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Volume 44, Issue 2
Displaying 1-17 of 17 articles from this issue
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Stefanos PALATZIDIS, Shigehisa YAMASAKI, Hachiro HIRATA, Takehiko IMAI1996 Volume 44 Issue 2 Pages 125-131
Published: June 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe consumption of two macrophytic algae, namely Ulva pertusa and Enteromorpha linza, by the adult gastropoda Aplysia dactylomela was studied for a period of 36 days under laboratory conditions. Animals were fed three times a day to satiation. Both algae species were well consumed and promoted increase in the body weight, body length as well as the egg production of the gastropoda. The consumption of Ulva by Aplysia was 22.5% of mean body weight eaten per day, and was independent of temperature, but Enteromorpha consumption was 15.0% and increased with increasing temperatures. Nevertheless, animals fed on Enteromorpha had a better growth rate and egg production than those fed on Ulva. The gross assimilation efficiency was highest on the algae giving the better growth (29% for Enteromorpha and 14% for Ulva) . The study found that the detrimental thalli of Ulva pertusa and also that of Enteromorpha may eventually be controlled by the introduction of gastropods in fish or shrimp ponds.View full abstractDownload PDF (784K) -
Shuuji TSUJI, Masahiro MUNEKIYO1996 Volume 44 Issue 2 Pages 133-139
Published: June 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSEarly young (less than 2mm in shell length), late young (2mm or more and less than 25mm in shell length) and adult (25mm or more in shell length) of Manila clam, Ruditapes philippinarum, were collected from depths of 0 to 5m Maizuru Bay (the western part of Wakasa Bay), Japan Sea, in November 1992, September and November 1993.
The distribution of early young clams ranges from depths of 0 to 5m, and of late young clams from depths of 0 to 3m. Adult clams distribute around the depth of 1m. Thus, the distribution pattern of Manila clam in Maizuru Bay shifts to the shallower depths in order of developmental stage.
Manila clams show high densities at depths of 1 and 2m in September 1993. In November 1993, the density of the clams at depth of 2m decreases, though it remaines high value at depth of 1m. These facts imply that movements and/or biolysis of the clams occurre at depth of 2m in the period from September to November 1993.
Early young clams mainly distribute from depths of 0.5 to 1.0m. The main distribution of early young clams matches with that of adult clams. On the other hand, there is a differrence in main distribution between the early young and late young clams (depths of 1.0 to 1.5m) .View full abstractDownload PDF (862K) -
Hiroyuki HATANAKA1996 Volume 44 Issue 2 Pages 141-146
Published: June 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSNaturally occurring differences in the number of sea cucumber, Stihopus japonicas juveniles attaching to polycarbonate collectors were used to examine the effects of rearing density on growth during artificial seed production.
A negative correlation was observed between growth rate and density. The coefficient of variation and the skewness of distribution of body length were larger under high density conditions. In contrast, the distribution of body length of the animals was closer to normal under low density. It is suggested that control of density in the collectors is effective to improve the performance in seed production of juvenile sea cucumber.View full abstractDownload PDF (649K) -
Katsumi HIRANO, Yukio IWATSUKI, Jyunichi YASUMOTO, Shigeyuki ODA, Fumi ...1996 Volume 44 Issue 2 Pages 147-150
Published: June 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSA comparsion of the numbers of three kinds of Ayu, Plecoglossus altivelis going upstream through the central fishway of Iwakuma weir in the Gokase River was made during 3 years. Fry bred in the Lake Biwa (A), sea-captured ones (B) and artificially hatched ones (C) were marked with ribbon tags of different colors and released into the downstream of the fishway. The upstreaming rates on the fishway were 1.44% for group C, 2.39-6.29 for group A and 3.96-9.65% for group B. The fry of group A and B mostly went upstream within 10 days after release, whereas many fry in group C swam up even after 20 days post release. The day on which most tagged fry swam up was consistent with the best upstreaming season for ayu.View full abstractDownload PDF (435K) -
Katsutoshi KAWABE, Kenji KATO, Johnson KIMURA, Yoichi OKAMURA, Kazuto ...1996 Volume 44 Issue 2 Pages 151-157
Published: June 20, 1996
Released on J-STAGE: December 10, 2010
JOURNAL FREE ACCESSSpawning of amberjack Seriola dumerili was observed using wild and hatchery broodstock fish reared at Tokyo Metropolitan Ogasawara Fisheries Center in 1990, 1991, and 1993. No artificial treatments such as hormonal injection or water temperature shock were required for induction of maturation and spawning. The number of broodstock fish was different every year, and varied from 11 to 46. The size of the fish ranged 63.7-97.6cm in fork length, and 4.7-16.5kg in body weight. Most spawnings occurred in May and June, and the total amount of eggs taken in 1990, 1991, and 1993 were approximately 54 millions. Throughout the spawning season, the water temperature varied between 21.2°C and 25.9°C. Optimum water temperature for spawning was estimated to be between 21.5°C and 23.5°C. The average rate of floating eggs and hatching rate were 78.4±24.44% and 84.0±21.90%, respectively. The average diameter of the egg was 1.10mm, and it ranged from 0.998 to 1.199mm. The average diameter of the oil globule was 0.27mm.View full abstractDownload PDF (697K) -
Nobuhiro SUZUKI, Yasuhisa KAYANO, Tuzumi MITO1996 Volume 44 Issue 2 Pages 159-168
Published: June 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSMorphological changes of free neuromasts in larvae of the red spotted grouper, Epinephelus akaara were described. A free neuromast was found on the epidermal free surface of the head region in newly hatched larvae (1.25-2.01 mm TL) and their number increased on both the head and trunk with larval growth. All free neuromasts contained sensory cells of opposing polarity. The orientation of maximum sensitivity of free neuromasts, judged from the polarity of the sensory cells, coincided with the minor axis of the outline of the apical surface of the free neuromasts. Four-day-old larvae (2.36-2.47 mm TL) were at the postlarval stage and the polarity of head neuromasts at this stage was usually oriented along the antero-posterior axis of the fish, but occasionally had a dorso-ventral orientation. The apical surface of free neuromasts changed in outline from a circle to a lozenge as the number of sensory cells started to increase in the pelagic larval stage (twelve-day-old larvae, 5.54-7.71 mm TL) . Free neuromasts were oriented on lines tangential to concentric circles around the eyes and nostrils. The development of schooling was recognized concomitant with the formation of the canal organ in the head region in thirtyfive-day-old juveniles (18.15-18.91 mm TL) . Forty-five-day-old juveniles (5.54-7.71 mm TL) attained a benthic-life stage and had nearly mature canal organs. The cupulae of the free neuromasts changed from a stick-like to a blade-like shape on both the head and trunk.View full abstractDownload PDF (11739K) -
Tatsuya UNUMA, Kooichi KONISHI, Hirofumi FURUITA, Takeshi YAMAMOTO, To ...1996 Volume 44 Issue 2 Pages 169-175
Published: June 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSWe examined the reproductive cycle of red sea urchin, Pseudocentrotus depressus in both cultured and wild populations. The cultured population consisted of two year class groups: seedlings artificially spawned in 1991 and in 1992. A rapid decrease of the gonadosomatic index found in the wild population, caused by gamete release from November to December, was not recognized in the cultured urchins. Histological observation showed that, in the 1991 group of the cultured population, maturation was delayed by about two months and it lasted for a longer period compared to the wild population. Most of the males in the 1992 group matured while a considerable number of females remained immature during the experimental period.View full abstractDownload PDF (3907K) -
Yasuhiko TOSHIMA, Eddy SUPRIYONO, Fukiko HORI, Fumio TAKASHIMA1996 Volume 44 Issue 2 Pages 177-180
Published: June 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSAcute toxicity and Bioconcentration of n-dodecylbenzenesulfonate (C12LAS) to Kuruma prawn, Penaeus japonicas were evaluated. LC50 value for 45-day larvae was determined to be 4.2mg/l at 96h. This value was in the range of LC (EC) 50 values reported for other aquatic organisms, indicating that the sensitivity of the prawn was the same as those of fresh water fish like goldfish and red killifish.
The bioconcentration factors of C12LAS for adult prawn were n.d.-4 and 4-17 in the muscle and internal organs, respectively, showing that the bioconcentration was relatively higher in the internal organs.However, comparison of these values with the reported no observed effect level (intake) of mammals suggests that the food hygienic risk of C12LAS in the prawn is quite low.View full abstractDownload PDF (450K) -
Shotaro OHYA, Toshikazu SHIMIZU, Yoshiaki HORIKAWA, Shin-ichi YAMAMOTO ...1996 Volume 44 Issue 2 Pages 181-184
Published: June 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThirty-day-old ayu fingerlings were raised in three ponds, A, B, and C, which were supplemented with artificial illumination everyday from 17: 00 until 22: 00 for a period of forty days each beginning on days 30, 70, and 110, respectively. After the period of artificial illumination, all ponds were in natural light for an additional forty days. Growth was normal in each of the ponds but came to a virtual halt from the 50th day through the 70th day. After the 130th day (the 100th day after the commencement of artificial illumination), fish were dissected and the gonads were inspected for signs of sex differentiation and sexual maturation. The longer the artificial illumination was delayed, the greater the improvement that was observed in the development of the gonads and maturation was also found to be more rapid. The same tendency could also be observed during the period of sex determination of the male by the length of the ventral fin.
Ayu also have a refractory period during which they do not react to light and the size limit is thought to be in the range of about 0.04g.
Since the period refferred to above during which there is virtually no growth corresponds precisely to this refractory period, it is thought that growth temporary comes to a halt in order to be able to overcome serious physiological obstacles.View full abstractDownload PDF (503K) -
Shotaro OHYA, Toshikazu SHIMIZU, Yoshiaki HORIKAWA, Shin-ichi YAMAMOTO1996 Volume 44 Issue 2 Pages 185-188
Published: June 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe effects of different water velocities (50-60, 40-50, 30-40, 20-30, 3-5 cm/sec) on oocyte development and fecundity in Ayu were investigated. Though the number of oocytes increased with body size, there were more oocytes at water velocities faster than 30 cm/sec. The number of oocytes per cm3 of the ovary became significantly between water velocities. There was also a higher proportion of small-size eggs in the case of high velocities. A physiological reduction stage was also observed in the Ayu during the development process of the ovary and, at water velocities of 30 cm/sec or greater, it is thought that there is a tendency toward a decrease in the extent of oocyte reduction. A relationship between mean oocyte weight (X mg) and oocyte number per cm3 (Y) of the landlocked form of Ayu in Lake Biwa was obtained as follows:
Y=e-3.94X+9.37 (r=-0.992, p<0.001)
Meanwhile, in the case of the sea-run form of Ayu, which has a different life history, different calendar years and different background prior to inclusion in the experiment, a total duprication in point distribution was observed.
Though the oocyte number obtained with water velocities in the range of 20-30 cm/sec, which can be easily attained with the energy in water inflows, is less than with faster flows, this is considered to be the optimum velocity in rationalizing egg collection since the existence of many large-size eggs would lead to an improvement in the survival rate.View full abstractDownload PDF (431K) -
Michiya MATSUYAMA, Hirohiko KAGAWA, Misao ARIMOTO, Keigo MARUYAMA, Hid ...1996 Volume 44 Issue 2 Pages 189-195
Published: June 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe changes in ovarian development and serum steroid hormone levels of the yellowtail, Seriola quinqueradiata, during final oocyte maturation induced by a human chorionic gonadotropin (HCG) were monitored at six different times (0, 6, 12, 24, 36, and 48 hours) after HCG injection to understand the mode of ovarian development and endocrine control of oocyte maturation of this species.
The ovarian stage of fish sampled at any one time showed a tendency to be similar to one another. Vitellogenesis was completed and germinal vesicle migration began in fish sampled at 24-36 hours. Fish sampled at 48 hours had fully mature oocytes. Serum testosterone (T) and estradiol-17β (E2) were maintained at a relatively high level until 24 hours after HCG injection (T, 3.0-4.7 ng/ml; E2, 16.7-20.0 ng/ml), then the levels decreased and showed the lowest values (T, 0.8 ng/ml; E2, 5.9ng/ml) at 48 hours. The putative maturation-inducing hormone (MIH) of many teleost species, 17α, 20β-dihydroxy-4-pregnen-3-one, showed a rapid increase (0.42 ng/ml) in serum concentration at 6 hours after HCG injection, but maintained constant low levels (0.12-0.21 ng/ml) during final oocyte maturation from 24 to 48 hours. These results are discussed in relation to other studies on changes in serum steroid levels during final oocyte maturation.View full abstractDownload PDF (2826K) -
Izuru KAKUTA, Hisashi KUROKURA, Hirohiko NAKAMURA, Koji YAMAUCHI1996 Volume 44 Issue 2 Pages 197-202
Published: June 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSBovine lactoferrin was evaluated for its ability to enhance the nonspecific defense activity of the skin mucus of red sea bream, Pagrus major. Oral administration of lactoferrin (4 to 400 mg/kg body weight/day) to the fish resulted in increased mucus production, and increased amounts of lactoferrin and a lectin in the skin, though no significant change in lysozyme activity in the mucus was observed. In lactoferrin-treated fish, the number of granulocytes and lymphocytes in the blood were also significantly increased. These results suggest that lactoferrin may enhance the biodefense ability of red sea bream through (i) promoting the secretion of mucus on the body epidermis and (ii) promoting an increase in nonspecific defensive factors secreted in the mucus, and (iii) promoting an increase in the number of granulocytes and lymphocytes in the blood. In the group administered lactoferrin at 400mg/kg B.W./day, however, the growth was inhibited slightly and the amount of mucus secreted on the skin decreased after 42 days.View full abstractDownload PDF (698K) -
Shigehiko KANAYA, Yoshihiro KUDO, Shouzo MOKI-TODA, Kazuhiko KATSURA1996 Volume 44 Issue 2 Pages 203-210
Published: June 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSIn order to characterize biochemically the embryogenic stages of Yamame Oncorhynchus masou, we analyzed the peptide constituents of the embryos during embryogenesis by means of twodimensional electrophoresis. New kinds of peptides were mainly detected in three periods, i. e. between 12 and 13 days, between 20 and 21 days, and between 30 and 31 days after fertilization. Hatching occurred between 34 and 37 days. Taking morphogenetic and genetical factors into cosideration, it is suggested that, these three periods of appearance of new peptides represent (1) the shifting stage from maternal to nuclear events in gene expression, (2) the development of external organs such as fins, and (3) the preparative stage for hatching, respectively.View full abstractDownload PDF (3081K) -
Hideki TAKAMI, Tomohiko KAWAMURA, Yoh YAMASHITA1996 Volume 44 Issue 2 Pages 211-216
Published: June 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSJuvenile abalone Haliotis discus hannai (30.6 mm mean shell length) were fed under replicate conditions (n=7 or 8 per replicate) on three species of benthic diatom (Achnanthes longipes, Cocconeis scutellum var. parva, and Navicula britannica) and on brown alga Laminaria japonica as a control. Growth and biochemical composition of juveniles were measured. The growth rates of juvenile abalone varied among food regimes; the highest rates were found for A. longipes, and the lowest for N. britannica. Further, abalone fed on A. longipes showed the highest muscle glycogen and mid-gut gland triglyceride contents. In contrast, animals fed on N. britannica showed little accumulation of these energy reserves and a reduction in total body weight. The differences in the growth rate and biochemical composition of juveniles fed on A. longipes and N. britannica are thought to be caused by differences in the digestion efficiencies. The cell wall of A. longipes was easily broken when grazed by abalone because of its high adhesive strength. N. britannica, however, has low adhesive strength and is readily ingested by abalone without any deformation of the cell wall. Also, the majority of N. britannica are excreted whole and still alive. The difference in the growth rate observed between juveniles fed on A, longipes and the ones fed on C. scutellum var. parva, which is also readily broken during grazing by abalone, was caused by the small size of C. scutellum var. parva which reduced feeding efficiency. Digested cell volume per day of A. longipes was much higher than that of C. scutellum var, parva.View full abstractDownload PDF (791K) -
Masaharu UKAWA, Kenji TAKII, Motoji NAKAMURA, Hidemi KUMAI1996 Volume 44 Issue 2 Pages 217-223
Published: June 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSA 36-day feeding trial was conducted to evaluate the dietary utilization of soy bean meal (SBM) as a partial substitute for brown fish meal in single moist pellet (SMP) for young tiger puffer, Takifugu rubripes. The fish with a mean body weight of 25 g were fed 3 % of wet body weight/day, and rearing water temperature was 26.3 ± 0.8 °C.
No remarkable differences were detected in weight gain and growth performances among the fish fed on SMP including 0, 10, and 20 % SBM. However, growth performances of the fish decreased with further increases in dietary level of SBM up to 40 %. Moreover, no improvement of performance was detected with supplementation of DL-methionine and L-lysine to the 20 % SBM diet.
These results suggest that tiger puffer, as yellowtail and red sea bream, are able to utilize SBM as a partial substitutive protein for dietary brown fish meal, and that the maximum level of dietary SBM is in the range of 20-30 %.View full abstractDownload PDF (738K) -
Takeshi WATANABE1996 Volume 44 Issue 2 Pages 227-229
Published: June 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSRecently in Japan, a quick decline of sardine catch has had a great impact not only on mariculture where the raw fish has been used as a main feed, but also on fish meal production where sardine has been the major material. However, newly developed dry pellets for marine finfish have successfully replaced the raw fish and also opened up a possibility of utilizing alternative protein sources in the diets for mariculture species. Dry pellets formulated with various alternates are being gradually developed as grow-out diets. Current information on broodstock and larval diets is also presented here.View full abstractDownload PDF (358K) -
Sadasivam J. KAUSHIK1996 Volume 44 Issue 2 Pages 231-234
Published: June 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSDownload PDF (470K)
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