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Volume 55, Issue 1
Displaying 1-22 of 22 articles from this issue
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Toshimitsu TANAKA, Makoto YAMAUCHI, Masahiro NOTOYA, Hajime KIMURA, No ...2007 Volume 55 Issue 1 Pages 1-8
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe morphologic diversity and the genetic variation were studied for Ecklonia cava Kjellman and Ecklonia kurome Okamura growing at seven points (Kada, Hiisaki, Noshima, Ezura, Koza, Shimotawara, Miwasaki) in Wakayama prefecture. E. kurome Sporophytes with rugae on pinna were recognized at three points (Hiisaki, Ezura, Shimotawara), but the state of rugae on pinna in Shimotawara has shown the middle morphological feature between E. cava and E. kurome. All samples show a thick and distinct median fascia and an undulate central lamina margin, and the shape of primary pinna is lanceolate or oblong in the Kui Channnel, but linear in the Sea of Kumano. Both the ITS-1 and the rbc-spacer sequences show little divergence among all samples in this study. This presented the necessity of taxonomic reexamination for these two extant species.View full abstractDownload PDF (7138K) -
Richard M. MIRANDA, Katsuaki FUJINAGA, Anthony S. ILANO, Shigeru NAKAO2007 Volume 55 Issue 1 Pages 9-15
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe incidence of imposex and parasite infection, and their relationship with Neptunea arthritica in Saroma Lagoon was evaluated. Imposex occurred in 30.9% of the females examined, and 25.1% of the males and females were infested by parasites. No difference in infection ratio was detected between the sexes, or between mature and immature individuals. The parasite infection index also showed no difference between sexes (male, 0.079 and female 0.074) . Parasite infection also showed no temporal pattern, but in general tended to be higher in large individuals than smaller ones in both sexes. A total of 19.3% of the females showed imposex and were infested by parasites. The number of infected whelks with signs of imposex showed a sharp decrease with the increase in imposex degree. This was clearly indicated by the proportion of infected whelks in imposex stage 1 (28.6%), 2 and 3 (7.4 and 10.3%, respectively) . The results suggests that the popu-lation of N. arthritica in the lagoon continue with the recovering trend based on the decrease of Imposex frequency, as refereed in previous works, and parasitism appears to be the most serious disruptive phenomenon to a complete restoration of this population, based on it's proportion.View full abstractDownload PDF (3110K) -
Ryo ISHIBASHI, Shinji YAMAMOTO, Toru KOBAYASHI, Kenichi IZUMI, Shigeru ...2007 Volume 55 Issue 1 Pages 17-22
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSHuman chorionic gonadotropin (HCG) was injected to one-year old captive chub mackerel (Scomber japonicus) in June 2005, a timing equivalent to the fish spawning period, to see if fertilized eggs would be formed. The sample fish were accommodated in a net cage and measured for total length, fork length, body length, head length, body depth, body width and body weight every 10 days until 100 days after hatching, then every 30-day thereafter. The sample fish were also checked for ovulation and spermiation by abdominal thrust 280 days after hatching. Their gonadal gland was then removed, weighed and measured for gonad somatic index (GSI) and, for females, KG value. Although spermiation was not confirmed in any males 280 days in age, spermiation was confirmed in half the male fish after 310 days in age and in all the male fish after 340 days in age. For the female fish, no ovulation was observed in individuals 310 days in age, but ovulation was confirmed in 8 out of 10 fish 340 days in age. Five groups of 10 male and 10 female in each received single injection of HCG (200 IU/kg BW) from 360 days in age (1st group) to 376 days in age (5th group) . The fish in four group spawned by the 3 days after the injection. In the group of eggs injected on June 27 (4th group), fertilized eggs were seen, although in a small quantity. When these fertilized eggs were cultured, they were observed to hatch normally and the hatchlings grew successfully.View full abstractDownload PDF (2893K) -
Kazumi NIMURA, Susumu TAKASE, Junji SHIMAMOTO2007 Volume 55 Issue 1 Pages 23-27
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe growth pattern of the Ecklonia cava sporophyte under continuous dark and subsequent natural light regime was investigated. All sporophytes (n=8) survived during the 13- and 26-day continuous dark condition. During the 70-day continuous dark condition, one sporophyte died on the 70th day and another sporophyte died on the 99th day. In each experimental condition, the primary blade lengths decrease during the continuous dark condition; however, they regrow in the subsequent natural light condition. This growth pattern was also observed for intercalary growth; the growth rates that were below 0.15 mm/day in the dark condition were found to be high in the natural light condition. Based on these results, although the growth of the E. cava sporophytes suppressed in the continuous dark condition, the sporophytes survived for approximately 1 month in this condition.View full abstractDownload PDF (2384K) -
Orhan UYAN, Shunsuke KOSHIO, Shinichi TESHIMA, Manabu ISHIKAWA, Fady R ...2007 Volume 55 Issue 1 Pages 29-40
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSTuna muscle powder (TMP), obtained from residues of tuna muscle, was replaced with fishmeal (FM) to evaluate its quality, substitution level and phosphorus loading for juvenile red sea bream. TMP was substituted for FM on a crude protein basis with levels of 25, 50, 75 and 100%, respectively. The feeding trial was continued for 50 days. Weight gain was not significantly different among the fish fed the control (0% TMP inclusion), 25 and 50% TMP containing diets. However, weight gain significantly (P<0.05) decreased in fish fed diets containing TMP at 75 and 100% with or without phosphorus (P) supplements compared to those fed diets containing 0, 25 and 50% of TMP. Feed intake of fish fed the control and 25% replacement was significantly higher than those fed 50, 75 and 100% replacement. The dietary free histidine level increased with increasing TMP levels while other free amino acids decreased. Negative correlation (R2=0.7784) was observed between dietary free histidine level and feed intake. Phosphorus loading markedly decreased with increasing TMP level in the diets. The inclusion of TMP did not negatively affect the hematological quality or health condition of the fish. In conclusion, the present study demonstrated that TMP is a suitable feed ingredient to reduce P discharge into the environment, and could replace FM with the level of 14.5 to 29% without retardation of growth and health of fish.View full abstractDownload PDF (2002K) -
Atsushi NARITA, Tadashi IMAI, Masahiko GOSHI, Yoichi TANAKA, Tomokazu ...2007 Volume 55 Issue 1 Pages 41-46
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThis study aims to investigate the effects of different diet sizes on the growth of Japanese flounderParalichthys olivaceusjuveniles by controlling diet sizes that are possible for the juveniles to feed on. For the experiment, diet was sieved out to six measured sizes. The modes (ranges) of minimum diameter were 375μm (225-538μm), 438μm (288-613μm), 500μm (350-700μm), 700μm (450-913μm), 800μm (563-1063μm) and 925μm (713-1138μm) . These diet sizes were smaller than the mouth size (=upper jaw length×√2) of the fish, thus all juveniles were able to feed on all sizes of diet. Few juveniles smaller than 10 mm in standard length (SL) fed on the diet. For fish of 10-15 mm SL, many of them fed on the diet when the size was 438μm or larger. For fish larger than 15 mm SL, decreasing proportion of non-feeding fish were found as the diet size increased. For the juveniles of 15-25 mm SL, food intake of 500μm size was less than that of 700μm, and of 25-30 mm SL, food intake increased as the diet size became larger. When comparing diet sizes between 500μm and 925μm with the total food intake weight being the same, it was found that fish which fed on the larger diet grew faster. In order to achieve the most efficient growth of Japanese flounder juveniles, it is necessary to feed them on the maximum size diet that they can take.View full abstractDownload PDF (3202K) -
Yukihiko SERISAWA, Zenji IMOTO, Yoshimi IMOTO, Kazuyo MATSUYAMA-SERISA ...2007 Volume 55 Issue 1 Pages 47-53
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSIn April 2003, seedlings ofEcklonia cava (plant length: 10 cm) were attached to two artificial reefs which had been placed on a breakwater at 4 m depth, off Usa in Tosa Bay, Japan. These transplanted fronds matured in October, and juvenile plants appeared around the reefs in February to March of the following year. Density and size ofE. cavawere measured at the bottom (1, 5, 10 m from the artificial reef) and lateral surface (2.5 and 3.5 m from the reef) of the breakwater by using a quadrat from April 2004 to February 2005. Density of 1, 5, 10 m was 36, 12, 4 ind./m2, respectively and 2.5 and 3.5 m was 104 and 56 ind./m2. Then density gradually decreased to February 2005 but half of the fronds which grew within 5 m from the reef survived. Many fronds ofE. cavamatured in October. In February, plant length and stipe length was 26.3-36.4 cm and 2.8-4.1 cm, and the density of juvenile plants was 32-172 ind./m2on average of quadrats. Thus a small but similar to naturalEckloniabed was formed around the artificial reefs.View full abstractDownload PDF (3699K) -
Possible Nutrients in Artemia Affecting the Larval Growth of Pacific Bluefin Tuna Thunnus orientalisManabu SEOKA, Michio KURATA, Yasuhiro HATANAKA, Amal Kumar BISWAS, Seu ...2007 Volume 55 Issue 1 Pages 55-64
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSFeeding ofArtemiaenriched with commercial enrichers (enrichedArtemia) induces the growth failure of the Pacific bluefin tuna (PBT) Thunnus orientalislarvae but feeding of yolk-sac larvae of marine fish promotes larval growth. However, the underlying causes of this phenomenon have never been explained. Therefore, in this study, two consecutive experiments, 1) a nutritional comparison among enriched rotifers, enrichedArtemia, and yolk-sac larvae of Japanese knifejawOplegnathus fasciatusand 2) a preliminary rearing trial of bluefin tuna larvae by feeding either enrichedArtemiaor yolk-sac larvae, were conducted to predict the possible nutritional cause (s) . No remarkable differences were found in proximate and amino acid compositions among the live feed, while phosphatidylchorine, sterol ester, and docosahexaenoic acid (DHA) levels were comparatively low in enrichedArtemia. The carbohydrate content in enrichedArtemiawas similar to that in enriched rotifers but higher than that in yolk-sac larvae. In the rearing trial for 6 days, the growth and survival of PBT larvae fed yolk-sac larvae were superior to those fed enrichedArtemia. The PBT larvae fed yolk-sac larvae had significantly higher levels of triacylglycerol and DHA. The results suggest that the nutritional inferiority of enrichedArtemiato yolk-sac larvae is partly responsible for the growth failure of PBT larvae fed enrichedArtemia.View full abstractDownload PDF (1679K) -
Katsutoshi KAWABE, Johnson KIMURA2007 Volume 55 Issue 1 Pages 65-69
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSGrowth, Survival and feed conversion of spotted parrot fishOplegnathus punctatusunder rearing condition were examined to assess the feasibility of aquaculture of this species in Chichi-jima, one of the Ogasawara Islands. Fish were reared for 254 days starting from 68 days after hatching (June 2003) until 321 days after hatching (March 2004) . During the rearing period, water temperatures ranged from 20.3°C to 29.6°C (mean 25.3°C) . These fishes were fed formula feed for red sea bream once or twice a day. Survival rate during the rearing period was 94.0%. Total length and body weight at 321 days after hatching were 26.8±1.5 cm and 659±106 g, respectively. Daily feed uptake and growth rates decreased during the rearing period. Feed conversion during the rearing period was 1.67 and to gain 1 kg body weight, about 362 yen per kg of fish in formula feed was required. These results suggest that spotted parrot fish can reach the market size within 1 year from hatching with excellent cost performance and therefore, it is a promising candidate for aquaculture in Chichi-jima.View full abstractDownload PDF (783K) -
Ken-ichi YAMAMOTO, Takeshi HANDA, Yasuaki NAKADA2007 Volume 55 Issue 1 Pages 71-75
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSIn the pen-shell, Atyina (Servatyina) lischkeana, effects of water temperature on ventilation and ciliary movement of the gills were examined by raising the temperature 3°C every 1 hour starting from 20°C. Ventilation volume was measured directly with an electromagnetic flowmeter under normoxic and hypoxic conditions (54mmHg oxygen partial pressure) . Under these conditions, ventilation volume increased gradually to 29°C, then ventilation stopped at 32°C. Ciliary movement, measured by moving speed of a piece of thin film on the gill surface, gradually increased with rising temperature and reached maximum at 32°C, then decreased at 36°C. From these results, the pen shell must prevent a rise in body temperature at the time of acute increase in ambient temperature by stopping the inflow warmer water into the mantle cavity and by circulating cooler water in the mantle cavity by ciliary movement. This should explain well the physiological behavior of the pen shell which burrows perpendicularly, and opens the inhalant and exhalant orifices on the sea bottom.View full abstractDownload PDF (796K) -
Ken-ichi YAMAMOTO, Takeshi HANDA, Masakazu KONDO, Yasuaki NAKADA, Hiro ...2007 Volume 55 Issue 1 Pages 77-82
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSIn the pen shell, Atrina (Servatrina) lischkeana (A. (S.) pectinata lischkeana), the mechanism on discharging foreign substances from the mantle cavity was examined by observing the moving sands or films through the ciliated canal of the mantle and the gill surface at 11°C. The average movement speed of sands on the ciliated canal (22.6 mm/min) was similar to those on the gill surface (22.4 mm/min) . The speed of vertical movement was slower by one-fourth to one-fifth compared with the speed of horizontal movement. The sands in the mantle cavity were discharged after being shaped into a cord mixed with mucus even when the mantle was closed. However, animals completely stopped discharging sand when they closed the shell valves in diluted seawater (salinity 18) . Morphological observation demonstrated that the ciliated canal formed tubular consisted of two walls of mantle and that many mucilage cells with cilia existed at the epithelium of the canal. Based on these findings, it was concluded that the ciliated canals as well as the gill surface work to remove foreign substances and subsequently discharge these substances from the mantle cavity after mixing with mucus to form a cord-like shape. Though discharge is carried out even if the mantles are closed, discharge stops when the shell valves close.View full abstractDownload PDF (9279K) -
Masahiro NAKAGAWA2007 Volume 55 Issue 1 Pages 83-89
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSEffects of rearing temperature on growth and maturation of black rockfish Sebastes schlegeli were examined in captivity. Rockfish were reared in three different temperature conditions: natural temperature (control), natural temperature +12°C in winter-spring (12°C) and natural temperature + 15°C in winter-spring (15°C), during the period from 7 months after birth (MAB) in December 1997 to 48 MAB in May 2001 (4-year-old) . Rockfish reared at higher temperatures in winter-spring showed significantly greater TL as 15°C>12°C>control up to 15 MAB. Significant differences in TL between treatments were not found after 16 MAB because of the higher growth rate of control>12°C>15°C during the subsequent warm period of 13-18 MAB. This phenomenon is thought to be compensatory growth of fish whose growth was limited because of low temperature in the winter-spring season. Female fish grew faster in the higher temperature treatment up to 2.5 years old, but no difference was found in the growth rate among treatments for male. A slightly higher maturation rate was apparent at higher temperature treatments in males, but no temperature effect was seen for maturation in female fish. Four-year-old control and 12°C female bore healthy larvae. However, those at 15°C had abnormal parturition. Within the present experimental conditions, the artificial increase of winter-spring temperature from a natural one to 12°C or 15°C is inferred to be of no use to enhance growth and maturation of black rockfish.View full abstractDownload PDF (1054K) -
Minoru TANDA, Yukinobu NAKAMURA, Shigeyoshi OKAMOTO2007 Volume 55 Issue 1 Pages 91-96
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSTo determine the life history of the marbled sole Pleuyonectes yokohamae in the Harima-Nada and Osaka Bay waters, gonadosomatic index (GSI), hepatosomatic index (HSI) and condition factors (CF1 and CF2, with and without gonads, respectively) of the species were examined in the periods of July 1986-January 1989 (late 1980s) and June 1998-January 2001 (early 2000s) . The life cycle of the marbled sole was classified into the following three stages: recovering stage (February-May), immature & maturing stage (June-November) and spawning stage (December-January) . Seasonal variations of the GSI and CF2 were similar between the periods of the late 1980s and the early 2000s. Successive three-year monitoring of the 1986 cohort in the present study clarified specific seasonal changes of the indices. Maximum value of HSI was observed in July in both sexes, and the index peaked secondarily before the spawning season in female. The value of CF1 temporarily increased during the spawning season, while that of CF2 increased in summer and then decreased before and through the spawning season.View full abstractDownload PDF (916K) -
Fumihito KATO, Katsuya ISHIMARU, Osamu MURATA, Hidemi KUMAI2007 Volume 55 Issue 1 Pages 97-101
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSTwo strains, R2 from red sea bream and GF0609 from Japanese flounder, of Tenacibaculum maritimum, causative agents of gliding bacterial disease, were grown on modified cytophaga agar medium containing 70% seawater for 48 h at 25°C and were inactivated with 1.5% (v/v) formalin-PBS for 48 h at 4°C (FKC-R2 and FKC-GF) . To evaluate efficacies of the FKCs in red sea bream and Japanese flounder, fishes were immersion-vaccinated with each FKC (20μg wet weight/ml) for 20 min, and were experimentally challenged with the R2 and/or GF0609 strains at 10 days post vaccination. In the challenge by R2 strain, survival rates of vaccinated red sea bream with FKC-R2 and FKC-GF were 80% (RPS: 75%) and 40% (RPS: 25%), with a significant difference from that of control (P<0.05) . No vaccination efficacy of the FKCs was observed in Japanese flounder challenged by the GF0609. Moreover, susceptibilities of red sea bream against GF0609 and Japanese flounder against R2 were revealed to be low.View full abstractDownload PDF (717K) -
Hiroki EBATA, Yoshio SATO, Satoshi SHIMADA, Norishige YOTSUKURA, Masan ...2007 Volume 55 Issue 1 Pages 103-108
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSLand-based cultivation of a green alga, Ulva prolifera, was tried by using the pumped saline groundwater at Miho Peninsula in Shizuoka, Japan, from August to December 2003. Fronds of 1 to 6-week-old were cultured in 6 outdoor tanks (500l or 1, 000l in volume) for a week at a turnover rate of three times a day under the sunlight. Initial frond density was 0.1g/l. The daily growth rates of 1- to 6-week-old fronds were 35.8, 47.4, 44.5, 24.8, 18.5 and 4.9%, respectively. Although maturation caused relatively low growth rates of a part of 4-and all 5-and 6-week-old fronds, but those of 2-and 3-week-old fronds were 45.8%, higher than previous records. Saline groundwater had constant and suitable water temperature (19.9±0.2°C), salinity (33.65±0.08 PSU) and pH (7.36±0.12) with suitable inorganic nitrogen (332.0±64.5 p mol/l) and phosphate (0.71±0.13μmol/l) . These revealed that saline groundwater is strongly recommended for the green algal culture.View full abstractDownload PDF (920K) -
Kouki KANOU, Syusei SAITO, Satoko FUCHIGAMI, Akinobu IMAMURA, Hitoshi ...2007 Volume 55 Issue 1 Pages 109-114
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSOccurrence patterns and food habits of introduced alien Loach Paramisguynus dabryanus and native Loach Misgurnus anguillicaudatus were studied at irrigation drainages around rice fields in the Watarase River system from January 2005 to January 2006. Alien Loach [n=171, 27-115mm in standard length (SL) ] occurred in only July, whereas native Loach (n=3023, 25-149 mm SL) occurred throughout the study period. During the co-occurring period in July, the stomach contents of alien Loach (n=91, 28-69mm SL) and native Loach (n=121, 27-85mm SL) were examined. The major food items of the two species overall were ostracods, insect larvae and the epibenthic crustacean Branchinella kugenumaensis. Ostracods were eaten mainly by smaller individuals (<30 mm SL) in both loaches. In larger individuals (≥30 mm SL), however, this prey item was replaced by insect larvae and/or B. kugenumaensis. Diet overlap between equivalent size classes of both loaches was high (Schoener index 0.69-0.90), indicating that partitioning of food resources was not evident when they occurred sympatrically.View full abstractDownload PDF (2977K) -
Takeshi YAMAMOTO, Takanobu GOTO, Natsumi TANAKA, Hirofumi FURUITA, Tsu ...2007 Volume 55 Issue 1 Pages 115-123
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe nutritional quality of test diets composed mainly of soybean, corn gluten and squid meals was evaluated in rainbow trout averaging 13g. A fish meal-based diet (43% protein, 14% fat) and three isonitrogenous test diets with a high fat content (21%) were prepared. Two of the test diets were supplemented either with essential amino acids (EAA) or bovine bile salts (BS) . The growth parameters were similar in all treatments. Although feed efficiency was higher in the test diet groups, the efficiency for the diet without supplemental EAA and BS was lower than the supplemented diets. Whole body crude protein content of fish fed with the EAA supplemented diet was higher than fish fed with the other test diets. There was little effect of feeding the test diets on the measured biological and biochemical parameters of blood, biliary bile, liver and intestine. A partial histological abnormality was observed in the distal intestine of fish fed with the test diets without BS while no such abnormality was found in fish fed with the BS supplemented diet. These findings indicate that diets containing soybean, corn gluten and squid meals support identical growth to the fish meal-based diet in rainbow trout. To attain more efficient utilization of dietary protein and normal intestinal histology, supplementation of EAA and BS to the diet is recommended.View full abstractDownload PDF (3807K) -
Yoshizumi NAKAGAWA, Shigeharu SENOO, Shigeru MIYASHITA2007 Volume 55 Issue 1 Pages 125-130
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSFeeding selectivity of the blue spotted snapper Lutjanus rivulatus, fed natural plankton during the first feeding period (42-66h after hatching), was investigated. In the first experiment, L. rivulatus larvae selectively fed on micro-flagellates, micro-ciliates and diatoms, with the highest feeding rate on micro-ciliates. In the second experiment, L. rivulatus larvae selectively fed on nano-flagellates, micro-ciliates and diatoms. For fish larvae such as L. rivulatus, which can not feed on larger zooplankton such as rotifers, smaller plankton (e.g. diatoms, flagellates and ciliates) play an important role in their survival. The present study suggested that, during the first feeding period, L. rivulatus larvae utilize energy and nutrients from the microbial loop via nano-protozoa. This is the first report to discuss the relationship between fish larvae and the microbial loop.View full abstractDownload PDF (944K) -
Motohiro TAKAGI, Tomo ISHIMARU, Isao TSUTSUI, Prapansak SRISAPOOME, Ka ...2007 Volume 55 Issue 1 Pages 131-132
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSGenetic variability of wild and cultured black tiger shrimp populations in Thailand was studied by the microsatellite DNA technique. In wild populations from the Gulf of Thailand, South Thailand, and South Myanmar, high genetic variability was detected. Mendelian inheritances were evaluated in juveniles from 4 farms. In three of the farms, more than 4 genotypes were identified, indicating that the farms did not use single parental line. Genetic approaches are required to achieve stable production rates in black tiger shrimp cultures.View full abstractDownload PDF (287K) -
Daisuke ARAI, Toshio TAKEUCHI, Daisuke SUGITA, Katsuyuki HAMASAKI, Kei ...2007 Volume 55 Issue 1 Pages 133-134
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThis study was conducted to examine the supplemental effect of n-3HUFA-Chlorella to rearing water on morphogenesis of swimming crab Portunus trituberculatus (Brachyura: Portunidae) zoeas. The longer supplementation with n-3HUFA-Chlorella conduced to excess morphogenesis of megalop at the fourth zoea stage, inhibiting normal metamorphosis from zoea to megalop. The longer supplementation also induced higher carcass DHA content of forth stage zoea. These suggests that n-3HUFA-Chlorella supplementation and carcass DHA content relate high mortality occurred at the metamorphosis from zoea to megalop.View full abstractDownload PDF (393K) -
Katsutoshi KAWABE, Johnson KIMURA2007 Volume 55 Issue 1 Pages 135-136
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe spawning of captive-reared spotted parrot fish Oplegnathus punctatus obtained from rocky shore waters around Chichi-jima, one of the Ogasawara Islands, was observed during rearing between 2002 and 2003. The two females which participated in the spawning were 3.2 and 4.5 kg in BW. Spawnings were observed on 18 occasions between late April and late June. The water temperature in the entire period varied between 18.8°C and 29.6°C whereas that on the spawning days varied between 21.1°C and 24.6°C. The total number of eggs taken was approximately 7 million. The average rate of buoyant eggs was 82.5±23.7%. The average diameter of the egg and oil globule were 1.045±0.017 mm and 0.245±0.006 mm, respectively.View full abstractDownload PDF (392K) -
2007 Volume 55 Issue 1 Pages 137-173
Published: March 20, 2007
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSDownload PDF (5808K)
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