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Volume 61 (1995)
- Issue 6 Pages 821-
- Issue 5 Pages 673-
- Issue 4 Pages 473-
- Issue 3 Pages 307-
- Issue 2 Pages 137-
- Issue 1 Pages 1-
Volume 61, Issue 3
Displaying 1-15 of 15 articles from this issue
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Takakazu Ozawa1995 Volume 61 Issue 3 Pages 307-310
Published: May 15, 1995
Released on J-STAGE: February 29, 2008
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Kenshiro Fujimoto1995 Volume 61 Issue 3 Pages 311-315
Published: May 15, 1995
Released on J-STAGE: February 29, 2008
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Nobuaki Arai, Wataru Sakamoto1995 Volume 61 Issue 3 Pages 316-319
Published: May 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSScale circuli of juvenile red sea bream Pagrus major were counted to investigate the relation between circuli deposition and seawater temperature. The samples were collected from three experimental stations; Momoshima: MS and Hakatajima: HT in the western Seto Inland Sea and Miyazu: MZ on the western coast of the Sea of Japan. The larvae which were collected from the same parents group in HT were distributed into MS and HT and reared until they grew to juveniles in each place. The samples in MZ were reared in Miyazu from larvae to juveniles and their parents were different from those in MS and HT. The thermal condition and size of rearing tanks were different among the three stations. Temperatures in the three stations showed characteristic fluctuations. Mean temperatures in the experimental periods were calculated as follows; MS: 26.5°C, HT: 21.7°C and MZ: 22.7°C. The daily deposition rate seemed to depend on their scale growth rate in accordance with their body growth since the circuli numbers were linearly proportional to their fork length. The circuli numbers per fork length were in proportion to the mean temperature; MS: 1.35numbers/mm, 26.5°C, HT: 1.28numbers/mm, 21.7°C and MZ: 1.27numbers/mm, 22.7°C. Number of days until first-circulus deposition was inversely proportional to the mean temperature: MS: 19 days, HT: 44 days and MZ: 48 days. These results indicated that seawater temperature affected the fish growth, therefore affecting the circuli deposition and that the thermal condtion in the different sea-farming stations was written into juvenile fish scales.View full abstractDownload PDF (333K) -
Shigeru Fujieda, Takashi Ishino, Hajime Niina, Yasuhisa Matsuno, Yuich ...1995 Volume 61 Issue 3 Pages 320-325
Published: May 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSAuditory thresholds of the tilapia Tilapia niloticus in a quiet water tank were investigated using a classical conditioning procedure in a stable temperature container converted into an acoustic chamber. The classical conditioning procedure followed Ishioka's method. Tilapia could hear a sound band width ranging from 100Hz to 1500Hz with maximum sensitivity 300Hz where the threshold was below 103.5dB (0dB re 1μPa). The background noise in the range of measurement frequency were in a low level of 37-47dB (0dB re 1μPa/√Hz), and signal/noise ratio in this investigation was above 50dB. Nevertheless the audiograms for tilapia from 100Hz to 1000Hz were significantly higher than in the red sea bream. It is evident that the auditory capacity of tilapia is poor, as compared to that of the red sea bream tested by the same method.View full abstractDownload PDF (393K) -
Takashi Matsuishi, Hirohisa Kishino, Ken-Ichi Numachi1995 Volume 61 Issue 3 Pages 326-330
Published: May 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSRecent advances in aquatic hatcheries with a variety of fish and shellfish made a large scale stocking of artificially produced seeds into natural fishing grounds possible. When the genetic properties of the stocking population are different from the wild population, displacement of the gene in the wild population will gradually occur by the gene of the stocking population through reproduction. In this study, we investigate the change of the composition of both genes, in terms of the rate of stocking and fitness of the individuals of each genotype, using a simple mathematical model. When the fitness is equal in each genotype and the rate of stocking is 10%, the term that the gene of the wild becomes half (Genetic Halving Time, GHT) is 8 generations, and the term that the gene of the wild becoms 1% (Genetic Displacement Time, GDT) is 49 generations. When the fitness of the hybrid between wild and stocking individuals is smaller that both parents, GHT and GDT are much smaller.View full abstractDownload PDF (1256K) -
Shigemi Seri, Tokuko Watanabe, Masashi Maita, Nobuaki Okamoto, Yuji Ha ...1995 Volume 61 Issue 3 Pages 331-338
Published: May 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSOur study focused on the evaluation of magnetic resonance imaging (MRI) with a contrast agent to living fishes.
Images were collected with a spin-echo pulse sequence using 1.5 and 2 tesla systems. Normal carps, eels and cold-injury induced carps, which could be kept alive for about two hours in the air, were examined in vivo. The enhancement study was performed by using Gd-DOTMA. The blood flow and renal excretion in a carp and an eel were clearly visualized by administering Gd-DOTMA. Normal brain parenchyma in rodentia is known not to be enhanced by Gd-DOTMA because of exis-tence of blood-brain-barrier (BBB). The normal carp brain wasn't enhanced by Gd-DOTMA, also. This fact indicates that the BBB exists in the carp. On the other hand, the disturbed region of BBB in-duced by cold-injury was enhanced by Gd-DOTMA. In addition, the existence of an unknown cavity tissue azound the brain in the carp was recognized by accumulation of Gd-DOTMA.View full abstractDownload PDF (4806K) -
Hideji Tanaka, Katsufumi Sato, Yoshimasa Matsuzawa, Wataru Sakamoto, Y ...1995 Volume 61 Issue 3 Pages 339-345
Published: May 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThe presence of feeding was examined in loggerhead turtles during internesting periods from 1989 through 1993 off southern Japan using the Time Temperature Recorder (TTR). The TTR was inserted into the stomach and temperature data were obtained from the nine free-ranging female loggerheads. The patterns of temperature fluctuation which consisted of a rapid drop and subsequent gradual rise were recorded in the stomach temperature data. This typical pattern proved to be caused by drinking or feeding. The pattern counted 5 to 19 times in the first 24 hours after nesting and decreased afterwards gradually. The loggerheads seemed to drink sea water just after nesting and not to feed during internesting periods.View full abstractDownload PDF (456K) -
Yong Chen, Hisayuki Arakawa, Tsutomu Morinaga1995 Volume 61 Issue 3 Pages 346-355
Published: May 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSAs a link in the chain of effective utilization programs of sea-bottom sediment (i.e. HEDORO), a survival-type seaweed culturing concrete block (which is hereinafter referred to simply as “block”) was designed. The block is quite different from the existing kind, and it has such a distinctive feature that a scanty detrition takes place on the block at all times so that its surface could be always renovated. The HEDORO collected from the coastal sea bottom off Tomioka-Machi, Fukushima Pref. consisted of clay and silt, and a volume mean diameter of those composites was 11.3μm; and its moisture content was 100%.
In the water standing still, the detrition degrees of the specimen block mixed with varied Portland cement rates differed one after another, indicating that the lower degrees was inversely proportional to the cement rates from 10% to 50%. For example, the degree showed 9.10×10-6cm/day when the cement rate was 10%, and 1.16×10-6cm/day when it was 30%. Any changes in the detrition degree were not observed from 40 days after setting on the blocks in the water. The block detrition degree had not any correlation with the growth rate of gametophyte as well as sporophyte of brown algae Eisenia bicyclis; and such a degree was in inverse correlation to the survival rate of algal sprouts. For instance, in case of the higher detrition degree of 6.07×10-6cm/day, the survival rate of those sprouts on 16 days was smaller showing the value of 23.2%; on the contrary, in case of the lower degree of 9.15×10-7cm/day, it stood for the larger value of 56.6%.View full abstractDownload PDF (1334K) -
Shigeru Fuwa, Munechika Ishizaki, Kazutaka Sako, Takehiko Imai1995 Volume 61 Issue 3 Pages 356-362
Published: May 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSA study was conducted to clarify the fish catching mechanism of a fish trap for the puffer fish. The authors have proposed a catching model for puffer trap fishery, taking into account the mutual relation between the entrance shape of the pot and fish behavior. The probability of fish being entrappead and relative catch efficiency were theoretically calculated from a model based on four main assunptions. The theoretical results were examined by comparing the measured values of turning diameter of puffer in a narrow water channel and the size of the entrance of traps presently used, through tank and field experiments.
From the turning motion analysis, two major ratios were introduced in the model to clarify the catch efficiency in terms of trap selectivity and escape. One is the ratio of width of water channel to total length of fish body and the other is the ratio of turning diameter of a given fish to total length of fish body. The catch efficiency was expressed by Eq. 7. The lower and upper selection limits were 1.24 and 1.38 times the width of trap entrance. These limits approximately agreed with the experimental values obtained from field research.View full abstractDownload PDF (394K) -
Tomonori Hiraishi, Katsuaki Nashimoto, Tsutomu Takagi, Kengo Suzuki, K ...1995 Volume 61 Issue 3 Pages 363-368
Published: May 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSTo estimate and control the water current velocity at the bottom of a net cage for aquaculture of benthic fishes, it is necessary to know the stationary-holding ability of the fish in the net. In this ex-periment, bastard halibut Paralichthys olivaceus and dead longsnout flounder Limanda punctatissima were used. A net was laid horizontally inside a small flume tank. Then the fish was carefully placed inside in such a way that its body axis was parallel to the stream line and its head was at the upper stream side. For bastard halibut, each fish was allowed to stay appoximately 5 minutes in the tank. A slow water current was applied and increased gradually. The current velocity at the time when the fish slipped and could not hold the same position inside, was recorded and termed as the slipping speed. The coefficient of static friction between the fish body and the net plane was calculated by the angle of the slope.
The relationship between total length l and slipping speed us was expressed by the function us=k3√l in both two species. The value of proportional constant k3 was 3.2 (CM/s2)1/2 in bastard halibut, 3.3(cm/s2)1/2 longsnout flounder. For bastard halibut of 1.0kgf weight and 45cm total length, the average slipping speed was 21cm/s.View full abstractDownload PDF (370K) -
Jun Han, Yoshinori Miyamoto, Etuyuki Hamada, Yoshihiko Nakamura1995 Volume 61 Issue 3 Pages 369-374
Published: May 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSWe have developed a new fish tracking system using a synchronising method. The system consists of an ultrasonic pinger, four hydrophones, a four channel receiver, an 8-bit single board computer with ADC, a personal computer, an electronic magnetic compass and a DGPS receiving system. In this system, the bearings of the pinger are calculated using the short base line by measuring the receiving time differences of a pulse between channels. The distance from the hydrophone to the pinger is calculated by using an original method, in which the receiver and the pinger are syn-chronised to measure the interval between received pulses. A Synchronising drift error which accumulates with time is corrected by using the distance calculated from the transmission loss. This method gives a more accurate measurement of distance. Using this system, we successfully tracked three striped jack Caranx delicatissimus for five days.View full abstractDownload PDF (484K) -
Zhenlin Liang, Tadashi Tokai, Ko Matuda, Haruyuki Kanehiro1995 Volume 61 Issue 3 Pages 375-379
Published: May 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThis paper describes the function of propulsive mechanism of tilapia Tilapia mossambica and improves the residual function in the fish behavior model. In the fish behavior model, the propulsive mechanism is the first component external force for the motion, which consists of the propulsive force and the drag force. The swimming velocity of tilapia increases approximately inversely proportional to its acceleration. Therefore the propulsive mechanism of tilapia can be expressed as a linear equation of velocity, i. e., Fi1=ai-vfivi, where ai, vfi and vi denote the propulsive parameter, drag parameter and the velocity. Although the quick whiteness tests of the residual was passed, the distribution of the residual was sometimes different from the normal distribution. The residual function assumed to be expressed as the equation of the two combined normal distributions. The swimming trajectory of fish in the simulation by the model including the new concept was consistent with that in observation.View full abstractDownload PDF (373K) -
Akira Kishi, Yoshiaki Itoh, Atsushi Obatake1995 Volume 61 Issue 3 Pages 380-386
Published: May 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSMyosin from carp muscle was heated at 80°C in 0.6M NaCl solutions containing various kinds of buffer (pH 6.8), and the polymerization behavior of proteins through SS bonding (SS polymerization) was analyzed by SDS-polyacrylamide gel electrophoresis.
In the phosphate buffer and Tris-HCl buffer, the oxidation of SH groups in myosin and SS polymerization of myosin heavy chain were promoted, which suggested that metal ions from the reagents used might be related to them. In Tris-maleate buffer and Tris-maleic anhydride buffer, the content of SH groups decreased more than in the phosphate buffer and in Tris-HCl buffer, but the decrease was not inhibited by a metal chelating reagent (EDTA) Moreover, in Tris-maleate buffer, SS polymerization was inhibited, and in Tris-maleic anhydride buffer, SS polymerization through covalent bonding other than SS bonding occurred. Therefore, it was concluded that these two buffers are not suitable for the research of SS polymerization.View full abstractDownload PDF (3028K) -
Kazuhiko Hiramatsu, Tatsuro Akamine, Shuichi Kitada1995 Volume 61 Issue 3 Pages 387-388
Published: May 15, 1995
Released on J-STAGE: February 29, 2008
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Toru Suzuki, Noriko Ono, Tikuo Takai1995 Volume 61 Issue 3 Pages 389-390
Published: May 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSDownload PDF (133K)
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