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Volume 54, Issue 2
Displaying 1-17 of 17 articles from this issue
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Ryo ISHIBASHI, Atsuko KUMAMOTO, Takeshi KATO, Takao NEMOTO, Akira KOMA ...2006 Volume 54 Issue 2 Pages 125-134
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe processes of meiosis and fertilization in exotic species Corbicula fluminea and C. papyracea collected at Tone River were compared with that of domestic C. japonica. Microfluorometric analyses revealed that C. fluminea included diploids and triploids and both produced non-reductional sperm. The eggs from C. fluminea showed androgenetic process. They extruded all maternal chromosomes at first meiosis as two first polar bodies. On the contrary, C. papyracea and C. japonica were diploids and produced haploid sperm. In both species the eggs showed normal process of meiosis and fertilization (i.e. formation of first and second polar bodies and female pronucleus) . The eggs from C. japonica inseminated by sperms from C. papyracea showed normal development up to D-shaped veliger larvae. This result suggests that hybridization of both species may occur at Tone River.View full abstractDownload PDF (7596K) -
Shigeru AOYAMA, Toshio DOI, Takeshi YANAGIUCHI2006 Volume 54 Issue 2 Pages 135-138
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSUnder laboratory conditions we investigated the use of spawning substratum and rearing of young in the fluvial eight-barbel Loach Lefua sp. (sensu Hosoya 1993), an endangered species in Japan. A net-covered plastic box on top of which spawning substratum was placed was used for collecting eggs, as the eggs fell through the net into the box. The Loach best selected the tuft of moss as a spawning substratum, and then dead leaves second. Further, they spawned under a stone or in sand-sized grains of active carbon. They were considered to spawn in narrow spaces where there was physical contact with their body. After the eggs hatched, we successfully reared the Loach for 10 months by feeding with Artemia nauplii first and then frozen chironomid larvae. Therefore, we have developed a method for artificially breeding of them.View full abstractDownload PDF (3140K) -
Koji YOKOGAWA, Yasuo KONDO2006 Volume 54 Issue 2 Pages 139-146
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSIsozyme polymorphim of four species of Japanese Donacidae (Bivalvia) (Chion semigranosus, Tentidonax kiusiuensis, Latona cuneata, and Latona faba) were examined by using starch and polyacrylamide gel electrophoresis, and the results of the molecular phylogenetic analysis were compared with the current taxonomic status obtained by morphological analysis of these taxa. Much higher genetic variability than that of the other mollusks was recognized in L. faba and T. kiusiuensis, while that of C. semigranosus and L. cuneata was regarded to be the standard level of the mollusks. The genetic data placed the four species in two clusters, one comprising the two Latona species, and the other consisting of C. semigranosus and T. kiusiuensis. The former is characterized by a roughly triangular shell without a crenelated shell margin, and the latter by a triangular shell with a crenulated shell margin. The molecular phylogenetic analysis corresponds well with the morphological classification.View full abstractDownload PDF (5587K) -
Takayuki TAKAHASHI, Takayuki AMANO, Kiyoshi FURUKAWA, Shuichi SATOH2006 Volume 54 Issue 2 Pages 147-152
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSIn order to investigate the optimum level of dietary equiponderance compound of monopotassium phosphate and monosodium phosphate (MPP+MSP) levels on the growth, feed conversion, vertebral deformity and body composition of juvenile tiger puffer, Takifugu rubripes, the fish were fed for 41 days with practial diets supplemented with 0-2% MPP+MSP. Dietary supplementation of 1.0% or more MPP+MSP improved considerably the growth, feed efficiency and vertebral deformity. In addition, the content of phosphorus and calcium in the whole body of fish almost became constant by adding MPP+MSP of 1.5% or more. These results indicate that the dietary supplementation of MPP+MSP can improve the growth and feed performance of the fish, and that its optimum level is likely to be 1.5%. Moreover, the amount of phosphorus fractionated with deionized water is 0.64%, it was similar to 0.6-0.7% that the amount of the requirement of carp.View full abstractDownload PDF (3157K) -
Jorge GALINDO-VILLEGAS, Haruhisa FUKADA, Toshiro MASUMOTO, Hidetsuyo H ...2006 Volume 54 Issue 2 Pages 153-162
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSSix commercial substances, known for its immunostimulatory effects in several fish species, were evaluated for their ability to enhance innate immune response and disease resistance against Edwardsiella tarda in Japanese flounder. Each substance (α-tocopherol, astaxanthin, β-glucan, DL-arginine, L-ascorbic acid or peptidoglycan) was mixed with a practical diet and fed daily for three weeks to duplicate fish groups. Growth, hematology, humoral (lysozyme) and cellular (chemotaxis, phagocytic and respiratory burst) activities were examined after one, two and three weeks. Oral administration of these substances did not affect growth or fish health status but caused enhancement in bacterial lytic and phagocytic responses. After one and two weeks, arginine and astaxanthin groups, respectively, showed some significant enhanced immune responses. However, by the end of the third week, only peptidoglycan-treated fish showed significantly higher level of lysozyme and leucocytes activities. After three weeks of dietary treatment with immunostimulants, the fish were challenged by intraperitoneal injection with E. tarda, where peptidoglycan and α-tocopherol-treated fish demonstrated significantly increased survival rate. Peptidoglycan appears to enhance resistance against infection in Japanese flounder with increased lysozyme and phagocytic activities. Alfa-tocopherol seems to have induced protection by enhancing some other resistant mechanisms than those measured in this study.View full abstractDownload PDF (1756K) -
Jorge GALINDO-VILLEGAS, Toshiro MASUMOTO, Hidetsuyo HOSOKAWA2006 Volume 54 Issue 2 Pages 163-170
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSPeptidoglycan (PG), derived from Brevibacterium lactofermentum, is known to enhance innate immune response and disease resistance. The present study investigated the effect of the interval dietary administration of PG on the innate immune response and the disease resistance against Edwardsiella tarda in Japanese flounder. Continuous and interval dietary administration at 2.5% body weight per day of supplemental 0.3% PG in dry diet were tested following one of four patterns for 40 days: control group (only control diet), 10/10 group (PG diet/control diet, every 10 days), 15/15 group (PG diet/control diet, every 15 days) or daily group (only PG diet) . Innate immune response (serum lysozyme activity, chemotaxis and intracellular respiratory burst) were evaluated after 7, 10, 15, 20, 25, 30 and 40 days. Furthermore, three bacteria challenges were conducted on days 10, 25 and 40. Significant enhancements in serum and leucocytes activities were observed along the trial. Chemotaxis was enhanced in all sampling day in most PG-administrated groups. The enhanced disease resistance was positively correlated with the enhancement of innate immune response in all PG-treated groups after 10 days and only in both 10/10 and 15/15 groups on days 25 and 40. These findings suggest that interval administration of PG persist the enhanced disease resistance of Japanese flounder against E. tarda infection through cyclical activation of the immune system, while daily administration for more than 15 days has inert effect in disease resistance.View full abstractDownload PDF (1280K) -
Tadashi IMAI2006 Volume 54 Issue 2 Pages 171-178
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe present study deals with reproduction and growth of the shrimp, Paratya compressa improvisa, a land-locked subspecies, in the Tsurugata Marsh, Akita Prefecture. This study was based on specimens at all the developmental stages from larvae through mature adults collected semimonthly during the period of two years between May, 2001 and June, 2003. Ovigerous females appeared from April or May to September. Among them, those taken during April through July were large-sized individuals which were born in the preceding year, while those taken in August and September comprised of small-sized individuals (0-age) spawned in June. Juveniles, about 5 mm in body length, were found during June through early September, the peak being in June and July. They were derived from adults that were born in the previous year. Even though young females started reproduction in the summer, only a few of the juveniles from them were collected in and after late September. The juveniles settled in June grew fast in summer and early autumn, and males and females reached 14.5 mm and 15.9 mm in body length, respectively in October. After retardation of growth in winter months and even apparent reduction of mean body length in March and April, the shrimps started to grow with the rise of the temperature, reached up to 16.4 mm for males and 20.0 mm for females by June, the major reproduction season. The growth curve after settlement defining June 9 as the starting point was expressed as Lt=20.351 {1-exp [-1.466 (t/365+0.372) + (0.222/2π) sin (2π (t/365-1.694) ) ] } for males and Lt=29.683 {1-exp [-1.030 (t/365+0.275) + (0.123/2π) sin (2π (t/365-1.652) ) ] } for females, where Lt is the body length in mm at age t in days after settlement. The shrimps finished their life span after reproduction.View full abstractDownload PDF (1174K) -
Katsuaki FUJINAGA, Anthony S. ILANO, Chiaki HAYAKARI, Yasutaka OYAMA, ...2006 Volume 54 Issue 2 Pages 179-185
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe present state of imposex in several whelks used for consumption from three localities along the coast of Hokkaido, Japan was examined based on RPSI, imposex frequency, and sex ratio. The extent of imposex was compared between species in shallow waters and deep waters. In whelks in shallow waters, imposex was observed, with low RPSI values. However, for whelks in deep waters, there is no need to put imposex in question in all localities. Imposex was not found at all among whelks, or if any, only very few whelks with very slight imposex were observed. From this fact, it is considered that whelks in deep waters are less subjected to the influence of TBT, or that at present, the whelk populations have recovered from imposex, even though they had been affected by the use of TBT compounds.View full abstractDownload PDF (1099K) -
Kazuhisa TERUYA, Kenzo YOSEDA2006 Volume 54 Issue 2 Pages 187-194
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThis study was conducted to find an optimum temperature, a rotifer density and a light intensity for feeding for rearing early-stage larvae of kelp grouper Epinephelus bruneus. In addition, three trials of mass seed production of the kelp grouper were conducted in 100 and 150 kl tanks. Newly hatched larvae were reared at different temperatures (24, 26, and 28°C), rotifer densities (1, 10, and 30 ind./ml), and light intensities (<0.01, 100, 250, 500, 750, and 1, 000 lx) in 100 and 500l tanks. Survival and growth were better at 26°C. The number of rotifers in larval digestive organs increased with the feeding amount and rotifer density in the larval rearing water. The feeding amount of larvae increased significantly in the tanks with light intensity 500 lx or greater. In mass seed production trials, tank water was stirred by aeration, which to prevented larvae from sinking to the tank bottom and resulted in a better survival rate of early larvae. Furthermore, temperature, rotifer density and light intensity were regulated at 26°C, 20-30 ind./ml, and 1, 100-2, 500 lx, which were determined as the optimal rearing conditions for early-stage larvae in the rearing experiments mentioned above. Early survival rates were improved to 50-100%. Final survival rates in the three tanks ranged between 20.9 and 29.6%; 359, 000 juveniles of mean total length 23.9-27.2 mm were harvested at 50-54 days post hatching.View full abstractDownload PDF (1367K) -
Ryo ISHIBASHI, Osamu MURATA, Shinji YAMAMOTO, Yusuke OKA, Hisashi YONE ...2006 Volume 54 Issue 2 Pages 195-200
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSGrowth, and seasonal changes in the gonadosomatic index (GSI) and KG values were investigated in captive chub mackerel, Scomber japonicus, kept at the Fisheries Laboratory, Shirahama Experimental Station, Kinki University. Mean monthly water temperatures ranged between 12.6 and 29.3°C. At the start of the experiment, the mean fork length and body weight of 30-days-old hatchings were 10.5±0.8 cm and 11.0±2.9g, respectively; while at the end of the two year experiment, these fish measured 33.0±0.8 cm and 353.0±50.0g, respectively. In one-year old fish, GSI and female KG values increased during February and June. In two-year old fish, GSI and female KG values increased in January. The GSI and KG values were high on average between March and July, with the highest GSI and KG values being 14.9, and 10.3, respectively. In April all males had mature spermatozoa and some females had mature eggs. The results suggested that males and females matured at one and two years, respectively, after hatching.View full abstractDownload PDF (882K) -
Teruyoshi NARITA, Takashi HOSOI, Masayasu NAGASAKI, Akira KOMARU2006 Volume 54 Issue 2 Pages 201-208
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe spawning possibility of Corbicula japonica in southwest part (lower salinity) of Lake Ogawara was examined by comparing the seasonal changes in maturity, condition index and oocyte diameter between northeast (higher salinity) and southwest part based on specimens monthly collected from August 2004 to September 2005. Judging from histological section on the gonads in northeast and southwest part, the spawning occurred in early July to early September. Furthermore, condition index and oocyte diameter both in northeast and southwest part were maximal value in those months and then, decreased in late September. The artificial spawning induction experiments were performed to know the minimum level of salinity and range of the temperature for spawning and survival of the larvae. Samples were exposed to water temperatures 29.0, 27.0, 25.0, 23.0, 21.0°C and salinities 4.0, 2.0, 1.5, 1.2, 1.0, 0.5, 0.0 psu. Spawning and normal development of larvae were observed at 1.0 psu and 29.°C. These results suggested that C. japonica in southwest part of the lake with low salinity may spawn the eggs, and the development normally occurred when salinity and water temperature could maintain more than 1.0 psu and 29.0°C.View full abstractDownload PDF (4206K) -
Toshimasa KOBAYASHI, Motoyuki HARA, Masahiro KOBAYASHI, Masashi SEKINO2006 Volume 54 Issue 2 Pages 209-215
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSWe addressed the growth performance of hatchery-produced Pacific abalone (Haliotis discus hannai) based on the comparisons of growth rate in shell-length between selected group, which had been subjected to selective breeding four generations, and non-selected group (first generation of wild captives) . With regard to the selected group, selection of young abalone was made at 14 months of the age for each generation. The growth rate of the selected group at hatchery-reared stage (up to 228 days after hatching) was approximately 30-40% higher than that of the non-selected group; however, the better growth performance uncovered in the selected group did not appear at aquaculture stage (from 14-months-old to 38-months-old) . The results presented here suggest that the growth performance of abalone at hatchery-reared stage could be encouraged through selective breeding operations but not at aquaculture stage. Future selective breeding programs should therefore be improved taking into account the possibility that a higher growth performance at initial stage would not necessarily be held up for ensuing stages.View full abstractDownload PDF (1075K) -
Kazuyoshi NAKATA, Tomoyasu YAMAZAKI, Hiroyuki MIZUTA, Tadashi KAWAI, H ...2006 Volume 54 Issue 2 Pages 217-224
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSTo clarify the effects of small herbivorous gastropods on the kelp Laminaria religiosa, we examined feeding traces left on the kelp by gastropods, and the morphology of gastropod radula. We conducted laboratory experiments with four species of the small herbivorous gastropods, Chlorostoma lischkei, Omphalius rusticus rusticus, Homalopoma amussitatum and Littorina sitkana, which frequently occur in habitats of L. religiosa in Hokkaido, Japan, to examine feeding traces left on a sheet of kelp gametophytes settled on styrene chambers or glass slides. In the experiments, all gastropod species fed on the kelp gametophytes both on the styrene chamber and the glass slide. We observed species-specific differences in feeding traces among gastropod species that were considered to be because of differences in the species-specific morphology and size of their radula and differences in feeding patterns. We observed similar traces in adult L. religiosa collected from its natural habitat in Esashi, Hokkaido, to those in our laboratory experiments, suggesting that the four gastropod species used in this study feed on the surface of the adult kelp.View full abstractDownload PDF (9543K) -
Osamu KATANO, Tomoyuki NAKAMURA, Shinichiro ABE2006 Volume 54 Issue 2 Pages 225-226
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSStomach contents of the torrent catfish Liobagrus reini captured in the Urano River, Nagano Prefecture, were investigated by a stomach pump method. Food contents ranging 12-787 mg were collected from 10 individuals of L. reini (SL 6.1-9.9 cm) . The fish mainly predated on aquatic insects such as ephemeropteran nymphs, trichopteran larvae, and chironomid larvae. Terrestrial insects, fish scales, and detritus (plant debris) were also observed in the stomach contents. Although the food habit of L. reini was similar to some other fishes in the Urano River, a more detailed investigation of the foraging time and behavior, and prey preference is necessary in future studies.View full abstractDownload PDF (337K) -
Kazuhiro HARADA, Tsuyoshi YAMAMOTO2006 Volume 54 Issue 2 Pages 227-228
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe rearing feed for the second zoeal stage of snow crab Chionoecetes opilio was investigated using 30 l tanks, by feeding with rotifers Brachionus plicatilis, Artemia nauplii (immediately after hatching) and grown Aytemia (enriched with compound feed for Artemia) . By feeding grown Aytemia only to the second zoeal stage produced high survival rates. Also feeding a combination of rotifers, Aytemia and grown Aytemia together to the second zoeal stage, the survival rate was high. If only unenriched Aytemia are fed to the second zoeal stage, the survival rate was lower. These results show that feeding grown Artemia that have enriched to the second zoeal stage is effective for their survival. Unenriched Artemia potentially are nutritionally deficient to support larval survival and molting. Based on results of these studies, the feeding regime for successful rearing to the megalopal stage of snow crab has been clarified.View full abstractDownload PDF (400K) -
Isao MARUYAMA, Shinji YAMAMOTO, Masahiro HAYASHI, Osamu MURATA2006 Volume 54 Issue 2 Pages 229-230
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSRearing of larval red sea bream Pagrus major was performed by feeding with rotifers cultured in Chlorella vulgaris K-22 enriched with n-3HUFAs (mainly DHA) . Results for larval growth, survival rate, activity, and air-bladder opening rate suggested the successful rearing of the red sea bream. The total content of n-3HUFAs in the larvae at the end of the rearing was even higher than the level immediately after hatching. It can therefore be concluded that the enhanced n-3HUFAs in C. vulgaris were effective via rotifer for the rearing of red sea bream larvae. The n-3HUFA-enriched C. vulgaris makes it possible to realize the rearing of red sea bream without a secondary rotiferculture process for enhancement of n-3HUFAs.View full abstractDownload PDF (377K) -
Munehiko KITSUKAWA, Motoo OHBA, Seitoku KUDOH2006 Volume 54 Issue 2 Pages 231-236
Published: June 20, 2006
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSAdhesion of Japanese smelt eggs was eliminated by using potter's clay, and the treated eggs were kept in a newly developed efficient jar hatchery to prevent infection by aquatic fungi. We compared the method of hatching using this jar hatchery with the conventional method of using spawning substrate in a breeding pond. When 2 × 108 eggs were incubated and hatched in the jar hatchery, the hatchery space was reduced to 1/5 that required with the conventional method and the volume of water to 1/3. The rate of occurrence of eyed eggs did not differ significantly between the two methods. However, disinfection against aquatic fungi and removal of dead eggs for incubation were possible with the jar hatchery method. Although the jar hatchery method took more time because of the need to eliminate egg adhesion, with this method it was possible to more efficiently control the hatching of Japanese smelt eggs.View full abstractDownload PDF (3546K)
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