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Volume 55, Issue 2
Displaying 1-20 of 20 articles from this issue
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Minoru TANDA, Yukinobu NAKAMURA, Shigeyoshi OKAMOTO2007 Volume 55 Issue 2 Pages 177-182
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSMarbled sole Pleuyonectes yokohamae is a commercially important flatfish in the Seto Inland Sea. The sexes of this species were examined for 6093 specimens collected from Harima Nada and Osaka Bay in May 1986 to Jan. 2001. The overall sex ratio (females/total) was 0.54, but it differed between fishing gears, months, ages and total-length classes. In the spawning season, the sex ratios in the compact trawls were higher than 0.5, while those in the gill nets were lower than 0.5, suggesting that migrations of the marbled sole differed between females and males in the spawning season. The sex ratios also varied between body sizes; fish under 240mm in total-length class had a tendency of the sex ratio to be under 0.5 and those of the over 240mm total-length classes were over 0.5. Cohort analyses simulated that the different growth patterns between the sexes could cause the difference of the sex ratio in the total-length classes. The sex ratio of the 1-age group was under 0.5 and those of the over 2-age groups were over 0.5. The sex ratio of the specimens collected by compact trawl showed no clear temporal trend in the period from 1986 to 2001.View full abstractDownload PDF (874K) -
Yousuke TAOKA, Hiroto MAEDA, Jae-Yoon JO, Taizo SAKATA2007 Volume 55 Issue 2 Pages 183-189
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSTo investigate the influences of live probiotic cells and dead probiotic cells on the digestive enzyme activities of tilapia, Oreochromis niloticus, were reared for 30 days in the closed recirculating system with or without Probiotics. Tilapia samples were divided into four groups; the first group was fed with a control diet without probiotics (control group), the second group was fed with the diet containing live probiotic cells (live group), the third group was fed with the diet containing formalin-killed probiotic cells (dead group) and the forth group was fed with the control diet and reared in water with commercial live probiotic cells (water supply group) . Both trypsin and amylase activities of stomach extracts and intestine extracts showed higher in all probiotics-treated groups than in the control group. The results obtained in this study indicated that probiotic cells, especially live cells, stimulate the synthesis of digestive enzymes in the gastrointestinal tract of tilapia.View full abstractDownload PDF (1048K) -
Tsuyoshi SUGITA, Takeshi YAMAMOTO, Hirofumi FURUITA2007 Volume 55 Issue 2 Pages 191-198
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe influence of high carbohydrate low protein diets on growth, apparent digestibility and hepatopancreatic enzyme activities were investigated in red sea bream Pagrus major. Fingerlings of 11.4g average body weight were fed for 12 weeks on 2 experimental diets containing different carbohydrate (20 and 28%) and protein (44 and 38%) levels, and on a low carbohydrate (12%) high protein (52%) control diet. Weight gain (WG) of the medium carbohydrate diet (MCD) group was lower than that for the control diet (CTD) group, though protein efficiency ratio (PER) and protein retention of the MCD group were higher than those of the CTD group. Furthermore, WG, feed efficiency, specific growth rate and protein retention for the highest carbohydrate diet group was the lowest among the dietary groups. Hepatopancreatic fructose-1, 6-bisphosphatase, glucose-6-phosphate dehydrogenase and aspartate aminotransferase activities were not different between the dietary groups, and these indicate that the amino acid mobilization as a gluconeogenic substrate was not affected even though the high carbohydrate low protein diets were fed. These findings suggest that fingerling red sea bream cannot effectively utilize a high carbohydrate low protein diet, so that adding a large amount of carbohydrate to the diet cannot spare dietary protein without retarding the growth performance.View full abstractDownload PDF (1466K) -
Kazumi NIMURA, Kazutoshi OKAMOTO, Susumu TAKASE2007 Volume 55 Issue 2 Pages 199-204
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSJuvenile Eisenia arborea sporophytes were cultured in indoor tanks containing deep-sea water (DSW, known as clean, cold and nutrient-rich) from Suruga Bay, central Pacific Coast of Japan, pumped from depths of 397 m and 687 m using pipelines. This experiment was performed to determine the most suitable growth condition for Eisenia arborea seed production. At the end of culture, blade lengths of the sporophytes cultured in deep-sea water (pumped from depths of 397 m and 687 m) were 122±15 mm and 128±15 mm [relative growth rate (RGR), 3.7%/day and 4.1%/day, respectively] . These values of blade length were higher than those obtained for sporophytes cultured in surface sea water (100±8 mm; RGR, 3.2%/day) . Small sporophytes (< 150 mm) had blade lengths of 141±19 mm and 138±17 mm (RGR, 4.1 %/day and 3.6%/day) at a water temperature of 12, 17°C, and these values were greater than those obtained for sporophytes at 21°C (100±9 mm; RGR, 3.3%/day) . At 8 -18°C, large sporophytes (> 150 mm) showed higher growth rate (ca 1.0%/day) in light conditions above 3.6 mol/m2/day.View full abstractDownload PDF (993K) -
Yo YOSHIMOTO2007 Volume 55 Issue 2 Pages 205-212
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe characteristics of fishing for the marine juvenile ayu (Plecoglossus altivelis altivelis) were investigated based on catch data from the fishing ground in the eastern coastal waters facing Kui Channel between 1980 and 2004. In years with rich yields, the amount of marine juvenile ayu fished remained the same for a prolonged period, and the area of the fishing ground was wider, compared to those years with poor yields. Age determination using the otolith between 1990 and 1997 indicated that in the years with rich yields, juvenile ayu would reach the fishing ground at a younger age in the order of hatching. In addition, these ayu resided in the fishing ground for shorter periods and their growth rates were higher than those in years with poor yields. These observations suggest a relationship between the growth rate and the level of the stock of the juvenile ayu.View full abstractDownload PDF (1032K) -
Ichiro KOMAZAWA, Takashi SUGINO, Kenji TAKIO, Kazuto ANDO, Takakazu AR ...2007 Volume 55 Issue 2 Pages 213-218
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSA trial of marine afforestation of the brown alga Eckloniopsis radicosa by using the spore bag method was tried at three ISOYAKE (barren ground) areas around Izu-Oshima Island, central Japan. Several net bags, in which mature E.radicosa sporophytes and each with a float, were set in summer 2002, 2003 and 2004 in different areas of 5 to 9 m depth. In each area, many young sporophytes appeared around the spore bags in the following spring to summer. In two areas, Senzugyokou and Goishihama, some sporophytes formed zoosporangial soni in the next August, and E. radicosa formed a small community for three years at Senzugyokou after the initiation of the trial. But in two areas, Goishihama and Nomashimaehama, all of the sporophytes were reduced in size due to herbivore grazing. At Goishihama almost all sporophytes were observed within a 5 m radius from the setting site of the spore bags.View full abstractDownload PDF (928K) -
Itaru IKEDA, Humiaki TAKAKUWA, Kunimasa AOKI2007 Volume 55 Issue 2 Pages 219-223
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSFeeding stimulants for the common japanese goby Acanthogobius flavimanus were examined by omission test using the synthetic krill Euphausia pacifica extract, based on a daily feeding of casein diet with various test solution. The complete synthetic extract of krill possessed a remarkable feeding stimulant activity. Subdivision of the synthetic extract showed that the group of neutral amino acids plus nucleotides was highly active. However, the individual amino acids, nucleotides and other bases groups as well as the groups of amino acids plus other bases and nucleotides plus other bases were inherently lower active. Therefore, the feeding stimulant activity of synthetic extract of krill for the fish was considered to be due to the synergistic effect of neutral amino acids plus nucleotides.View full abstractDownload PDF (698K) -
Yasuro IWASHITA, Takeshi YAMAMOTO, Takanobu GOTO, Nobuhiro SUZUKI2007 Volume 55 Issue 2 Pages 225-230
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThree diets, defatted soybean meal based non-fish meal diet (SBM), soybean meal based non-fish meal diet containing 1.5% bovine gall powder (SBM+B) and control fish meal-based diet (FM), were fed to rainbow trout, Oncorhynchus mykiss, to examine effects of bile salts in gall powder on the histology of liver as well as distal intestine. Hepatocytes and epithelial cells in hepatic ducts of the fish fed SBM diet were considered to be atrophied. Lacking of microvilli and pinocytotic vacuoles, fatty degeneration of intestinal epithelial cells and proliferation of connective tissue in lamina propria were shown in distal intestine of fish fed the SBM diet. However hepatic and intestinal histological features in fish fed SBM+B diet are similar to those in FM control diets. These results suggest a possibility that supplementation of bovine gall powder to the SBM improves digestion and absorption of lipid in distal intestine probably due to increasing secretion of bile salts from liver into intestine.View full abstractDownload PDF (8550K) -
Tomoya MURAKAMI, Satoshi AIDA, Kouji YOSHIOKA, Masanori HIROOKU, Hiroa ...2007 Volume 55 Issue 2 Pages 231-236
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSHatchery-reared juvenile black rockfishSebastes inermis (3 cm in total length) were released near a Zosterabelt around Ikuno Island in the Seto Inland Sea, central Japan, in April 2000 after marking with a fluorescent marker (alizarin complexone: ALC) . The released fish were monitored and recaptured for 3.5 years (total recapture rate: 1.0%) from April 2000 to November 2003. Although the sizes of 0-3 year-old released fish were smaller than those of wild fish collected at the same area, the growth rate of the former was almost equivalent to that of latter. The percentages of released fish in total catch of the species near the release site were as high as 79.5, 51.0, 62.3 and 50.6% for age 0, 1, 2 and 3, respectively (68.8% for all ages combined) . This result indicates that the released fish did not move far away from the release site and stocking 3 cm juveniles was effective in stock enhancement for the species.View full abstractDownload PDF (2590K) -
Motohiro TAKAGI, Yoshimitsu ISHII, Takaaki SHIMIZU2007 Volume 55 Issue 2 Pages 237-243
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSGenetic variability and divergence of the largemouth bass, Micropterus salmoidesinvaded Ehime Prefecture, Japan, were surveyed by using 10 samples from seven reservoirs, based on 5 microsatellite loci. Investigation of these marker loci of the largemouth bass sample showed the difference of genetic variability from each other. The estimated heterozygosity ranged from 0.231 to 0.487. Genetic divergence among the largemouth bass samples was observed in the genotype and allele frequencies at the marker loci. Considerable genetic difference was observed within Nomura samples between 2003 and 2004, 2005 year stocks in the population pairwise FST. Relationship between geographic and genetic similarities was not observed among some samples. The results suggested that the present distribution of largemouth bass in Ehime Prefecture originated from several degree of artificial introduction. Occurrence of recent introduction of largemouth bass among the inland waters of Ehime Prefecture was also suggested. The microsatellite markers showed a potential as indicators to evaluate genetic variability and to trace genetic changes in largemouth bass.View full abstractDownload PDF (1048K) -
Kazunori ARAYAMA, Hiroshi KOHNO, Masato MOTEKI2007 Volume 55 Issue 2 Pages 245-252
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSWe examined seasonal and diel occurrence patterns of ayu, Plecoglossus altivelis altivelis, larvae and juveniles at the shoreline and offshore areas of a sandy beach in Tateyama Bay. Sampling was conducted from April 1999 to March 2001 using a small seine net. Fish were present in daytime from early November to early January. The offshore area yielded many more fish than the shoreline area (527 vs. 41 individuals), and the body lengths of fish were similar in both areas (approximately<20mm) . In February and March, fish were present in nighttime at the shoreline, although absent in daytime. The early life history of the ayu at the sandy beach is summarized as follows. Fish<20mm in body length are distributed offshore mainly in the daytime and aggregate near the shoreline at morning twilight. Fish>20mm in body length are distributed at the shoreline from early evening to nighttime, but do not occur at the sandy beach during the daytime.View full abstractDownload PDF (1574K) -
Masahiro NAKAGAWA, Hiroyuki OKOUCHI, Keita HATTORI2007 Volume 55 Issue 2 Pages 253-257
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSEffective conditions for alizarin complexone (ALC) staining of otoliths were examined in black rockfish to establish the optimum ALC marking methods. Juvenile black rockfish (45 mm TL) were immersed in three immersion concentrations (15, 30 and 50 mg/l) of ALC for three treatment durations (6, 12, 24 h) . The survival rate, ALC mark visibility and duration of the mark were investigated over two years. The survival rates 10 days after ALC immersion for 15 mg/l treatment were 99.9% in two water tanks, showing significantly higher values than the 52.4% and 81.7% for 30 mg/l, and 13.7% and 3.9% for 50 mg/l. In addition, the 15 mg/l treatment showed the highest value in visibility of ALC marks on otoliths. The ALC marks were visible for over two years without polishing the otolith. Costs of ALC marking per fish under the conditions of 15, 30 and 50 mg/l were 1.50, 4.47 and 57.0 yen, respectively. Among the concentrations used in this experiment, 15 mg/l was concluded to be the optimum concentration of ALC for otolith marking of black rockfish.View full abstractDownload PDF (787K) -
Toshiyuki NAKATSUBO, Masahiro KAWACHI, Nobuhiro MANO, Hitomi HIROSE2007 Volume 55 Issue 2 Pages 259-264
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSWe investigated gonad maturation in 180 captiveMola molaand 148 wildMola mola. We compared the Gonad Somatic Index (GSI) based on body weight and the Gonad Index (KG) based on body length, and found a strong relationship between the two. Since it is difficult to measure the body weight of large ocean sunfish in the wild, KG is more useful for estimating maturity than GSI. This study also revealed that both GSI and KG are higher in captive specimens than in wild ones suggesting that gonad maturation of mola in captivity is faster than for mola in the wild.View full abstractDownload PDF (576K) -
Reiko FUSEYA, Masashi YOKOTA, Seiichi WATANABE2007 Volume 55 Issue 2 Pages 265-269
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSTo classify species of the mud crab genus Scylla for stock managements, color variations among species were observed using a simple digital imaging analysis. Using digital images obtained from 42 crabs, we sampled original color specification (sRGB) values of 4 lines on a chela of each crab. These data were translated into L* a* b* color specification values by the color matching functions. The characters of L*, a* and b* values were different among three species in several observed regions. In particular, a* values of Scylla olivacea on Line 1 and 2 were almost higher than the other 2 species, and b* values of Scylla serrata on Line 1 and 2 were lower than the others. Principal component and discriminant analyses also demonstrated apparent color differentiation among three species. Therefore, we can distinguish three species by these features of color specification.View full abstractDownload PDF (729K) -
Minoru KIHARA, Kozo KIRYU, Takashi SAKATA2007 Volume 55 Issue 2 Pages 271-278
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSSome dietary oligosaccharides increase bone calcium content, often depending on hindgut fermentation of the saccharide in mammals. Dietary lactosucrose, an indigestible and fermentable oligosaccharides, also stimulates osteogenesis in mammals. This sugar is also fermented by gut microbes of a teleost, red sea bream Pagrus major. However, we do not know the effect of this sugar on the calcium metabolism of teleosts. If dietary lactosucrose affects calcium metabolism in the fish, calcium content in the bone or scales should be modified by this saccharide. Therefore, we tested the effect of dietary lactosucrose on calcium content of vertebrae and scales in red sea bream under artificial rearing for four months. Since the lactosucrose product we added to the diet included 57% lactosucrose and 20% lactose, we added a lactose-fed group to elucidate the influence of lactosucrose by itself. Fish fed lactosucrose had lower body weight gain than those fed control or lactose diet. Fish fed lactosucrose had greater calcium content in scales than did control fish. However, fish fed lactose had greater vertebral calcium and indifferent scale calcium when compared with control fish. The above results suggest that dietary lactosucrose, but not the associated lactose, increased calcium concentration in scales. It is likely that indigestible and fermentable sacharides such as lactosucrose increase calcium retention in the hard tissue not only in mammals but also in marine teleosts.View full abstractDownload PDF (1375K) -
Takeshi KIMURA, Jun MORITA, Yoshinori NOMURA, Jungo ENOMOTO, Hideki MI ...2007 Volume 55 Issue 2 Pages 279-284
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSFebantel is a prodrug metabolized in vivo to fenbendazole which has been shown to be effective the against monogenean Heterobothrium okamotoi in cultured tiger puffer Takifugu rubripes. In this study, we investigated the relationship between the concentration-time profile of fenbendazole in the plasma and efficacy against H. okamotoi in tiger puffer following oral administration of febantel at the dose of 25 mg/kg 5 days. The concentration of fenbendazole was 4-5μg/g 2-4 days after first administration, and the number of parasites started to decrease from 3 days after the first administration. In addition, we measured the connentration of the remainig febantel and metabolites of fenbendazole in the muscle and skin in tiger puffer following oral administration at the dose of 50 mg/kg for 5 days. They were not detected 2 weeks after the last administration.View full abstractDownload PDF (1028K) -
Toshimasa KOBAYASHI, Tatsuya MUSASHI, Takashi ENDO, Motoyuki HARA2007 Volume 55 Issue 2 Pages 285-286
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSArtificial spawning was induced in 74 wild matured Pacific abalone Haliotis discus hannai collected at Taro, Iwate prefecture, in September 2005.The spawning was conducted just after the sample collecting. The relationship between the shell length (X mm) and number of spawned eggs (Y) is expressed by the equation: Y=0.000096 X5.073481 For abalones of shell length <70 mm, as the shell length decreased, the spawning rate decreased. The results also suggest that the rate of total number of spawned eggs for the population of shell length >90 mm was 59.5%, although the actual frequency found in that area was 23.1%.View full abstractDownload PDF (322K) -
Takanobu GOTO, Akiko SAKURAI, Taiju KURAMOTO, Masaharu UKAWA, Shusaku ...2007 Volume 55 Issue 2 Pages 287-288
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe physiological role of taurine on bile salt metabolism in yellowtail Seriola quinqueyadiata fed on soybean protein diets supplemented with graded levels of taurine were investgated by a 41-weeks rearing trial. Among the dietary treatments, fish given a non-taurine supplemented diet showed the lowest biliary bile salt, hepatic taurine and plasma cholesterol levels, but the highest plasma 7α-hydroxycholesterol concentration. In addition, the non-taurine supplemented diet induced the hightest proportion of cholyltaurine in gallbladder bile. However, dietary taurine improved these variables with increasing in supplement levels to soybean protein diet.View full abstractDownload PDF (358K) -
Manabu SEOKA, Keitaro KATO, Toshihiko KUBO, Yoshio MUKAI, Wataru SAKAM ...2007 Volume 55 Issue 2 Pages 289-292
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSGonadal maturation of Pacific bluefin tuna (PBT) Thunnus orientalis reared in a net cage at Amami Island was investigated. The investigation was carried out during the period from 2 to 4 years old. Histological observation of the gonad indicated that male PBT reached sexual maturation at 2 or 3 years old, while female PBT started to spawn from 4 years old. The gonad-somatic index was high in July, with the highest values of ca. 3% for 4-year-old female and male PBT. The maturation of PBT might be promoted by the elevation of water temperature and/or the elongation of day length.View full abstractDownload PDF (3600K) -
Norio ONIKURA, Akiko NAKAMURA, Katsuyuki KISHI, Kazuki TANIGUCHI, Mits ...2007 Volume 55 Issue 2 Pages 293-300
Published: June 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSHatching inhibition tests of the Japanese whiting Sillago japonica were undertaken as toxicity tests that used marine fish species. The fertilized eggs were exposed to several chemicals within 4 h after spawning. After 24 h, we observed the eggs for hatching, and the median-effective concentrations (EC50) were calculated based on the normal hatching rates. Organic solvents such as dimethyl sulfoxide, N, N-dimethylformamide, and ethanol had low toxic effects on the hatching of this species. Toxicity tests using pentachlorophenol and sodium dodecyl sulfate were conducted several times, and the toxicity values obtained for each chemical were observed to remain constant between tests.View full abstractDownload PDF (3164K)
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