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Volume 52, Issue 1
Displaying 1-17 of 17 articles from this issue
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Gregory N. NISHIHARA, Yuko MORI, Ryuta TERADA, Tadahide NORO2004 Volume 52 Issue 1 Pages 1-10
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSA simplified method to isolate and cultivate the red alga, Laurencia brongniartii J. Agardh was established to prepare it for indoor tank cultivation. This method was addressed so that relatively inexperienced personnel can start and maintain laboratory cultures of the organism. The method uses the apical tissue of branch tips which are relatively free of epiphytes and requires almost no specialized equipment or facilities. The effect of size and location of apical tissue on the relative growth rates (%RGR) and survival rates (%SR) were examined to determine the size and location of apical tissue that would promote the highest survivability and fastest growth rates. The larger sizes (5.0 mm) showed higher %SR (62.5%) and smaller sizes (1.0 mm) showed higher %RGR (4.43%/day) . There was also a significant effect of tissue location, with material closest to the apex showing the highest %RGR (2.16%/day) . Different concentrations of nitrate were not significant, however higher concentrations appeared to have a negative impact on %RGR. Temperature and light had a significant effect on %RGR. Optimal growth was observed at 24 and 28°C and at an irradiance of 20μ mol photons/m2/s.View full abstractDownload PDF (4587K) -
Akira WATANUKI, Norikazu HIROSE, Shigeru MONTANI2004 Volume 52 Issue 1 Pages 11-16
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSMass mortality in pearl oyster farming by virus infection has become a serious problem. This occurs due to food shortages in the summer. An experiment was conducted on the hypothesis that with artificial feeding, the mass mortality could be decreased. A low cost semi-continuous culture system, outdoors for Chaetoceros gracilis is required. The object of such a system would be to achieve a supply of 600l culture solution in chlorophyll a of 600μg/l per day using four 500l tanks. In a continuous culture system, the cost of addition of nutrients is high so. A simple semi-continuous system was utilized using algae propagation water soluble glass to release trace minerals and nutrients (e.g. silicate, phosphorus, iron) along with nitrogenous fertilizer. It proved possible to control the rate and amount of dissolution. As a result of cultivating with this system during the summer, chlorophyll a, 550 to 850μg/l and 290 to 370 million cells/ml were produced on average. Cultivation of C. gracilis outdoors was achieved in high concentration.View full abstractDownload PDF (904K) -
Manabu HATTORI, Yoshifumi SAWADA, Naoko SUDOU, Manabu SEOKA, Nobuhiro ...2004 Volume 52 Issue 1 Pages 17-22
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSIn our previous study, it has been elucidated that one of the causes of centrum defects in cultured red sea bream Pagrus major is oxygen deficiency during embryonic development. In the practical production of red sea bream seedlings, it is expectable that the condition of oxygen deficiency occurs during egg transportation and egg collection by dividing floating and sunken eggs. In this study, the ontogenetic change in oxygen consumption was investigated at 11 stages during the embryonic development at three different incubating temperatures of 16, 19, and 22°C for red sea bream. Based on these data, the change of dissolved oxygen concentration was simulated in the high density layer of developing eggs. The oxygen consumption rate of eggs was higher at the higher incubating temperature, that is, the oxygen consumption rate at 16°C, 19°C, and 22°C was 0.9×10-4, 1.3×10-4, and 1.9×10-4μl/ind/min at blastula stage, and 6.9×10-4, 7.8×10-4, 11.0×10-4μl/ind/min just before hatching, respectively. At all temperatures, the oxygen consumption rate increased almost linearly except for Kupffer's vesicle appear stage. Calculation from the obtained data suggested that the concentration of dissolved oxygen rapidly decreases in the pore space water in the high density layer of floating eggs. Therefore, it is recommended to control dissolved oxygen concentration during egg transportation and collection processes to prevent the deformity in cultured red sea bream, especially shortened body condition by centrum defects.View full abstractDownload PDF (935K) -
Kenichi WATANABE, Masashi KAITA, Rikako FUKAYA, Azuma ITO2004 Volume 52 Issue 1 Pages 23-28
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe effect of water temperature on egg development of the devil stinger Inimicus japonicus was examined. The time between each developmental stage decreased exponentially with the increasing of temperature. The relationship between hatching time and the incubation temperature was expressed by the two regression lines which intersected at 24°C. Values of temperature characteristics and Q10 in temperatures ranging from 18°C to 24°C were higher than those in temperatures ranging from 24°C to 30°C. The eggs hatched at temperatures ranging from 16°C to 32°C. No eggs hatched below 14°C. Viable hatching occurred at temperatures ranging from 16°C to 28°C. More than 50% of the total eggs hatched normally at temperatures ranging from 18°C to 28°C. The relationship between viable hatching rate and the incubation temperatures was expressed by the curve of which the maximum value was at 24°C. The rate of anomalous hatching was the lowest at 24°C. The results showed that 24°C would be a flection point and the most suitable water temperature for hatching would be temperatures ranging from 24°C to 26°C.View full abstractDownload PDF (927K) -
P.Robin RIGBY, Yasunori SAKURAI2004 Volume 52 Issue 1 Pages 29-36
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe effect of temperature and diet on the energy flow in immature octopuses Enteroctopus dofleini was investigated. The energy used in respiration, voided in waste and consumed and stored in somatic tissue by captive immature octopuses was monitored. The results suggest that a mixed low lipid diet of approximately 3% body weight provided every 3 days, and temperatures of between 7-9.5°C lead to the largest amount of energy being available for growth and activity. The efficiency of different temperatures and diets are discussed in terms of importance to aquaculture and implications on the behaviour of immature E. dofleini in the field.View full abstractDownload PDF (1357K) -
Arun Prasad BAIDYA, Shigeharu SENOO2004 Volume 52 Issue 1 Pages 37-44
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThis study observed the fertilization and hatching rates of African catfish Clarias gariepinus eggs stripped at different times after ovulation in three females (0.8-1.3 kg) . Ovulation was induced by Ovaprim (20μg salmon gonadotropin releasing hormone analogue and 10 mg domperidone per ml) with a single dose of 0.5 ml/kg. Ovulation occurred between 8-9 h after the hormone treatment at 26.3-29.1°C. The fertilization and hatching rates decreased with time after ovulation (AO) at 26.7-28.9°C. The mean fertilization rates were 92.1% at 0 h AO and 47.4% at 6 h AO. The mean hatching rate was 81.4% at 0 h AO; this finally decreased to 0% at 6-8 h AO. This study concludes that C. gariepinus eggs should be stripped and fertilized within 3 h AO in order to achieve good quality eggs (more than 50% hatching rate on average) .View full abstractDownload PDF (6367K) -
Heisuke NAKAGAWA, Makoto FURUHASHI, Tetsuya UMINO, Ikuko KONDO, Shuich ...2004 Volume 52 Issue 1 Pages 45-50
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSUsefulness of corn meal as a protein source in diet of ayu Plecoglossus altivelis was evaluated by growth performance, biological and biochemical parameters. The diets were prepared by 67% fish meal and various ratios of corn meal and wheat flour. Crumbling extruded diets (dimension 0.9-1.5, 1.5-1.9 mm, >52% total protein) were fed to the fish of initially weighing 11.7 g for 43 days in duplicate tanks. Replacement by 10% corn meal tended to increase growth performance and feed efficiency, but the replacement by 20% and 30% significantly decreased the parameters. The effect would be due to the coexistence of both plant proteins. The dietary corn meal had no affect on liver weight, muscle ratio, intestine length and biochemical parameters of muscle. Starvation for 7 days after feeding experiment did not differentiate the parameters such as survival, body weight loss, liver weight and proximate composition of muscle among the dietary groups, implying no difference in mobilization of lipids to energy. The results that supplementation of corn meal at 10% to the composed diet hardly influenced biological and biochemical parameters under the rearing condition suggested the utility of corn meal as well as wheat flour in a practical diet for ayu.View full abstractDownload PDF (846K) -
Jun OHTOMI, Hiromasa YOKOMURA, Tatsuo HAMANO2004 Volume 52 Issue 1 Pages 51-55
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe relative growth of the deep-water stomatopod crustacean Squilloides leptosquilla (Squillidae) was analyzed using a total of 440 specimens collected on board the small-scale bottom trawlers in Kagoshima Bay, southern Japan. The relationships of the total length (TL), total body weight (TBW), body weight without raptorial claws (BW), telson length (TEL), and telson width (TW) to the carapace length (CL) were described by the power function. By the analysis of covariance, significant differences were revealed between sexes except CL-TBW and CL-BW relationships. The relative growth between CL and TW was allometric in males, resulting a sexual dimorphism but not a secondary sexual character.View full abstractDownload PDF (777K) -
Hiroshi YAMAKAWA, Ikuo HAYASHI2004 Volume 52 Issue 1 Pages 57-63
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSField surveys on the food habits of Turbo cornutus were carried out in semi-sheltered and wave-exposed coastal areas in Awashima Island, Japan Sea. Stomach contents of Turbo cornutus in the semi-sheltered areas were composed of mainly Sargassum species including S. hemiphyllum, S. patens, and S. macrocarpum. Stomach contents of Turbo cornutus from wave-exposed areas were composed of a few dominant species of small algae, e. g. Dictyota spp. and Polysiphonia morrowii that grew on rocks and giant boulders along with crustose corallines in the 2-6m depth zone. These suggest that the typical difference in algal distributions between the two types of areas were due to wave action in the winter season. The algal species in stomach contents were compared with standing crop in both coastal stations. Analyses using the finite correction of Akaike's information criterion supported the finding that Turbo cornutus had a food habit of selective preference rather than one of random feeding. D. spp. and P. morrowii have been reported to contain chemicals that inhibit comsumtion by herbivorous animals. However, Turbo cornutus fed commonly on these algae, showing the same condition factor value in both types of areas. This showed that Turbo cornutus was capable of wide adaptation in food habits responding to environmental variations.View full abstractDownload PDF (1073K) -
Yuuki KITADAI, Shusaku KADOWAKI2004 Volume 52 Issue 1 Pages 65-72
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSBiological water purification by culturing Ulva pertusa in coastal fish farms was estimated as a function of light intensity, dissolved inorganic nutrients and water temperature. Ulva pertusa was cultured from 0.5 m to 8 m depths in coastal fish farms from August to November, 2002. The maximum growth of thallus area, wet weight and thickness were recorded at 0.5 m depth. The maximum growth of thallus area reached to 640 cm2 on August. The maximum growth of thallus thickness reached to 0.11 mm on November. Average contents of total nitrogen (N) and total phosphorus (P) in Ulva pertusa reached to 35 mg N/g dry and 2.1 mg P/g dry in October, respectively. The maximum N, P uptake rates of Ulva pertusa were 3.6 mg N/m2/day and 0.19 mg P/m2/day at 0.5m depth, respectively. Michaelis-Menten's constants of N, P uptake rates were 26μg N/l and 8.6μg P/l, respectively. Downward irradiance of 730μmol/m2/s resulted in the maximum N, P uptake rates. N, P uptake rates of Ulva pertusa at 25°C were 2.5 mg N/m2/day and 0.13 mg P/m2/day, respectively. Water temperature coefficients of N, P uptake rates were 1.076 and 1.084, respectively. The N and P uptake rates of cultured Ulva pertusa were formulated from dissolved inorganic nutrients, light intensity and water temperature characteristics found in coastal fish farms, and the calculated values corresponded well with the observed values.View full abstractDownload PDF (1200K) -
Toshihiro KUGE, Kunihiro NOBUSAWA, Masashi MAITA2004 Volume 52 Issue 1 Pages 73-80
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe abundance and feeding habits of largemouth bass Micropterus salmoides were investigated in Haruna Lake, Gunma, Japan. A total of approximately 2500 largemouth bass (total length ≥ 25cm) were estimated in 1997 by using mark-and-recapture method. Population hatched during 1995-1997 suggest the dominant year classes by age composition. Fish and crustacean were the important prey according to investigated stomach contents of 241 specimens. As regards preyed fishes, the main one was lake goby Rhinogobius sp. in 1997, the poor fishing year of pond smelt Hypomesus nipponensis, whereas pond smelt occupied the largest proportion in 2001, the bumper fishing year of it. The condition factor and stomach-content-somatic index were lowered in 1997, but increased in 2001. The body weight of largemouth bass in fishing tournament had been lowering during the poor fishing years, before recruitment of dominant year classes as weighed bodies. Therefore, it is suggested the poor abundance of pond smelt causes lack of bait for largemouth bass, and the increased population of largemouth bass affect the abundance of pond smelt by predation pressure to adult pond smelt in spring, the spawning season of pond smelt and young after summer in Haruna Lake.View full abstractDownload PDF (1224K) -
Kazutoshi OKAMOTO2004 Volume 52 Issue 1 Pages 81-89
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe fishery and reproductive characteristics of the Japanese mitten crab, Eriocheir japonica, were investigated in Lake Hamana, a semi-enclosed bay in Shizuoka prefecture. During the 10 years between 1989 and 1998, the average yearly crab catch at Kiga fish market run by Hamana Fisheries Cooperative Association was about 831.4 kg and the average yearly price was 747.6 yen/kg. In the levels of catch and CPUE, two peaks were observed in spring and autumn. A census of commercial landings was carried out at the market from September 1997 to December 1998. The carapace width of the landed crabs ranged from 37.2 to 84.0 mm and that of the smallest female carrying eggs was 42.0 mm. Ovigerous females accounted for 75.9% of the total females. The catch of crab landed and the appearance of ovigerous females revealed that the downstream and breeding season is from September to May. Crabs in small number that migrated to the tidal area in September tended to be larger than those migrating in large number in October and November. Although the sex ratio in total is female-biased, that of the large crabs is female-biased, while that of the small crabs is male-biased. Comparison of the reproductive characteristics with those at other reproductive areas showed that the carapace widths of the smallest ovigerous female, the largest crab, and the early maturing group were larger than those elsewhere.View full abstractDownload PDF (1357K) -
Shin HORIE, Kou TANIURA, Tetsuya UMINO, Heisuke NAKAGAWA, Katsutoshi A ...2004 Volume 52 Issue 1 Pages 91-98
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSIn the loach Misgurnus anguillicaudatus, triploid (3n) and tetraploid (4n) individuals were produced by crosses using diploid (2n) gametes of natural tetraploids, which had been found in the specimens obtained from fish dealers. Long-term communal rearing experiments from the age of 1 month old to 3 years 1 month old were carried out among diploid (2n female×2n male), triploid (4n×2n) and tetraploid (4n×4n) to compare their performance under a laboratory condition. At the end of experiments, significantly retarded growth was observed in tetraploids and they showed significantly lower body length/head length proportion than diploid and triploid individuals. Triploid females exhibited less developed gonad than tetraploid and diploid individuals, when compared gonad somatic index (GSI) . Triploid and tetraploid males showed lower GSI than diploid males, but tetraploid males gave better gonadal development than triploid males.View full abstractDownload PDF (1280K) -
Kingo ITO, Yasunori SAKURAI2004 Volume 52 Issue 1 Pages 99-100
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSWe examined the effects of low salinity on the embryonic development and hatching of the squid Loligo bleekeyi (Cephalopoda: Loliginidae) . Egg capsules were incubated in seawater with salinity ranging from 20.4 to 34.6 psu at 9°C and 15°C. The duration of embryonic development increased slightly at low salinities. The hatching rate decreased markedly below 50% between 27.2 and 28.8 psu at 9°C, and between 25.4 and 27.2 at 15°C. Hatching did not occur for embryos kept at 23.8 psu, 9°C, or for those kept at 20.8 psu, 15°C. During the embryonic development, all embryos exposed temporally (8 days, 18 days) to low salinity (21 psu) seawater died.View full abstractDownload PDF (358K) -
Yuzuru IKEDA, Yasunori SAKURAI2004 Volume 52 Issue 1 Pages 101-102
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSFertilizing capacity of spermatozoa in spermatungium attached on female outer lip in the Japanese common squid Todayodes pacificus was examined by artificial insemination experiment. Similar to spermatozoa stored in female seminal receptacle in buccal membrane, which is fundamental sperm storage site in this squid, rate of fertilization for spermatozoa of spermatungium origin was around 90%. This indicates that spermatungium may function as an extra sperm storage site beside seminal receptacle.View full abstractDownload PDF (2854K) -
Yasuhiko TAGO2004 Volume 52 Issue 1 Pages 103-104
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSDifference in number and size of ayu Plecoglossus altivelis larvae collected by bow side tow and stern tow of a ship was examined in the inner part of Toyama Bay in 1999. The tows were conducted eight times using two larvae nets at the same time. The mean lengths of larvae collected at the bow side ranged from 4.9±0.3 to 10.9±6.2 SD mm, whereas those collected at the stern ranged from 5.2 to 7.6±1.6 mm. The lengths of larvae collected at the bow side were distributed significantly to a larger size compared with those collected at the stern. In water tank experiments ayu larvae escaped from the surface to the bottom when an object was thrown and floated on the surface. These facts suggest that in collecting ayu larvae at the rear of a ship, larger larvae tend to escape from the surface in fright response of approaching ship. Some of larvae collected at the middle layer by a larvae net towed at the rear of the ship might, in fact, inhabit the surface layer. It is concluded that bow side tow is more effective than stern tow in collecting ayu larvae inhabiting the surface layer.View full abstractDownload PDF (382K) -
Tatsuya KOBAYASHI, Yasuharu ISHITAKA, Makoto IMAI, Yoshifumi KAWAGUCHI2004 Volume 52 Issue 1 Pages 105-106
Published: March 20, 2004
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSIn October and November 2000, mass mortalities of the cultured amberjack Seriola dumerili have occurred in the southern part of Kyushu, Japan. The gross pathological signs of diseased fish were abnormal swimming with wide-opened mouth and opercula, which are typical signs of suffocation. Histopathological examination revealed definite epitheliocystis cysts accompanied by hyperplasia and fusion of epithelial cells of gills.View full abstractDownload PDF (1959K)
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