Aquaculture Science
Online ISSN : 2185-0194
Print ISSN : 0371-4217
ISSN-L : 0371-4217
Volume 60 , Issue 3
Showing 1-17 articles out of 17 articles from the selected issue
Original Papers
  • Taiko Miyasaki, Yoshito Kitamura
    2012 Volume 60 Issue 3 Pages 307-312
    Published: September 20, 2012
    Released: March 23, 2015
    JOURNALS FREE ACCESS
    Effect of feedstuff oil supplementation on flavor compounds in Nile tilapia Oreochromis niloticus body was investigated. Tilapia (20 g average body weight) were fed on the diet supplemented with only feed oil (F diet) or soybean oil (S diet) for 17 days. Flavor compounds in the muscle (with skin and without scale), viscera (with gill and heart) and diets were analyzed using a gas chromatography mass spectrometer with headspace solid-phase micro-extraction. F diet group exceeded S diet group in kinds and amounts of flavor compounds detected in the muscle and viscera. Muscle and viscera of F diet group smelled unpleasant. These findings were reflected the abundant flavor compounds (lipid oxidatives) in the F diet, such as 1-heptanol, 5-methyl-1,3,6-heptatriene, 1-octene-3-ol, 2-ethyl-1-hexanol, 1-octanol, nonanal, 1-decanol and tridecane. In contrast with F diet group, only 1-octene-3-ol and 5-methyl-1,3,6-heptatriene which were not detected in the S diet, were detected from the S diet group fish. Fresh fish flavor of the S diet group muscle was considered to be largely composed of these two compounds. Elimination of lipid oxidatives from feed oil may be important to avoid oily flavored fish.
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  • Yuji Machiguchi, Hitoshi Kitamura
    2012 Volume 60 Issue 3 Pages 313-322
    Published: September 20, 2012
    Released: March 23, 2015
    JOURNALS FREE ACCESS
    The dietary value of five common species (a kelp Saccharina longissima, two red algae Ptilota filicina and Tichocarpus crinitus, a green algae Ulva pertusa and sea grass Phyllospadix iwatensis, common around releasing spot in the eastern Hokkaido) to growth of the juvenile of a sea urchin Strongylocentrotus intermedius were examined in land-based tank culture. Fresh material of each species was fed to juveniles of 5 and 12 mm in test diameter (n=100 and 15, respectively) in flowing seawater of natural temperature every three to four days for four years. These juveniles increased their test diameter and body weight when S. longissima, U. pertusa or P. iwatensis was fed; the daily amounts of feeding were higher during summer and highest in S. longgisima. The 12 mm-size juveniles grew up to >50 mm in test diameter (common commercial size) with S. longissima one and a half year. P. filicina and T. crinitus were hardly consumed, resulting in lower growth, but growth was rapidly improved when feed was changed from T. crinitus to S. longissima. Survival rate was low when fed with T. crinitus (in both sizes), P. filicina or P. iwatensis (in 5 mm sized juveniles).
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  • Yuji Machiguchi, Kunio Takashima, Hiroyuki Hayashi, Hitoshi Kitamura
    2012 Volume 60 Issue 3 Pages 323-331
    Published: September 20, 2012
    Released: March 23, 2015
    JOURNALS FREE ACCESS
    The effect of six algae and one sea grass species abundant eastern Hokkaido to the gonad development in the sea urchin Strongylocentrotus intermedius was examined in land-based tank culture. Each diet was fed to the sea urchins of commercial size (> 45 mm in test diameter, n = 5) in flowing seawater of natural temperature for 75 days after two months of starvation. The gonad index (GI) was higher when kelp (Saccharina longissima, Costaria costata and Alaria praelonga) or a green alga (Ulva pertusa) was fed but lower when red algae (Ptilota filicina and Tichocarpus crinitus) or a sea grass (Phyllospadix iwatensis) was fed; T. crinitus never developed gonads. Feeding of stocked diets (dried S. longissima or frozen U. pertusa) resulted in lower GI than indices in the case of feeding each fresh sample. In comparing two feeding periods with four diets (fresh and dried S. longissima, frozen U. pertusa or fresh P. iwatensis), higher GI was obtained in longer culture (249 days from July) than in shorter culture (186 days from September). The taste sampling test showed higher scores in longer culture (highest in fresh S. longissima) expect dried S. longissima, in which bitterness was not improved.
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  • Yusuke Tanaka, Chia-Hui Chen, Terukuni Kozaki, Yusuke Komiya, Shiro It ...
    2012 Volume 60 Issue 3 Pages 333-340
    Published: September 20, 2012
    Released: March 23, 2015
    JOURNALS FREE ACCESS
    This study was undertaken to investigate the bacterial diversity of intestinal tracts of six coastal fish by using the clone library method. Total counts in intestinal contents of fish ranged from 2.2×109 to 5.8×1010 cells/g. A total of 299 clones constructed from 6 fish specimens were composed of 9 classes, 18 orders, 25 families, 46 genera and 75 species. Major components in clone libraries were different among fish species as follows: Filefish Stephanolepis cirrhifer and black rockfish Sebastes inermis, Actinobacteria, Alphaproteobacteria and Gammaproteobacteria; rudder fish Girella punctata, Actinobacteria, Alphaproteobacteria, Bacilli and Gammaproteobacteria; spotbelly rockfish Sebastes pachycephalus and multicolorfin rainbowfish Halichoeres poecilopterus, Actinobacteria, Alphaproteobacteria and Betaproteobacteria; moon dragonets Callionymus lunatus, Alphaproteobacteria and Betaproteobacteria. This result reveals that the intestinal tracts of coastal fish were composed of many bacterial species belonging to different bacterial classes. Members of family Vibrionaceae were not found in all six fish specimens. This fact strongly suggested that members of the Vibrionaceae are colonized in the intestinal tracts of coastal fish as minor components though the plate count method showed that these bacteria were dominant in marine fish intestiens.
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  • Shigeaki Gorie, Kazuya Nagasawa
    2012 Volume 60 Issue 3 Pages 341-348
    Published: September 20, 2012
    Released: March 23, 2015
    JOURNALS FREE ACCESS
    This paper reports on various biological aspects of whitespotted conger (Conger myriaster) on the basis of a long-term pot survey conducted in the Akashi Strait from 1982 to 2009. The fish caught consisted of one or two major size groups, and large females (>500 mm total length) were predominant. Both the gonadosomatic index and condition factor of large females were higher in winter (January and February) than those in other seasons. Females appear to spend for up to four years in this strait and then begin a spawning migration by age-5 to other waters. While catch per unit effort (CPUE) in the pot survey showed considerably large annual and seasonal fluctuations, it was high from May to August and from November to January when bottom water temperature ranged from 10-25°C but low from September to October (>25°C) and from February to April (<10°C). The Akashi Strait is likely to be an important habitat of large whitespotted conger for their early maturation.
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  • Taiko Miyasaki, Yoshito Kitamura
    2012 Volume 60 Issue 3 Pages 349-357
    Published: September 20, 2012
    Released: March 23, 2015
    JOURNALS FREE ACCESS
    Effect of seaweed supplementation to diet on muscle odor of Nile tilapia Oreochromis niloticus was investigated. Setting 6 test diet groups (without seaweed as a control group, Hizikia fusiforme group, Laminaria japonica group, Porphyra sp. group, Ulva pertusa group, Undaria pinnatifida group), tilapia were fed on the diet supplemented with each freeze-dried seaweed powder (3.6%) for 14 days. Oily muscle odor could not be detected organoleptically in Hizikia and Ulva groups unlike in other groups. This result was confirmed by gas chromatography mass spectrometer with headspace solid-phase micro-extraction analysis. Organoleptic test showed that the Ulva group diet smelled like Ulva and other diets smelled oily. Vaporization of many lipid oxidatives having oily odor from all seaweed diets remarkably decreased compared with the control group diet. These results indicate that supplementation of seaweeds to diets diminished vaporization of oily odor compounds from diets and tilapia muscle, and oily odor could not be felt from the muscle of tilapia fed on the diet supplemented with Hizikia and Ulva.
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  • Takashi Kawano, Tadamitsu Igari, Yuji Imayoshi, Toshihiro Tanaka, Shig ...
    2012 Volume 60 Issue 3 Pages 359-369
    Published: September 20, 2012
    Released: March 23, 2015
    JOURNALS FREE ACCESS
    Distribution of thirteen species of seagrass in Satsunan Islands and adjacent waters (Kagoshima Prefecture) was determined by herbarium specimens at Kagoshima University and Kagoshima Prefectural Fisheries Technology and Development Center. Furthermore, a field survey was carried out at two sites of seagrass meadows in Amami-Oshima Island to reveal the community structure of these meadows and their distributional ecotone of tropical and temperate species. Zostera japonica and Halophila nipponica, collected from Amami-Oshima Is., were the only temperate species occurring in this region. Distributional limits of tropical species differed by the taxa. Six tropical species, Cymodocea rotundata, Cymodocea serrulata, Syringodium isoetifolium, Thalassia hemprichii, Halophila ovalis and Halophila decipiens, were confirmed from Amami-Oshima Is. and is appear to be at their most northern limit in the world. Meanwhile, two species of Halodule were confirmed at all major islands from south of Tanegashima Is., and Halophila major were confirmed from both Satsunan and southern part of Kyushu Islands. In general, T. hemprichii occurs as one of the more dominant species in reef-associated habitats in the Pacific tropical islands including the southern part of Satsunan Is. (i.e., Yoronjima, Okinoerabujima, Tokunoshima Islands). However, in Amami-Oshima Is., Halodule and Zostera were more common rather than the former.
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  • Naohiko Takeshita, Kunimasa Aoki, Kazuhiro Yamabayashi, Akira Araki
    2012 Volume 60 Issue 3 Pages 371-376
    Published: September 20, 2012
    Released: March 23, 2015
    JOURNALS FREE ACCESS
    Age and growth of the bagrid fish Pseudobagrus nudiceps in the Koya River, western Honshu Island, Japan were studied by examining ring marks of the vertebral centrum. A total of 212 males and 155 females were caught in the lower and middle reaches of this river between April 2009 and January 2010. The outer margins of the translucent band in the vertebral centrum formed annual rings in June. The spawning of this population was considered to take place mainly in July. The von Bertalanffy’s curves showed close agreement to age-standard length data of males and females as follows: Male, Lt=595.9 [1-exp {-0.064 (t+0.790)}] (t≦8); female, Lt=186.6 [1-exp {-0.273 (t+0.347)}] (t≦6). Where Lt is standard length in mm and t is age in years. These results indicate that males grow faster and live longer than females.
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  • Lideman, Gregory N. Nishihara, Tadahide Noro, Ryuta Terada
    2012 Volume 60 Issue 3 Pages 377-388
    Published: September 20, 2012
    Released: March 23, 2015
    JOURNALS FREE ACCESS
    The photosynthetic performance of two species of Meristotheca (Solieriaceae, Rhodophyta), M. coacta and M. papulosa, was investigated under a variety of temperature and light conditions to derive basic information regarding their physiology. A pulse amplitude modulated-chlorophyll fluorometer (Imaging-PAM) was used to generate rapid light curves (RLCs) to provide the relative electron transport rates (rETR) over 21 levels of photosynthetic active radiation (PAR), ranging from 0 to 1,078μmol photons m-2 s-1 at 14 temperatures (i.e., from 8 to 34°C). The initial slope (α), photoinhibition (β) and coefficient (γ) was calculated by fitting the RLCs to a nonlinear model of the form rETR=γ(1-exp(-α・PAR/γ)) (exp(-β・PAR/γ)) using a two-level hierarchical Bayesian model. Both species required temperatures ranging from 18 to 28°C to maintain optimal photosynthetic activity, as revealed by the estimated model parameters. The optimal PAR (PARopt) increased with increasing temperature. Meristotheca coacta and M. papulosa can be considered well-adapted to the current natural light and temperature conditions of southern Kyushu, Japan. Finding in this study should be useful to the design and manage mariculture programs to conserve the natural resources.
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  • Ken-ichi Yamamoto, Takeshi Handa, Tatsuya Tsunoji
    2012 Volume 60 Issue 3 Pages 389-392
    Published: September 20, 2012
    Released: March 23, 2015
    JOURNALS FREE ACCESS
    We examined the effects of temperature on ventilation volume (Vg), the oxygen utilization (U) and the amount of oxygen uptake (Vo2) in the abalone Haliotis (Nordotis) discus discus. The experimental water temperature was elevated at a rate of 3°C/hr from the acclimated seasonal temperatures: 13°C (March), 18°C (May) and 22°C (June). Vg, U and Vo2 increased with the elevation in experimental water temperature at the three seasons. However, Vg, U and Vo2 did not change in spite of the elevation of the experimental water temperature at any season. From the results, the type of the temperature compensation of Vg, U and Vo2 in the abalone were classified into Precht type 4 and Prosser type I.
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  • Ken-ichi Yamamoto, Takeshi Handa
    2012 Volume 60 Issue 3 Pages 393-396
    Published: September 20, 2012
    Released: March 23, 2015
    JOURNALS FREE ACCESS
    Flow under the influence of elevated temperatures through three respiratory pores of the abalone Haliotis (Nordotis) discus discus was examined by the direct measurement method of the volume of flowing water. The water temperature was elevated from 18°C at the rate of 3°C every hour. Through the three respiratory pores, the water was only exhaled from the shell cavity. The exhaled water volume of the pore in the forefront (28 ml/min/kgTW: total weight) was smaller than those of other two pores (57-67 ml/min/kgTW) at 18°C. When water temperature rose to 30°C, the water volume of the other two pores increased to 1.5-1.6 times, although the water volume of the pore in the forefront hardly changed. At each temperature, the total water volume of all pores maintained to be constant by the coordinated volume of each pore, even if the volume of each pore changed.
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  • Koji Kawana, Nakahiro Iwata, Takeshi Handa, Yoshihiko Baba, Kazumasa U ...
    2012 Volume 60 Issue 3 Pages 397-403
    Published: September 20, 2012
    Released: March 23, 2015
    JOURNALS FREE ACCESS
    The Japanese flounder Paralichthys olivaceus exposed to environmental hypoxia died at dissolved oxygen levels 1.13±0.25 mgO2/l (20°C) within 12.5~21.5 h. Some blood properties of the flounder suffocated to death remarkably changed: significant rises in levels of lactate, plasma sodium ion, plasma potassium ion, plasma magnesium ion and blood total ammonia; significant falls in levels of plasma glucose and plasma calcium ion. However, the levels of hemoglobin (Hb), plasma total protein (Tpro) and plasma chloride ion did not shift significantly. Thus, the low lethal dissolved oxygen levels and no significant changes in Hb and Tpro suggest that the flounder, a generally inactive benthic teleost, probably has an intrinsic hypoxic tolerance which is attributed to a high blood O2 affinity and a low oxygen demand at rest.
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  • Yoshiaki Imaoka, Atsushi Yamamoto, Kyosuke Araki, Erlinda C. Lacierda
    2012 Volume 60 Issue 3 Pages 405-410
    Published: September 20, 2012
    Released: March 23, 2015
    JOURNALS FREE ACCESS
    Outbreaks of mycobacteriosis have been frequently observed in cultured yellowtail Seriola quinqueradiata in the northern part of Kagoshima prefecture, Japan. On the other hand, those outbreaks have seldom occurred inside of Kagoshima Bay. Antibody titers against the pathogen (Mycobacterium spp.) and frequency of detection of the pathogen from gill and kidney between those fish culturing ground showed no difference. However, water temperature was different in summer; 28°C in the northern part of Kagoshima pref. and 30°C inside of Kagoshima Bay. Then we injected the pathogen cultured at 25°C (optimum) or 30°C onto yellowtail maintained at 27-29°C and 17-23°C to confirm the influence of water temperature on outbreaks of mycobacteriosis. Cumulative mortalities showed 100% on both the 25°C- and 30°C- injected group maintained at 27-29°C, but the average days to death of the former group were significantly shorter than the latter. However, those maintained at 17-23°C were 30% and 0% for the 25°C- and 30°C- injected group respectively. These results show water temperature has an effect on the virulence of the pathogen and the disease resistance of yellowtail.
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Short Papers
Note
  • Katsutoshi Kawabe, Hiroshi Kohno
    2012 Volume 60 Issue 3 Pages 421-425
    Published: September 20, 2012
    Released: March 23, 2015
    JOURNALS FREE ACCESS
    We describe a simple sorting method for separating hatchery-reared blacktip grouper Epinephelus fasciatus juveniles (4.6-6.7 cm in total length) with and without swimbladder inflation based on body density differences. The body density of the juveniles was measured in a series of anaesthetic-hypersaline salt water solutions from 3.5 to 16% with 0.5% steps. The density of a hypersaline salt water floated the juveniles with swimbladder inflation was 1.030-1.098 g/cm3 at 27.8°C and 1.025-1.081 g/cm3 at 19.4°C, and that of nonswimbladder inflation was 1.094-1.116 g/cm3 at 27.8°C and 1.078-1.112 g/cm3 at 19.4°C. As a result, it was impossible to sort completely the juveniles with and without swimbladder inflation by the buoyancy difference because the values overlapped. Therefore, the density of an anaesthetic-hypersaline salt water solution for eliminating juveniles without swimbladder inflation was considered in 1.090 g/cm3 at 27.8°C and 1.075 g/cm3 at 19.4°C. When the efficiency of separation for large population was tested at 1.075 g/cm3 at 19.6°C, 96% of the juveniles with swimbladder inflation floated and without swimbladder inflation all sank.
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