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Vol.01-10
No.11-20 No.21-30
No.31-40
No.41-50
No.21 No.22
No.23 No.24
No.25 No.26
No.27 No.28
No.29 No.30
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Sci. Rep. Hokkaido Fish Hatchery
(29), 1975
- 30-1
Morphological changes in the corpuscle of Stannius of the
salmonid fishes during the sexual maturation. Hiroi, O. pp.
1-45. (In Japanese with English summary)
 (85,644KB)
Abstract
The corpuscle of Stannius of masu
salmon, sockeye salmon and rainbow trout was examined by light
and electron microscopes. The corpuscles of Stannius in salmonid
fishes showed an obvious changes in both sexes along with their
sexual maturation. With the advancement of maturation, the
glandular cells of the corpuscle displayed a regular
palisade-like arrangement along the lobule wall. Then, a
decrease in size of glandular cells and in number of secretary
granules occurred gradually in maturing fishes with nuptial
coloration. In mature and spent fishes, the corpuscle was
conspicuously modified by disturbances of cellar arrangement in
the lobule followed by the extensive deformation of some
lobules. The present observations suggest that the corpuscle of
Stannius of salmonid fishes may accomplish its function in
association with physiological changes related to the sexual
maturation.
- 30-2
On the coho salmon transplanted from North America into the
Shibetsu River, Hokkaido. Ishida, T., Tsuji, H., Hosokawa,
T., and Nara, K. pp. 47-53.(In Japanese with English summary)(399KB)
Abstract
One hundred and ninety thousands
of coho salmon fry (mean wet weight 1.1 g) introduced from North
America were released into four tributaries of the Shibetsu
River, eastern Hokkaido, in the April of 1975. The dispersal and
density of released fish were surveyed in the following June and
July. Coho fry dispersed downstream within the range of about 3
km from the released point. They grew well, but the fish density
varied depending on the stream type. It was observed distinctly
that their growth and density were better in the artificially
developed regions including short-cut route and concrete-paved
bank than in undeveloped waters.
- 30-3
Aquatic fauna of the Anebetsu River during downstream migration
of chum salmon fry. Mayama, H. pp. 55-73.(In Japanese with
English summary)(919KB)
Abstract
Aquatic animals in the Anebetsu
River, running through the peat area of eastern Hokkaido, were
ecologically surveyed using net- and cage-trapping methods
during the period of downstream migration of chum salmon fry,
from March to July in 1973. The amount of drifting animals was
0.86-24.19 mg/m3 in the upper gravel bottom area
which included abundant benthic animals, and 0.99-7.54 mg/m3
in the middle and 0.10-5.20 mg/m3 in the lower area,
which had poor benthos because of the muddy bottom. The aquatic
animals originated from the upper area repeated constantly the
drifting and rooting in the downstream area because of the muddy
bottom unsuitable for their habitats. In a stream in the peat
area with a comparatively low biotic productivity, a
conservation of the upper stream ground and the surrounding
flora should be necessary for the growth of salmon fry.
- 30-4
Ecological study on the aquatic animals of the Nuppuku River.
Kaeriyama, M. pp. 75-85.(In Japanese with English summary)(548KB)
Abstract
Seasonal variation in the fauna,
standing crop, and life form of aquatic animals were surveyed in
the Nuppuku River of the Tokachi River System from August 1973
to May 1974. Dominant species in the benthic animal community
was caddis fly. Their succession attained to climax because of
high net-spinning coefficient in life form (68.3 %), abundant
standing crop, and stabilized drifting ratio. In winter, the
net-spinning coefficient and standing crop of drifting animals
increased, indicating that the benthic animal community may be
changed by decreases of water flow and bottom area in the river.
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Sci. Rep. Hokkaido Fish Hatchery
(29), 1975
- 29-1
Kokanee in Lake Numazawa-numa, Fukushima Pref., North Japan.
Appendix: bibliography of Lake Numazawa-numa. Tokui, T. pp.
1-10. (In Japanese with English summary)(826KB)
Abstract
This report described dwarfed
sockeye salmon in Lake Numazawa, Fukushima Prefecture, northern
Honshu. Lacustrine sockeye salmon were most abundant in the
secondary thermocline having a temperature of 6-13°C in the end
of September. A comparison of the specific growth rate suggests
the fast-growing salmon during the first year of life may have
low growth in the second year. Some salmon grew little or not at
all year round. There was a linear relationship of between
number of eggs (Y) and weight (X) of sockeye salmon in Lake
Numazawa, Lake Towada, and Lake Shikotsu, being indicated by
Y=1.70X+46.
- 29-2
On the coho salmon transplanted from U. S. A. into Yurappu
River, Hokkaido. Ishida, T., Tanaka, T., Kameyama, S.,
Sasaki, K., and Nemoto, Y. pp. 11-15. (In Japanese)(304KB)
Abstract
Coho salmon eggs were transplanted
from USA to Hokkaido in 1973 for the first time. Coho fry were
released in the Yurappu River in May, 1974. There was no
difference in feeding habit between coho and masu juveniles in
the river. Both species favored a pool as feeding site, but masu
salmon was dominant when both species cohabited.
- 29-3
Some properties on fresh water fish survey field. Ishida, T.
pp. 17-19. (In Japanese)(826KB)
Abstract
The author introduced several
tools for field survey of freshwater fishes in rivers.
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Sci. Rep. Hokkaido Fish Hatchery
(28), 1974
- 28-1
Sex differentiation of the gonad in the masu salmon (Oncorhynchus
masou). Nakamura, M., Takahashi, H., and Hiroi, O. pp.
1-8. (In Japanese with English summary)(6,267KB)
Abstract
Sex differentiation was studied
for the gonad of masu salmon alevins and fry cultured at 8°C at
the Chitose Hatchery. The specimens were sampled at intervals of
1 or 2 weeks until 13 weeks after hatching. In masu salmon, the
time of gonad sex differentiation either in the testis or ovary
could be delimited from 4 to 5 weeks after hatching, when fry
started to feed.
- 28-2
Notes on the phase differentiation and smolt transformation of
juvenile masu salmon (Oncorhynchus masou). Kubo, T.
pp. 9-26. (In Japanese with English summary)(2,936KB)
Abstract
The phase differentiation and
smolt transformation of juvenile masu salmon during the stream
life prior to seaward migration were studied. From summer to
autumn, changes in the body form and coloration or "phase
differentiation" occurred in masu juveniles, and these phenomena
were closely associated with their life form variation. The body
size and growth pattern might be important factors for the phase
differentiation and smolt transformation. As a distinctive
feature in a progress of smolt transformation, gradual blacking
of the dorsal fin tips occurred with a silverization of body
surface. Such phase differentiation and smolt transformation in
the external morphology were accompanied by notable changes in
blood characteristics and migration behavior.
- 28-3
Observation on the abundance of plankton crustaceans in Lake
Shikotsu. Results in 1971-1973. Ishida, T. pp. 27-31. (In
Japanese with English summary)(273KB)
Abstract
Seasonal changes in abundance of
plankton crustaceans in Lake Shikotsu were examined by vertical
net towing samples collected in 1971-1973. Acanthodiaptomus
transformed from nauplius to copepodid stage in the end of June.
Abundance of this species was about 12-32x103 per
surface area 500 cm2 in July. A decrease in number of
Acanthodiaptomus from summer to early winter was rather small,
reflecting their low fecundity. The reproduction of Daphnia
longispina was entirely parthenogenetic around the year. An
exponential increase started in spring by a small number of D.
longispina survived over winter, and their abundance peaked in
October or November.
- 28-4
Notes on the kokanee salmon in Tagokura Reservoir, Fukushima
Pref., North Japan. Tokui, T. pp. 33-36. (In Japanese with
English summary)(1,583KB)
Abstract
The present report described the
growth and scale pattern of lacustrine sockeye salmon
experimentally transplanted from Lake Shikotsu to Lake Tagokura,
Fukushima Prefecture. Seven thousand fry (mean weight 3.5 g)
were released in this artificial reservoir on June 19, 1970.
Thirty thousand fry (mean weight 2.5 g) were again planted in
the reservoir on June 13, 1972. One adult female (age 3+) and 10
juveniles (age 1+) were captured by gillnet in the October of
1973.
- 28-5
The effect of the water temperature on the development of chum
salmon, Oncorhynchus keta (Walbaum), eggs and sac fry.
Hashimoto, S. pp. 37-43. (In Japanese)(1,149KB)
Abstract
Effects of water temperatures on
the development of salmon eggs and alevins were observed. Their
development was affected by water temperature, and it was showed
by a formula. Absorption of alevin yolk was affected with
ambient water temperature, and high water temperature had a tend
to cause high absorption, producing small fry. The yolk
absorption rate might be controlled not only by ambient
circumstance but also by biological internal conditions. Thus,
the high absorption rate was closely related with earlier
emergence and occurrence of small fry.
- 28-6
On the fecundity of fresh water plankton Copepoda,
Acanthodiaptomus pacificus. Ishida, T. pp. 45-46. (In
Japanese)(79KB)
Abstract
Fecundity, egg size, and body size
of the freshwater copepod Acanthodiaptomus pacificus were
compared among the Lake Shikaribetsu, Lake Chuzenji, and Lake
Shikotsu populations. The mean fecundity was 10.4 eggs in Lake
Shikaribetsu and 6.45 in Lake Chuzenji. In Lake Shikotsu, it was
7.72 in 1964, but decreased to 4.7-4.9 in 1971-72. The mean egg
diameter was 0.118 mm in the Lake Chuzenji population, while
0.127-0.130 in other populations.
- 28-7
Heavy metals of the water of Lake Shikotsu. Tokui, T. pp. 47
(In Japanese)(55KB)
Abstract
A metal mine is located near Lake
Shikotsu, discharging liquid waste into the Lake Shikotsu
throughout the Bifue River. The author examined copper and zinc
concentrations in waters of the Bifue River and Lake Shikotsu.
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Sci. Rep. Hokkaido Fish Hatchery
(27), 1973
- 27-1
Studies on the planting of hatchery-cultured masu salmon fry
into streams-4. Observations on dispersal and residual of
juveniles in the Mena River and its tributaries. Results in 1971
and 1972. Ishida, T., Tanaka, T., Kochi, K., Kunda, M., and
Yoshida, N. pp. 1-10. (In Japanese with English summary)(537KB)
Abstract
Dispersal and residual behavior of
masu salmon fry released to the Mena River was observed in 1971
and 1972. The dispersal pattern and density of released fry were
almost same as those in the previous reports (25-1, 25-2). It
was suggested that there were some relations between the
released timing and fish dispersal. The priority effects
appeared to affect the residual rate of fish in the upper
reaches where large pools and riffles were absent, and did the
growth of fish in the lower reaches where large pools and
riffles presented enough for their social hierarchy.
- 27-2
Studies on the planting of hatchery-cultured masu salmon fry
into streams-5. An observation on dispersal and residual of
juveniles in the Pankenai-kawa, a branch of the Teshio River.
Result in 1972. Ishida, T., Ohata, T., Ishigaki, K., Sasaki,
K., and Maekawa, K. pp. 11-16. (In Japanese with English
summary)(341KB)
Abstract
In the late May of 1972,
hatchery-reared masu salmon fry were released to three points of
the Pankenai River, a branch of the Teshio River, and their
survival and growth were observed. Their survival rate by early
August were estimated to be approximately 40-50% by the density
in each station, showing much discrepancy to the low value in
previous year. In August, the average density of juvenile masu
salmon was estimated to be about 0.4 fish per square meter, and
the average fork length was 85 mm. Microhabitats of masu
juveniles were detected in each season.
- 27-3
Studies on the planting of hatchery-cultured masu salmon fry
into streams-6. A preliminary trough experiment on residing
process. Tanaka, T. pp. 17-24. (In Japanese with English
summary)(1,013KB)
Abstract
A preliminary experiment was
carried out to clarify the residual process of masu salmon fry
stocked in an artificial trough. Masu fry were measured and
released at several intervals in running water in wood trough
(33 cm wide and 350 cm long) with two pairs of mini-pools and
riffles. The growth and residual rate of early released fry were
better than these of later released fish. Early-resided fish
maintained their residual habitat strongly. Number of resided
fish in the trough (1.1 square meter) was 4 or 5, and became
twice after the successive release in August. Through the period
primarily resided fish did not move from their resided place. In
fall, residents showed a tendency to migrate to the downstream.
- 27-4
A preliminary report on the development of chum salmon (Oncorhynchus
keta) egg kept in the spring water of 8°C. Hiroi, O.,
Yasukawa, M., Suetake, T., Sasaki, S., Tomita, T., and Sato, Y.
pp. 25-30. (In Japanese with English summary)(355KB)
Abstract
Chum salmon eggs taken from a
female captured in the Chitose River was inseminated and kept in
the spring water of 8°C, and their development was observed. A
first cleavage furrow appeared vertically 10 h after
insemination. Two, four, eight, and sixteen cell stages appeared
at 10-15, 15-19, 19-24, and 25-28 hours, respectively. Eggs
showed early blastula 3 day after insemination. The estimation
of fertilization rate of eggs should be carried out most easily
and exactly during the period of 17-24 hours after insemination
when eggs developed to 4 or 8 cell stage.
- 27-5
Studies on the retention of gametes of salmonid fishes-1. On the
fertility of chum salmon eggs after storage. Takano, K.,
Hiroi, O., Yasukawa, M., and Suetake, T. pp. 31-37. (In Japanese
with English summary)(363KB)
Abstract
Chum salmon eggs were stored in
coelomic fluid under darkness at 8°C. The fertilization rate was
over 90% after 48 hours, but decreased suddenly to less than 30%
after 120 hours. Under the same condition, the fertilization
rate of eggs kept in the physiological saline was lower than
that of eggs stored in the coelomic fluid. The survival rate of
fertilized eggs stored in the physiological saline under
daylight at 8°C declined rapidly to about 3% after 24 hours.
Eggs stored in the physiological saline under darkness at high
temperature (19°C) lost their fertility completely within 24
hours.
- 27-6
Studies on the retention of gametes in salmonid fishes-2. On the
storage of chum salmon (Oncorhynchus keta) sperm.
Hiroi, O., Yasukawa, M., and Suetake, T. pp. 39-44. (In Japanese
with English summary)(387KB)
Abstract
Chum salmon spermatozoa stored at
the temperature of 15, 8.0, and 3.5°C could maintain its active
mortility for 2, 6, and 11 days, respectively. No mortility,
however, was shown by milt stored at -9.0°C even one day after
preservation. A lot of milt stored for 4 days at 8.0°C could
fertilize 89.3% of eggs which were preserved for 1 day at 8.0°C
in the Ringer's solution. When chum eggs kept for 1 or 4 days in
the Ringer's solution of 8.0°C were inseminated with sperm kept
for 4 or 7 days at 3.5°C, the fertilization rate was 96.9% and
53.8%, respectively.
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Sci. Rep. Hokkaido Fish Hatchery
(26), 1972
- 26-1
Studies on the planting of hatchery-cultured masu salmon fry into streams-3. An
observation on dispersal and residuary of juveniles in the Pankenai-kawa, a
branch of the Teshio River. Matsukawa,
H., Nagahara, K., Ishida, T., Ishigaki, K., and Inagaki, K. pp. 1-9. (In
Japanese with English summary)(466KB)
Abstract
Dispersal and survival of
hatchery-released masu salmon juveniles were observed from May to October 1971,
in a tributary of the Teshio River, Hokkaido. One day after release, a majority
of masu salmon juveniles remained within 20-30 m from the released point, while
some fish migrated to the upstream about 60 m above, or drifted to downstream
within the range of 1.8 km. In October, masu juveniles expanded their
distribution to the upstream, and the density of released and natural masu
salmon juveniles decreased considerably. The mean fork length of fish was 43 mm
when released, 90 mm in early August, and 110 mm in early October.
- 26-2
Studies on the Pacific salmon of the Yurappu River and in the Volcano Bay 1. On
the present status of the reproduction of chum salmon. Kobayashi, T., and
Abe, S. 11-21. (In Japanese with English summary)(604KB)
Abstract
In order to recover salmon
resources in the Yurappu River and the Volcano Bay coasts, a series of
ecological study of chum salmon has been carried out since 1966. The Yurappu
River is most important to maintain chum salmon along the coasts of the Volcano
Bay. From 1927 to 1950, the annual catch of adult chum salmon was almost stable
in the river, being more than 5,000 fish. Since 1950, however, the catch has
been gradually declined as a result of the increased commercial fishing in the
coasts, and reduced to about 1,000 fish. Chum salmon eggs have been transplanted
from other rivers almost every year since 1953. However, the percentage of adult
returns derived from transplanted eggs was very low. The relation between the
number of fry released (F) and adult returns (R) is seen as the following.
Taking logarithm of R/F, a linear relation comes out between F and log R/F, as
is given; log R/F = 1.236 - 0.0538 F (r = -0.682). This formula shows that the
reproduction rate of maximum sustainable yield (MSY) level is 8.12, and the
maximum expected return is 51,000 fish.
26-3
Observations on the differentiation of leucocytes and thrombocytes in blood of
chum salmon fry (Oncorhynchus keta). Takeda, S. pp. 23-39. (In
Japanese with English summary)(480KB)
Abstract
The development and specialization of the
leucocytes and thrombocytes in chum salmon fry were investigated. Large
lymphocytes were recognized to transpose and differentiate into leucocytes,
while small ones into thrombocytes. However, the process of differentiation into
erythroblast from small lymphocytes could not be recognized in the present
observation. The presence of acidophilus or eosinophilic leucocytes and also
neutrophilic leucocytes were found in the fluid, but no basophilic leucocytes in
their matured form. Acidophilic leucocytes had two types: fine granulocytes and
rough ones. Neutrophilic leucocytes showed two types: monocytes and segmented
leucocytes. Lymphocytes, both of small and large ones, were recognized to
transpose each other.
- 26-4
Efficiency of an electro-fishing gear for estimating the population size of a
stream dwelling fish. Miura, T., Shiraishi, Y., and Ishida, T. pp. 41-48.
(In Japanese with English summary)(447KB)
Abstract
Efficiency of electric shocker for
estimating population size of fish in small mountain brooks was examined. The
procedure was to collect many amago salmon (Oncorhynchus masou rhodurus)
using a German 200 volt DC electric shocker once a day during the four day
experimental period. Fish size selectivity by the shocker gear seemed to occur,
although it was not statistically significant. No significant difference in
probability of capture was observed between previously captured fish and newly
caught ones. This suggests that shocking on previous days did not affect the
vulnerability of the fish.
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Sci. Rep. Hokkaido Fish Hatchery
(25), 1971
- 25-1
Studies on the planting of hatchery-cultured masu salmon fry into streams-1.
Observations on dispersal and residuary of juveniles in the Mena River and its
tributaries. Tanaka, T., Ishida, T., Matsukawa, H., Ishikawa, Y., and Kunda,
M. pp. 1-17. (In Japanese with English summary)(1,154KB)
Abstract
Observations were carried out on
the dispersal and residuary of hatchery-reared masu salmon juveniles released
into the Mena River, a branch of the Shiribetsu River, in 1970. Masu salmon
juveniles in the main stream dispersed widely from the released position to
downstream, at least 10 km below, within 24 hours after their releases. A
tendency of moving upstream was observed soon after the planting in the fish
distributed in the main stream. This tendency continued until July, and fish
expanded their distributions to barren brooks. The abundance of fish in late
July was estimated at 0.57-2.6 /m2 in the main stream, and 0.49-2.5
/m2 in the tributaries. In late September, the abundance of juveniles
extremely decreased. This change suggests that the considerable number of fish
moved to anywhere.
- 25-2
Studies on the planting of hatchery-cultured masu salmon fry into
streams -2. An observation on dispersal and residuary of juveniles
in the Sannosukezawa-kawa, a branch of the Mena River.
Matsukawa, H., Ishida, T., and Tanaka, T. pp. 19-27. (In Japanese
with English summary)(467KB)
Abstract
The dispersal and residuary of
hatchery-reared masu juveniles were observed in a brook of the Mena
River, the Shiribetsu River System, from May to October, 1970. A
majority of masu salmon juveniles released in the brook dispersed
downstream from the released position to out of the brook, and a few
fish moved to the upstream. In early July, some fish in the brook
and from the Mena River shifted to the upstream. Number of fish per
stream length was 3.1-0.9/m in late July, and the value was higher
in the lower part than in the upper part. In late October, it
decreased to about one third of the value in late July.
- 25-3
A note
on the ecology of juvenile masu salmon, Oncorhynchus masou in a brook.
Supplement report. Ishida, T., Kosaka, S., and Maekawa, K. pp. 29-34. (In
Japanese with English summary)(295KB)
Abstract
Dispersal pattern of
hatchery-reared masu salmon fry released in a brook near Hakodate in 1969 was
similar to that in 1968. Age-2 fish did not change their resident place in the
previous year by June at least, and they shifted upward in the fall. Supplement
data on the growth of masu salmon in the first and second year of freshwater
life were noted.
- 25-4
Yolk
absorption and translocation of liver in chum salmon (Oncorhynchus keta)
development. Nishida, H., and Kobayashi, T. pp. 35-43. (In Japanese with
English summary)(2,858KB)
Abstract
The authors investigated the liver
formation and yolk absorption in chum salmon alevins. The liver of alevins
located at the right of the body axis. During the growth period, the liver
transferred to the ventral and then to the left side. In chum fry, a reduced
yolk sac was connected with the blood vessels to the posterior-dorsal part of
the liver, and it disappeared gradually. The yolk did not remain in chum fry
cultured in gravel with spring water, but remained in almost all the fry
obtained from other methods even at about 240 days after fertilization.
- 25-5
The
effect of treatment with salt water on the development of chum salmon,
Oncorhynchus keta (Walbaum), eggs-I. Removing the unfertilized and
undeveloped eggs from the trays using salt water. Hashimoto, S. pp. 45-51.
(In Japanese with English summary)(1,792KB)
Abstract
The sedimentation property of
maldeveloped eggs resembled that of dead eggs in a salt water solution. In 12%
salt solution, it is possible to cull the maldeveloped eggs together with dead
eggs in 2-3 minutes after the start of treatment. The removing of dead eggs was
almost complete in 13% solution, but it was necessary to continue the treatment
for a long time. Moreover, living eggs such as maldeveloped eggs were likely to
be mixed with dead eggs. It is concluded that 12-13% salt solution is sufficient
for removing worthless eggs.
- 25-6
The
effect of treatment with salt water on the development of chum salmon,
Oncorhynchus keta (Walbaum), eggs II. The appearance of dead eggs and
unusual phenomena of incubation. Hashimoto, S. pp. 53-61. (In Japanese with
English summary)(687KB)
Abstract
The present investigation examined
the impediment of development of chum salmon eggs caused by salt water. The
hatching rate of eggs treated with salt solution was decreased by the occurrence
of dead eggs and abnormal hatching. Moreover, a period from fertilization to
hatching was reduced and dispersed. Salt absorbed on the egg surface should be
removed within eight minutes to prevent the decrease of hatching rate. Saltwater
bath should be carried out using a solution below a concentration of 12%.
- 25-7
The
effect of treatment with salt water on the development of chum salmon,
Oncorhynchus keta (Walbaum), eggs III. The most suitable time of the
treatment on the eyed stage. Hashimoto, S. pp. 63-70. (In Japanese with
English summary)(488KB)
Abstract
The purpose of this work was to
clarify the influence of saltwater treatment on egg development of chum salmon.
Dead eggs and abnormal hatching did not occur when the treatment period did not
extend more than 5 minutes. The disperse of hatching period did not occur within
this period. When eggs were treated within 35 to 53 days after fertilization,
the egg incubation period increased.
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Sci. Rep. Hokkaido Fish Hatchery
(24), 1970
- 24-1
Studies on the kokanee salmon (VI). On the kokanee smolts (Oncorhynchus nerka)
emigrated out of Lake Shikotsu in 1962. Tokui, T. pp. 1-8. (In Japanese with
English summary)(1,761KB)
Abstract
This paper contains a record of
observations on "himemasu" (= lacustrine sockeye salmon) smolts migrated from
Lake Shikotsu in the early summer of 1962. Age-2 smolts migrated downstream from
middle June to early July, especially during night. Their total length ranged
from 166 to 204 mm.
- 24-2
Studies on a bacterial disease occurred in the adult "sakuramasu" (Oncorhynchus
masou) and pink salmon (O. gorbuscha) rearing for maturity.
Kimura, T. pp. 9-100. (In Japanese with English summary)(17,627KB)
Abstract
A bacterial disease occurred among
adult masu and pink salmon reared for maturation at the Shokotsu Hatchery. The
results of macroscopic and histological observations indicated that this disease
was almost coincided with furunculosis of salmonid fishes. The causative
bacteria had some differences from Aeromonas salmonicida in terms of its
important properties in its taxonomic and serological properties. The author
proposed that the bacterium was named Aeromonas salmonicida subsp. masoucida.
The immunological and serological diagnostic methods of this disease were also
studied.
- 24-3
The
succession of plankton in Lake Abashiri, eastern Hokkaido. Kurohagi, T. pp.
101-124. (In Japanese)(3,943KB)
Abstract
Long-term changes in plankton
fauna in Lake Abashiri were monitored for 1926-67. Zooplankton fauna was changed
gradually by increasing chloride concentration, while phytoplankton fauna was
not until the chloride concentration reached over 500-600 ppm.
- 24-4
IBP-PF
study of Yurappu River in Hokkaido: results obtained to date, and plans for
future. Tokui, T. pp. 125-140. (In Japanese)(1,961KB)
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Sci. Rep. Hokkaido Fish Hatchery
(23), 1969
- 23-1
An
ecological study of the masu salmon (Oncorhynchus masou (Brevoort)).
Artificial rearing and marking of masu smolt. Sano, S., and Ozaki, Y. pp.
1-8. (In Japanese with English summary)(1,238KB)
Abstract
In the rearing experiment of
juvenile masu salmon, the percentage of sea-run form, sex ratio and growth were
investigated. A part of masu salmon parr were transformed into sea-run smolts
after about one year rearing, and its ratio is 43.8 %. Sex ratio was different
among two groups. The sea-run form was consisted of 70.7 % in females, while the
river resident form was 66.1% in males. All female parrs stayed in fresh water
were transformed into sea-run form, and only large male parrs stayed as river
resident form. Throughout the experimental rearing for two years, 65.8% of
reared fishes became the sea-run form. They were marked with fin-clipping and
released into the Yurappu River, southern Hokkaido, and several fishes were
recaptured in the coast and offshore.
- 23-2
A
hematological study of chum salmon (Oncorhynchus keta) during upstream
migration for spawning-III. Biochemical study on the chum salmon blood.
Nishino, K., and Saito, K. pp. 9-13. (In Japanese with English summary)(7,824KB)
Abstract
An extremely colored phenomena of
serum was examined for adult chum salmon during their upstream migration in the
Tokachi River. The pigment of colored serum was identified as astaxanthin. In
the maturing process of salmon, the serum showed the colored phenomena along
with increasing astaxanthin, but it disappeared after spawning. The colored
serum might be a phenomena in process that astaxanthin of muscle moved through
serum into other tissues.
- 23-3
Biochemical studies of carotenoid in the chum salmon (Oncorhynchus keta)
during upstream migration for spawning-I. Nishino, K., Saito, K., and
Kitahara, T. pp. 15-22. (In Japanese with English summary)(503KB)
Abstract
The quantity of astaxanthin in the
muscle of adult chum salmon decreased with an advance of their maturation, and
this tendency was especially noticeable in females. In adult females, with the
process of maturation, the muscle astaxanthin moved through blood serum to the
ovary. There was just a trace of astaxanthin in the male testis, but
cholesterol-like components increased. The carotenoid content in the skin
increased in adult salmon, and it contained more than 60% of lutein system
pigments during the complete maturation. It is usual in animals that lutein
transformed to astaxanthin, but in adult salmon during their spawning
maturation, a reverse transformation of carotenoids-producing metabolism from
astaxanthin to lutein occurred.
- 23-4
On the
kokanee salmon smolts, Oncorhynchus nerka (Walbaum), taken from eastern
coastal waters of Hokkaido, with some remarks on their scales. Hikita, T.
pp. 23-28. (In Japanese with English summary)(2,963KB)
Abstract
Sockeye salmon smolts, which were
derived from Lake Shikotsu sockeye salmon, were released to the Nishibetsu River
after one year of rearing. They were captured on the Nemuro Coast in August.
They grew 23.0 cm and 24.1 cm in fork length, and formed 2-13 circuli on scale
during the ocean life period. It was estimated that sockeye smolts migrated to
the coastal water from May to early July.
- 23-5
Reports on the resources research of the pink and masu salmons returning up to
the rivers in Hokkaido. Sano, S. pp. 29-44. (In Japanese)(939KB)
Abstract
Pink salmon migrate to the natal
rivers mainly in July and August, and spawn from early September to late
October. Masu salmon return between March and June, and their spawning time is
from late August to early October.
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Sci. Rep. Hokkaido Fish Hatchery
(22), 1968
-
22-1
A note of the seaward migration of pink salmon fry.
Kobayashi, T. pp. 1-5. (In Japanese)(255KB)
Abstract
In the Iwaobetsu River, eastern
Hokkaido, seaward migrations were investigated for pink salmon
fry originating from experimental natural spawnings on October
9-10, 1965. Pink salmon fry migrated seaward immediately after
the emergence during May. Hatchery pink salmon fry reared with
river water had the same migration time as the wild ones. In the
river pink salmon fry rarely fed with no growth.
- 22-2
Some observation on the natural spawning ground of chum and pink
salmon in Hokkaido. Kobayashi, T. pp. 7-13. (In Japanese
with English summary)(429KB)
Abstract
Environmental conditions of
spawning redds were compared between chum and pink salmon in
three rivers of Hokkaido. Chum salmon spawned where ground water
run throughout the gravel. Water temperature in the redd ranged
from 6°C to 11°C, being higher than that of river water in
winter. Dissolved oxygen and pH in the redd were lower than
those of river water. Pink salmon constructed a redd where water
velocity was fast (60-80 cm/sec) with a high dissolved oxygen
concentration. Water temperature and quality in pink redd were
same as those of river water, suggesting that river water was
supplied into the redd.
- 22-3
Ecological observation on the salmon of Nishibetsu River III.
The feeding habit of chum salmon fry, Oncorhynchus keta
(Walbaum), and the food taken during seaward migration.
Kobayashi, T., and Harada, S. pp. 15-35. (In Japanese with
English summary)(1,027KB)
Abstract
The feeding ecology of chum salmon
fry and the benthic animal community were examined in the
Nishibetsu River between February and June, 1963. Chum salmon
fry fed on benthic animals such as chironomids (dominant
species), caddis flies, mayflies, and terrestrial insects. In
the main period of seaward migration (March and April), few fry
stayed in the river because of the high population density. From
May to June, however, they fed much food and grew rapidly in the
river. The standing crop of benthic animals was extremely higher
in the upper part than in the lower part of the Nishibetsu
River.
- 22-4
A study of the ecology of chum salmon fry, Oncorhynchus keta
(Walbaum), in Abashiri Lake and its protection. Kobayashi,
T., and Kurohagi, T. pp. 37-71. (In Japanese with English
summary)(1,915KB)
Abstract
Chum salmon fry released to the
Abashiri River, immediately migrated downstream, and entered in
Lake Abashiri. In the lake, they could scarcely grow and feed
during the ice thawing period. Thus, most chum fry migrated to
the coastal sea from early April. However, chum salmon fry
stayed in the lake fed well and grew rapidly in middle May and
June. Dominant organisms in their stomach were chironomids and
Sinocalanus spp.
- 22-5
The unpublished notes on the kokanee salmon, Oncorhynchus
nerka var. adonis (Jordan et McGregor), of Lake
Shikotsu, 1916-1928. Kurohagi, T. pp. 73-92. (In Japanese)(1,185KB)
Abstract
The author reviewed unpublished
information of lacustrine sockeye salmon in Lake Shikotsu,
including adult catch, number of eggs taken, and their
transplantation in 1916-28.
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Sci. Rep. Hokkaido Fish Hatchery
(21), 1967
-
21-1
Ecological studies of masu salmon (Oncorhynchus masou
(Brevoort)). The observation on the smolt in the coastal waters.
Sano, S., and Abe, S. pp. 1-10. (In Japanese with English
summary)(3,163KB)
Abstract
A series of ecological study on
masu salmon smolts was made from May to July, 1965 in coastal
waters near the mouth of the Kushiro River . Masu salmon smolts
appeared at the beginning of May and disappeared between late
June and early July in the coastal waters. The school of smolts
was consisted of 75.9 % female and 24.1 % male. The peak of fish
body length was 140-160 mm. The mean number of scale circuli in
the first year zone was 18.3. The results suggest that some
group may migrate out to sea in this season but others remain
relatively for a long period in the coastal waters near the
river mouth.
-
21-2
Ecological and physiological studies on the Dolly Varden char (Salvelinus
malma) in Lake Shikaribetsu, Hokkaido. Kubo, T. pp.
11-33. (In Japanese with English summary)(8,678KB)
Abstract
The life history of Dolly Varden (Salvelinus
malma) was examined in Lake Shikaribetsu and a stream
flowing into the lake. The juveniles dwell in the stream at fry
and parr stages, and migrate to the lake in the second winter of
their life. In the lake, they are divided in two groups by their
behavior, body color, and smoltification: the pelagic offshore
migration group and the benthic inshore colonized one. The
silvery offshore migrating fish swim upwards of the thermocline,
feeding on zooplankton. On the other hand, the duller and
brownish inshore colonized fish dwell at the shallow bank
between the shore near the river mouth and the edge of land
shelf, and feed mainly on benthic insects and worms. Smolt
transformation may occurs in the former group after entering the
lake as 2 years old fish. Most fish mature in the lake during
the 4th year of life, and they ascend the stream to spawn in the
autumn. It is presumed that Dolly Varden in Lake Shikaribetsu
should be regarded as a typical anadromous type.
-
21-3
A hematological study of chum salmon (Oncorhynchus keta)
during up-stream migration for spawning II. Nishino, K. pp.
34-47. (In Japanese with English summary)(16,781KB)
Abstract
Physiological changes in adult
chum salmon migrating to the Tokachi River were investigated.
The number of erythrocytes, hematocrit value, and hemoglobin was
influenced by environmental conditions, but the change with the
fish maturation was not found. The quality of serum protein
decreased just before the ovulation period. A/G ratio of serum
protein remarkably differed between male and female. During the
coastal migration, A/G ratio of adult females already decreased
under 1.0. However, A/G ratio of adult males suddenly decreased
just before their maturation.
-
21-4
Studies on the metabolic function of adult chum salmon,
Oncorhynchus keta (Walbaum) -II. Erythrocyte sedimentation
rate and serum protein concentration of chum salmon ascending
the river for spawning. Hashimoto, S. pp. 49-70. (In
Japanese with English summary)(1,422KB)
Abstract
The author investigated
physiological changes of adult chum salmon held in ponds during
their maturation. The serum protein concentration decreased in
the course of the maturation, especially in females. The serum
protein concentration were affected by environmental conditions
such as water temperature, and quantity of water supply. In the
complete mature stage, the serum protein level remarkably
changed from 4.5 to 2.7 g/dl. The health of adult fish may be
judged by the serum protein level and erythrocyte sedimentation
rate.
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21-5
On the sea-run sockeye salmon, Oncorhynchus nerka
(Walbaum), ascended to the Nishibetsu River and the large size
kokanee salmon from the lakes in Hokkaido. Hikita, T. pp.
71-76. (In Japanese with English summary)(3,133KB)
Abstract
The present paper reported the
morphology of sockeye salmon (n=3) ascending to the Nishibetsu
River in 1965, and large lacustrine sockeye salmon captured in
several lakes in Hokkaido. Anadromous sockeye salmon might
originate from Lake Shikotsu sockeye salmon juveniles released
in the Nishibetsu River.
-
21-6
An example of the pink salmon (Oncorhynchus gorbuscha
Walbaum) from the Chitose River. Hikita, T., and Terao, T.
pp. 77-79. (In Japanese)(3,640KB)
Abstract
Pink salmon was rarely distributed
in rivers along Japan Sea coasts of Hokkaido. An adult male pink
salmon was captured in the Chitose River on July 14, 1966. The
morphology of this specimen was recorded in this paper.
-
21-7
Bibliography of limnology in Hokkaido (1893-1966). Tokui,
T., and Kawai, T. pp. 81-112. (In Japanese)(2,129KB)
Abstract
Literatures dealing with limnology
in Hokkaido were compiled for 1893-1966. The bibliography
included 981 papers. A history of limnology in Hokkaido was also
noted.
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