Aquaculture Science
Online ISSN : 2185-0194
Print ISSN : 0371-4217
ISSN-L : 0371-4217
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Volume 69, Issue 1
Displaying 1-15 of 15 articles from this issue
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Original paper
  • Behavior of organic acids content of pallial cavity fluid in the Manila clam Ruditapes philippinarum under hypoxia in the aquaculture ground
    Masahiko Matsuda, Akira Shinagawa, Junya Higano, Keiji Hirano, Akihiko ...
    2021 Volume 69 Issue 1 Pages 1-11
    Published: 2021
    Released on J-STAGE: March 20, 2022
    DOIhttps://doi.org/10.11233/aquaculturesci.69.1
    JOURNAL FREE ACCESS
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    We studied the changes in the concentrations of organic acids (succinate, acetate, and propionate) formed in the pallial cavity fluid by anaerobiosis in the Manila clam during hypoxic events occurred on a culture ground in Isahaya Bay, Kyushu, Japan in 2003, 2004 and 2008.
    　In 2004, a prolonged (14 h), severe hypoxia with an average dissolved oxygen (DO) concentration of 0.16 mg/l, and an average temperature of 31.3°C resulted in 70% mortality of Manila clam in the affected area. This coincided with significant increases in all three organic acids in the clam.
    　In contrast, mortality was less than 8% in 2003 and 2008, where the hypoxia lasted for shorter duration (6-11 h) at lower temperatures (under 30°C). Organic acid concentrations increased significantly but to a lesser extent than in 2004. The cause of mass mortality in 2004 was suggested to be hypoxia with high water temperature (above 30°C).
    　These results indicates that the concentration of organic acids in the pallial cavity fluid is useful in monitoring stress levels of the Manila clam in the field.
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  • Characteristics of mantle gene expression and bacterial flora in Akoya pearl oysters, Pinctada fucata with mantle atrophy
    Natsumi Sano, Isao Kuriyama, Akira Komaru
    2021 Volume 69 Issue 1 Pages 13-20
    Published: 2021
    Released on J-STAGE: March 20, 2022
    DOIhttps://doi.org/10.11233/aquaculturesci.69.13
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    Akoya pearl oysters at a farming ground in Ago bay in Mie Prefecture showed mantle atrophy during June to mid-August in 2019. To characterize this syndrome, we compare the expressions of shell matrix protein genes associated with prismatic and nacreous layer formation (msi60, msi31), tyrosinase genes associated with melanization and sclerotization (OT47, pfty1), and lectin gene associated with an innate immunity (PoGal) of the healthy oysters and the oysters showed this syndrome. Total RNA was extracted from three mantle regions (the edge, pallial, and center) and expressions of the target genes in each tissue were measured using qPCR. Different expression patterns of the target genes were observed between the apparently healthy and the oysters with symptoms. Especially, a decrease of OT47 expression in the mantel edge and an increase of msi31 expression in the mantle pallial were detected in the oysters with symptoms. This finding may explain symptoms that included mantle detachment from the shell and subsequent atrophy, brown deposits, lost luster, and a rough nacreous layer surface. Additionally, we performed 16S metagenomic analysis of bacterial flora on surface of the mantle edge. Occupancy of the genus Tenacibaculum of the oysters with symptoms was higher than the apparently healthy oysters.
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  • Relationship between water temperature and spawning in Hemigrammocypris neglectus
    Tadahiro Teramoto, Kodai Kato, Tomonari Asaka
    2021 Volume 69 Issue 1 Pages 21-29
    Published: 2021
    Released on J-STAGE: March 20, 2022
    DOIhttps://doi.org/10.11233/aquaculturesci.69.21
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    To improve the breeding technique of Hemigrammocypris neglectus, we examined whether spawning was induced by changes in water temperature. In pattern 1, the water temperature was increased from 22°C to 26°C, and then maintained for 5 days at 26°C. The water temperature was then decreased by 2°C per day, to 22°C, from after 7 days. In pattern 2, the water temperature was increased from 22°C to 26°C, and then maintained at 26°C for 3 days. The water temperature was then decreased by 1°C per day, to 22°C, from after 7 days. In pattern 3, the temperature was maintained at 22°C throughout. In pattern 4, the temperature was increased by 2°C per day from 22°C, then maintained after it reached 26°C. A GLM, with glm.n.b of the number of spawning eggs as a logarithmic link function, was used to select a representative model of the spawning probability in a round-robin method, using the mean water temperature, the difference in average water temperature on the previous day, the diurnal range in water temperature, and the adding water as explanatory variables. The main factor affecting spawning was the difference in the mean water temperature from the previous day.
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  • Seasonal and diurnal patterns of feeding habits of channel catfish in Lake Kasumigaura, Ibaraki Prefecture, Japan
    Ryohei Kamei, Kazunori Arayama, Masashi Yokota, Noriyuki Sunoh, Carlo ...
    2021 Volume 69 Issue 1 Pages 31-42
    Published: 2021
    Released on J-STAGE: March 20, 2022
    DOIhttps://doi.org/10.11233/aquaculturesci.69.31
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    This study aimed to clarify the influence of predation on important fish resources consumed by the channel catfish in Lake Kasumigaura, we examined the feeding activity and stomach contents of catfish in August and November 2013 and February and May 2014. Samples (685 individuals, standard length 78-720 mm) were collected by fishing throughout for 24 hours at 6 stations in the lake. The catch numbers changed seasonally, with the highest observed in August (mean = 49.0 fish) and least in February (14.0 fish). The results indicated that catch numbers are related to seasonal changes in water temperature and their distribution pattern. Based on the diurnal changes in catch numbers each month, we concluded that fish prey more actively at night, although feeding was continued in the daytime. The food consumption of almost all specimens was not satisfactory, given that food consumption was 1% of body weight in 89.9% of all caught individuals. Each month, the catfish vacuity indices varied from 23.2% to 32.0%. The main food resources were freshwater prawn and large fish fragments, fish, mysid, plants and algae. Among the important fish species of Lake Kasumigaura, freshwater prawn was strongly influenced by predation pressure by catfish.
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  • Feeding protocol on energy partitioning and growth performance in Pacific bluefin tuna (Thunnus orientalis) fingerlings
    Takayuki Ohnishi, Takashi Ido, Mitsugi Gohda, Osamu Takaoka, Kenji Tak ...
    2021 Volume 69 Issue 1 Pages 43-53
    Published: 2021
    Released on J-STAGE: March 20, 2022
    DOIhttps://doi.org/10.11233/aquaculturesci.69.43
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    The following feeding protocols were used to determine its influence on energy partitioning in Pacific bluefin tuna fingerlings weighing 1.8 g in a commercial-scale tank to improve fish husbandry; fasting (F), daily feeding at 2, 3, 4 and 5 times until satiety (2S, 3S, 4S and 5S, respectively), and 4 days feeding at 5 times daily until satiety followed by a fasting day (4/5S) with an artificial diet. When energy partitioning was expressed as percentages of gross energy intake, the sum of fecal, urinary and heat increment was near 40% on all feeding protocols, excepting F. The energy for standard metabolism was higher in 2S, followed by 4/5S, 3S, 4S and 5S groups. The highest retained energy (RE) of 24.4% was found in 5S, followed by 23.8% in 4S, 22.1% in 3S, 18.0% in 4/5S and 12.1% in 2S. Although there was no significant difference in final mean weight between groups 4S and 5S, that of 5S group showed significant difference than juveniles under 2S, 3S and 4/5S groups (P < 0.05). These results revealed that 4 or 5 times daily feeding until satiety will be recommended to ensure better growth, and that even a single day fasting after a 4-day satiety cause a remarkable RE reduction.
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  • Trial of stable outdoor mass culture of Chaetoceros calcitrans
    Tadashi Sasaki
    2021 Volume 69 Issue 1 Pages 55-69
    Published: 2021
    Released on J-STAGE: March 20, 2022
    DOIhttps://doi.org/10.11233/aquaculturesci.69.55
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    To clarify the stability of Chaetoceros calcitrans in outdoor mass cultivation, culture trials using 100 l, 500 l and 5 kl tanks were conducted outdoors from spring to fall, with C. neogracile as the control group for comparison. In addition, experiments were conducted to clarify the use of commercially available C. calcitrans products as a starter culture and the effectiveness of culturing C. calcitrans with a shade curtain in summer. In spring, which is an optimal season for cultivation, the maximum density of C. calcitrans cells reached approximately 6 million cells/ml in the 100 l and 500 l tanks. Furthermore, the results demonstrated that C. calcitrans can be stably cultured like C. neogracile, although the maximum cell density was slightly inferior to that of C. neogracile. The results also confirmed that C. calcitrans can be efficiently cultured as a starter culture using commercially available products. The use of a shade curtain to reduce the water temperature in summer was also found effective for the stable culture of feed algae, suggesting that even heat-sensitive strains such as C. calcitrans can be cultured during summer.
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  • Effect of dietary moisture content on growth and feed intake in conger eel Conger myriaster
    Wastu Ayu Diamahesa, Haruhisa Fukada, Toshiro Masumoto
    2021 Volume 69 Issue 1 Pages 71-77
    Published: 2021
    Released on J-STAGE: March 20, 2022
    DOIhttps://doi.org/10.11233/aquaculturesci.69.71
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    Two feeding experiments were conducted to examine effect of moisture content (dry or moist) of diets on growth and feed intake of Conger eel. Commercially available dry pellets (2 mm) and moist feed hydrated after crushing the dry pellets were used in both experiments. In the first experiment, the two diets were fed to individually kept 10 fish (5 fish per treatment) 5 days a week for 6 weeks. There were no significant differences in body weight gain (%), specific growth rate and daily feed intake of the two treatments. In the second experiment, those fish used in the first experiment were fed the opposite feed and measured daily feed intake amount and feed ingestion time (time spent to initiate ingestion of feed). Fish of both groups took a long time before day 11 but it took shorter (within 30 seconds) after 11 days. No significant differences were detected in both parameters in the two groups, indicating there is no strong preference between the two diets. Taken together, this study demonstrated the moisture content did not display significant effects on growth, feed intake and palatability of conger eel, suggesting that dry feed can be applicable for practical conger eel culture.
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  • Effects of a soybean lecithin-supplemented mealworm-containing diet on the growth performance and lipid utilization of common carp (Cyprinus carpio L.)
    Kakeru Iwai, Wastu Ayu Diamahesa, Haruhisa Fukada, Toshiro Masumoto
    2021 Volume 69 Issue 1 Pages 79-86
    Published: 2021
    Released on J-STAGE: March 20, 2022
    DOIhttps://doi.org/10.11233/aquaculturesci.69.79
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    In the present study, the effects of supplementing a mealworm meal (MWM)-containing diet with soybean lecithin (SBL) were assessed in common carp (Cyprinus carpio L.) by measuring the body weight gain, plasma biochemical parameters, and nutrient retention of fish. Three diets were tested: a control diet (CONT; containing 20% fishmeal) and two diets containing 20% MWM without fishmeal, one with 2% SBL supplementation diet (SBLD) and one without SBL diet (MWMD). In a 4-week feeding trial, the growth performance [body weight gain (%) and feed conversion rate] of fish fed the MWMD was significantly lower than that of CONT-fed fish; however, the growth performance of fish fed the SBLD was significantly better than those fed the MWMD and comparable to that of CONT-fed fish. The same trend was observed for plasma triglyceride levels 8 h after feeding and for lipid retention rate. In conclusion, dietary inclusion of 20% MWM significantly affected the lipid utilization of carp, but 2% SBL supplementation in a MWM-containing diet restored these adverse effects and showed comparable growth performance and lipid utilization to the fish fed CONT.
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  • Predation on larval honmoroko Gnathopogon caerulescens in daytime and nighttime by six fish species
    Yasuhiro Fujioka, Morihito Nemoto, Takeshi Kikko
    2021 Volume 69 Issue 1 Pages 87-91
    Published: 2021
    Released on J-STAGE: March 20, 2022
    DOIhttps://doi.org/10.11233/aquaculturesci.69.87
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    We examined predation on larval honmoroko Gnathopogon caerulescens during the breeding season in daytime and nighttime by six sympatric fish species which inhabit in satellite lakes of Lake Biwa. Although all of the fishes consumed honmoroko larvae in both daytime and nighttime, Sarcocheilichthys variegatus microoculus and Lepomis macrochirus macrochirus fed significantly less on honmoroko larvae in the nighttime than in the daytime. Honmoroko cannibalized its larvae in the daytime and nighttime. These our results suggest that various fishes inhabiting in the satellite lakes during the spawning season of honmoroko potentially have a strong predatory pressure on honmoroko larvae, and the predation pressure might play a role to decrease of the early survival of honmoroko.
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  • Effect of temperature on the ammonia oxidizing microorganism activity of filter materials with nitrification stored for a long time
    Tadashi Imai, Kazuya Dehama, Tomoko Sakami, Toshinori Takashi, Tetsuo ...
    2021 Volume 69 Issue 1 Pages 93-100
    Published: 2021
    Released on J-STAGE: March 20, 2022
    DOIhttps://doi.org/10.11233/aquaculturesci.69.93
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    The propose of this study was to assess the suitable conditions to preserve filter materials which were attached nitrifying microorganisms for a long period. We investigated the effect of the preservation temperature on the ammonia oxidation activity of filter materials kept in saturated humidity in plastic bags. After the ammonia oxidation activity of filter materials was measured at 25°C, filter materials were removed from seawater and kept at eight temperatures (1-35°C) in plastic bags for 180 days. Ammonia oxidation activity of the filter material preserved at 1°C was similar to that of the initial activity value. In addition, the relative abundance of ammonia-oxidizing archaea and bacteria in the filter materials preserved at 1°C exhibited only a slight decrease of 14% and 10% of the initial abundances, respectively. Activity of filter materials preserved at 5-20°C decreased to about 50%. Greater decrease of activity was recognized in filter materials preserved at over 25°C. An additional preservation experiment over a three year period at 1°C showed that the activity of filter materials remained at 33%. Therefore, highest retention of the ammonia oxidizing microorganism for long preservation of filter materials with nitrification was 1°C in the designed temperature.
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  • Growth performance and edible ratio of myostatin-knockout young red sea bream Pagrus major produced by genome editing with CRISPR/Cas9
    Youhei Washio, Mitsuki Ohama, Kenta Kishimoto, Masato Kinoshita, Keita ...
    2021 Volume 69 Issue 1 Pages 101-112
    Published: 2021
    Released on J-STAGE: March 20, 2022
    DOIhttps://doi.org/10.11233/aquaculturesci.69.101
    JOURNAL FREE ACCESS
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    Genome-edited organisms are not only of scientific interest but could also be used for human edible organisms. Myostatin (mstn), which belongs to the transforming growth factor beta superfamily and acts as a negative regulator of skeletal muscle growth, is a main target for improving finfish farming productivity. We previously reported that mstn (Pm-mstn)-deficient juvenile red sea bream (Pagrus major) displayed higher weight gain, specific growth rate, and feed efficiency compared to those of wild type (WT) fish in an 8-week feeding trial using apparent satiation feeding. In this study, to investigate the potential use of the Pm-mstn mutant in aquaculture, we conducted a similar feeding trial at the young stage, close to shipping size, and compared the growth performance and processing yield of the WT and mutant fish as fillets. The mutant fish, with 0.08% less food intake, showed similar growth and an almost 9% higher feed efficiency than those of the WT fish. Moreover, the fillets of the Pm-mstn mutant increased the edible weight by 7%-8% compared to that of the WT. Based on the growth performance and processing yield of the young fish, we concluded that Pm-mstn-deficient red sea bream would be a beneficial breed for future aquaculture.
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Short Paper
Note
  • Factors affecting the survival and growth of pen shell spats in suspended intermediate culture
    Masayuki Yamamoto, Atsushi Ito, Hideki Yamazaki, Masaei Kanematsu, Tak ...
    2021 Volume 69 Issue 1 Pages 123-129
    Published: 2021
    Released on J-STAGE: March 20, 2022
    DOIhttps://doi.org/10.11233/aquaculturesci.69.123
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    Pen shells Atrina spp. distributed along the coast of East Asia are major commercially important bivalves. We estimated growth rates of pen shell spats Atrina lischkeana and examined monthly survival rates and body weight gains in relation to environment factors in suspended intermediate culture using artificially reared spats in Yashima Bay, central Seto Inland Sea, from July to November in 2017 and 2018. Water temperature, chlorophyll a concentration and number of days with low salinity (<21 psu) ranged from 18.9 to 27.5°C, from 2.9 to 11.8 µg/l and 0 to 3 days, respectively. Spats grew from ca. 5 mm in shell length to 43-58 mm within three months. Those spats that settled in July grew faster than that settled in August. Survival rate and body weight gain per month ranged from 16.7 to 100%/month and 0.03 to 1.50 g/month, respectively. Generalized liner mixed models indicated that the survival rate was negatively affected by the number of days with low salinities, while the body weight gain was positively affected by water temperature and body length.
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