All issues
Volume 68, Issue 1
Displaying 1-19 of 19 articles from this issue
- |<
- <
- 1
- >
- >|
-
Hideaki Yamanaka2002 Volume 68 Issue 1 Pages 5-14
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSIn order to prolong the pre-rigor period, live specimens of red sea bream and plaice were spiked at the brain and stored at 10°C and 5-10°C, respectively. Rigor mortis of cultured red sea bream developed more rapidly than of wild ones. The rigor of scallop adductor muscle progressed most slowly at 5°C. It was most desirable that adductor muscle was washed in artificial seawater at 15°C for 20 min to remove bacteria and not to accelerate rigor mortis. Packaging with 100% oxygen gas was a practical method to retain the quality of scallop adductor muscle. The browning of cooked scallop adductor muscle was responsible for the Maillard reaction between glucose-6-phosphate and fructose-6-phosphate, and taurine and alanine. To prevent the browning it was necessary to cook live scallop adductor muscle immediately after exuviation and to cook frozen adductor muscle in the frozen state without thawing. Soaking in potassium chloride solution followed by storage at low temperatures induced the aggregation of melanosomes in the skin and was useful to maintain the vivid skin color of the cultured red sea bream.View full abstractDownload PDF (1200K) -
Hisashi Yokoyama, Tomoko Sakami2002 Volume 68 Issue 1 Pages 15-23
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSA new law, which was established in 1999 to prevent environmental deterioration around aquaculture farms, determined that the rates of benthic oxygen uptake (BOU) should be used as an environmental criterion. This criterion is based on the Omori-Takeoka theory in which the peak of BOU against the loaded organic matter is regarded as an indicator of the maximum phase in the process of biological remineralization. The present study aimed to clarify whether this criterion is applicable to fish farms in Gokasho Bay. Organic carbon and nitrogen in the sediment and sediment trap samples and sulfides in the sediment decreased with increasing distance from a cage. However, the peak of BOU was not found in the observed gradient of loaded organic matter. Therefore, we cannot use the criterion based on the Omori-Takeoka theory to the fish farms in Gokasho Bay. This finding may be explained by the severe organic pollution resulting in the decrease of biological remineralization and/or by the possible variation of biological BOU in its immediate response to the change of dissolved oxygen in the overlying, near-sediment-surface water.View full abstractDownload PDF (1409K) -
Tatsuya Takami, Takuji Yoshihara, Yasuyuki Miyakoshi, Ren Kuwabara2002 Volume 68 Issue 1 Pages 24-28
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSIn the Monbetsu River, a small branch of the Ishikari River basin, west Hokkaido, a brown trout population that was probably introduced 15 years ago is dominant. The population of brown trout was estimated to be 1.8 times greater than that of the native white-spotted charr. The brown trout occurred markedly in the mid- and downstream reaches. On the contrary, the white-spotted charr was predominant only in the upstream reaches above weirs in the river. The water temperature ranged from 5 to 16°C during the summer-autumn period at the lower reaches of the stream. In the mid- and downstream reaches of this stream, the non-native brown trout have likely replaced the native white-spotted charr over the last 15 years.View full abstractDownload PDF (659K) -
Hideo Hori, Masahiro Tateishi, Hisashi Yamada2002 Volume 68 Issue 1 Pages 29-36
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSEffects of moulting and experimental conditions such as water temperature and salinity on acute toxicity of hazardous chemicals to shrimps were investigated in order to establish a toxicity test using Penaeus japonicus and Heptacarpus futilirostris as test organisms. 96h LC50 of tributyltin chloride (TBTCl), triphenyltin chloride (TPTCl), γ-hexachlorocyclohexane (γ-HCH), fenitorthion (MEP), carbaryl (NAC) and pentachlorophenol (PCP) to P. japonicus was 3.4-48 μg/L, 23-260 μg/L, 4.1 μg/L, 0.49 μg/L, 10 μg/L and 1100-24000 μg/L, respectively. The 96h LC50 of these hazardous chemicals to H. futilirostris was 3.6 μg/L for TBTCl, 3.8-4.2 μg/L for TPTCl, 1.7-2.1 μg/L for γ-HCH, 0.96-1.1 μg/L for MEP, 6.8-7.6 μg/L for NAC, 140 μg/L for PCP and 17000 μg/L for chromium (Cr(VI)). TPTCl and PCP showed higher acute toxicity on H. futilirostris, however, acute toxicities of tested chemicals other than TPTCl and PCP were almost the same for the two shrimp species. The acute toxicities of TBTCl, TPTCl and PCP to P. japonicus increased ten times after it moulted in the experimental period. On the other hand, acute toxicity to H. futilirostris was not affected by moulting. The acute toxicity was not affected by temperature and salinity of the rearing seawater.View full abstractDownload PDF (983K) -
Hideo Hori, Masahiro Tateishi, Hisashi Yamada2002 Volume 68 Issue 1 Pages 37-45
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSPenaeus japonicus was exposed to tributyltin chloride (TBTCl) and triphenyltin chloride (TPTCl) for 56 days in a closed circulating experimental system. The bioconcentration factors (BCFs) and uptake and elimination rate constants of TBTCl and TPTCl were determined. TBTCl concentration in the shrimp reached equilibrium at the 14th day of the uptake experiment. BCF of TBTCl ranged from 4700 to 7500, and was larger than the values previously reported in crustaceans such as Daphnia magna, Amphipods and mud crab. On the other hand, BCF of TPTCl ranged from 130 to 260, and was significantly smaller than that of TBTCl. The elimination rate constant of TBTCl and TPTCl was 0.031-0.072 day 1 and 0.058 day 1, respectively.View full abstractDownload PDF (1061K) -
Yoshikazu Taniuchi, Kenichi Tajima, Isao Shimono, Yoshio Ezura2002 Volume 68 Issue 1 Pages 46-51
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSFlexibacter sp. represented by strain F-2, the causative bacterium of spotting disease of sea urchin Strongylocentrotus intermedius, was detected in various samples from mid July to mid August when seawater temperature reached 20°C or more, but the bacterium was not detected in any samples from winter to early summer. From this phenomenon it is suspected that this bacterium enters into a viable but nonculturable (VBNC) state during low-temperature seasons. To obtain fundamental data of survival of this bacterium at low temperatures, we examined some factors for entering the VBNC state. Direct viable count (DVC) was also carried out. The bacterial cells in the mid-log phase quickly became nonculturable at 5°C in artificial seawater (ASW). No decrease in total counts or DVC was observed during storage, indicating that the bacterium entered the VBNC state. During storage periods, a morphological change from long rod cells to short rods or spheroid cells was observed by scanning electron microscopy. Cells in the VBNC state lost the pathogenicity to sea urchin.View full abstractDownload PDF (850K) -
Daisei Ando, Yasuyuki Miyakoshi, Katsumi Takeuchi, Mitsuhiro Nagata, T ...2002 Volume 68 Issue 1 Pages 52-60
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSTo estimate the catch of juvenile masu salmon Oncorhynchus masou by anglers in a river which flows in an urban area in central Hokkaido, we randomly surveyed anglers from June to October 1999 using questionnaires and interviews. Total numbers of anglers were estimated using a two-stage sampling design; fishing days were sampled at the first stage, vehicles at the second stage, and numbers of anglers in each vehicle were recorded. Of 21, 874 (95% confidence interval: 20, 785-22, 963) juvenile masu salmon inhabiting the study area in June, we estimated that 14, 219 (4, 613-23, 825) fish were caught by anglers. Our study indicates that the mortality of juvenile masu salmon caused by recreational fishing in an urban area is substantial although the precision of the estimate was not high.View full abstractDownload PDF (1050K) -
Yasuhiko Tago2002 Volume 68 Issue 1 Pages 61-71
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSThe distribution patterns and body size ranges of ayu larvae (Plecoglossus altivelis) were investigated in the estuary regions of Toyama Bay from 1992 to 1998. Ayu larvae commonly occurred in the surface layer above the halocline from October to December, but rarely collected in the layer below the halocline. Occurrence of the larvae was restricted to the 2.5 km area from the coast. Standard length or notochordlength of the larvae collected ranged from 3 to 22 mm including individuals of 9-12 mm size, which were rarely reported in the previous studies. Most of the larvae larger than 10 mm occurred in the shallow waters within 1 km off the coast, especially near the rivermouth. The halocline existed within 1 m depth. It was suggested that the shallow water layer near the estuaries of Shou, Oyabe and Jinzu Rivers is an important habitat for the early larvae of ayu less than 16 mm. Ayu larvae would disperse widely and then with growth migrate to the surf zone through the surface layer of the estuary regions in Toyama Bay.View full abstractDownload PDF (1681K) -
Minoru Kimura, Takuma Imamura, Masanao Narita, Hideki Ushio, Hideaki Y ...2002 Volume 68 Issue 1 Pages 72-77
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSSeasonal variation of chemical components was examined in the adductor muscle of scallop Patinopecten yessoensis that was harvested at Monbetsu from March to November 1998. The adductor muscle weight and glycogen content increased from spring to summer, and decreased from autumn to winter. While the protein content was highest in October, the content of protein per sample was highest in August. The relation between glycogen and protein contents on a dry matter basis showed a converse correlation. Total amounts of ATP and its related compounds and free amino acid were highest in July and June, respectively. The level of glutamic acid was remarkably high in May after the spawning season. The levels of glycine, alanine, arginine and proline showed an annual cycle with a maximum in summer. These results suggest that scallop adductor muscle of this area is most palatable in summer.View full abstractDownload PDF (746K) -
Satomi Koseki, Chikako Muranaka, Toru Sakai, Hirotake Nakajima2002 Volume 68 Issue 1 Pages 78-84
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSPreparation of a large amount of allomerized products of chlorophyll molecule as an edible green pigment from salted Konbu was studied. Ethanol extract containing a large amount of 10-hydroxy chlorophyll a/a', the allomerized products of chlorophyll molecule, was obtained from salted Konbu. When the extract was then subjected to illumination under fluorescent light, which produced a small amount of 10-ethoxylactone chlorophyll a/a', different allomerized products were produced from chlorophyll a remaining in the extract and developed its green color. However, prolonged illumination caused the decomposition of chlorophyll-related compounds and was accompanied by the fading of color. To increase the content of the allomerized products, chlorophyll a was supplied to the extract and followed by illumination under 500 lx fluorescent light for 6 hours. Thus, the total content of allomerized products in the extract amounted to 85% as measured by high performance liquid chromatography analysis. The preparation took on a bluish green color.View full abstractDownload PDF (759K) -
Meiko Kimura, Nobuo Seki, Ikuo Kimura2002 Volume 68 Issue 1 Pages 85-91
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSMarine fish species such as the gadoid family contain a large amount of trimethylamine-N-oxide (TMAO) which is cleaved to equimolar amounts of dimethylamine (DMA) and formaldehyde (FA) during storage. The cleavage of TMAO was investigated at subzero temperatures in a model system containing Fe2+ and reductants, ascorbate and cysteine, in the presence or absence of TMAOase which was prepared from walleye pollack muscle. At -4°C in the supercooled solution, TMAO was cleaved to DMA and FA with TMAOase depending on enzyme concentration. Almost no nonenzymic cleavage occurred practically. However, in the frozen state at -4°C as well as at -20 and -40°C, the enzymic cleavage was completely depressed and DMA was rapidly and greatly produced by the nonenzymic pathway in a Fe2+ -Cys system accompanied by a little formation of trimethylamine. Both enzymic and nonenzymic reactions required only Fe2+ with reductants to maintain the reaction.View full abstractDownload PDF (873K) -
Hideaki Achiha2002 Volume 68 Issue 1 Pages 92-93
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESS -
Kiyoshi Takigawa2002 Volume 68 Issue 1 Pages 95-96
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSDownload PDF (439K) -
Taiji Kikuchi2002 Volume 68 Issue 1 Pages 97-98
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSDownload PDF (360K) -
Shigeru Itakura2002 Volume 68 Issue 1 Pages 99-100
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESS -
Hiroaki Tsutsumi2002 Volume 68 Issue 1 Pages 101
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSDownload PDF (269K) -
Yuji Fujita2002 Volume 68 Issue 1 Pages 102-103
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSDownload PDF (408K) -
Masahiko Isobe2002 Volume 68 Issue 1 Pages 104-105
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSDownload PDF (416K) -
Osamu Matsuda2002 Volume 68 Issue 1 Pages 106-107
Published: January 15, 2002
Released on J-STAGE: February 01, 2008
JOURNAL FREE ACCESSDownload PDF (428K)
- |<
- <
- 1
- >
- >|