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Volume 53, Issue 2
Displaying 1-14 of 14 articles from this issue
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Mimid Abdul HAMID, Kiyoshi SAKAI, Toshio TAKEUCHI2005 Volume 53 Issue 2 Pages 99-106
Published: June 20, 2005
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThis study was conducted to determine the minimum dose of ovaprim (contains 20μg synthetic salmon gonadotropin releasing hormone analogue (sGnRHa) and 10 mg domperidone per ml), human chorionic gonadotrophin (HCG), and silver carp pituitary (SCP) to induce ovulation in Japanese catfish, Silurus asotus. The minimum dose was defined as the dose that induces ovulation of all injected fish, an egg somatic index (ESI) >6%, fertilization rate (FR) >60%, and hatching rate (HR) >50%. Broodstock with vitellogenic oocytes of at least 1, 300μm in diameter were injected by using various doses of ovaprim: 0.02, 0.05, 0.1, 0.2, 0.3, or 0.5ml/kg, HCG: 2, 500, 5, 000, 7, 500, or 10, 000IU/kg, or SCP: 0.5, 1, 3, or 5mg/kg. The hormone was given as a single intraperitoneal injection. Each treatment was performed in triplicate broodstock, with saline as a control. The results showed that the minimum dose of ovaprim, HCG, and SCP was 0.05ml/kg, 5, 000IU/kg, and 1mg/kg respectively. These treatments produced relatively high percentage of ESI (>6.9%), FR (83.8-91.9%), and HR (74.4-95.2%) . The fertilization rate was relatively high and did not differ significantly (P>0.05) among the doses of three hormones that induced ovulation. The results indicate that the currently used doses of hormones in Japanese catfish could be reduced by 2-10 times that of previously reported levels.View full abstractDownload PDF (1372K) -
Kenichi WATANABE2005 Volume 53 Issue 2 Pages 107-114
Published: June 20, 2005
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSOne female and three males of the devil stinger Inimicus japonicus were reared in an indoor tank (1t) from late March to late September. Spawning was observed from June 8 to August 26, and the 14 times spawning occurred intermittingly. The total wet weight of eggs spawned from one female was 277.68 g and the largest wet weight in one day was 48.57 g. The average diameter of eggs varied between 1.146 mm and 1.323 mm, decreased as spawning season passed, and a significant correlation was detected between the average diameter and the water temperature on the spawning day (r=-0.954, P<0.01) . The total hatching rate varied between 28.47% and 97.11%. The normal hatching rate varied between 1.81% and 87.50%, and the survival activity index (SAI) varied between 23.81 and 0.58, both decreased as spawning season passed. On the contrary the abnormal hatching rate increased. Statistically significant correlations between egg diameter and normal hatching rate (r=0.726, P<0.05), and egg diameter and SAI (r=0.741, P<0.05) were observed, however no relation was observed between egg diameter and total hatching rate. These results indicate that the devil stinger used in this study is a multiple spawner and eggs spawned at the beginning of the spawning season had high quality.View full abstractDownload PDF (1147K) -
Osamu KATANO, Tomoyuki NAKAMURA, Shoichiro YAMAMOTO, Shinichiro ABE2005 Volume 53 Issue 2 Pages 115-119
Published: June 20, 2005
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSSeventy-five young bluegill Lepomis macrochirus were captured by electro-fishing in the Aa-Bb river-type section of the Urano River in June and July, 2003. All bluegill were within 1 m of the river bank. Only 8 of the 75 bluegill did not have food present in the stomach. The index of stomach fullness was 0.63%±0.69 SD, reaching the maximum of 2.86%. Bluegill predominantly preyed on chironomid larvae (>60%), followed by ephemeropteran nymphs, trichopteran larvae and terrestrial insects. The diet of bluegill overlapped considerably with that of some other native fishes in the Urano River. Bluegill is considered to have a negative effect on the fish community in rivers and streams and needs to be eradicated.View full abstractDownload PDF (3236K) -
Takayuki TAKAHASHI, Takayuki AMANO, Toshio TAKEUCHI2005 Volume 53 Issue 2 Pages 121-126
Published: June 20, 2005
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSEuryhaline rotifers Brachionus plicatilis and B. rotundiformis are indispensable live food organisms for mass culture of marine fish larvae. However, these rotifers contain small amount of taurine which is one kind of free amino acids. This experiment is conducted that S type rotifer B. rotundiformis can be enriched taurine by the direct method that dissolved taurine in the rotifer medium. As a result, it was clarified that taurine was accumulated in the rotifer by the direct method. Moreover, it was observed that the taurine concentration of the rotifer medium and the taurine content in the rotifer showed a straight-line proportion. In addition, the content of taurine in rotifer would almost become constant amount after 16 hours, and the enriched taurine levels were kept about 75% of initial amount after eight hours from final enrichment. Therefore, it was proved that direct method is the most practical method to enrich taurine in rotifer.View full abstractDownload PDF (1005K) -
Joebert D. TOLEDO, Erlinda S. GANZON-NARET, Heisuke NAKAGAWA2005 Volume 53 Issue 2 Pages 127-134
Published: June 20, 2005
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe lipid content and fatty acid composition were examined in the liver, eye, muscle, brain and intraperitoneal fat body (IPF) of hatchery-bred and wild-caught orange-spotted grouper, Epinephelus coioides. The cultured and wild grouper were classified into three different body weights (small, medium and large size), and submitted to lipid content and fatty acid analysis. Muscle lipid in cultured grouper increased lineally with growth, but that of wild fish decreased. The amount of lipid in the IPF in cultured fish was higher than wild fish. Lipid content and essential fatty acids in cultured fish showed significant change with growth. All organs in the early growth stage of cultured fish seemed to contain poor arachidonic acid (AA) than the wild fish. The liver of small sized cultured fish contained low AA and docosahexaenoic acid (DHA), but no profound change was found in AA during growth of fish. While the proportion of DHA in the liver and IPF increased with growth in cultured fish, muscle DHA decreased with growth. The difference in fatty acid composition between cultured and wild fish disappeared with growth.View full abstractDownload PDF (1021K) -
Phyu Phyu THAN, Takeshi YOSHIKAWA, Taizo SAKATA2005 Volume 53 Issue 2 Pages 135-143
Published: June 20, 2005
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSA marine bacteriolytic bacterium Al-J25a was isolated from the coastal seawater of Kagoshima Bay, Japan and identified as Pseudoalteromonas sp. based on phylogenetic analysis using small subunit ribosomal DNA sequence. Proteases produced extracellularly by this strain were purified using ammonium sulfate precipitation, TOYOPEARL SuperQ-650M anion-exchange chromatography and TOYOPEARL HW-55F gel-filtration chromatography. Proteolytic activity was found in two fractions, fractions I and II, which were separated using anion-exchange chromatography. Molecular weights of fractions I and II were estimated to be approximately 42 kDa and 39 kDa, respectively by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Purified fraction I protease exhibited optimum activity at pH 11 and 50°C and purified fraction II protease showed optimum activity at pH 9 and 50°C. The fraction I and II proteases were identified as a serine protease and a metal protease, respectively on the basis of sensitivity to various inhibitors. Both proteases exhibited bacteriolytic activity to the dead cells of a Vibrio parahaemolyticus strain.View full abstractDownload PDF (3668K) -
Koji YOKOGAWA, Katsuki NAKAI, Kentarou FUJITA2005 Volume 53 Issue 2 Pages 145-155
Published: June 20, 2005
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe introduction of Florida bass Micropterus floridanus into Lake Biwa, where largemouth bass M. salmoides from North America had been propagating, was recognized. Isozymes of 194 individuals from four coastal localities in Lake Biwa from 2000 to 2003 were examined for comparison with former samples collected in the 1990s. M. salmoides and M. floridanus were genetically identified with the diagnostically polymorphic loci of AAT-1 , IDHP-1, MDH-1, and SOD. Alleles symbolized M. floridanus frequently appeared at all of the loci among the individuals examined; in general, about half of the total had those alleles. All of the sample lots fitted the Hardy-Weinberg equilibrium for each polymorphic locus, and most of them showed an excess of heterozygotes. Based on the genotypes at the diagnostic loci, most individuals were identified as F2 hybrids, backcross or higher-generation offspring, indicating that the hybridization between M. salmoides and M. floridanus has already progressed considerably in Lake Biwa. Considering the predominance of M. salmoides in Lake Biwa in the 1990s, the present results indicate the possibility that mass introduction of M. floridanus was carried out on a large scale so as to greatly influence the genetic characteristics of the M. salmoides population.View full abstractDownload PDF (4560K) -
Syozo YAMAMOTO, Hiroyuki SUGINO, Kenji CYUURIKI, Nobufumi MASUNARI, Ma ...2005 Volume 53 Issue 2 Pages 157-165
Published: June 20, 2005
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSDiel changes in feeding activity and daily food consumption were investigated in hatchery-reared larval and juvenile marbled sole Pleuronectes yokohamae ranging from 4.4 to 44.7 mm in total length (TL) . Feeding activity was examined by counting number of food organisms in the gut, and the daily food consumption was estimated using the method developed by Elliott and Persson (1978) . During the larval and juvenile stages, the number of food organisms in the gut increased gradually after dawn and reached their peak at dusk. Larvae in the swimming period (TL 4.4 - 7.5 mm) ingested food organisms only during daylight hours. Just after settlement (TL 7.9 mm), they were able to feed on a few food organisms in the dark after sunset, and the juveniles of bottom dwellers fed continuously throughout both the day and night. It was confirmed, for the first time in this species, that the larvae were able to feed in the dark of night. Although daily food consumption increased exponentially, the rate of daily food consumption (dry daily food consumption/dry body weight×100%) decreased from over 100% to under 30% with growth. The range of these rates was nearly equal to the ranges of the other species which pass their larval stage during the warm season in spring. It was speculated that the feeding environment would be very severe for this species that grows in the wild during the cold winter season, when the water temperatures are very low, and plankton, as food organism, is scarce.View full abstractDownload PDF (1440K) -
Sayumi SAWAGUCHI, Nobuyuki OHKUBO, Tadashi ANDOH, Shigenori SUZUKI, Ma ...2005 Volume 53 Issue 2 Pages 167-173
Published: June 20, 2005
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSMaintaining a high genetic variability in fertilized eggs through the avoidance of the loss of facility-held mature females is fundamental importance for artificial insemination in barfin flounder, Verasper moseri, and spotted halibut, V. variegatus, which are potentially endangered species. The objective of the present study is to establish a new method for collecting ovulated eggs without causing harm and minimizing stress to females, instead of the hand-stripping, using peristaltic pumps with artificial ovarian cavity fluid (AOCF) . By pumping about one liter of sterile AOCF though a vinyl tube which was inserted into an upperpart of the ovarian cavity from the urogenital pore, ovulated eggs were efficiently extruded with the introduced AOCF When ovulated eggs were preserved in AOCF at 4°C, high fertilizability was maintained during 4 and 24 hours in eggs of barfin flounder and spotted halibut, respectively. The developed technique, coupled with our previously developed short-term sperm preservation technique, will enable more controlled conditions for artificial fertilization. The present results demonstrated the practical usefulness of the newly developed method for a convenient and minimally-damaging method of collecting eggs from barfin flounder and spotted halibut.View full abstractDownload PDF (6268K) -
Tetsuya UMINO, Satoru SEIKE, Jun TAKATSUKA, Miho HIRANO, Heisuke NAKAG ...2005 Volume 53 Issue 2 Pages 175-180
Published: June 20, 2005
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSA stock separation study by otolith Sr/Ca ratio of ayu Plecoglossus altivelis among native amphidromous, landlocked form (transplanted from Lake Biwa) and hatchery-stock was conducted at the Hii River which has the largest brackish-lake (Lake Shinji and Nakaumi) at the river mouth. On the spawning population, we discussed the contribution of the landlocked form to reproduction and the possibility for the introgression between native amphidromous and landlocked form. Totally 80 individuals captured from May to October can be discriminated into 59 native amphidromous, 6 landlocked form and 15 hatchery-stock. Of the 40 individuals, 37 individuals were native amphidromous in October. Allele frequencies of them on Gpi-1 and Mpi loci indicated conservative amphidromous form. Therefore, the introgression between amphidromous and landlocked forms has not occurred in the Hii River.View full abstractDownload PDF (3446K) -
Chikara KAWAGOE, Takashi TANI, Jeane Rimber INDY, Hiroyuki MIZUTA, Haj ...2005 Volume 53 Issue 2 Pages 181-187
Published: June 20, 2005
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSIn order to develop the growing technique, which is the base of planning propagation of Sargassum oonfusum in Hokkaido, effect of seawater temperature on the growth and the morphogenesis of S. confusum was investigated. Fertilized eggs of S. confusum collected at Esashi coast in June 2000 were cultured in batch at a photoperiod of 12 h L: 12 h D, an irradiance of 40μE/m2/s, and different water temperatures (3, 5, 10, 15, 20°C) .
At 3°C, fertilized eggs developed into embryos at primary-rhizoid stage in 7 days, and the growth was still sustainable. At 5°C, fertilized eggs developed into embryos at primary-rhizoid stage in 60 hours, and secondary-rhizoid stage in 10 days, and the growth was still sustainable. At 10°C, fertilized eggs developed into embryos at primary-rhizoid stage in 48 hours, secondary-rhizoid stage in 7 days, and young thalli at main-axis formation stage in one year. At 15°C, fertilized eggs developed into embryos at primary-rhizoid stage in 36 hours, secondary-rhizoid stage in 5 days, young thalli at main-axis formation stage in 2 months, holdfast formation stage in 3 months, and principal-branch formation stage in 6 months. At 20°C, fertilized eggs developed into embryos at primary-rhizoid stage in 36 hours, secondary-rhizoid stage in 3 days, young thalli at main-axis formation stage in one and a half months, holdfast formation stage in 3 months, and principal-branch formation stage in 6 months. However, some young thalli at holdfast formation stage died.
In conclusion, the optimum temperature for growth of S. confusum from Hokkaido was 15°C, and for long-term embryo preservation was 3°C and 5°C.View full abstractDownload PDF (4070K) -
Hiroaki CHIBA, Shigeho IJIRI, Munehico IWATA, Masaru NAKAMURA, Shinji ...2005 Volume 53 Issue 2 Pages 189-198
Published: June 20, 2005
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSSeasonal changes in gonadosomatic index (GSI), ovary and pituitary histology, and serum concentrations of estradiol-17β (E2) and testosterone (T) were investigated in the captive common Japanese conger Conger myriaster. The GSI increased from December to June then, after peaking at 4.8 in July, decreased to its initial level by September. Although at the start of the experiment, oocytes were in the oil droplet stage, ovaries spontaneously started vitellogenesis from December to April in accompaniment with the increase in GSI. With the peak in GSI in June, oocytes in most fish were at the vitellogenic stage, but atretic oocytes were observed in the ovaries of some; in August, all showed atretic oocytes. Histochemical observations of the pituitary revealed that aldehyde-fuchsin (AF) positive cells in the region of the proximal pars distalis increased with progression of vitellogenesis from December to June, but they decreased with the increase in atretic oocytes. Serum E2 levels increased to a peak of 3.53 ng/ml at the initiation of vitellogenesis in January, but subsequently decreased to the initial level and remained low during vitellogenesis. Average serum T levels dramatically increased to a peak of 7.93 ng/ml in fish showing early atresia of vitellogenic oocytes in June, followed by a sharp drop to initial levels (3.86 ng/ml) in the late atretic stage.View full abstractDownload PDF (8146K) -
Tohshi KON, Tatunori ADACHI2005 Volume 53 Issue 2 Pages 199-204
Published: June 20, 2005
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSSeasonal changes in the development of embryos spawned by primiparous and multiparous female snow crabs (primiparae and multiparae), Chionoecetes opilio, were observed in rearing experiments and in samples collected off Wakasa Bay. Embryonic durations previously reported of one and half years for primiparae and one year for multiparae were confirmed embryologically. The duration between fertilization and the end of the gastrula stage was 275 days for embryos spawned by primiparae and 79 days for embryos spawned by multiparae. The duration between the start of the nauplius stage and hatching was almost equal for primiparae and multiparae, thus the difference in embryonic duration between them resulted from the slower development in the early embryonic stages of the primiparous eggs. Observations on reared specimens suggest that the cause of the difference in embryonic duration between primiparae and multiparae is not environmental temperature.View full abstractDownload PDF (878K) -
Shunichi HONDA, Tetsuya ICHIBU, Osamu ARAKAWA, Tomohiro TAKATANI, Kats ...2005 Volume 53 Issue 2 Pages 205-210
Published: June 20, 2005
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSA total of 4 feeding experiments were carried out, in which non-toxic cultured specimens of the tiger puffer Takifugu rubyipes were reared for 60 days with various types of tetrodotoxin (TTX) -containing diets. At the end of each experiment, the test fish were determined for their serum antibody titer against sheep red blood cells (SRBC) . The result showed that the test fish administered with TTX-containing diets exhibited slightly or significantly higher agglutinating titer than those of the fish fed with non-toxic diet in all the four experiments. Furthermore, in the 2nd to 4th experiments, the test fish were also examined for their splenocyte proliferation by stimulation with three mitogens, Poke weed mitogen (PWM), concanavalin A (ConA), or lipopolysaccharide (LPS) . Consequently, the splenocytes from toxic diets groups were found to show significantly higher proliferation than those from non-toxic diet group when they were stimulated with 1-3 types of mitogens in all the 3 experiments. These results suggest that TTX or TTX-containing diets has an immnopotantiating effect on the cultured puffer fish T. rubyipes.View full abstractDownload PDF (962K)
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