All issues
Volume 46, Issue 1
Displaying 1-22 of 22 articles from this issue
- |<
- <
- 1
- >
- >|
-
Tadashi YAMADA1998 Volume 46 Issue 1 Pages 1-6
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe occurrence and distribution of planktonic larvae of the Japanese top shell, Turbo (Batillus) cornutus, were studied by plankton net sampling (100 μm mesh, opening 46 cm) and artificial collectors sampling in the coastal waters of east Shimane Prefecture during the period from June to November, 1995. The results showed that planktonic larvae were commonly distributed in middle and upper layers of the coastal waters. Study of the presence of larvae in relation to water temperature and mean height of wave showed that the spawning of the Japanese top shell is stimulated by the change of water temperatures rather than the action of wave.View full abstractDownload PDF (1029K) -
Akihiko FUJII, Nobuhiko MAESAKO, Koji TAKESHITA1998 Volume 46 Issue 1 Pages 7-11
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSA tagging experiment was performed to estimate the exploitation rate in three shell size groups. A total of 1881 tagged shells, ranging from 59 to 110 mm in shell height, were released in an experimental area of 200×200m. Exploitation rates for three groups, large, medium and small size, were estimated from the release-recapture data. The highest rate was attained in the large size group during the former half of the fishing season (14 days fished) and in both the large and medium size groups during the latter half of the season (17 days fished), indicating the size selection of capture. A trend that the shell size in 50% retention of capture decreased as the fishing effort increased, was observed. This fact suggested that the size selection was closely related to magnitude of the total effort in the fishing ground.View full abstractDownload PDF (693K) -
Toyomitsu HORII1998 Volume 46 Issue 1 Pages 13-17
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSI investigated abalone diving fishery in Are area, the Tsushima Islands off northern Kyushu, in 1990-1994, by measuring landed shells and the catch logs in each fishing grounds. The yearly survival rates of wild and released shells were 0.64 and 0.37, respectively. Fishing intensity on released shells was expected to be higher than that of wild shells. Fishing intensity on stocked fishing ground was higher than that of the non-stocked, suggesting that the increment of stock density by seed-stocking induced a boost of fishing intensity on stocked ground. As the result, wild shells landed were smaller in size at the days when rates of released shells landed were high. For enhancement of abalone stock by seed-stocking, adequate management on stocked ground was indispensable.View full abstractDownload PDF (733K) -
Katsuaki FUJINAGA, Shigeru NAKAO1998 Volume 46 Issue 1 Pages 19-24
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSSubstratum preference in egg deposit and differences in predation rates on embryos at spawning sites in Neptunea arthritica in Usu Cove, Hokkaido, were investigated. Large hard substrata, such as rocks (including concrete blocks) greater than 50 cm in height, played an important role in spawning. There were more egg masses deposited on rocks than small substrata, such as boulders less than 50 cm in height and oyster shells. Egg masses were usually deposited on the upper part of hard substrata. Predation rates on embryos were closely related to the presence of large hard substrata. The predation rates at the spawning sites with rocks (the mean predation rate = 29.7%) were significantly lower than at the spawning sites with only small hard substrata (the mean predation rate = 50.8%) .View full abstractDownload PDF (793K) -
Shoko YAMAMOTO, Jun OHTOMI1998 Volume 46 Issue 1 Pages 25-30
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe fecundity of the two Solenocerid shrimps, Solenocera melantho and Haliporoides sibogae (Decapoda, Penaeoidea), which are commercially important for bottom trawlers and boat seiners in southern Kyushu, Japan, was examined. The number of oocytes at prematuration or later stage which would spawn within a few days, was counted for each female, for both species. For S. melantho, the fecundity was estimated to be 95, 400-384, 700 (26.1-43. 1mm in carapace length), while for H. sibogae, it was 89, 200-295, 800 (28.4-37.3mm in carapace length) . There was a significant positive correlation between the fecundity and the body size (carapace length and body weight) for both species. S. melantho had relatively higher fecundity in comparison to the same body size of H. sibogae.View full abstractDownload PDF (714K) -
Katsutoshi KAWABE, Johnson KIMURA, Kazuto ANDO, Kimio KAKIUCHI1998 Volume 46 Issue 1 Pages 31-36
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSSpawning of 2-year-old amberjack, Seriola dumerili reared from hatching was tried in Chichijima, one of the Ogasawara Islands. Rearing methods and characteristics of fertilized eggs were examined. During the rearing, from July 1994 to June 1996, mean monthly water temperatures ranged between 19.0 and 28.3°C (mean 23.8°C) . Fork length and body weight of one-year old fish were 46.3±1.7 cm and 1, 973±210g, and those of two-year old were 67.8±3.1cm and 7, 258±1, 049g, respectively. Mean daily feeding rate for the first year was 6.4% and dropped to 2.4% for the second year. Mean daily growth rate for the first year was 0.9% and dropped to 0.3% for the second year. Mean food conversion efficiencies for the first and second years were 12.2% and 13.6%, respectively. The spawning was observed between May and June. No artificial treatments such as hormonal injection or temperature shock were required to induce maturation and spawning. The total number of eggs obtained was approximately 10 millions. Water temperature varied between 20.3°C and 23.6°C during the spawning season. Optimum water temperature for the spawning was estimated to be between 22.0°C and 23.4°C. Floating egg rate was 82.9±8.2% and hatching rate was 97.1±2.9%. Egg diameter was 1.10±0.02 mm and oil globule was 0.26±0.01mm.View full abstractDownload PDF (636K) -
Naoyuki SUGURO, Kunio TODA1998 Volume 46 Issue 1 Pages 37-46
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSTo collect basic data necessary for restoring the habitat of the metropolitan bitterling Tanakia tanago, we conducted breeding trials in a bitterling pond (63 m2), one of the ecological test ponds of the Fisheries Reserch Center's Freshwater Test Station. In 1995 we stocked 20 of each metropolitan bitterling males and females, along with 20 of each Anodonta woodiana and Inversidens japonensis. Breeding behavior of the fish was observed and 30 newly-bred juveniles at free swimming stage were obtained. When the fish were culled in the following April, we caught 13 of the stocked fish and 22 newly-bred juveniles. In 1996, in addition to the surviving metropolitan bitterling from the previous year, we further stocked another 20 of each metropolitan Bitterling males and females, along with 20 of each Anodonta woodiana and Inversidens japonensis, and 10 Margeritifera laevis. Active breeding behavor of fish was observed particularly around Margeritifera laevis. In autumn, numerous juveniles surfaced. During cullig in November, we caught 40 1-2 year-old fish and 522 newly-bred juveniles, indicating that the bitterling pond was a relatively suitable environment for this species. Data such as water temperature and water quality will provide vital indicators for selecting candidate sites for restoring habitats in future. We used traps, four-armed scoop nets, towing nets, and other fishing gear for catching the fish. Although all of them was effective, depending on the type of gear used, a certain selectivity arose with respect to the fish caught. With traps, larger fish were caught than with other kinds of gear. Meanwhile, there was a difference in the size and numbers of the fish caught according to the position of the traps and the length of installation time.View full abstractDownload PDF (1412K) -
Kiyoshi YOSHIHARA, Nobuo OHI1998 Volume 46 Issue 1 Pages 47-56
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSAfter investigating water conditions of the Oka marsh in Nihon University Yakumo Practice Forests for 3 years, we stocked juvenile kokanee Oncorhynchus nerka in the marsh. The marsh was abundant in aquatic insects and other small creatures as fish baits but has no fish. Then follow up surveys were carried out to check the growth process of the stocked kokanee for six consecutive years. The results showed the body length of the fish and the condition factor rapidly increased at early days after stocking, but the body length increase became slow and condition factor tended to decrease afterward. However from the time when the number of accumulated catch exceeded 90, both the body length and the condition factor showed a tendency of increase. Therefore, the stocked kokanees might have reach a type of density-dependent growth at this in the marsh.View full abstractDownload PDF (2727K) -
Shoichi AKAIKE, Kazuo KIKUCHI, Haruhiro MONMA, Yasushi NOZAWA1998 Volume 46 Issue 1 Pages 57-65
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSLaminaria ochotensis Miyabe, Phaeophyta, is widely distributed in the northern coast of Hokkaido, Japan. L. ochotensis is an important species both as an edible seaweed and as a component of seaweed beds. Recently production for human consumption has continued to decline. Reasons for this decline are considered to be the progress of the “Isoyake” phenomenon in this region. “Isoyake” occurs in areas dominated by sea urchins and crustose coralline algae. The cause of “Isoyake” is suspected to be that the Tsushima warm current extends to this region and causes the water temperature rise and severe nutrients shortage. The fertilizer-controlled nitrogen and phosphorus treatments were studied from late spring to autumn in fields. The results showed that the fertilizer treatments increased the seaweed size, promoted its maturity and suppressed new blade formation, but the effect on blade photosynthetic products was not clear. The severe nutrient shortage period in this region was from May to November. The effecting area of the fertilizers was within a radius of 50 m from where the fertilizer was dispensed.View full abstractDownload PDF (1163K) -
Jacobus J. WENNO, Shigehisa YAMASAKI, Hachiro HIRATA1998 Volume 46 Issue 1 Pages 67-73
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSA mechanism of Nannochloropsis oculata growth enhancement by sodium acetate was considered in axenic culture and xenic culture, estimating roles of ammonium and dissolved inorganic carbon (DIC) in the latter culture. Four experiments were conducted, namely, Exp. 1: axenic culture of N. oculata, Exp. 2: observation of bacterial density, dissolved carbon concentration, and ammonium concentration changes by addition of sodium acetate into a modified PES medium (without Tris buffer) under xenic conditions, Exp. 3: xenic culture of N. oculata in medium enriched with ammonium chloride, Exp. 4: xenic culture of N. oculata in modified PES medium enriched with both ammonium chloride and sodium hydrogen carbonate. In axenic culture in Exp. 1, the lower the concentration of sodium acetate was, the higher the algal density increased. In the modified PES medium with sidium acetate in Exp. 2, the values of optical density and DIC concentration reached peaks within 24 h. In addition, ammonium concentration increased rapidly 24 to 48 h after sodium acetate addition. In Exp. 3, N. oculata density increased significantly at 24 h after ammonium chloride addition. In Exp. 4, the algal density in the treatment of ammonium chloride + sodium hydrigen carbonate maintained high during the culture period. N. oculata density increment in modified PES medium with sodium acetate was considered to be caused at least by an increase in the concentrations of both ammonium and dissolved inorganic carbon, which were released from the bacteria.View full abstractDownload PDF (983K) -
Hideyuki IMAI, Nobuhiko AKIYAMA, Katsuyuki HAMASAKI, Sachio SEKIYA, Si ...1998 Volume 46 Issue 1 Pages 75-82
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSSamples of the female swimming crab, Portunus trituberculatus were collected by gill net near the sea shore of Shimizu City, Shizuoka Prefecture, from April 1993 to February 1995. We investigated seasonal changes of gonadosomatic indices and histological change of ovaries. Ovigerous females occurred from May to August. Oogenesis of swimming crab was divided into ten stages: chromatin nucleolus, early perinucleolus, late perinucleolus, oil globule, yolk granule, primary yolk globule, secondary yolk globule, prematuration, maturation and atretic stages. Based on the results of the examination of the histological features of ovaries and occurrance of ovigerous females, annual reproductive cycle was divided into five ovarian maturity phases: multiplication phase (in October), developing phase (from November to early January), maturation phase (from January to early April), spawning phase (from May to August), and recovery phase (from middle August to September) . Our present study suggested that both the water temperature and the daylength influenced the begging of spawning of Portunus tyituberculatus.View full abstractDownload PDF (10412K) -
Teruo AZUMA, Yasuo ITAZAWA1998 Volume 46 Issue 1 Pages 83-92
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe minimum requirement of dissolved oxygen in the ambient water for a porgy Pagrus major was estimated by examining respiratory responses and blood properties under stepwise hypoxic conditions induced either by nitrogen bubbling or in a closed system at 21°C. The minimum requirement was estimated to be around 60 mmHg without carbon dioxide accumulation (N2-bubbling method), and around 80 mmHg under carbon dioxide accumulation (closed method) . This difference is considered to be attributed to Bohr effect, because the partial pressure of carbon dioxide in the arterial blood dropped in the former and elevated in the latter. The practical criterion as the minimum requirement of ambient oxygen for the porgy is considered to be around 80 mmHg (around 50% in air saturation), because hypoxic conditions in fish farms and natural environments are usually accompanied with accumulation of carbon dioxide.View full abstractDownload PDF (1525K) -
Izuru KAKUTA, Tomohiro OGATA, Kazuaki IGARASHI, Takashi SUNADA, Hirohi ...1998 Volume 46 Issue 1 Pages 93-96
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe effects of orally administrated bovine lactoferrin (LF, 75 mg/kg body weight/day) on growth, survival rate, and mucus secretion on the body epidermis of juvenile ayu, Plecoglossus altivelis, were studied at 12°C for a period of 39 days. Effect of LF on the survival rate of ayu held under deteriorating environmental conditions was also examined. No significant differences in growth and survival rate were found between the control and the LF-treated groups. In LF-treated fish, increased skin mucus secretion was observed. The survival time of LF-treated fish exposed to hypoxic condition, formalin and copper sulfate solutions was longer than that of the control. This result suggests that LF treatment can reduce stress response of ayu held under deteriorating environmental conditions and extend its survival time.View full abstractDownload PDF (629K) -
Kadoo MIYAKI, Hisashi TYUDA, Takahiro WATANABE, Koji MIZUTA, Yasuo TSU ...1998 Volume 46 Issue 1 Pages 97-100
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSTannic acid solution was used to eliminate the adhesiveness of the eggs of tiger puffer Takifugu rubripes for increasing the hatching rate and simplifying the egg handling procedures during incubation. The concentrations tested on groups of eggs about 500 per petri dishes, ranged from 0.01% to 0.30% of tannic acid. The optimum concentration of the tannic acid was estimated to be 0.05%. Hatching rates for two replicate trials of eggs treated with 0.05% tannic acid solution (pH 8.2) were 68.2% and 70.1%, respectively, higher than the non-treated (control) eggs of 50.9% and 65.9%, respectively. The larvae hatched from the treated and non-treated eggs were reared in 2-kl tanks for 45 days. During the experiment, the larvae from treated eggs showed the same growth and survival rate as those from non-treated eggs. It is concluded that this treatment can effectively be used to increase the hatching rate and simplify the handling procedures for seed propagation of this species.View full abstractDownload PDF (666K) -
Gen MIMURA, Toshiya NAGASE, Yasuto KATAYAMA, Takako NAGAMITU, Kenji NA ...1998 Volume 46 Issue 1 Pages 101-110
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSDelayed hatching of eggs (DHE) of Japanese flounder, Paralichthys olivaceus were observed, following rinsing with sea water containing ozone-produced oxidants (OPO) . Although they did not hatch at the same time as normal eggs, the embryos continued to develop and remained alive for two more days. When the embryos were exposed to 0.8mg O3/l for 10 min, DHE occured 91.3-95.1%, less than 3 min, exposure did not affect hatching. When the embryos were exposed to 3-10 mg O3/l for one min, DHE occured 94.3-98.1%. At concentrations of less than 2 mg O3/l, however, very little effect of OPO on hatching was observed. When the embryos at blastula to heart beat stage were exposed to OPO 0.8 mg O3/l for 6 min, delayed hatching of eggs were observed at almost the same rate.View full abstractDownload PDF (3873K) -
Shigeru MIYASHITA, Keitaro KATO, Yoshifumi SAWADA, Osamu MURATA, Yutak ...1998 Volume 46 Issue 1 Pages 111-120
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSDevelopment of digestive system and changes in the activity of trypsin-like enzyme, pepsin-like enzyme and amylase were studied in larval and juvenile Bluefin tuna, Thunnus thynnus reared in the laboratory. Liver, gall bladder, pancreas, and the demarcating region between intestine and rectum formed within 36 h after hatching. After feeding commenced trypsin-like enzyme and amylase activities increased as the larvae grew. During the preflexion phase (within 10 days after hatching), revolution of the intestine concluded; and pharyngeal teeth and mucous cells of esophagus differentiated. During the flexion phase (11 to 17 days after hatching), functional jaw teeth were found and blind sac, gastric glands and pyloric caeca begin to form. Pepsin-like enzyme activity increased and functions of stomach and pyloric caeca developed from the postflexion phase to the transitional period to the juvenile (17 to 25 days after hatching) . The rate of percentage of preanal length to standard length was constant (around 40%) until 11 days after hatching, then increased to 65% at day 26, and did not change from 26 days to 30 days. These results suggest that the developments of the digestive system until 11 days (preflexion phase) are mainly qualitative and those from then to 26 days (flexion phase to postflexion phase) are both qualitative and quantitative. This quantitative and qualitative development of the digestive system might contribute to the rapid growth in the juvenile stage.View full abstractDownload PDF (13483K) -
Hideo AOKI, Masayuki FURUICHI, Voranop VIYAKARN, Yoichi YAMAGATA, Take ...1998 Volume 46 Issue 1 Pages 121-127
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSTwo experiments were conducted to investigate the possible incorporation of suitable combinations of soybean meal (SBM), corn gluten meal (CGM), and meat meal (MM) as substitute protein sources for fish meal in diets for juvenile red sea bream. A commercial diet for red sea bream containing 65% local fish meal was used as a control. Test diets contained combinations of the three protein sources at a total level ranging between 41-46% thereby reducing the fish meal levels to 25-30%, respectively. Another test diet contained 50% of soy protein concentrate (SPC) along with fish meal at a level of 10% in order to examine the availability of SPC as a protein source. The fish weighing approximately 36g (Exp. I) and 27g (Exp. II) on an average were fed the experimental diets for 122 days and 57 days, respectively. The fish fed the diets containing the combination of SBM, CGM, and MM showed the same performance as fish fed the control diet in Exp.I. However in Exp. II, fish of the combination test diet groups showed slightly inferior performance than that of the control. The same tendency was observed for fish fed the SPC diet. There were no significant differences in performance parameters among the test groups. Besides, both the control and test fish were generally evaluated to be in good physiological condition, on the basis of the hemochemical examination. Thus the combination of SBM, CGM, and MM in some proportions was confirmed to be an adequate alternative protein source for juvenile red sea bream.View full abstractDownload PDF (1036K) -
Xiuqin SUN, Riichi KUSUDA1998 Volume 46 Issue 1 Pages 129-136
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSHepatopancreatic parvo-like virus disease (HPV disease) is a kind of viral disease which is epidemic among cultivated Chinese prawn, Penaeus chinensis. In order to establish preventive countermeasures the authors made extensive investigations on this disease in penaeid seedling ponds and culturing farms in China. The frequency of incidence of this disease during inspections on seedling rearing facilities was about 30%. Mass mortality from acute infections during the culture period does not occur but the cumulative mortality can be very high and bring about tremendous losses. Moreover, HPV can reside in the body of host prawn for a long time and is responsible for prolonged epidemic. Therefore, HPV is considered a viral pathogen of medium virulency. Based on results of investigations of the culture environment it is suggested that the prevalence of HPV disease infection of prawns is greater in deteriorating environments. Furthermore, pathological examinations of parent prawns and their eggs and larvae showed that infected parents are the main source of infection with HPV and that surviving diseased prawns are important infectants. Beside this, wild mysis and Palaemon carinicauda also play a definite role. Since HPV infection occurs in the midgut and hepatopancreas and has also been detected in the feces, it is suggested that transmission of HPV disease might be through oral infection.View full abstractDownload PDF (4264K) -
Xiuqin SUN, Huaqen MYO, Qinggang XUE, Riichi KUSUDA1998 Volume 46 Issue 1 Pages 137-139
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe present paper describes a rapid procedure for the diagnosis of hepatopancreatic parvo-like virus disease (HPVD) of Chinese prawn, Penaeus chinensis using the immuno-gold and silver staining (IGSS) method. This is the first time that the IGSS method has been used for the diagnosis of viral diseases of marine invertebrates. The results of light microscopic observation showed round (3-15μm in diameter), black spots corresponding to the inclusion bodies of HPV with distinct contours within the nuclei of epithelial cells of the hepatopancreas. The IGSS method has been proved to be a rapid and accurate diagnostic method for HPVD.View full abstractDownload PDF (2923K) -
Hideo YAMANOI, Yoshie SOUMYO, Kiyokuni MUROGA1998 Volume 46 Issue 1 Pages 141-144
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSEffective duration of sodium nifurstyrenate (NS) bath and effects of simultaneous bath with nutritional additives (n-3 HUFA) on bacterial populations associated with rotifer (Brachionus rotundiformis), were investigated. Bacterial counts of rotifer on TCBS agar decreased from 106-107 CFU/g to 103-105 CFU/g by NS treatment (5 mg/l) for 3 h. But the bacterial counts on TCBS increased to 107 CFU/g 6 h after the medicated rotifers were transfered to seawater. The efficacy of 3 h-NS bath was partially inhibited by the simultaneous bath with the nutritional additives used. In addition, the density of Vibrio-like bacteria of rotifers decreased to 104-105 CFU/g, irrespective of inhibitory effects of the additives, after 5 h of NS bath.View full abstractDownload PDF (616K) -
Megumi MORINO, Tsuyoshi MORI, Hitomi HIROSE1998 Volume 46 Issue 1 Pages 145-150
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe acute toxicity of hinokitiol, citral and allylisothiocyanate to common carp, Cypyinus carpio, was examined. Their LC50 values at 48h were 1.48, 14.32 and 1.00μg, μl/ml, respectively. Significant histological changes, such as degeneration and necrosis of renal tubules and gill lamellae were observed.View full abstractDownload PDF (10262K) -
Takaya INUI, Sadao NOGAMI, Hitomi HIROSE1998 Volume 46 Issue 1 Pages 151-155
Published: March 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSAntigenicity of swimbladders nematoda, Anguillicola crassus, to Japanese eel, Anguilla japonica was examined by Ouchterlony's immunodiffusion in an agar gel. When the eel were immunized with an extract prepared from adult worms of nematoda as antigen, the eel sera reacted with the extracts prepared from the whole adult worms of nematoda and showed precipitation lines in the agar gel, indicating the presence of the anti-swimbladders nematoda antibody in the eel sera. Of 24 eels infected with the nematoda, two sera reacted with the extracts prepared from the whole adult worms and various parts of the worm. The results indicate the presence of common antigen among various tissues of the worm and antigenicity of cuticle was dominant in the immunological responses. The sera collected from the eels of no nematoda infection did not react with the extract prepared the worms.View full abstractDownload PDF (5146K)
- |<
- <
- 1
- >
- >|