins first along the
southern part of the coast, while the autumn and winter season starts first along the northern part of the coast.
The relationships between the fishing season and the mantle length for various districts of the Japanese coasts have been des- cribed briefly above. The small squid, which are caught mainly in the spring, are found closer to the shore than the large squid caught in autlImn and winter. These small ones are usually caught with fixed nets or in drag nets. The small squid can be caught, with nets, in gulfs or inlets, such as the Gulf of Osaka, where no large squid are caught as they live further offshore. The large squid, found further out from the shore in autumn and winter, are caught by angling in most districts, with the exception of the 11
Funka Gulf district in Hokkaido and a few other small places.
Movement of the optimum temperature zones in
( the coastal waters of Japan
During the spawning period, the Surume-squid require
special conditions and are therefore not considered in this section.
The squid caught commercially are those which are feeding, and
therefore their migration is not only determined by the change in
the water temperature but must also be closely related to their food.
Sasaki (1921) has reported that the small squid found in spring
feed mainly on floating crustacea, and the food of the large squid
caught in the later season consists of small fish (about 70%),
squids (about 20%), and floating crustacea (about 10%). Hence
the suitable conditions for these live foods are important and
necessary conditions for the squid. The squid feed on the follow- ing 4 types of fish:
1 0 Mackerel. Scomber japonicus Houttyn
2. Common sardine. Sardina melanostica (T. et S.)
3. Hard-mouth sardine. Engraulis japonicus (T. et S.)
4. Dull...eyed sardine. Etrumeus micropus (T. et S.)
The localities where the squid are found must thus be
related to the conditions which are suitable for these fish.
Suitable temperatures for the squid are given below. Sasaki
(1921) has stated that squids are found in the highest density,
and are therefore fished most productively, in water in the
temperatue range of 10 to 17 °C.. Uda (1942) reported that squid
can live in water whose temperature is between 5 and 25 °C, and
that the temperature range most suitable for fishing is 13 - 16 °C.
If the movement of these suitable temperature zones in the coastal
waters of Japan is compared for the Pacific Ocean and the Japan
Sea coasts, it is found that they are not related. This is due
to the difference in the sea currents. There are two currents 12 which flow along the Pacific Ocean coasts: the warm Kuro-Shio which comes up from the south-western coasts of Japan and the
cold Oya-Shio, which flows down from the Kuril Islands. These
two currents meet on the coasts between Hokkaido and North East
Japan, and the conditions where they meet differ each year
depending on their relative strengths. The water temperature
is thus considerably affected. The currents in the Japan Sea,
on the other hand, are relatively simple. The only important
current is the warm Tsushima Current, which flows south-west p.8
to north-east, although some minor changes in the direction of
the current occur. The water temperature depends on the strength
of the Tsushima currnnt only. The only current which meets the
Tsushima Current is the very small cold Liman Current, flowing
southward from the Primorsk Coast along the east coast of Korea
and meets the Tsushima Current between South Korea and west Japan.
There is no variation in the current at any other part of the
Japan Sea coasts.
The movements of the suitable temperature zones of 10 - 17 °C
in which according to Sasaki (1921) the surume-squid are found
in greatest density (and where the fishing is therefore most
productive) in the coastal waters of Japan, whose various currents
have been described above, are discussed in conjunction with the
oceanographic chart issued in 1940 (Fig. 3). The chart shows
the monthly changes in the 10 °C isothermals, which are roughly the
lower limit of a suitable temperature zone. •
(Surume-squid are found at different dePths in the water,
depending on the time of day. In this paper, however, the temper-
ature differences between the surface, the bottom and the inter-
mediate layers of the sea are neglected. The discussion is based
only on the surface temperatures measured at the beginning of each month. It is thought that these assumptions will not cause any
significant errors).
13
Po 9
• •
/5?2- 4z. s
:
•t • • • ee 7.7=*.7:27.17 .e.7- ..e''... Ç.::
• / ...."-* . e• ,
g ■ i ,, ---)-''' , I ,s...-...... ------7--- ..;• ‘.7. ,..:(1.2 f.,.. . :.:\ \--, 1, e' -.1....,,,,,..... • 1: : . ',...,., '7. -."'"'".% ,-;..tr • • . — 1-141 : .-,•""e"'s •
I •
-
Fig. 3: The monthly movement of the 10°C
isothermals in the coastal waters
of Japan
On the Pacific Ocean coasts the isothermal line is furthest
south in February and March, and extends in an easterly direction
from the Ibaragi Prefecture coast. - It gradually moves northwards
in April and May, and in June it lies slightly north of the Tsu-
garu Strait, in July it reaches the Kushiro coast, in August it
reaches the south of Urup Island in the Kuril Islands, and in
September, when the water temperature is at its maximum it reaches
as far as the north of Urup Island. In October it begins to
change direction and move south, coming down . to the north of
Etorufu Island, in November it reaches Shibotsu Island, in
December the Hidaka coast, in January:of the following year it
lies offshore of the Ojika Peninsula, and in February and March 14
it moves down to the Ibaragi Prefecture coast, mentioned above.
The cycle is then repreated.
In the Japan Sea, on the other hand, the movement of the
line is much simpler. It is furthest south in March, when it
lies near the Noto Peninsula. It starts to move northwards in
April and in May it moves through the north of the Tsugaru Strait
up to the Hinokiyama coast. In June it reaches the Islanàs of
Rishiri and Rebun, and in July it moves further north to Rakmacka
in Sakhalin. In August and September the isothermal line still
continues to move north, and the coastal temperature at Rakmacka
reaches as high as 18 00. It then begins to move south, and in
October a 15 °C isothermal appeamsat Rakmacka. The 10°C isothermal
reappears in November near the south of Umiuma Island. In
December it moves close to the Shikotan Peninsula, and in the
January of the following year it comes down to the Tsugara Strait.
At this time in the Pacific it comes down as far south as the
Ojika Peninsula. In February it comes down to Sado Island, and in
March it returns to the Moto Peninsula. The cycle is repeated.
The monthly movement of the 17 °C isothernals, which is
the upper limit of the suitable temperature zone, is shown in
Fig. 4. In both the Pacific Ocean and the Japan Sea the line is furthest south in March, where it passes from South Kyushu,
thruugh the Kii and Boso Peninsulas to the Pacific in the east.
In April, when the line begins to shift northwards, it branches
out into the Japan Sea and into the Pacific.
At this time, in the Pacific, the line reaches the Kii
Peninsula, in May it reaches the Inuboe Promontory, in June and
July it reaches the Ojika Peninsula, and in August it reaches the
Tsugaru Strait, In September it moves up to the east of the
Kushiro coast and then begins to move southwards. In October, it
comes down to the Tsugaru Strait and then continues moving south- wards in November and December. At the end of the year it lies on
the Ibaragi Prefecture coast. The southward movement is slower 15
P.:firA 1. re Prr,- 1934> - ' OrE2
Fig. 4: The monthly movement or the 17 °C
isotherinals in the coastql waters
of Japan
.in January and February, and the line returns to the starting point in March.
In the Japan Sea on the other hand, the line hardly moves from south Kyushu between January and April. In May it shifts
to the west of the Saga Prefecture, and in June to the north of
the Moto Peninsula, In July it moves rapidly and reaches as far north as the Shikotan Peninsula in Hokkaido: In August and
September it continues northwards, and the temperature near
Rakmacka in Sakhalin rises to 18 °C. In October the line begins to move south, and appears south of the Rishiri and Rebun Islands; and in November it reaches the Tsugaru Strait. In December it comes down to near the Moto Peninsula and in January to the sOuth
1 6
of Kyushu, where it stays till April before moving northwards again in May. This cycle is repeated annually.
The temperature distribution of the water in the Okhotsk p.10
sea in the summer,.taken from the monthly bulletin on oceanography
of the Hokkaido Fisheries Institute (1935) is shown in Fig. 5.
FIZZey PION; r;._y r eArnir ea. Ira ve,,V.A71.7..,.. "157.37 • (..s›,,.>juo ;13YeRIEJ
Fig. 5: Temperature distribution in the
Okhotsk sea in the summer
In August the 5°C line lies around the islands north of
Urup Island, and is surrounded by lines of higher temperatures.
The 13°C line in the Okhotsk Sea lies north of Etorofu Island .
and extends to the north west part of the sea, while in the
Pacific the 13 °C line lies south of the island and extends
approximately eastwards. In the west part of the Okhotsk Sea
in July, the 10°C line extends from Roben .Island to the Kushiro
coast in a reverse S-shape pattern. In August the temperature
near Roben Island is 11°C and in September it reaches its highest
at 14 °C, a very suitable temperature for the Surume.
' The annual variations in the water temperature of the coastal
waters of Japan have been described briefly above. It may be
concluded from a comparison of the variation of temperature 17 distribution in the Japan Sea and in the Pacific Ocean, that
the temperature rise in the spring, i.e. when the isothermals poll begin to move northwards, occurs earlier in the Japan Sea than in the Pacific Ocean and that the rate at which the lines move northwards is greater in the former than in the latter, but in
the autumn the decrease in temperature, i.e. when the lines
start to move southwards, occurs earlier in the Pacific Ocean than in the Japan Sea. In both cases the isothermals for the suitable temperature zones for squid are distributed not only near the coast but also far from the shore. Yamamoto (1946) reported
that he caught young surume-squid on the Korean coasts of the
Japan Sea and Professor Kuroda (1915) of the Fisheries Department of Hokkaido University reported that while sailing in the Depart- ment's training ship, he found it possible to catch surume-squid anywhere between Otaru and Vladivostok. Professor Saito (1947) of the Daiichi Fisheries Training Department of the University, was able to catch 200 large surume-squid in J. hour, from the middle to the end of August, at Yamato-Tai in the middle of the
Japan Sea about 150 nautical miles north west of Wajima in Noto.
Hence the distribution of the squid far from the shore must be considered as well as that in coastal waters. In this per,
the offshore distribution of the squids is not discussed however, because insufficient data are available.
Marking and Releasing
In the past the only aim of the marking tests was to dis- cover the migration routes of the squid from the points of release and capture. Nowadays, however, the tests aim not only at proving the suggested migration routes but also at a detailed study of the movements of the squid within the fishing grounds and at collecting data important in preserving the natural resources and in ecological studies. The marking tests are therefore continuously carried out. 1 8
Historically, marking tests were carried out for the first time by Isahaya in the Tsugaru Strait in 19279 This worker marked the squid with holes of various shapes using pincers. His experiments were'however unsuccessful because he failed to realize that similar holes could be made by the fishermen and by the squids attacking each other, and also that such holes might• not be preserved until the recapture of the specimen. Isahaya and Kawana then carried out tests over a period of 4 years from
1928 to 1931, using silver-coated papers as shown in Fig. 6 (A) •
(these used to be available commercially under the trade name of
'Bunke, Tsuzuril). They were numbered and had long clips on the reverse side to prevent them from being lost. They were fitted on the squid as shown in Fig. 6 (B). The time between fishing the specimen on board and releasing it is important. If it is too long, the specimen is considerably weakened and does not swim normally on being released. It is therefore necessary to carry out the marking and releasing operations as quickly as possible.
\\ / ili !Jo iul ‘...,,
Fig. 6: Tagging piece for marking (A) and
its fitting (B)
Using the above-described method, Isahaya and Kawana marked a total of 9772 specimens in 38 experiments during a 4-year period, as shown in Table 3. 19
Table 3: Marking and releasing tests carried
out by Isahaya and Kawana
Released -rear Rol eaFed t.rms ' Times :Sos.
lt-;2S :10, July — 29, Ocr. 3,191
- .192;? 4, Sept. 20, Oct. 13 2,771
1930 IS, June.-- 5, ".or.e. 13 2,863.
1931 . , July — 1 , Sept. 5 947 Tom: 3zi
Isahaya (1932) has published the results of marking tests m.13
carried out during the 4-year period. He assumed that the Surume migrate in a north-westerly direction and that they stay in the
Tsugaru Strait region. The migration routes that he obtained
from the experimental results are shown in Fig. 7. If his experi-
ments are examined carefully, however, it can be seen, as shown
in Table 4, that the majority of the tests were carried out before
S eptember.
MIERATORY PA777$ IN TN& TSW:jikU-STRX17:. 7-HaugHy; 7: I 7)
•
Fig. 7: Migration routes proposed by Isahaya
20
Table 4t :aaarking and releasing tests in each
,:season,, carried out by Isahaya and
Diawana, and the recapture of released .
specimens
. • . Released Recaptured Year _ 1-',er cr. e Sept. After O. : Nos-.. Ratio
. 1928 1,861 1.330 53 1
1929 2,206 I 565 77 .2.77
1930 1,926 937 52 – 1.81 ' •1931 947 — 5 0.52
Total .6, 94 0 2,832 187 1.9]
The majorii."-7- of the marking and releasing tests were
therefore not 'carr.ied. out at the time of year when the isothermals
are moving northwrds. Moreover, the relationships with fisher-
men at several ple:_ces- were unsatisfactory at that time. These
are the reasons w'rzy the assumed migration routes are inaccurate.
In May 1946 the present author 'published a review of the migration
of Surume-squid after studying the various conditions under which
the squid live and the experimental results of other.workers.
In order to confirm the migration routes suggested by the author,
marking and releasing tests using a similar method to that of
Isahaya and Kawana were carried out in the same year on the
autumn Surume-squid. The marking and releasing tests were made
on the Hakodate coast, which is the centre of the Tsugaru Strait,
and on the Esan coast, in the east part of the Strait. The limits
within which the marking and releasing tests were carried out are
shown in Fig. 8.
21
I .1W? ee w LIMITS 1VHDF.1
J.A1Z RAI-EASES rernz 7A/s4
eveuve c,/:• - 7Ceoreon-et EWE ■1 ri.cs
07.1MA nty.11YI,
j P,AeepAre L. e é-10.eer2f, Per H: l'{A•rwmorr cely I wl t.,...1. .^.- - i - Arro n.o, ,• , e «i• , -..r.up• j • ./..? • e , • • •-• , I ...1 1. • •\, AVI:JI„. ' .I % . % I _,-;e_z-e,P.Aj • - ZreikrA % „'' . \,---' goewSM .5- MILLS
Fig. 8: Map of the limits in the Tsugaru
Strait where the releasing tests
were carried out
One of the released sPecimens was recaptured the saine year
on the Hamanohan coast of Fukne Island in the Goto Islands in
Nagasaki Prefecture. The marking and releasing tests were made
bontinuously in 1947 and 1948, and are still in progress. The
marking and recapture of specimens during the 3 years from 1946
to 1948 inclusive are described below.
In 1946 the marking and releasing was carried out on the
Hakodate and the Esan coasts, and in 1947 also at Okushiri. In
1948, like 1946, the tests were carried out only at Hakodate and
at Esan. The results are summarized in Table 5.
22
Talle_2:.An1ilia2. releasing and recapture in each
O limit (A,B,C).
A) Hakodate limit 3) Esan limit
C) Okushiri limit
1
( A) (B) Releascd Recapred Released Recaptured Date Nos. ! • Nos. : Ratio'r, Date Nos. Nos. Ratio «X, 20, Sept., '40 ou 2 i 4-00 is, 9 .?, Oct., '46 SI 2 3.92 fŸ /I 25, ...- y 41S G 1.45 r/ • Go G .dG 4. Nor.. I/ 2$5 5 2.44 10, Oct , 11 157 5 3 . 27, .. . .o. 422 9 0. 47 4, Dec., .. 271 - — 21, 10 — 0, Nov., // 200. 1.0 . Total 1,361 15 • 1:10 — 21, i, • • // 5•1 — , 1, Oct., '47 07 2 2.98 Total 099 1 14 I 2.02 14. ,.. ..., 2.n 3 1.0G 9 ,47Oct.,Oa 1ou 2 2.0u 15 ,, ,, 70 1 1.42 3, // 300 12 4.00 10, /.., , 300 2 0.66 4, 100 17, // 4, 100 1 1.00 0, // // 209 2.00 29, ...., /.. 197 2 • 1.01 0 // 200 7 3 .;5 0 31, /..• « se 2 2.09 Total 999 2.70 3, _Wov., ., loo ; 2 2.00 2, Nov., '48 . 4, ...., . .. 69 i • -- -- - 20, 200 a 1,50 ' 15. ..... .,... 493 i s 1.62 Total 202 3 1.49 Hii , , Soo : G 1.20 Total in above 3 yeas 1,893 44 2,824 2:), If .., 598 • 3 . 0.50 Total 2,870 32 . 1.11 (C) gtç 21, 'Oct., '48 . 55 2 3.02 4, Nov., /e 89 _ __ . 1-te1elsecl Recaptured 12, ..... .P. GO9 G 0.99 13, /. J.. 398 1 0.25 Date Nos. Nos. !Ratio % 17, .... .... COO 1 0.17 21, ..‘• .., -329 1 0.30 2, Sept., '17 20 0 - — '3; , ., 200 2 1 1.00 Total. 2,030 11 0.50 .1; I., ... 10') Total in above 3 years G,312 58 09 I8 'r II I/ 199 1 0.50 ' Total . 699 3 I 0.43
As can be seen in the table, most of the tests were . p0 15
carried out after October, except for 699 specimens at Okushiri (the limit was a sector 5 nautical miles in radius, south west of
the Aonae Gulf in the south of Okushiri Island), and 133 specimens on the Hakodate coast in 1946. The annual percentage recapture was
0.618% in 1948, which was the lowest, and the average percentage
recapture for 1946-1948 was 1.179%. These recapture results have been published previously (1948, 1949) and will be discussed in
the future together with the results of current experiments.
23
The recapture of the specimens released in each limit
each year is shown in Table 6 (A, 1-3; B 1 1-3; C) (at the
end of the text). The paths of the migration routes obtained
from these results are shown in Fig. 9:
Fig. 9: Tracing of the migration rôute by the
recaptured stDe cimens (A B)
(11) From the specimens released in Esa n limit
- • - !Wig; NAP OF N14'EATe.reZY PAZIe t (i4) 11-Pe 7 ES/IN Le117: ... % ' • S24. ,,, . .1 . y LP " `-.- ,._; ... 2 P K in.. 0 . ,.....,..„›..d, ..,:- • 1..5' ,...... ; • a. ' ,4 *DATE - h ....e .,...... ,,,, 2„. . . .i,.> . 7.:•
''' e • k..,--•,./v.r.,-‘,,,...i_----,,,, ,. ‘,„..., ___,...... ,-,...._, . • . . -,,,,,,,,,,,,,,,, . . • 1, N...... ,700...,,,,,. .- , •ro 'il ,,,, - 11.4.,kmpow , e3' • ,-,:ore,-,,E r t...-"...-± *.7""\ ,e2te, v, . ,.‘. 1:1.,,.«,....,%. ...,.. 'f.j.:1 ESN/ berg r rpn.•.-. " Lrer•-, ,,
't,,.; •,, in...... ,,, •••:,...... ,./ J.- it> ' ■ '; •'•,....,..? û f../).yreer,1 "".2:"''i« . 1., - 1 é? - ...,--•-•;"-i! .
,i> P'ed e r . • ■i . •If it • - • Jer el- _ <" I
/k> :, q i• ; f . - „.,1 . . eA • . --1. T l:7;...vp-r...gieif.)1 . I.■? . I. . . i . ‹' «. ni,„,. • r---;':44 ,. . .ve....>-, • .. re i.'....yr..ew.71 , ey fri.,
• . l'i:r --• . • .....e.i' - e: • - `2./, (2.2.ir...i P›.. • f?` • ,f( - , .
.. • • . 24
(B) From the specimens released in Hakodate and Okushiri limit
PURsepe tehP 77-zr. 1WFW-YiTeRY PATH (3) RZLel • Al.e.e.2 --tATE-. ORWICRI: 1.1.11PU
g • K'rlger.“0..pc!
_ •re • . 1st, ne • r?"";•\ • „.„ ""i` f(c, -;et t thri.,:->x77: 1 1,-fe° 1?Er2Aza • r--rrpy. 7 K I - Y`
A, 1P A . ro (h1 111-
ef) • I , efnmSe-71 •v4),
- çz' 1 ;
! - • •
r!f." TO -
UOVN.A. P..
_49
From these results it can be concluded that most of the
Surume-squid in the Hakodate limit in autymn move westwards into the Tsugaru Strait in the direction of the Japan Sea. During the period when the temperature of the Japan Sea has not yet decreased 25
sufficiently, they begin to migrate southwards. The autumn
squid in the Esan limit seem to stay there for a short period,
and then divide into three groups. The first group travels
northwards and enters the Funka Gulf:-. 1 forming the autumn and
winter fishing season. One of the other groups migrates down 1 the Pacific coast south of the Esan limit, thus providing the
autumn and winter fishing season at the Shimokita-gun coast of
Aomori Prefecture. These squid more further south as the temper-
ature of the coastal water decreases, following their aitable
temperature zone and thus the fishing season begins on the Sanriku
coast, Miyagi Prefecture coast, etc. in that order. After a
temporary stay in the Esan limit, the third group travel westwards
through the Tsugaru Strait, providing fishing along the coasts
of the strait. The squid in this group follow the same route as
those from the Hakodate limit. They are joined by squids coming
down from the north Japan sea as the water temperature decreases.
The two groups then migrate south together as the suitable temper-
ature zone moves south. They travel past Sado Island in Niigata
Prefecture (see recapture table for Hakodate in 1948) and Oki Island
in Shimane Prefecture (see recapture table for Esan in 1948) and
in the following year reach as far south as the Goto Islands in
Nagasaki Prefecture (see the recapture table for Eaan in 1946).
Some specimens released in the west Tsugaru Strait and at Hanare-
jima Kojima in the summer of 1949 have been recaptured on the
Hyogo Prefecture coast, at Oki Island, and at other localities.
A discussion of these later results will be presented in the future together with the results obtained to date since 1949.
Monthly Distribution of the Squid on the Japan Sea Coasts
No sufficient data and reference material on the offshore
distribution of Surume-squid are at present available. Hence only
the monthly distribution of the squid,in the coastal waters is
summarized below, based on the data described previously. 26
January : The north and south ends of the distribution are the Tsugaru Strait and Kyushu respectively. The cold water zone which is formed near the north Sanriku coast in the
Pacific ocean in late December by the Oya-Shio coming in through the Tsugaru strait, divides the squid into the Pacific and the
Japan Sea groups.
February: The connection between the Pacific and the Japan p.18 sea groups is clearly cut at the north end. In the Japan sea • the squid are distributed from the Noto Peninsula to the Kyushu coasts while in the Pacific ocean they are distributed between the Boso Peninsula and Kyushu.
March : The temperature of the coastal waters of Japan is at its lowest in this month, and therefore the groups of Surume-squid also reach their farthest south. The distribution in the Japan sea is from the Shimane prefecture to west Kyushu, and that in the
Pacific ocean is west of the Kii Peninsula.
April: As the température of the coastal waters rises, in this month, the groups of Surume-squid start to move north, and the distribution becomes similar to that in February.
May : The leading group migrating northwards reaches areas near to the Tsugaru strait and the south end of the distribution also gradually shifts north. In the Japan sea the distribution stetches from the Tsugaru strait to all the Honshu coasts, and in the Pacific ocean the squid are distributed from the Sanriku coast to the Kii Peninsula.
June : The squid continue travelling north. The south ends of the distributions are the Noto Penihsula in the Japan sea and the Izu Peninsula in the Pacific ocean. On the coasts of Oki island in the Shimane-Prefecture, the squid are found all the year round except for March, when thé temperature of the coastal waters is at its lowest. Sasaki (1921) has explained the reason 27 for this as being due to the Liman cold current coming from the Korean coast, and a suitable temperature zone for Surume squid being formed near the island. In this month the leading groups reach the Shikotan Peninsula in the Japan sea and the Muro- ran and Hidaka coasts through the Tsugaru Strait in the Pacific ocean.
July : Except for the coasts of Oki island, the distributions in both the Japan sea and the Pacific ocean shift further north; from Sado Island to Soya Strait in the Japan sea and from the
coasts of Miyagi and Ibaragi Prefectures to Erimo-misaki in
Hokkaido in the Pacific. The centre of the distribution in this month is the Tsugaru Strait.
August : In the Japan sea, the squid migrate further north and
form a branch group, at Soya Strait, which enters the Okhotsk
Sea. The main group reaches as far north as Rakmacka in
Sakhalin, and the south end of the distribution is near Tobi Island
in Yamagata Prefecture, with small groups left behind at Sado
Island and Oki Island. In the Pacific ocean, the squid are
distributed from the Kushiro coast to near the Ojika Peninsula.
September : In this month the temperature of the Japan sea reaches
its annual maximum, and the Surume squid reach the most northerly
point in their migration, and the southernmost point of the
distribution is the Tsugaru channel, and the fishing in the Strait
becomes less productive. The leading group reaches as fax north
as the western coasts of Sakhalin and north of Mamiya Strait.
In the Pacific ocean the squid are distributed from Namur° coast,
Kunigo and Etorofu Islands, and in the Okhotsk Sea they are found
as far north as Hoban Island.
October: From the end of last month the squid begin to migrate
south, and in this month the leading groups of southbound squid
reach the Sanriku coast and the Ibaragi Prefecture clest in the 28
Pacific coast. In the Japan sea however, as the decrease in p.19
temperature in the 41an sea is not sufficient, the leading group
comes down only as far as the Hinokiyama coast of Hokkaido. Those
which entered the Tsugaru Strait in this month from the Pacific
ocean seem to stay in the strait for a while before they start
the southbound journey. These squid provide the autumn fishing
in the strait.
November : With the temperature decrease in the coastal water,
the small fish which are eaten by the Surume migrate southward.
The speed with which the squid migrate south increases in propor-
tion to the speed at which the isothermal line moves south. In
the Japan sea the leading group reaches as far - south as the Noto
Peninsula, through Tobi island and Sado island where some of the
squid spent the whole summer • The northernmost point of the
distribution is however still around Soya Strait. In the Pacific
ocean, on the other hand, the squid are distributed from Tokachi coast in the north to areas near the Boso Peninsula in the south.
December : The isothermals of temperatures suitable for the squid shift continuously southwards. The leading group of Surume migrat. ing south in the Japan sea reaches the Yamaguchi Prefecture coasts through Oki Island where some of the squid remained during the summer. However-1 the northernmost point of the distribution is still around the Rebun and Rishiri Islands of Hokkaido. In the Pacific ocean on the other hand, the southernmost point of the distribution is as far south as the Tàushima Prefecture coasts of Shikoku, while the northernmost point is still near Hidaka coasts of
Hokkaido. From the middle of this month, the strength of the °ye..
Shio increases, and a cold zone appears near the east of the
Shimokita Peninsula in the Aomori Prefecture.. The connection between the squid in the Japan sea and the Pacific ocean, which has 29 existed since the spring, iS thus broken, and the squid to the north of the cold zone in the Pacific ocean enter the Tsugaru strait and are separated from those migrating south in the Pacific ocean. In January of the following year, the di s tribution is as it was at the start. The above-mentioned migration cycle is repeated every year.
The monthly distribution of the squid was briefly described above. The distribution is not distinct each month, as shown in the figures, but is continuous changing day by day, and varies slightly depending on the year. The annual variation in the temper- atures of the coastal waters influences the distribution. However, the annual change in the distribution is definite, and the sequence of the monthly distributions is the sanie every year. In a year in which the temperature of the coastal water is high the northbound migration is more active and the fishing in the Tsugaru Strait in summer becomes very unproductive. In a cold year, such as 1945, the northbound migration is slow and inactive, and there is no break in the fishing season from spring to winter near the Tsugaru
Strait.
The monthly distributions of the migrating squid are shown in Fig. 10. The migration of the squids to near Roben Island in the Okhotsk sea was confirmed by observations on seals caught at the island, which had recently fed on-squid. 30 p.20
Fig. 10: The monthly distribution of the squid in the coastal waters of Japan.
The migration of souid in the coastal waters of Hokkaido, in particular
South Hokkaido
There are two groups of .Surume which migrate to the coastal waters Of Kokkaido from the south providing the spring fishing seasons at various coasts of Honshu on bOth the Japan sea and the 31
Pacific Ocean. The first group reaching Hokkaido is that which migrated along the Japan Sea coasts where the Tsushima current flows, and the squid of this group appear on the Matsumae coasts west of the Tsugaru Strait in the beginning of May. Some of the squid of this group migrate eastwards through the Tsugara Strait, providing the summer fishing season in the strait, while the main group continues to travel further north in the Japan Sea. Those which entered the Tsugaru Strait then meet up with the second group, migrating from the Pacific coast of the mainland, at Esan limit, the east entrance to the Tsugaru Strait, where the Tsugaru current joins the Kuro-Shio in the Pacific Ocean, and the squid provide the fishing season of summer squid. These squid then travel further north along the Kokkaido coasts in the Pacific
Ocean and, in August and September fishing can continue as far p.21 north as Kushiro, Neûbro, and the Shiretoko Peninsula. On the other hand, those migrating north in the Japan Sea, provide the fishing season of summer squid on the coasts from Hinokiyama to
Goshi, and in August and September they reach the west coast of
Sakhalin and as far as the north of Mamiya Strait. This group forms a branch which travels through the Soya Strait, enters the
Okhotsk Sea, and then reaches as far north as Roben Island in the Okhotsk sea, providing the summer squid season on the coasts of north Hokkaido. While the summer squid are caught.in the coasts of north Japan Sea, Okhotsk Sea and northeast Pacific the fishing in the Tsugaru Strait and south Hokkaido becomes less productive.
In autumr, as the strength of the Japan current increases, the temperature of the Okhotsk Sea and the north Japan Sea decreases, and the Surume begin to migrate south. The southbound journey is however somewhat different from the northbound; in the latter case the squid migrate following the suitable temper- ature zone, while in the former case they are driven away by an unsuitable temperature zone. Hence the density of the southbound groups is muCh higher than that of the northbound spring groups.
32
In the Pacific Ocean the squid corne down along
EtOrofu island, Nemuro, Kushiro, and Hidaka coasts in this
order, to the Muroran-Esan limits, where, from the middle ar
• September, the density of the squid croup increases ancfprovides
the busiest fishing season for autumn squid. The squid in those
areas eventually migrate south, but by two different routes;
one straight down to Shikoku along the coasts of the Pacific
Ocean and the other through the Tsugaru Strait into the Japan
Sea. In October and November the fishing in south Hokkaido
and it is not rate for 1675 to 2625 becomes most productive, ,.onsiday
of squid to be landed in Hakodate city. The monthly amounts of
squid caught in the Tsugaru strait and s)uth Hokkaido in the
last 5 years are shownsin Table 7.
Table 7: (A) Monthly catches in Hokkaido in the
last 5 years (Kan; 1 kan = 5.75 kg)
Year i ; 1944 1945 1946 . 1947 1948 ! Month 2,020 27,395 1,572 9,953. 55,607 Feb. . 12 40 5 923 ' 08 ' Ùar.. 1,055 • .. 2,370 Apr. 4,200)-- 351 8,104 - - 20,117 59,965 May 91,392 9,529 • .143,603 . 114,415 153,815. June - . - 28 : 477 .. 85,656 . ' 703,849 .. • 125,287 1,241,089 . -.11-"Ily 598,611 102,567 : 528,589 1 ,003,515 1,992,922 Aug. :1,316,611 551,792 ; 982,549 - . 1,948 ‘127 5;399.478 ' Sept. 1,8h4,035 . 1,720,64 5 1 1,003,178 4,480,298 11,200,170 ••Oct. 4,124,241 2,903,190 - 3,191,786 12,053,152 11,755,891 f ' Nov. 8,232,079 7,241,520 10,463,086 ' 12,511.480 • 15,197,215 " Dec.- - 1.921,930 1,824,604 3,25(;,672 - 3,122,115 ' 8,523,704
.;Total 15,185,168 14,527,587 20,289.796 35,959,385 55,618,334
33
Table 7 (B) Monthly catches in the Tsugaru Strait in the last 5 years
(Kan)
1944 1045 1946 11,47 I Montt 1948
Jan. - 9, 090 . 27,395- 1,570 -"SOO 44,495 Feb. J • 023 68 Mar. 160 - • 523 • 1111Y 22,800 19,472 June 1,422 25,943 • . 50,384 " 18,085 232,520 july 70,254 47,315 106,129 103,850 • 745,156 Aug. 521,147 .103,874 488,353 851,058 2,989,467 Sept 043,520 -530,083 1,&87,3:-)4 1,911,004 6,349,093 Oct. 2,032,260 1,528,722 2,064,582 6,200,160 6,735,165 :Soy. 2,006,167 3,201,927 5,320,379 0.458,714 7,058,165 Dec. 663,057 -513,820 64:3,850 1,294,155 3,542,536
6,549,370 Total 5,982,979 • 9,785,470 16,841,079 28,050,497
At the end of December, owing to the cold zone formed
east of Shimokitagun in the Aomori Prefecture by the increase
in the strength of Oya-Shio, the migration of squid from Esan
.limit to the Pacific coasts of the mainland is interrupted, and
all squid within the limit enter the,Tsugaru.Strait and migrate
westwards. This is why the fishing Season in -gie Tsugaru Strait
lasts for a long time, while no squid are seen on the Sanriku
coast. On the other hand, the rate of migration of the squid
rhich started the southbound journey in early October in the '
north Japan Sea is slower than that of the squid in the Pacific
Ocean.' In January of the following year the squid are still found
in the Tsugaru Strait. • These however eventually migrate south in
the Japan Sea together with the squid from the Esan limit, and 34
they reach as far south as the west coasts of Kyushu in
February and March.
Sin/MARY p.23
1. The fishing season of the Surume-squid in various coasts of Japan and the change in the mantle length of the squid caught are briefly described.
2. The squid caught during spring and summer are mainly snail, although they include some large full-grown and some spawning specimens. The spawning squid can be found only in particular localities, and are seldom caught commercially.
3. There is only one fishing season in the north and in the south of the islands of Japan, and the seasons are complimentary between the north and the south. However, there are two fishing seasons, spring and autumn-winter, in the middle parts of the islands of Japan.
4. The mantle length of the squid caught in autumn and winter is much greater than that in spring and summer.
5. The shifts of suitable temperature zones for the surume in the coastal waters of Japan during the year, agree well with the movements of the fishing seasons at various coasts.
6. The results obtained from the marking and releasing tests on Surume carried out todate are briefly explained. It was found from the recaptùre results of the tests carried out by
the present author since the autumn of 1946, that the Surume-
squid in the coastal waters of Japan all belong to the same species. 35
7. rrom the experimental results and the information available the monthly migratl-ons of the squid in the coastal waters of Japan are expiai i, with diagrams. The migration of the squid
in South Hokkaido and the Tsugaru Strait, where the majority of
the squid fishing is carried out, is also described.
8. The breeding characteristics and other ecological studies
on the Surume are now in progress as well as the marking and
releasing tests and studies on the offshore distribution.
Table 6 p. 25 Table of recapture (A.1) 1946
Esan-limit
o. Date of Release Date of Recapture I ••)ff'tert«\s Release Recaptured point
1 18, Oct., '46 - 30. - Oct., '46' . 12 t I Yoshioka coast of Wataxijima 2 ' ••• ' 5, ov., ,-' • I .18. . Ohata coast of Aomori • I 3 • 25, 25, Oct., 0 Ofudabe coast .of Watarijima . • 4 // Nov., - 7 Ohata coast of Aomori œr . 7, ev 13 Esan cOast of Watarijima 9 , 15 6 ff. Yoshioka coast of Watarijima • - 10, et 16 Uenokuni coast of Hinokiyama
• 2G,- ef. I I It 5, O 4, :Nor., ••■ Furube coast of Watarijima 10, ef 6 Ofudabe coast of Watarijima H , Last decade 7.. Sumiyoshimachi coast of Hakodate city 1, Dec., I 27 Ofudabe coast of Watarijima
13 , 90, Feb.. '47 108 Hamahan coast of Fukuejima of Goto . of the Nagasaki prefecture 27, Ycv., «14 27, 7/ Esan coast of Watarijima
15 If .7 Hebiura coast of Aomori 3 6
Table of recapture (A.2) 1947
Esan limit '
. - Days I No. Date of Release • Datc of Bcapturo after ! Recaptured point Release •
1 r; Oct., 2, Oct., ;47 Esan coast tt it // 21, No 20 ' 3 •. 30, Oct., » 17 - Shimoburo coast of Aomori Hakodate city' coast 4 28, Nov., ft .15 Ojiro nai of Watarijima 5 1/ ' 21, Dec., .//• coast Esan coast G 15,`. » » • 17, Oct., » 2 Ofudabe coast of Watarijima • 16, » re • 8, oy., // Fukushima coast of Watarijima 7 • Dec., » 52 Esau coast 9 17, » 30, Oct., • Datenonbetsu coast of Iburi 10 • 29, It ft. 2, Nor., ff 4 Esan coast 11 ff 5, • re
// // 8 Nodaoi coast of Watarijima 19 31, » • 8 , I f 94 Mobechi 13 rr ff coast of Watarijima
- •3; ov,. '47 i • 3, Nov., '47 O ' Esan coast p.26 7! ' .4 . tt !tt 15 • tt It 16 15, ft ft 16, // // tt Il 11 1 17 • IV ' 1 - n ' 18 11 : It 19 f/ // It st • •. 1/ ; 20 f/ i s. tt . • tt 21 3 Tsubaki Island of Hirotamura of ft 17 - I/ Kisen-gun in the Iwate Prefecture
1/ 4, Jan., '48 50 Inshore of Enganteichi of Osagoko in 23 Iwate Prefecture 9.1 17, Nor., '47 1 " Esan coast
95 21, ft 5 ; Hakodate city coast Fukushima coast of Watarijima 26 16, 25, if // •o ; Hakodate city coast 27 4, Dec., if
. 9, . • ' 93 Fukushima coast of Watarijima 28 // 1 5, ff Esan coast 29 1f: 19 Kanidacho coast of Aomori 30 » fr 20, er 21 95, » Mobechi coast of.Watarijima 31 If
/1 27 Otsuki isl and of Karakuwa of 32 26, » Motoyoshi-gun in the Miyagi Prefecture
,s> ••■■ 37
Table of recapture (A.3) 1948 Esan limit .
Days No. Date of Release - Date of Recapture 1 ater Recaptured point • tRelease 21, Oct, '48 • " 21, Oct., '4S o ,Esan coast 25, ..•• 4 . 7 miles from IwaYa of Shimokita-gun in .•••• ••• the Aomori Prefecture 3 42, . 16, Nov:, n . 4 - 2 miles from Ofudabe
20, r/ 8 . Kinao coast .of Esan " • • u 1, • le 21, A. • // 9 " 23 , n 60 yards from Kakema shore of Sunabara
S, Dec„,- ; Yoshioka coast 9 Ojironai coast of Morimachi 13, •n• • 22, Nov., - 0 Esan cOast O 17, .1 17, • .n . • 10 21, t • o •
11 12, .e/ . // 21, Jan., '49 • 70 200 m from Baigpmisaki of Oki in the Shimane Prefecture
Table of recapture (B.1) 1946 Hakodate limit p.27
Days No.- • Date of Release Date of Recapture after Recaptured point • - ;Meuse
' 20, Sept., .'46 20, Sept., '46 • 0 , Hakodate city coast
9 • • .7, Nov., •••••• 17 . Otsube coast of. Hinokiyama • 8 , Yoshioka coast of Watarijima 3- ". 26, -/i - 4, Oct., rr • L - - 11 tt • It 4 10, n 14 - • Oshima coast of Watarijima 5 li 12, • /f // 16 11 11 11 6 . 9, Nov, n • 44 7 19, Oct.,' •19, . Oct., Hakodate city coast :20, Mobetsu coast of Watarijima
9 re- 24,' - 5 .-Hakodate city coast
10 26, * • // . 7 . Yoshioka coast of Watarijima 11 11 11 7, Nov.; 19 Senkamezawa coast of Watarijima .12 . 5, • Nov.., // 1
t. 13 // - . 1 Yoshioka coast of Watarijima.
14 Dec., 27. Hakodate city coast
38 Table of recapture (B.2) 1947 Hakodate limit
Days Recaptured point No. Dr....e of ReleaFe Date of Recapture cf ter 1 Release-I - - - r city coast 1 2, Oct., '47 5, Oct., '47 , 3. - . Hakodate
// 10 Fukushima coast of Watarijima // 12, I 1 i Kuzutoshi coast of Watarijima 3 s, // ft It It t , . et 2 I/ 5;: _ city coast 5 2 Hakodate
6, // Ft 3 Fukushimk coast of Watarijima Izumizawa coast of Watarijima 8, // //' • 5
r/ Hiradate coast of Aomori 8 l/ 11 Yagoshi coast of Watarijima . 9 14, 12- Fukushima coast of Watarijima 10 // 15, •• Yoshioka coast of Watarijima • 11 16, // // 13 • Kojima coast (island) of Watarijima 16 • 1 12 I/ 19, " •
// Y ag shi coast of Watarijima 13 26,.. t,. . . 0
14 \ 3, Oct,. '47 22, Nov., '47 . _Shikabe coast of Watarijima p. 28 _Kuzutoshi coast of Watarijima 15 5, I • 8, Oct.,' tf
16, 11 - ,.Fukushima coast of Watarijima
Il 17 25, // • // 20 Yagoshi coast of Watarijima 18 26, 21 •Shikabe Watarijima 19' .14. Nov, coast of Furutakei coast of Watarijima - 20 /- 1G, e. Yoshioka coast 6f Watarijima 6, // // 16, Oct., t, ShiragaMi coast of Watarijima 9,) // // 10 Fukushima coast of Watarijima 23 t/ 20, // // 14 1 Yago.shi coast of Watarijima 24 26; II // 20
25 . // • f Kojimamogusa coast of Watarijima Fukushima coast of Watarijima - 26 IV* • 29, // 1/ 3 It I t 11 27 fe 30, . 4
Table of recapture (B.3) 1948 Hakodàte limit
No. Date of Release . Date of Recapture aft*, Recaptured ne;_ point 1 .. 20, Nov., tIS 21, Nov., '48 , 0 ,1 Hakodate coast - ,,. 22, el e/ 2- Mobetsu coast (Mitsuishi) - i 7. Jan, '49 .48 : 200 m from Matsugazakimura of Sado is: and 'i
Table of recapture (C) 1947 - Okushiri limit
Days 1 No. Date of' Release Date of Recapture after Recaptured point jumaqe,
3, Sept., '47 • 19, Sept, '47 16 Tsurikake coast of Okushiri island Otobe coast of Hinokiyama 2 3, Oct., 30 • A-kaishi of Okushiri island 7, t/ //• 8, - Sept, I/ . 1 coast
e All distances given in nautical miles