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Volume 69, Issue 1
Displaying 1-17 of 17 articles from this issue
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KEN-ICHI WATANABE, TAKASHI MINAMI2003 Volume 69 Issue 1 Pages 3-9
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSHatchery-reared barfin flounder Verasper moseri were released and recaptured in Akkeshi Bay, and their stomach contents were examined. Food organisms were classified into Mysidacea, Flabellifera, Crangonidae, other Decapoda, Pisces, and others. Five indices were applied to analyze the stomach contents : frequency of occurrence, percentage of number and weight, index of relative importance and trophic level index. Dominant prey items changed with size, Mysidacea (size≤150 mmTL), Mysidacea and Crangonidae (150-250 mmTL), Crangonidae and Flabellifera (250-300 mmTL), Crangonidae (300-400 mmTL) and Crangonidae and Pisces (>400 mmTL). Trophic level index also increased with size, indicating a higher food niche of larger barfin flounder. The food niche of the barfin flounder was low in spring and increased in summer and autumn.View full abstractDownload PDF (911K) -
HIROKI SAKAI, RIE KASAI, SHIN TAKAHASHI, SHINSUKE TANABE2003 Volume 69 Issue 1 Pages 10-22
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSButyltin compounds (MBT, DBT, TBT) were determined in surface sediments, sediment cores, cultured fishes and pearl oysters collected from Uwa Sea, Japan. TBT concentrations in surface sediments ranged from 2.8 to 930 ng/g dry wt, which were comparable to those in urban regions such as Tokyo Bay, Osaka Bay and Dokai Bay. ΣBTs (MBT + DBT + TBT) concentrations in surface sediments from fish culture areas were significantly higher than those from pearl oyster areas. In case of sediment cores, BTs concentration was the highest in the surface layer and decreased with core depth. ΣBTs concentrations in pearl oysters were lower than those in other species of bivalves from various coastal waters around the world, whereas ΣBTs concentrations in cultured fish from Uwa Sea were comparable to those reported in Osaka Bay. Higher proportions of TBT in ΣBTs residues were found in fish and pearl oysters than in sediments. Although TBT concentrations found in cultured fishes were less than the tolerable level estimated from ADI suggested by the Ministry of Health and Welfare, efforts to reduce the residue levels are needed for the conservation of ecosystems.View full abstractDownload PDF (1604K) -
KEN MORI, YOSHIKAZU NAKAMURA2003 Volume 69 Issue 1 Pages 23-29
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSThe distribution pattern of juvenile Japanese common squid, Todarodes pacificus, in the Kuroshio-Oyashio transition region was investigated in 1994-1996. The investigation was carried out in the offshore area of Boso-Joban districts every April. The juvenile squids of 5-35 mm (in dorsal mantle length, mainly 7-15 mm) were caught with 2 m ring-plankton-net (mesh size 3 mm). The research area was divided into four sub-areas by the hydrographical conditions namely, Oyashio area, Cold water area, Warm water area, and Kuroshio area. The distribution patterns of juvenile squids were compared among these four water areas. Juveniles occurred dominantly in the Warm water area. In the other areas, juvenile density was relatively low. High density occurrences of juveniles were recognized around the frontal area. Differences in the distribution pattern among size classes were not recognized. The distribution pattern of juvenile squids might be due to passive transport by the ocean current. The warm water area where many juvenile were distributed is a warm water area of more than 10°C at 100 m depth and corresponds to the area with high biomass of zooplankton. The passive system of transfering juveniles into this area influences the survival and growth for later juvenile stages.View full abstractDownload PDF (1034K) -
YUKO NAGATO, SHIGEO KAWAGUCHI2003 Volume 69 Issue 1 Pages 30-35
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSSeasonal changes in the vegetative morphology and reproductive state of Sargassum fusiforme (Harvey) Setchell were investigated over a 10-month period at Shikanoshima on the northern coast of Kyushu, Japan. The population was sampled at nearly monthly intervals, and the main branches from individual plants were weighed and divided into 5 dry-weight classes. The frequency of larger size classes increased from May to June, then decreased rapidly in August. Maximum plant dry weights were measured in June, minimum dry weights in September. Growth of new branches commenced in July and the frequency of branches within the smallest size class was highest in September. Reproductive activity was restricted to the period from June to August. Receptacles were present on all plants in July and August, when most of the larger branches and parts of the smaller branches were fertile. The proportions of male and female plants were approximately equal.View full abstractDownload PDF (808K) -
YASUNORI ISHIBASHI, MASARU OZAWA, HACHIRO HIRATA, HIDEMI KUMAI2003 Volume 69 Issue 1 Pages 36-43
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSChanges in tolerances to certain environmental stressors, e. g., low and high temperatures and salinity as well as high concentrations of ammonia, were studied in the red sea bream Pagrus major during its early life stage up to 42 days post-hatch. Relative tolerance was assessed by determining 24-h median lethal level. In laboratory experiments, metamorphosis was observed mainly from days 14-21, and the morphological shift from larva to juvenile was indicated at 9.5 mm total length at 28 days post-hatch. Among the stages tested, larva immediately after hatching showed maximum tolerance to all stressors. Tolerances to both low and high temperatures decreased up to 14 days post-hatch and increased thereafter. Hypo-and hyper-salinity tolerances also decreased up to the 14th day post-hatch and then showed a gentle increase. In regard to ammonia tolerance, the 50% lethal concentration diminished drastically between days 2 and 7, showed the lowest level on day 21, and subsequently rose. These results indicate that, in red sea bream under these experimental conditions, all tolerances to temperature, salinity, and ammonia stress temporarily fell during metamorphosis from days 14-21. It is considered that the depression of the scope for activity based on increasing oxygen consumption induced the decrease in various stress tolerances during metamorphosis. It is also suggested that the 50% lethal levels of various environmental stressors can be used as a stress test to evaluate the hardiness of a hatchery-produced red sea bream.View full abstractDownload PDF (1081K) -
CHOI SOKJIN, HISAYUKI ARAKAWA, TAKAFUMI ARIMOTO, YOSHIHIKO NAKAMURA2003 Volume 69 Issue 1 Pages 44-51
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSThe cross sectional pattern of the underwater illuminance for the coastal squid jigging boat was calculated with a formula based on the line light source model which consists of the spatial luminous distribution of fishing lamp and the surface reflectance of light by Fresnel's law. The calculated pattern of the contour map of the cross sectional underwater illuminance fits with the observed pattern under the coastal squid jigging boat equipped with the total light output of 150 kW, 200 kW and 240 kW respectively, by considering the decreasing factor of luminous flux for fishing lamps due to their time of use.View full abstractDownload PDF (1016K) -
HOZI IWATANI, TOMOMI WATARI, KOJI INOUE, YOSHIO TAKEI2003 Volume 69 Issue 1 Pages 52-56
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSIn this study, we reared 0 - and 1+ -year-old four-spine sculpin, Cottus kazika, in artificial seawater (SW), 1/3 SW and freshwater (FW) and the survival rate and growth were compared. When 0+ fish were reared in SW and FW, the survival rate of the SW group decreased to approximately 60% within the first 50 days, then became stable thereafter. The survival rate of the FW group gradually decreased to almost the same level after 110 days while 0+ fish reared in 1/3 SW revealed a higher survival rate than those in SW. The survival rates of 1+ fish reared in SW and FW were not different. The growth was greater in SW-reared fish than in FW-reared ones in both 0+ and 1+ fish. The growth of 0+ fish reared in SW and that of those reared in 1/3 SW were not different. These results suggest that rearing in SW or diluted SW would increase the efficiency of culture in this species.View full abstractDownload PDF (717K) -
SHIGENOBU OKUMURA, SEIICHI TSUMURA, KEIGO MARUYAMA2003 Volume 69 Issue 1 Pages 57-64
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSThis study examined the possibility of artificial nursery reef for released red spotted grouper, Epinephelus akaara. Two types of test reefs, nylon brush reef and scallop shell reef, were made and sank offshore of Kama Island, Seto Inland Sea, Japan on 5 August 1999. One thousand artificially reared red spotted grouper (95 mm in TL) were released into each test reef on 9 November 1999. Scuba divers observed and counted the fish in and around the reefs nine times throughout the experimental period. Most parts of the reefs were salvaged on 3 April 2000 (146 days after release) to recapture the resident fish. The total number of recaptured fish was 103 in the nylon brush reef and 204 in the scallop shell reef. This result indicates that the idea of artificial nursery reefs for released grouper is effective. The scallop shell reef is superior to the nylon brush reef, since the former attracted and kept twice as many juveniles as the latter. Sixty-five percent of recaptured fish fed on crustaceans which were commonly found on the reefs. These types of test reefs had a food organism propagation function in conjunction with shelter function.View full abstractDownload PDF (1149K) -
MASATO ARITAKI, KATSUYUKI HAMASAKI, KOICHI SAOTOME2003 Volume 69 Issue 1 Pages 65-71
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSThe relative growth and swimming behavior of larval Pandalus eous were examined for reared individuals during the zoeal and postlarval stages. Larval rearing was conducted using a 20 kL tank maintained at a mean temperature of 8.0°C, and larvae were fed with diatoms (Thalassiosira spp.) and Artemia nauplii. Larval development consisted of seven zoeal stages and metamorphosis to the first postlarval stage (decapodid stage) occurred after 54 days. Larval characteristics were examined based on morphological development, swimming behavior, and points of change in relative growth of body parts to carapace length expressed in terms of allometric equations. The first and second zoeal stages were a period of transition during which swimming behavior changed from passive to active. All body appendages appeared in the third zoeal stage and active swimming behavior was fully apparent in the fourth zoeal stage. Between the sixth and seventh zoeal stages, larval behavior changed gradually from pelagic to benthic. After metamorphosis to the first postlarval stage, larvae became fully benthic. The points of change in relative growth occurred at two molting periods, that between the second and third zoeal stages, and that between the fourth and fifth zoeal stages. These points coincided with the critical periods at which larval mass mortality ordinarily occurs during seed production.View full abstractDownload PDF (931K) -
WEI WANG, YUMIKO YOSHIE, TAKESHI SUZUKI2003 Volume 69 Issue 1 Pages 72-79
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSSoluble dietary fiber is reported to have an effect on high lipid inhibition, and also to have different properties depending on the viscosity. In this study, we compared the effect of viscosity of soluble dietary fiber using high cholesterol diet rats. Rats were fed the test diets : basal (B), cholesterol (C), cholesterol plus high viscosity sodium alginate (C + H) and low viscosity sodium alginate (C + L) for 20 days. Rats on the C + H diet showed significantly lower alginate digestibility than those on the C + L diet during the feeding period, and the C + H diet also made a bigger difference than the C + L diet in molecular weight between / Days 1-4 and / Days 17-20. Rats fed with the alginate diets showed decreased total cholesterol and LDL-cholesterol concentration in the serum, compared with those fed with the C diet. A reduction effect on liver lipid concentration was found in rats fed with the C + H diet, whereas those fed on the C + L diet did not show this effect. According to the observations images of the stained liver and adrenal tissues, high viscosity alginate was found to lower lipid accumulation.View full abstractDownload PDF (1339K) -
YASUSHI ENDO, CHANG-MO LI, KENSHIRO FUJIMOTO, MISAKO TAGIRI-ENDO, KAOR ...2003 Volume 69 Issue 1 Pages 80-81
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
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XI-CHANG WANG, KIMIYOSHI NARITA, YOSHINOBU HIRAOKA, ERI OHSAKA, HIROYA ...2003 Volume 69 Issue 1 Pages 82-84
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
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NOBUAKI ARAI2003 Volume 69 Issue 1 Pages 98
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
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TATSUKI NAGAI2003 Volume 69 Issue 1 Pages 99-103
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
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SATORU ABE2003 Volume 69 Issue 1 Pages 104-108
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
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KAZUHIKO KOBAYASHI2003 Volume 69 Issue 1 Pages 109-115
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
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HIDEMI KUMAI, SHIGERU MIYASHITA2003 Volume 69 Issue 1 Pages 124-127
Published: January 15, 2003
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSDownload PDF (680K)
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