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Volume 63, Issue 1
Displaying 1-14 of 14 articles from this issue
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Original Papers
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Mahiko Abe, Yuji Fujita, Masahiro Kobayashi, Eiji Fujiyoshi, Motoya Ta ...2015 Volume 63 Issue 1 Pages 1-8
Published: March 20, 2015
Released on J-STAGE: June 20, 2015
JOURNAL FREE ACCESSWe investigated a way of isolating axenic protoplast of Pyropia yezoensis and the effect of twelve antibiotics on the survival and growth of the protoplasts. The axenic protoplasts were able to be isolated, by carrying out a series of treatments with 0.5% sodium citrate seawater. The survival of the protoplasts was not almost influenced by neomycin (FRM), ampicillin (ABPC), penicillin G (PCG) and streptomycin (SM) during a culture period of 2 weeks. The growth rates of the protoplasts treated with FRM and ABPC were 1.1-2.7 times higher compared with the control, while PCG and SM suppressed growth. More than 80% of the protoplasts treated with FRM formed rhizoidal cells. Treatment with FRM, ABPC, PCG and SM is thought to be a practical method for culture of axenic protoplasts. Our data would contribute to the clarification of the factors involved in the survival, growth and morphogenesis of the protoplasts of P. yezoensis.View full abstractDownload PDF (481K) -
Natsuki Hasegawa, Junya Higano, Yoshimi Fujioka, Yuka Ishihi, Tomomi M ...2015 Volume 63 Issue 1 Pages 9-16
Published: March 20, 2015
Released on J-STAGE: June 20, 2015
JOURNAL FREE ACCESSManila clam Ruditapes philippinarum were grown in suspended culture using plastic containers and on-bottom culture using mesh bags on a tidal flat in Oonoura Bay, Mie, Japan. The suspended culture methods included containers of two substrate depths (36 and 72 mm) and two types of substrate (gravel and pumice). Clams grew faster and were in better nutritional condition in suspended culture than in on-bottom culture. However, losses of clams in suspended culture were higher than on-bottom culture as some were able to pass through the coarse net covering the container. Clams grew faster in containers with deep substrata (72 mm) than those with shallow substrata (36 mm), but growth of suspended clams was similar between the types of substrate. This study demonstrated the feasibility of suspended culture for yield of clams of commercial size and emphasized the value of enough deep substrata. Pumice can be used instead of gravel to reduce the weight of the container for easier handling without affecting the growth of the clam.View full abstractDownload PDF (913K) -
Kamarudin Ahmad Syazni, Satoshi Tomano, Kanako Ueno, Kenichi Ohara, T ...2015 Volume 63 Issue 1 Pages 17-27
Published: March 20, 2015
Released on J-STAGE: June 20, 2015
JOURNAL FREE ACCESSYellowfin black seabream Acanthopagrus latus is an important fish species found in the coastal waters along the Pacific coast of Japan. The genetic variability of A. latus was estimated by analyzing seven populations in western Japan, using highly variable microsatellite loci (n=312) and the sequence variability in the mitochondrial DNA (mtDNA) (n=42). The microsatellite loci revealed a high level of genetic variability, with the mean number of alleles per locus ranging from 22 to 47 and the mean observed heterozygosity ranging from 0.840 to 0.904 across populations. The sequence variability in the control region (289 bp) of 42 individuals yielded 27 haplotypes. The global fixation index (FST) of -0.00024 (P>0.05) and 0.0160 (P>0.05) for microsatellites and mtDNA, respectively, suggested that there was no significant differentiation among the seven putative populations. High gene flow caused by random dispersal of pelagic eggs and larvae likely explains the occurrence of a single stock of A. latus in western Japan. Information about the genetic population structure of A. latus can aid in designing proper management strategies for this species in the near future.View full abstractDownload PDF (251K) -
Tatsuo Tsuzaki, Kazunori Yoshida, Takuro Hotta, Masahiro Nakagawa, Mas ...2015 Volume 63 Issue 1 Pages 29-38
Published: March 20, 2015
Released on J-STAGE: June 20, 2015
JOURNAL FREE ACCESSA six month feeding experiment was conducted to evaluate the nutritional value of plant and animal proteins as alternative protein sources for fish meal to one year old yellowtail. An anchovy meal based diet was formulated as a control, and three types of non-fish meal diets were prepared by replacing the fish meal completely with plant proteins such as soy protein concentrate, defatted soybean meal and corn gluten meal, and pork meal together with supplementation of taurine, digestive enzyme mixture and feeding stimulants. The test diets were fed to 750 g one year old yellowtails to satiety three times a week for six months. There were no differences in total feed intake, weight gain, and mortality amongst the dietary treatments. Moreover, physiological and pathological abnormalities were not observed in the fish fed non-fish meal diets during the rearing period. These findings suggest that non-fish meal diets for yellowtail can be developed by formulating pork meal, soy protein concentrate, defatted soybean meal and corn gluten meal together with supplements of taurine, digestive enzyme mixture and feed stimulants.View full abstractDownload PDF (736K) -
Satoshi Tomano, Yukio Ueta, Noriyasu Kasaoka, Tetsuya Umino2015 Volume 63 Issue 1 Pages 39-47
Published: March 20, 2015
Released on J-STAGE: June 20, 2015
JOURNAL FREE ACCESSStock identification of oval squid Sepioteuthis spp. in the coastal waters of Tanega-shima Island were examined using ten polymorphic microsatellite loci and partial nucleotide sequences of cytochrome oxidase subunit I (COI) in the mtDNA. Also, we suggested spawning depth through eggs identification collected from artificial reefs from 20-50 m in depth. Adult specimens collected from Tanega-shima Island, identified as Akaika Sepioteuthis sp. 1 based on phenotypic characters and Tokushima waters (referred as Shiroika Sepioteuthis sp. 2) were genetically differentiated in both microsatellite allele frequencies and mtDNA sequences, which supported presence of reproductive isolation inferred by isozyme analysis. Eggs and embryos at three artificial reefs from 40-50 m in depth were identified as Sepioteuthis sp. 1, except for 20 m. Preset results indicate that Sepioteuthis sp. 1 living in Tanega-shima Island utilize 40-50 m in depth as a spawning zone. The partial COI sequences used in the present study allowed inferring phylogenetic relationship among Sepioteuthis spp. generated from Indo-Pacific region and detecting co-existence of Sepioteuthis sp. 1 and sp. 2 in Vietnam and Indonesia.View full abstractDownload PDF (483K) -
Tomoki Endo, Seiya Kaneko, Kenta Igari, Kouki Kanou, Ryoji Nakazato, R ...2015 Volume 63 Issue 1 Pages 49-58
Published: March 20, 2015
Released on J-STAGE: June 20, 2015
JOURNAL FREE ACCESSTo ascertain the feeding characteristics of the introduced catfish Ictalurus punctatus, the stomach contents of 268 specimens (14.7-59.1 cm in standard length, SL), collected at night time (19:30-21:00) by bait fishing and casting net in the littoral zone (< 1.2 m in water depth) at Tsumagi and Ofunatsu, Lake Kitaura, Ibaraki Prefecture, Japan, from April to October 2013, were examined. Mean numbers of catfish individuals collected per 30 minutes by fishing were significantly greater in reed areas than in bulkhead areas. Overall food items included small fishes, benthic and epibenthic crustaceans, fragments (flesh, scales, ovary and bones) of large fish, terrestrial plants, aquatic and terrestrial insects, and filamentaous algae. In particular, native species, such as the gobiid Tridentiger brevispinis, cyprinid Pseudorasbora parva, oriental river prawn Macrobrachium nipponense and several sessile chironomids (e.g., Glyptotendipes tokunagai, Dicrotendipes pelochloris and Cricotopus sp.), were frequently observed, such mainly inhabiting the reed areas. The results indicated that I. punctatus mainly utilized food items available in the reed areas at night time, such possibly impacting upon co-occurring native fishes by predation and competition for food resource.View full abstractDownload PDF (856K) -
Manabu Furushita, Tsubasa Fukuda, Yutaka Fukuda, Azumi Yamashita, Soet ...2015 Volume 63 Issue 1 Pages 59-64
Published: March 20, 2015
Released on J-STAGE: June 20, 2015
JOURNAL FREE ACCESSSusceptibility to 14 antimicrobials was examined for 221 strains of Lactococcus garvieae isolated from the several species of genus Seriola cultured in Japan from 2004 to 2009. Of the 221 isolates, 182 strains showed at least one resistance to oxytetracycline (OTC), erythromycin (EM) and Lincomycin (LCM). Multiple resistance to OTC, EM and LCM was observed in 11.3% of the isolates. Resistant to LCM was observed in 64.7% of the isolates. Ratio of sensitive isolates increased from 4.0% in 2003 to 23.1% in 2009. The strains resistant to OTC or EM decreased to 0% in 2009, whereas isolates resistant to LCM were found every year.View full abstractDownload PDF (251K) -
Jun Nakajima2015 Volume 63 Issue 1 Pages 65-70
Published: March 20, 2015
Released on J-STAGE: June 20, 2015
JOURNAL FREE ACCESSI surveyed the temporal appearance of adult individuals and the number of flowing eggs and larvae of the pike gudgeon Pseudogobio esocinus three times for 24 h in a spawning site in Nakagawa River, northern Kyushu Island, Japan. Sixty-four adult individuals were observed, but only at night-time; females appeared between 8:00 PM and 1:00 AM, and males appeared between 8:00 PM and 5:00 AM. A total of 11,293 flowing eggs were captured, and most of the eggs were found between 9:00 PM and 2:00 AM. Compared with the number of flowing eggs, the number of pelagic larvae was very small. Therefore, it was assumed that the spawning of P. esocinus occurs at night between approximately 8:00 PM and 1:00 AM, and that the spawned eggs floating downstream but the larvae do not.View full abstractDownload PDF (466K) -
Hiroyuki Matsunari, Yasuro Iwashita, Shunji Amano, Nobuhiro Suzuki, Hi ...2015 Volume 63 Issue 1 Pages 71-78
Published: March 20, 2015
Released on J-STAGE: June 20, 2015
JOURNAL FREE ACCESSThe effects of alcohol treatment of dietary soybean meal on growth performance, biliary bile status and liver morphology of red sea bream Pagrus major were investigated. A fish meal-based diet (FM) and four low-fish meal diets, each composed mainly of defatted soybean meal (SBM), soy protein concentrate (SPC), soy protein isolate (SPI), or ethanol-treated soy protein isolate (EtSPI), were prepared. Each of the diets was fed to duplicate groups of red sea bream (average body weight: 9 g) for 6 weeks. Weight gain and feed efficiency of fish fed the SPC and EtSPI diets tended to be improved among the soybean meal fed groups. The hepatosomatic indices of fish fed the FM, SPC, and EtSPI diets were significantly higher than the index of fish fed the SBM diet. Although morphological changes occurred in the hepatopancreas of fish fed the SBM and SPI diets, the morphological features of fish fed the SPC and EtSPI diets were similar to those of fish fed the FM diet. These results indicate that ethanol-treated soybean meal and soy protein isolate has certain effects on normalizing growth performance and hepatopancreatic histology of red sea bream.View full abstractDownload PDF (558K) -
Kentaro Hashiguchi, Kenji Kawai, Masayuki Imajoh, Syun-ichirou Oshima2015 Volume 63 Issue 1 Pages 79-87
Published: March 20, 2015
Released on J-STAGE: June 20, 2015
JOURNAL FREE ACCESSBathing in fresh water is performed at aquaculture sites to exterminate parasites of yellowtail. However, fresh water bathing is likely to be associated with stress in fish due to the change in osmotic pressure. Here, the stress reaction after fresh water bathing was examined in yellowtail Seriola quinqueradiata followed by examination of the changes in sensitivity to infection using experimental infection. The blood cortisol concentration, which is used as a stress indicator, tended to increase at 0.5 and 1 h and then again 24h after fresh water bathing. In addition, an impact on host defense, such as reduction in phagocytic activity of leukocytes of the head kidney, was observed in five fish after 1 and 6h. When experimental infection using a nodular disease-causing bacterium, Photobacterium damselae subsp. piscicida, was carried out 1 h after fresh water bathing, the cumulative mortality rate was 90%, which was significantly higher than that in the control group. The viable bacteria count adhering to the gills was examined during the experimental infection, and adherence in the fresh water bathing group was significantly higher than that in the control group. In conclusion, fresh water bathing increases susceptibility of yellowtail to infection in addition to causing stress.View full abstractDownload PDF (1449K) -
Daisei Ando, Yoshitaka Sasaki, Yasuyuki Miyakoshi, Ryohei Yasutomi, An ...2015 Volume 63 Issue 1 Pages 89-98
Published: March 20, 2015
Released on J-STAGE: June 20, 2015
JOURNAL FREE ACCESSTwenty-five chum salmon Oncorhynchus keta families were produced using a 5×5 diallel mating design, and the body weights and specific growth rates (SGRs) were measured from 0 to 99 days after emergence. The body weights of the fry differed in the same developmental stages among the families. In addition, the mean body weights of fry that originated from small eggs were low, but their SGRs were high. These results suggest that the body sizes of chum salmon fry are strongly governed by the initial egg size, but that their body size and growth rate at each developmental stage vary depending on the combination of sire and dam.View full abstractDownload PDF (1001K) -
Riho Miyazaki, Hasumi Yamaguchi, Ken-Lin Huang, Katsuya Hirasaka, Sato ...2015 Volume 63 Issue 1 Pages 99-104
Published: March 20, 2015
Released on J-STAGE: June 20, 2015
JOURNAL FREE ACCESSThis study examines the effects of forced exercise and recovery on burnt meat of horse mackerel Trachurus japonicus. The endogenous glycogen content in dorsal ordinary muscle decreased after forced exercise. The lactic acid content in recovered specimens was slightly lower than that in control specimens (without exercise) after 2 h storage. A slight decrease of muscle pH and slight increase of color L∗ during storage at 30°C were observed when fish were killed using both spinal cord destruction and suffocation in air of recovered specimens after forced exercise. Although burnt meat phenomenon occurred during storage in the control specimens, there was not observed in the recovered specimens. These results suggest that forced exercise and recovery suppressed burnt meat in ordinary muscle of horse mackerel.View full abstractDownload PDF (479K) -
Tsuneo Maeda2015 Volume 63 Issue 1 Pages 105-112
Published: March 20, 2015
Released on J-STAGE: June 20, 2015
JOURNAL FREE ACCESSIn order to elucidate the molting activity of juvenile beni-zuwai crab Chionoecetes japonicus, a rearing experiment was conducted using running deep-sea water from Toyama Bay, which was maintained at a temperature of 0.7±0.1°C (median±interquartile range). The molting date for individuals was examined until January 2005 for 167 crabs at 3rd-8th instars (carapace width: 5-39 mm), which were collected from Toyama Bay in January and February 2003 and January 2004. Although each molting activity for the 4th-7th instars lasted for 7-11 months, the peak of molting was limited seasonally and was different between instars (4th instar, August-September; 5th instar, March-April; 6th instar, October-January; 7th instar, August-September). The midpoint date of the molting season was defined as total of the base point date and the median of the days from the base point date to each molting date, and these were calculated as August 26th, April 2nd, November 23rd, September 9th from 4th to 7th instar, respectively. These findings suggest that the duration (intermolt period) at each instar from 5th to 7th instar is about 7.3, 8.0, and 9.7 months long, respectively.View full abstractDownload PDF (835K)
Short Paper
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Hideyuki Imai, Shuta Kumamoto2015 Volume 63 Issue 1 Pages 113-115
Published: March 20, 2015
Released on J-STAGE: June 20, 2015
JOURNAL FREE ACCESSSpecies identification was conducted on egg masses collected from artificial spawning beds of bigfin reef squid, which were installed at 40 m depth off the coast of Tanegashima Island, Japan. Three egg masses were collected from the spawning beds. The mean number of ova of the three egg masses were 6.2 from 14 egg cases, 6.6 from 24 egg cases, and 6.0 from 30 egg cases, respectively. Phenotypic characters were identical to "shiro-ika type" Sepioteuthis sp. 2. egg cases. Interestingly, allozyme analysis indicated that the egg cases were from "aka-ika type" Sepioteuthis sp. 1, and not "shiro-ika type" Sepioteuthis sp. 2. Genetic analyses are essential to properly identify egg cases of Sepioteuthis to species level.View full abstractDownload PDF (551K)
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