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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 5
Displaying 1-23 of 23 articles from this issue
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Hitoshi Semura1995 Volume 61 Issue 5 Pages 673-678
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSChanges in filtering and digestion rates of adult japanese bay scallop were examined by feeding four species of microalgae, Chaetoceros gracilis, Pavlova lutheri, Nannochloropsis oculata, and Tetrasel-mis tetrathele at various concentrations. Filtering rates ranged from 4.9 to 58.9 l/ind./h, and were highest for Ch. gracilis and lowest for Nanno. oculata among the four species. Maximal filtering rates were observed at algal concentrations between 19.3 to 49.2×10-8g/ml. Ingestion rates ranged from 52.6 to 94.1% in these concentrations and were highest for P. lutheri and lowest for Ch. gracilis. In-gestion rate decreased with increasing algal concentrations. Assimilation rates of organic matter, which were estimated from filtering rates and ingestion rates at the above algal concentrations, ranged from 24.1 to 201.0×10-5g/ind./h for Ch. gracilis, 46.3 to 247.7×10-5g/ind./h for P.lutheri, 6.0 to 23.3×10-5g/ind./h for Nanno. oculata, and 101.7 to 720.2×10-5g/ind./h for Tetra. tetrathele.View full abstractDownload PDF (441K) -
Tatsuki Nagai1995 Volume 61 Issue 5 Pages 679-683
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThe total mortality coefficient (Z) in the 1930's was once reported as 0.18 from the catch curve of those days. In the present papaer, Z was divided into fishing mortality (F) of 0.04 and natural mortality (M) of 0.14 based on the life span being 18. The cohort analysis considering partial recruit-ment (HISTAVG) was run to the catch-at age data of the 1980's. Then, the yield per recruit analy-sis (Y/R) was made using the two data sets of those periods. The average weight was calculated as 1, 670g under the equilibrium condition in the 1930's. It being roughly equivalent to the observed value of 1, 720g, the separated F mentioned-above seemed rationale. The F value in the 1930's was 40% compared to the F0.1 of those days. While, the F was about two times as big as the F0.1 in the 1980's. It means less of a fishing effort in the 1930's and too much effort in the 1980's. As the fishery mainly caught the small-sized fish in the 1980's, the level of Y/R values was reduced by about half and the average weight became only 8% comparing those in the 1930's.View full abstractDownload PDF (399K) -
Kazuhiro Tashiro, Yukio Iwatsuki1995 Volume 61 Issue 5 Pages 684-688
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSFifty-eight young Japanese centropomid fish Lates japonicus were captured from the Hitotsuse River estuary, Miyazaki Prefecture, southeastern Kyushu, Japan, through April to September, 1989, and their sizes of total length (TL) (mean TL 222mm) and body weight (BW) (mean 147g) were recorded. They were reared in a concrete tank (20 ton) until the end of November, 1992, growing to a mean TL of 500mm and mean BW of 1, 825g. The diet of the fish was comprised mainly of raw sardines, shrimp, jack and mackerel. However, negative Feeding efficiency rates and Conversion fac-tors were apparent over the two winter seasons. Feeding activity, based on the mean quantity of food taken per individual, was closely related to water temperature and salinity (S) changes, especially being highest over about 25°C (S 28-30) and reduced to zero below about 16°C (S 34). The species seemed to be strongly resistant to disease, skin erosion and transportation stress, because all individ-uals used for the experiment survived.View full abstractDownload PDF (379K) -
Koji Yokogawa1995 Volume 61 Issue 5 Pages 689-694
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSTo determine the spawning ecology of fish, changes in ovarian egg number and egg diameter composition during the spawning season were examined with material of spanish mackerel Scomberomorus niphonius.
Gonadosomatic indices of female and male both fluctuated very similarly. The indices indicated peaks in early June, thereafter reduced rapidly, and tended to rise again in late June. The Relationship between fork length (L) and ovarian egg number (E) was expressed by a linear regression as follows:
E=6.881•103•L-3.244•106 (γ=0.768)
Thereafter, individuals whose egg number plotting points shifted below the initial regression line increased gradually with the lapse of time. Since considerable numbers of eggs still remained in the ovaries of individuals, they would continue to spawn. The composition of egg diameter showed plain polymodal forms at any sampling time. This indicated that some different egg diameter groups always existed at the same time.
According to the results obtained, it was concluded that Scomberomorus niphonius spawns several times within a spawning season. This method of tracing egg number and egg diameter composition was considered to be useful to determine the spawning ecology of fish.View full abstractDownload PDF (386K) -
Yong-jin Chung, Yasuhisa Matsuno, Shigeru Fujieda, Yuichi Yamanaka1995 Volume 61 Issue 5 Pages 695-699
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThe purpose of this paper is to investigate the auditory threshold of Japanese horse mackerel which is one of the important pelagic fish for Japanese fisheries. The hearing of fish was studied by means of a cardiac conditioning technique. Classical conditioning method was performed with the sound coupled with a delayed electric shock. The threshold was determined by analyzing the elec-trocardiogram. The sensable frequencies ranged widely from 70Hz to 3000Hz which was most stimulative to the Japanes horse mackerel. As the frequency becomes higher than 70Hz, the auditory threshold decreased. At 1000-1500Hz (sound pressure 81-75dB) when the fish's hearing was most sensitive, the threshold tends to increase more than one. Lastly, it was assumed that a round haul netter traffic noise caused an escape action for the fish shoal.View full abstractDownload PDF (1143K) -
Mineo Yamaguchi, Shigeru Itakura, Ichiro Imai1995 Volume 61 Issue 5 Pages 700-706
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThe horizontal and vertical distributions and abundance of resting cysts of Alexandrium tamarense and A. catenella were investigated in sediments of Hiroshima Bay in April, May and July 1993. Cysts were counted using fluorochrome primuline-staining and epifluorescence microscopy. Cysts of Alexandrium spp. were found at all stations examined. Higher densities were observed in coastal waters off Hiroshima City and Kure City. These horizontal distributions were almost identical throughout the investigation from April to July. The cyst densities ranged from 50 to 1304 cysts/cm3 in April, 16 to 1476 cysts/cm3 in May and 57 to 1912 cysts/cm3 in July, respectively. It was found that the cyst density has increased ca. 30 times within the last 6 years. The vertical distribution of the cysts indicated that about 80 to 98% of all cysts existed in 0-3cm depth. This suggests that mass deposition of the cysts has occurred in the past several years. The present investigation found that the cyst abundance in Hiroshima Bay is so high that shellfish poisoning should be carefully monitored to prevent a PSP incident.View full abstractDownload PDF (550K) -
Hiroyuki Tsutsui, Toshikuni Nakatani, Tetsuya Takatsu, Toyomi Takahash ...1995 Volume 61 Issue 5 Pages 707-712
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSGonadal maturation of female ribbon prickleback, Lumpenus sagitta, collected in Funka Bay, Hokkaido, from September 1991 to Mayebruary 1994 was examined histologically. Oocytes from the chromatin nucleolus stage to the migratory nucleus stage were observed in the ovary. Based on the developmental stages of ovarian eggs, the maturity of female of L. sagitta was divided into five stages: the yolk vesicle stage, the oil drop stage, the early yolk formation stage, the late yolk formation stage and the migratory nucleus stage. In January, 91.6% of the femals had oocytes at the yolk vesicle stage and 8.4% at the oil drop stage. In the same period, postovulatory follicles were found in the ovary. Percentages of oocytes at the oil drop stage increased to 80% in May. In the middle of September, all of the females were in the late yolk formation stage. In Novemver, many oocytes at the migratory nucleus stage were observed. These observations, indicate that L. sagitta spawn from December to January in Funka Bay.View full abstractDownload PDF (1528K) -
Seiji Akiyama, Koji Yasuda, Takafumi Arimoto, Yozo Tawara1995 Volume 61 Issue 5 Pages 713-716
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSIn order to understand the capture process of trolling gear, the fish response towards a trolling line was observed by a towed underwater video camera. Fishing tackle consisted of a main line, a depressor board, a leader line, and a lure. The underwater video camera was mounted on the depressor board to observe and record the sequence of responses towards the lure. Fish species that could be identified, were yellowtail Seriola quinqueradiata, frigate mackerel Auxis rochei, amberjack Seriola dumerili, and mackerel Scomber japonicus. Behaviour patterns were classified as follows: appearance into the camera view, approach to the lure, attack on the lure, touching the lure, being hooked, and captured. The total number of appearances in the camera view was 1361, in which the catch was only 18 due to the low attack response frequency to the approaches. A slight difference was also observed on the proportion of missed-hookings, which was attributed to the difference in struggling escape behaviour between yellowtail and frigate mackerel.View full abstractDownload PDF (323K) -
Nobuhiko Taniguchi, Seiji Matsumoto, Akihiro Komatsu, Mitsuo Yamanaka1995 Volume 61 Issue 5 Pages 717-726
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSQualitative and quantitative traits of 5 red sea bream strains developed for fish farming were evaluated using offsprings which were propagated under the same rearing conditions. The fertilized eggs collected from five different hatcheries on the same day were used to remove the effects of age and environmental differences on the traits. The genetic variability observed in the parameters, average number of alleles per locus (q<0.99) and proportion of polymorphic loci were reduced in selection strains (S2, S3). These reductions of genetic variability seemed to be caused mainly by extinction of minor alleles, possibly caused by the bottle-neck effect.
Growth performances of selection strains (S2, S3, S4, S5) were significantly different from the non-selection strain (Sl). Significant differences among the 5 strains were also found in the morphological traits such as body depth and orbito diameter. Slight genetic change and genetic improvement were observed in qualitative and performance traits respectively, but there were no symptoms of inbreeding such as homozygous excess in the genetic traits.View full abstractDownload PDF (681K) -
Kazuhiro Matsumura, Nariharu Yamashita, Takayoshi Mikami, Shinobu Hash ...1995 Volume 61 Issue 5 Pages 727-731
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSExperimental investigations in a laboratory tank were conducted on the property of the submerged shape change and the buoyancy of a Soft-Shell-Float with an open bottom. The characteristic shape change and buoyancy are important factors which affect the stability of constant depth maintenance and control of rise and fall motion of the float.
Experimental results using scale models have shown that there are two different relationships between the buoyancy and the inner water volume in all of the models, which are sepwrated by around 45% of non-dimensional buoyancy. This difference in the relationship between the buoyancy and the inner water volume can be considered due to the characteristic shape change of the float, which depends on the location of the hanging rope. These results will provide useful information on the optimization of future design of a Soft-Shell-Float with an open bottom.View full abstractDownload PDF (1080K) -
Hiroshi Inada, Sumio Hirokawa, Katsuo Miyazaki, Masaharu Kimura1995 Volume 61 Issue 5 Pages 732-737
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSExperimental daytime jigging operation was conducted to develop the optimum fishing technology, instead of drift net fishery, for large-size neon flying squid in the North Pacific Ocean. Using underwater fishing light set at a depth of 180m, the only target species was caught at depths of 240m-300m. The observation of capturing characteristics and echo images with a fish finder indicated that the squid made their sparse school with a small number of the individuals. Besides this way of jigging seems to provide useful information to determine the fishing position and to make an effective start for the evening operation.View full abstractDownload PDF (522K) -
Seiji Akiyama, Mulyono S. Baskoro, Takafumi Arimoto1995 Volume 61 Issue 5 Pages 738-743
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSIn order to identify the entrapping time of fish into the set-net, experimental operations were conducted at a small scale set-net fishing area in Tateyama Bay, Chiba prefecture. The bag net was hauled up 6 times per day at 03:00, 07:00, 11:00, 15:00, 19:00 and 23:00 hours at 4 hour intervals. A total of 60 hauls at 6 different times of day were made and the catch was recorded for each species for studying the entrapping time of fish. Total catch was increased at the twilight time and the catch patterns of the main species were classified as the diurnal, nocturnal, crepuscular and aperiodic types. For example, the diurnal type included frigate mackerel Auxis thazard, the nocturnal type bottom perch Apogon semilineatus and flying fish Prognichthys agoo, and the crepuscular type round herring Etruneus teres and jack mackerel Trachurus japonicus.View full abstractDownload PDF (431K) -
Akira Nomura, Yoshiaki Itoh, Hirokuni Toyoda, Atsushi Obatake1995 Volume 61 Issue 5 Pages 744-749
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSFor the sake of utilizing the washed meat from Type IV (the fish which exhibits a modori at around 40°C in the washed meat, not in the unwashed meat) fish, this meat was mixed with the unwashed meat and the washed meat from the fish Types I and II which have excellent gel-forming ability. Type I is the fish which does not exhibit a modori at all in the unwashed meat and the washed meat, and Type II is the fish which exhibits the modori at 60°C only in the unwashed meat.
The mixed meat pastes with the unwashed meat of these two types did not exhibit the modori at 40°C, while that with the washed meats exhibited it. However, the modori at 60°C was occurred in the mixture with the unwashed meat of Type II. The gel-forming ability at 80°C was improved in the mixed meat pastes.
Sarcoplasmic protein fraction of the meat of not only Type IV but also Type I inhibited the modori at 40°C as well as the myosin heavy chain (HC) degradation of the washed meat pastes from Type IV. The floating lipid on the wash water did not have the inhibitory effect.
Therefore it was suggested that an inhibiting factor against the modori at 40°C of the washed meat may be contained in the sarcoplasmic protein fraction of fish meats.View full abstractDownload PDF (2937K) -
Yoichi Abe, Kosaku Yasunaga, Seiichi Kitakami, Takao Ota1995 Volume 61 Issue 5 Pages 750-755
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSSix kinds of walleye pollack frozen surimis of different grades were subjected to the preparation of kamaboko gels with and without the addition of 0.5% bovine plasma powder. The quality of the kamaboko gels thus obtained was evaluated by measuring the gel properties such as the breaking strength, breaking strain, gel strength, and spring constant. It was found that the addition of bovine plasma powder remarkably enhanced the gelling ability of all kinds of frozen surimis, although the apparent increment in gel properties of the kamaboko was larger in the frozen surimi of lower grade than that of higher grade. However, the quality of the kamaboko gel prepared from the frozen surimi of lower grade on addition of plasma was still remained inferior to that from the highest grade without the addition of plasma. These results also supported our previous conclusion that the gelling of frozen surimi with bovine plasma powder proceeded via slightly different way as compared to the case without plasma.View full abstractDownload PDF (466K) -
Feng Zheng, Toshio Takeuchi, Kenzo Yoseda, Jun Hirokawa, Takeshi Watan ...1995 Volume 61 Issue 5 Pages 756-761
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThe changes of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in total lipids were compared between fed and unfed cod Gadus macrocephalus larvae during development. The EPA and DHA contents in 100g of larvae on dry basis were different. The EPA content increased while the DHA content markedly decreased in the fed larvae till 20 days post-hatch. On the other hand, the DHA content was almost constant in the unfed larvae, however, the EPA content was reduced. Up to 5 days post-hatch, polar lipids notably decreased compared to the neutral lipids of the unfed larvae during the fasting period. It was also found that the mass mortality of fish coincided with a decrease in DHA level of live foods offered during the feeding period. In other words, the des-cent of DHA in the fed group of cod larvae was clearly related to the DHA levels in rotifers. Therefore, enrichment of the live initial foods with DHA is important for improving their dietary value, which in turn promotes the normal growth of larvae.View full abstractDownload PDF (417K) -
Toshitaka Nishijima, Jingguo Zhang, Kimio Fukami1995 Volume 61 Issue 5 Pages 762-768
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThe method for analizing vitamin B12 binder in natural seawater was evaluated. Based on this evaluation, the distribution and seasonal variation of free and bound B12 in the water of Uranouchi Inlet were investigated. Through these studies, the relationship between the content of B12 compounds and other environmental factors in seawater is discussed.
The protein-coated charcoal method was found to be an applicable and reliable why to determine the B12 binder in seawater samples. The water of Uranouchi Inlet is rather eutrophied, and the content of total B12 in the water ranged from 1.5 to 15.2ng/l. The concentration of free B12 was 0.02-12.9ng/l. The content of B12 bound to B12 binder (bound B12) ranger from 0 to 5.1ng/l in the water. The ratio of bound B12 to total B12 averaged 35%. The content of bound B12 correlated closely with the concentration of chlorophyll a, phosphorus, and COD, therefore some of the sources of B12 binder in seawater seem to be produced by phytoplankton and/or organic substances.
The result reveals that the B12 binder exists in eutrophic seawaters to some extent all year round, and that the B12 binder in the water could influence the growth of organisms requiring B12 and the succession of phytoplankton species.View full abstractDownload PDF (511K) -
Shigeru Nakajima, Tomohiro Sakuta, Takahide Tsuchiya1995 Volume 61 Issue 5 Pages 769-770
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
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Hiroki Abe, Minoru Sato, Katsuko Watanabe1995 Volume 61 Issue 5 Pages 771
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
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Minoru Sato1995 Volume 61 Issue 5 Pages 772-773
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
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Katsuko Watanabe1995 Volume 61 Issue 5 Pages 774-775
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSDownload PDF (158K) -
Emiko Okuma1995 Volume 61 Issue 5 Pages 776-777
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSDownload PDF (176K) -
Eizoh Nagahisa1995 Volume 61 Issue 5 Pages 778-779
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSDownload PDF (161K) -
Hiroki Abe1995 Volume 61 Issue 5 Pages 780-781
Published: September 15, 1995
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSDownload PDF (178K)
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