All issues
Volume 64, Issue 1
Displaying 1-15 of 15 articles from this issue
- |<
- <
- 1
- >
- >|
Original Paper
-
Hiromasa Sato, Saichiro Yokoyama, Ya Yu, Shunsuke Koshio, Takayoshi O ...2016 Volume 64 Issue 1 Pages 1-12
Published: March 20, 2016
Released on J-STAGE: March 20, 2017
JOURNAL FREE ACCESSThe development of amberjack Seriola dumerili seedlings production has popularized its aquaculture in Japan. However, no information has been disclosed regarding the performance of seedlings after transferring to offshore net cages. In addition, the effect of extruded pellets (EP) with decreased fish meal content on the performance of amberjack has not been clarified. In the present study, artificially produced juvenile amberjack were fed a commercial EP with 2 different fish meal (FM) contents (60% and 40%) for 64 days under cage culture conditions at two different experimental stations (Nejime and Kushima) in southern Kyushu, Japan. At the end of the feeding trial, no differences were observed in growth performance and survival between dietary treatments at either experimental station. Shortly after transferring the juveniles from the hatchery to experimental cages, fish had low levels of blood chemical constituents, such as total cholesterol and triglyceride, however these values increased with time regardless of the FM content in the diet. These results suggest that artificially produced amberjack seedlings could be cultured using EP containing 40% FM under cage culture conditions.View full abstractDownload PDF (1088K) -
Kentaro Hashiguchi, Yuko Inami, Masayuki Imajoh, Syun-ichirou Oshima2016 Volume 64 Issue 1 Pages 13-20
Published: March 20, 2016
Released on J-STAGE: March 20, 2017
JOURNAL FREE ACCESSYellowtail Seriola quinqueradiata is commonly placed in a freshwater bath as a means of removing the skin flukes. However, this treatment was shown to increase susceptibility to infection and reduce nonspecific immunity. Therefore, it is necessary to determine methods to mitigate the effects of this stress on the fish. In this study, yellowtail were orally fed inulin in bait (5 g/kg diet) for a certain period, and subjected to a freshwater bathing. A stress index and nonspecific immune capability were monitored, and differences in susceptibility to experimental infection were examined to determine the protective effect of the inulin. The stress indicator, blood glucose concentration, was lower in the inulin group than in the control group before and 24 hours after the freshwater bathing. Nonspecific immune capability, i.e., phagocytic activity and complement levels, were higher in the inulin group prior to the freshwater bath than the control group. In the experimental infection of pseudotuberclosis, the mortality rate of the inulin group was lower than that of the control group.View full abstractDownload PDF (581K) -
Naohiko Takeshita, Itaru Ikeda, Kunimasa Aoki, Yasutomo Miura, Toru Ka ...2016 Volume 64 Issue 1 Pages 21-27
Published: March 20, 2016
Released on J-STAGE: March 20, 2017
JOURNAL FREE ACCESSEffects of water temperature on feeding and growth of the catadromous roughskin sculpin Trachidermus fasciatus were studied at 9 different temperatures from 12 to 28°C for 30 days. At each of the 9 temperatures, six young fish were reared in aquaria and the rearing examination was repeated in 3 consecutive years (n=162). Results indicated that for daily feeding rate the optimal water temperatures ranged from 21 to 26°C, while ranging from 19 to 20°C for daily growth rate, and ranging from 16 to 18°C for feeding efficiency. The optimal water temperatures for daily growth rate and feeding efficiency were lower than those for daily feeding rate. These results indicate that the optimal water temperature range is from 16 to 22°C, and that a water temperature of 12°C is too low and 28°C is too high for sustainable growth of T. fasciatus.View full abstractDownload PDF (333K) -
Hikari Izumi, Koichiro Gen, Moemi Horiuchi, Noriaki Matsuya, Shigeho I ...2016 Volume 64 Issue 1 Pages 29-42
Published: March 20, 2016
Released on J-STAGE: March 20, 2017
JOURNAL FREE ACCESSThe current method of artificial egg production in Japanese eel does not always yield good quality eggs, but the molecular basis for the decrease in egg quality remains unclear. In this study, we compared the levels of 74 maternal transcripts related to cell division among good quality eggs, developing poor quality eggs (i.e., those producing a viable morula embryo without hatching), and non-developing poor quality eggs (i.e., developmentally incompetent eggs) to determine the molecular characteristics of poor quality eggs produced by artificially matured Japanese eel. Only one transcript (lsm7) had a lower level in developing poor quality than in good quality eggs, with the others being present at similar levels between the two types of egg. The levels of 11 transcripts (e.g., cdc26, psma7) were lower in non-developing poor quality than in good quality eggs. These results suggest that insufficient or reduced levels of maternal mRNA related to cell division are associated with the loss of egg quality in artificially matured Japanese eel, and that maternal characteristics other than quantity may affect the developmental competence of poor quality eggs.View full abstractDownload PDF (329K) -
Kouta Miyamoto2016 Volume 64 Issue 1 Pages 43-51
Published: March 20, 2016
Released on J-STAGE: March 20, 2017
JOURNAL FREE ACCESSObservation were undertaken to determine whether exposure to a visual (a model bird) or a chemical stimulus (skin extracts from a conspecific) were capable of inducing predator avoidance behaviors in masu salmon Oncorhynchus masou. The results showed that both visual and chemical stimuli induced predator avoidance behavior: hiding under a shelter, partially concealing themselves in gravel, freezing and ceasing to feed. To test whether the fish reacted differently to the two stimuli, the locations in the aquarium selected by the fish when exposed to the stimuli were compared. The number of fish that selected the gravel on the bottom as a hiding place was significantly greater during the visual (bird attack) than the chemical alarm cue stimulus. On the other hand, the number of fish that selected the shelter as a hiding place was significantly greater during the chemical alarm cue than the bird attack trial. These results suggest that both visual and chemical stimuli are capable of inducing predator avoidance behavior in masu salmon and that each stimulus has a different effect on their selection of hiding place.View full abstractDownload PDF (499K) -
Masayuki Yamamoto, Jun Shoji2016 Volume 64 Issue 1 Pages 53-61
Published: March 20, 2016
Released on J-STAGE: March 20, 2017
JOURNAL FREE ACCESSTo examine seasonal changes in composition of dominant species in demersal fish community on a sandy beach in the Seto Inland Sea, we conducted a beam trawl survey between May 2002 and September 2005. A total of 14,013 individuals, belonging to more than 39 species, were collected at 1.0-5.7 m depths (measured at each tow). The tidal variation was approximately 3 m at this beach, the water temperature ranged from 9.0 (February) to 30.3°C (August), and the salinity from 28.7 (July) to 33.7 (March). The mean number of fish species per tow ranged from 1.25 (January) to 9.50 (June) and fish abundance (number of individuals /100 m2) from 0.6 (January) to 103.5 (October). Both species number and the abundance increased from spring to summer and decreased from autumn to winter with a significant positive correlation with water temperature each month. The numerically dominant species were Favonigobius gymnauchen (62.6%), Tarphops oligolepis (11.4%), Sillago japonica (6.7%), unidentified Repomucenus (6.4%), Heteromycteris japonica (3.3%) and Paralichthys olivaceus (3.2%).View full abstractDownload PDF (721K) -
Mamoru Maebayashi, Yuhei Inaoka, Tatsuya Yoshida, Seishi Hagihara, Osa ...2016 Volume 64 Issue 1 Pages 63-76
Published: March 20, 2016
Released on J-STAGE: March 20, 2017
JOURNAL FREE ACCESSMolecular cloning of cDNAs encoding an egg yolk precursor, vitellogenin (Vtg), was performed using the liver of estrogen-treated Amur sturgeon. Three kinds of vtg cDNA were cloned and temporarily named as vtg1, vtg2 and vtg3. These vtg cDNAs were obtained as contiguous sequences; each of vtg1, vtg2 and vtg3 sequences contained a complete open reading frame (5,307, 5,247 and 5,319 bp, respectively), each encoding 1,769, 1,749 and 1,773 aa residues, respectively. Similarity among amino acid sequences deduced from the three vtg cDNAs were relatively low, ranging from 64.3% to 47.9%. Three Vtgs appeared to be a complete-type, consisting of all representative yolk protein domains. Phylogenetic analysis revealed that Amur sturgeon Vtg1 formed a clade together with a published white sturgeon Vtg, while Amur sturgeon Vtg2 and Vtg3 formed another distinct clade. The results of phylogenetic analysis confirmed all three Vtgs belong to VtgAB type; vtg1/Vtg1, vtg2/Vtg2 and vtg3/Vtg3 were hereby designated as vtgAB1/VtgAB1, vtgAB2a/VtgAB2a and vtgAB2b/VtgAB2b, respectively. This study provided a basis to understand multiplicity in sturgeon vtg/Vtg and set a stage for their future application as reproductive biomarkers in sturgeon aquaculture.View full abstractDownload PDF (838K) -
Izumi Sakurai, Tadaaki Takeda, Kimihiko Maekawa2016 Volume 64 Issue 1 Pages 77-85
Published: March 20, 2016
Released on J-STAGE: March 20, 2017
JOURNAL FREE ACCESSWe examined valve movement pattern of the Japanese scallop Mizuhopecten yessoensis related to several environmental changes such as water temperature, turbidity, dissolved oxygen and wave height, to develop a method for monitoring the environment of scallop aquaculture site. The valve movements were recorded by a Hall element sensor. Several characteristic waveform patterns (I-VII) were classified by the shape and the interval of the spikes and were then divided into three groups based on the amplitude of the spikes; I and IV of amplitude about 6 mm were presumed escape behavior from environmental changes, III and V of amplitude about 1 mm were presumed behavior for water exchange in the mantle cavity, and II, VI and VII of amplitude about 5 mm were presumed the two former behaviors. The frequency of patterns I, III, V and VII were significantly increased when exposed to water temperature rise, high waves, high turbidity and hypoxic water, respectively. Judging from waveform pattern in the present study, when we detect twice / hr or more in I and III and once / hr or more in V and VII, unsuitable environmental change may be occurred.View full abstractDownload PDF (1215K) -
Koji Kusaka, Koshiro Tada, Sohei Yoshida2016 Volume 64 Issue 1 Pages 87-95
Published: March 20, 2016
Released on J-STAGE: March 20, 2017
JOURNAL FREE ACCESSSpawning rhythm, number of eggs spawned, and spawning time were examined in wild caught three-lined tonguefish, Cynoglossus abbreviatus. Four females (total length: 312-355 mm) were reared separately with three males in each tank under natural temperature. The start of spawning and the spawning period differed between individuals. One female spawned 14-22 times during a single spawning season. During the spawning period, which began in late April and ended in early June, all females continued to spawn with frequencies of 44-81% across all days. The total number of eggs spawned during the entire spawning season and the maximum number of eggs spawned in 1 day were 334,000-521,000 and 45,000-53,000, respectively. These results indicate that the three-lined tonguefish is a multiple spawner. Mean egg diameter was 0.96-1.10 mm, and egg diameter decreased as the spawning season progressed. A significant correlation was detected between mean egg diameter and water temperature on the day of spawning. Moreover, spawning time in three-lined tonguefish maintained in tanks was estimated to occur between 14:00 and 0:00.View full abstractDownload PDF (899K) -
Yasuhiro Fujioka, Haruo Okamoto, Daisuke Ishizaki2016 Volume 64 Issue 1 Pages 97-102
Published: March 20, 2016
Released on J-STAGE: March 20, 2017
JOURNAL FREE ACCESSThe hatching time of eggs of “honmoroko” (Gnathopogon caerulescens), a small cyprinid fish endemic to Lake Biwa, was investigated under different rearing regimes of either constant temperature or fluctuating temperature representative of coastal water in Lake Biwa through the spawning season. Under constant temperature, eggs could hatch normally in the range of 10-29°C. Under fluctuating temperatures, spawning and hatching of eggs occurred in the range of 10-27°C and hatching rates of all batches of eggs were high. The hatching time was shorter at the fluctuating temperature than that of the same constant temperature. These results indicate that the lower temperature limit for hatching is 6-10°C, the upper temperature limit is 29-32°C, and the optimum temperature range is 10-29°C, coinciding nearly with the range of successful spawning and hatching under fluctuating temperature condition. Hatching time was more than 16 days in April and 7 days in June, and the water level of the lake should be maintained in order to protect the eggs laid at the lakeshore.View full abstractDownload PDF (675K)
Short Paper
-
Effect of sampling procedures on skin darkening in juvenile Japanese flounder Paralichthys olivaceusMasaharu Iguchi2016 Volume 64 Issue 1 Pages 103-105
Published: March 20, 2016
Released on J-STAGE: March 20, 2017
JOURNAL FREE ACCESSThe effects of anesthesia, fixation and handling on skin darkening in Japanese flounder Paralichthys olivaceus were assessed using luminance (brightness) values calculated from photographs containing two gray scales. The fish body darkened following exposure to anesthetic, ice-cold formalin or handling for 2 min, but not following exposure to hot physiological saline or handling for 30 s. These results indicate that handling within 30 s and exposure to hot saline prevent darkening associated with the sampling procedure in flounder.View full abstractDownload PDF (236K) -
Teruwo Morita, Chie Suzuki, Michihiko Kumon, Akio Douke2016 Volume 64 Issue 1 Pages 107-108
Published: March 20, 2016
Released on J-STAGE: March 20, 2017
JOURNAL FREE ACCESSSargassum miyabei was the only species of Sargassaceae in Aso Lagoon, Kyoto Prefecture. Biomass and seasonal changes in an S. miyabei population in Aso Lagoon were monitored from 2008 to 2011. Annual plant growth decreased tremendously in the latter 2 years of that period, which was considered to be due to inferior growth in the growing season. Additionally, we considered that the growth of S. miyabei was inhibited by low temperature and low salinity. This finding indicates the need to conserve and restore the S. miyabei population at this site.View full abstractDownload PDF (370K)
Note
-
Tsutomu Tomoda, Kazunori Kumon, Ken-ichi Watanabe, Daisuke Arai, Masah ...2016 Volume 64 Issue 1 Pages 109-119
Published: March 20, 2016
Released on J-STAGE: March 20, 2017
JOURNAL FREE ACCESSThe present study intends to develop larviculture techniques for mass production of Pacific cod Gadus macrocephalus juveniles possessing better seed quality and lower cost. We evaluated the efficiency of semi-extensive larviculture of Pacific cod utilizing wild zooplankton in the sea net-cage. Main food was light-allured zooplankton and supplementary foods were enriched Artemia nauplii, commercial frozen copepoda and dry feed. Metamorphosing cod larvae (12 and 13 mm in total length, TL) were raised until approximately 30 mm TL, and larvae and metamorphosed juveniles (17, 19, and 20 mm TL) were raised until 45 to 50 mm TL. Survival rates ranged from 46.4 to 48.7% in the former groups, and from 51.4 to 76.5% in the latter groups. A total of 204.8 and 183.7 thousand juveniles were produced in each semi-extensive trial. Moreover, semi-extensive method offered the benefits of labor saving and cost reduction. One juvenile with 30 mm and 45 to 50 mm TL cost only 6.4 yen and 6.2 to 10.5 yen, respectively. These results suggest that cod larviculture utilizing wild zooplankton in the sea net-cage provides faster growth, higher survival rate, and lower cost. We propose that this rearing method may be applicable to various fish species for stock enhancement.View full abstractDownload PDF (939K) -
Kagao Itoh, Takumi Yamamoto, Shusaku Takagi2016 Volume 64 Issue 1 Pages 121-129
Published: March 20, 2016
Released on J-STAGE: March 20, 2017
JOURNAL FREE ACCESSGrowth performance and physiological conditions of red sea bream fed low-fishmeal (FM) diet for extended periods were investigated. A diet containing 15% FM with other protein sources was used as a low-FM diet (LFMD), and a commercial diet (CMD) was used as the control. Juvenile fish (initial body weight 92 g) were fed until satiation from December 1998 to October 2000. Mortality of the two groups was approximately 2%. At low water temperatures, the feeding activity was lower in the LFMD group than in the CMD group. During the period of sexual maturation from January to June 2000, the specific growth rate was markedly lower in the LFMD group than in the CMD group. In October 2000, the growth performance was lower in the LFMD group than in the CMD group. In April 2000, green liver syndrome was observed in all test samples from the two groups. These results suggest that the growth performance and physiological conditions of red sea bream, particularly of the fish fed with LFMD, were significantly affected by sexual maturation. Therefore, future studies should investigate the interrelation among dietary nutrients, nutrition status, and physiological conditions of fish during the period of sexual maturation.View full abstractDownload PDF (324K) -
Shozo Sugiura2016 Volume 64 Issue 1 Pages 131-136
Published: March 20, 2016
Released on J-STAGE: March 20, 2017
JOURNAL FREE ACCESSDetecting early phosphorus deficiency in fish is important in environmentally conscious aquaculture. This study evaluated the utility of measuring mRNA expression of NaPi-IIb (phosphate transporter, a putative dietary phosphorus-responsive gene) as a practical biomarker for the diagnosis of body phosphorus status in aquacultured Biwa salmon Oncorhynchus masou rhodurus. To do this, a partial mRNA sequence (1200 bp) encoding NaPi-IIb was isolated from the intestine. The deduced amino acid sequence was 99% identical to the intestinal NaPi-IIb of rainbow trout. Then, 1.5-year-old Biwa salmon were fed either a plant-based low-phosphorus diet (LP) or a fish meal-based commercial diet (Cm) for 3 months. The bone phosphorus content of fish fed the LP and Cm diets was, respectively, 8.97% and 10.03% (P<0.01). However, the NaPi-IIb mRNA abundance was significantly higher in the Cm fish than in the LP fish in both the colon and pyloric caeca (P<0.05), which is contrary to previous in-lab observations reporting upregulation of NaPi-IIb under dietary phosphorus restriction. These results suggest that NaPi-IIb mRNA abundance may not be used as a practical diagnostic biomarker for phosphorus status of aquacultured fish. Also, there are as yet unidentified dietary factors involved in NaPi-IIb mRNA expression, thereby possibly affecting dietary phosphorus absorption.View full abstractDownload PDF (295K)
- |<
- <
- 1
- >
- >|