Aquaculture Science

Fatty Acid Compositions of Lipids from Some Tissues of Cultured Red Sea Bream, Pagrus major

Hisashi MURATA, Kiyoshi YAMAUCHI

1990 Volume 38 Issue 2 Pages 99-103
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.99

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Fatty acid compositions of total lipids from the ordinary muscle and liver of 3-year-old cultured red sea breams, Pagrus major were investigated in connection with its dietary lipids from July, 1986 through Jaunary, 1987. The main fatty acids were 18: 1ω9, 16: 0, 22: 6ω3, 20: 5ω3, 18: 2ω6 and 18: 0, acids for the ordinary muscle lipids and 18: 1ω9, 16: 0, 22: 6ω3, 18: 0, and 20: 5ω3 for the liver lipids. The fatty acid compositions of the ordinary muscle lipids seemed likely to be affected by the nature of lipids of the diets fed, but not by season. On the other hand, for the liver lipids, the concentrations of polyunsaturated fatty acids (PUFA>18: 2) such as 22: 6ω3 and 20: 5ω3 acids were found to be consistently lower in summer and higher in winter. This seasonal variation may be explained as being dependent on the specific activity of fatty acid desaturase that is expected to increase when enviromental temperature falls.

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On the Body Weight-Length Relationship of Ayu Fish in Lake Biwa

Takashi ITO, Toshio IWAI

1990 Volume 38 Issue 2 Pages 105-112
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.105

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Based on the result of statistical analysis on the Body Weight-Standard Length relationship and on the Standard Length/Total Length ratio of Ayu fingering populations in Lake Biwa, we deduced the following transformed equations of the Weight-Length allometries.
w=-3.48282 + 3.81355 1
w=-3.72104 + 3.81355 1'
where w : weight (mg), 1: standard length (mm),
1' : total length (mm)

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Avoidance Reaction of the Eel to Water of Low Oxygen Saturation

Ken-ichi YAMAMOTO

1990 Volume 38 Issue 2 Pages 113-116
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.113

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Experiments were carried out to examine the oxygen saturation when avoidance reaction began, and the oxygen consumption under normoxic and hypoxic conditions, by gradually decreasing the oxygen saturation at 1 hour intervals, in the Japanese eel Anguilla japonica (5g) .
The avoidance reaction began when the oxygen saturation decreased below 35%. But in the water of below 5% in oxygen saturation, the fish often went in the water of low oxygen saturation from the oxygen saturated water. The oxygen consumption decreased markedly below the oxygen saturation when the avoidance reaction began.

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Energy Budget in an Artificial Ecosystem Culture of the Rotifer (Brachionus plicatilis)

Shigehisa YAMASAKI, Yuichi ARAMAKI, Hachiro HIRATA

1990 Volume 38 Issue 2 Pages 117-126
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.117

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Energy budget was observed to make clear the efficiency of an artificial ecosystem culture of rotifer. Metabolism of microorganisms in rotifer culture tank and dissolved organic matter in the rotifer culture medium were also considered on calculation of energy budget. Percentage of recycling Nannochloropsis sp., which was produced with nutrients of waste water and decomposed biodeposits, occupied 29.1% of total energy supply on feeding. Nannochloropsis sp. and baker's yeast as input food were supplied at percentages of 63.4 and 6.9%, respectively. Dissolved organic matter, which remained in the culture medium of recycling Nannochloropsis sp. was only 0.6%.
The total energy supply was distributed mostly to rotifer growth, metabolism of rotifer, biodeposits, and metabolism of microorganisms in rotifer culture medium, at percentages of 29.0, 30.7, 24.3, and 8.6%, respectively, whose total showed 92.6% of whole energy supply. Distributions to other elemets, i. e., metabolism of microorganisms attached on rotifer culture tank, biodeposits, dissolved organic matter in the waste water of rotifer culture, were only 0.7, 0.6, and 2.5%, respectively. Dissolved organic matter remained in the rotifer culture medium at the end of experiment and desorption of ammonia from rotifer culture medium by aeration were both 0.1%.
It was suggested that almost of the energy of recycling Nannochloropsis sp. was supplied from irradiation of the Sun, and that concentration of dissolved organic carbon in the rotifer culture medium was nearly negligible for energy budget.

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Method of Measuring Seawater Flow Rate with Plaster Balls

Yasunobu NABESHIMA, Washiro KIDA

1990 Volume 38 Issue 2 Pages 127-133
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.127

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Procedures for measuring the flow rate of seawater using plaster balls in a laver culture farm were investigated. At the beginning of the study, the method of making plaster balls and the method for measuring their wear in flow were examined and improved. The amount of wear (weight and volume) of the plaster ball in water flow increased in proportion to the water volume that they received within 24-48 hours, however, it was also affected by the hardness (density) of plaster balls and seawater temperature. From the results of experiments, it is considered that plaster ball is suitable material for measuring the flow rate of seawater.

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Growth of Engraulid Fish (Coilia nasus TEMMINCK et SCHLEGEL), in Ariake Sea

Koich ISHIDA

1990 Volume 38 Issue 2 Pages 135-145
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.135

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The present report deals with age and growth estimation based on ring marks of scales and frequency distribution of body length at intervals of one month and on each number of scale mark for Coilia nasus. Materials used on this study consist of 1235 individuals rainging from 29-358mm in body length, collected by larva net, set net and gill net in the Chikugo River and in Ariake Sea during the period from 1966 to 1985.
Several scales taken from the back side above the pectoral fin were used for measurement.
Results obtained are as follows.
1.The relationship between body length (mm) and scale radius (mm) was discribed by the following equations.
R=0.0110BL-0.2190 (Female)
R=0.0108BL-0.1952 (Male)
2.First mark was formed from November to March (5-9 months after hatching out), the second from June to December, the third from May to December, the froth in June, November and December.
3.Females of this fish grow up to 170-210mm in body length after one full year, 220-282mm after full two years and 260-320mm after full three years.
Males attain 150-195mm after one full year, 200-270mm after full two years and 238-305mm after full three years.
4.Spowning groups consist of mainly two and three years old fishes.

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Reduction of Albinism in Hatchery-Reared Flounder “Hirame”, Paralichthys olivaceus by Feeding on Rotifer Enriched with Vitamin-A

Noritatsu MIKI, Tomohiro TANIGUCHI, Hideo HAMAKAWA, Yukio YAMADA, Nori ...

1990 Volume 38 Issue 2 Pages 147-155
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.147

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Reduction of albinism in hatchery-reared larval flounder Paralichthys olivaceus was reported in the previous paper in which effect of feeding on rotifers enriched with fat-soluble vitamins by the larvae during metamorphosis was discussed. In order to establish a more effective technology to reduce albinism, the essential vitamins for reducing albinism were investigated and identified by larval rearing experiments.
Rotifers were enriched by dissolving vitamins into the culturing water of rotifers. The dosages of the vitamins were 50, 000IU/l for A, 25, 000IU/l for D₃, and 20IU/l for E.Dosages of 250, 000IU/l for D₃ and 200IU/l for E were also tried as a single vitamin.
Albinism was reduced in only the flounders being fed on rotifers enriched with vitamin-A. In the case of various combination treatment of the vitamins, albinism was reduced in only the flounders being fed on rotifers enriched with both vitamin-A and D₃ or both vitamin-A and E. Thus, vitamin-A was well evaluated as a essential fat-soluble vitamin to reduce albinism. Furthermore, there was no significant difference between albinism rate of the larvae being fed on rotifers enriched with vitamin-A alone and with all of the three vitamins.
Administration by any dosages of vitamins gave no impact to growth and survival rate of larvae. But, in the larvae being fed on rotifers enriched with vitamin-A alone, abnormity of the caudal portion occurred at a high rate.

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Feeding Habit of Juvenile Chum Salmon, Oncorhynchus keta, Released into a Chilean Fjord, South America

Kazumasa HIRAKAWA

1990 Volume 38 Issue 2 Pages 157-163
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.157

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The stomach contents of juvenile (FL: 8-12cm) chum salmon, Oncorhynchus keta, released into Aysen Fjord (45°15'S-45°30'S, 72°50'W-73°30'W) in the southern Chile were compared with the regional and diel vertical distributions of zooplankton collected with a Norpac net and MTD nets during the period from September to October 1985. Their primary preys drastically changed from terrestrial insects, small epibenthic gammarid amphipods and barnacle larvae in the fjord to large calanoid copepods, callianassid decapod zoeae, euphausiid furcilia larvae and fish eggs in Moraleda Channel connected to the fjord. These copepods which mainly consisted of the copepodite IV, V stages and adults of Calanus chilensis, Calanoides patagoniensis, Rhincalanus nasutus and Metridia lucens were very important diets, in particular, adult females of whih comprised numerically about 70-90% of each population found in the stomach.
Feeding conditions of the fish are discussed from the relationship between diel vertical migrations of these females and salinity gradients at the surface layer in the fjord and the channel.

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Age and Growth of Kokanee, Oncorhynchus nerka in Lakes of Nikko National Park, Central Japan

Toshinobu TOKUI

1990 Volume 38 Issue 2 Pages 165-169
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.165

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[in Japanese]

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On the Adhesive Mechanism of Epiphytic Diatom Attached to Nori Fronds

Tomoyuki KOUZUMA, Masaharu OHGAI

1990 Volume 38 Issue 2 Pages 171-176
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.171

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The present study was undertaken to elucidate the adhesive mechanism of epiphytic diatom attached to noni fronds in both field and laboratory experiments. The following results were obtained;
1. The main diatoms attached to the fronds were Licmophora spp. Among the upper, the middle and the basal parts of the fronds, the diatoms adhered predominated in the upper one in the cultivation ground of Saigawa coastal area in Shimonoseki.
2. It was observed by using SEM that the existence of the ruggedness based on the cell diameters was recognized at the surface of the fronds and that especially the ruggedness at the upper parts was the most minute.
3. The cell numbers of diatom attached to the fronds increased when seawater was running in the laboratory conditions.
4. From the laboratory observations, the diatom was mostly attached to the upper parts of the fronds, and the cell numbers remarkably increased with the increase of the frond-length.
5. Therefore, the adhesion manners of diatom were found to be related to the surface structure, the frond-length and to be depended on the running of seawater.

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Effects of Feed Additive Ulva Reproduced in Feedback Culture System on the Growth and Color of Red Sea Bream, Pagrus major

Botao XU, Hachiro HIRATA

1990 Volume 38 Issue 2 Pages 177-182
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.177

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In order to maintain the homeostasis of ecosystem in the water, a feedback culture system was examined for rearing the red sea bream, Pagrus major juvenile.
Six “pan-light” tanks (A: 500l×2; B: 100l×2 & C: 100l×2) were set outdoors at a rearing place with transparency plastic roof. The water recirculated in arrange of tank A→B→C→A by an air-lift pump. The tanks A both in the feedback and control experiments were employed for rearing the red seabream (1.1g in initial average body weight) . The tanks B and C in the feedback experiment were used for reproducing the sterile Ulva pertusa. The U. pertusa harvested from those tanks were powdered and additively feed back to the fish (15.7g w.w. Ulva/84.3g moist pellet) . No Ulva was reproduced in tanks B and C in control experiment.
Results showed that the survival rates were 94% and 62 % in feedback experiment and control, respectively. Daily growth rates of the fish in feedback experiment and control were 44.5% and 31.5%, respectively. The food conversion ratio were 4.21 and 6.16 in feed-back experiment and control, respectively. Body color of the red seabream cultured in the feedback experiment was more reddish than that of the fish in the control. Average NH_4-N and NO_3-N in the water during the experiment were 100.7μg-at⋅l^-1 and 27.3μg-at⋅l^-1 in the feedback experiment, and 284.0μg-at⋅l^-1 and 43.1, 1μg-at⋅l^-1 in the control. Averag e PO_4-P in the water during the experiment were 2.4μg-at⋅l^-1 and 4.9μg-at⋅l^-1 in the feedback experiment and control, respectively.

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The Distribution of Planktonic Juveniles of Octopus vulgaris CUVIER in Harima Nada

Raisuke TAKEDA

1990 Volume 38 Issue 2 Pages 183-190
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.183

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The distribution of planktonic juveniles Octopus vulgaris were investigated in the Northwestern part of Harima Nada during the period from May 1980 to September 1982. In total, 159 specimens were collected at 8 cruises among 14 cruises or 49 larva-net tows out of 113 in the season between August and December.
Ranges of total length, body weight and sucker counts of the collected specimens are 2.4-13.2mm, 1-110mg and 3-22, respectively.
The planktonic juveniles were collected from only near-bottom layer in daytime, but from both surface and near-bottom at night.
Many specimens were collected from nearshore area rather than from offshore region.

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Growth of the Frog Flounder in the Harima Nada

Ken-ichi WATANABE, Yukio UETA

1990 Volume 38 Issue 2 Pages 191-197
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.191

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The growth of frog flounder Pleuronichthys cornutus was studied by growth data of juvenile fish in seeding production and 3, 569 specimens (included 223 specimens which wouls be threw away for no economy size) collected from catch by small trawlnet in the Harima Nada. The growth equation after age at first capture of this species was estimated as TL_t=168.9270 (1-exp (-0.0472 (0.0389t+1.3392+0.0849sin (0.5236t+1.1190) ) ) ), where TL_t is the total length (cm) at tth month after hatching in December. The growth grew well from August to December, The difference of the growth of male and female were a little.
The growth equation of yearling fish was estimated as TL_t=13.7867/ (1+exp (4.1529-0.8095t) ), where TL_t is same as above. The growth traced a typical sigmoid curve and grew up hastily about February and March when yearling fish began benthic life form and completed metamorphosis.
In respect of the relationsip between coefficient of fatness and total length, coefficient of fatness rose from January to june and after that total length increase from August to December.

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Systematic Position of Ayu, Plecoglossus altivelis

Tamotsu IWAI

1990 Volume 38 Issue 2 Pages 199-200
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.199

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Notes on the Range of the Ayu, Plecoglossus altivelis with Reference to the Ryukyuan Subspecies

Mutsumi NISHIDA

1990 Volume 38 Issue 2 Pages 200-203
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.200

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Cormorant Fishing and Ayu, Plecoglossus altivelis in Nagara River

Fumio TASHIRO

1990 Volume 38 Issue 2 Pages 203-204
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.203

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Diagnoses of Seedlings and Multiple Implanting of Ayu, Plecoglossus altivelis

Makoto ARAI

1990 Volume 38 Issue 2 Pages 204-205
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.204

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The Flavor and the Shape of Ayu, Cultured or Catched in River

Rikizo ISHIDA

1990 Volume 38 Issue 2 Pages 206-207
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.206

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The Structure of Spawning Ground of Ayu, Plecoglossus altivelis

Rikizo ISHIDA

1990 Volume 38 Issue 2 Pages 207-208
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.207

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Ecological Aspects and Resources of Ayu, in the Marine Habitat

Katsumi TSUKAMOTO

1990 Volume 38 Issue 2 Pages 208-209
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.208

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Fish Quality and Up Stream Migration of the Ayu

Kazuo UCHIDA

1990 Volume 38 Issue 2 Pages 210-211
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.210

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Release of Ayu and Inland Water Fisheries

Yoshikazu SAKAI

1990 Volume 38 Issue 2 Pages 212-213
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.212

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Ayu and Fish Way in the River

Masato AKAZAKI

1990 Volume 38 Issue 2 Pages 213-214
Published: June 30, 1990
Released on J-STAGE: March 09, 2010

DOIhttps://doi.org/10.11233/aquaculturesci1953.38.213

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