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Volume 44, Issue 4
Displaying 1-22 of 22 articles from this issue
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Makoto SAKURAI, Toyotaka MATSUMOTO, Akinobu NAKAZONO1996 Volume 44 Issue 4 Pages 395-405
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSAnnual reproductive cycle, sexual dimorphism and mating behavior of the viviparous embiotocidNeoditrema ransonnetiwere studied. Both histological evidence of maturity of testis and behavioral evidence of courtship and mating behavior showed that mating occurred in autumn. At this time, although oocytes were immature, sperm was found in the ovarian cavity. Pregnant females gave birth to young from April to June.
At the mating season, besides the copulatory organ on the anal fin, males also displayed sexual dimorphism in body color, caudal fin morphology, and serrations in dentary and premaxirally. During the mating season, males maintain territories. On the other hand, females swim around the territories. When they invade these territories, they are courted by the male. Following courtship, copulation took place in the mid water column or near the bottom. Two size groups of older (over than one year) and YOY (young of the year=yearling) groups were recognizable. Competitive behavior was observed between males of two size groups. Mating behavior (size assortative mating) differed strikingly between them. The older males only courted females of their own size group. The YOY male, however, courted both YOY and older females in proportion to their abundance. Furthermore, YOY males rushed toward a pair of the older male and female, and tried to copulate to the older female (streaking-like behavior) .View full abstractDownload PDF (2987K) -
Hisao OGAWA, Natsuhiro KANAYA, Etsuko KIUCHI1996 Volume 44 Issue 4 Pages 407-411
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe effects of temperature and salinity on the rhizoid development of brown alga, Hizikia fusiformis (Harvey) were examined. Rhizoid was developed in the range of 10-25°C and 19.5-55.2S, and showed a good growth at 15°C and 26.9-39.2S. Temperature enhanced rhizoid development under high salinity conditions.View full abstractDownload PDF (478K) -
Shigehisa YAMASAKI, Muneyuki MATSUDA, Tatsuya YAMAUCHI, Hachiro HIRATA1996 Volume 44 Issue 4 Pages 413-418
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe effects of light intensity and water temperature on growth of Ulva sp. were studied as part of fundamental study of“harmonized fish culture with environment”, where substances are recycled through the alga. Ulva. sp was cultured in net bags of 50×50×10cm at the Azuma-cho Fish Seedling Center (32°13'N, 130°10'E) . Five net bags connected in rectangle were set on the surface of the sea water in an empty fish culture cage. The culture was continued for 1 year from Oct. 1994, with harvesting every week. Light intensity and water temperature were also measured during the period.
Low and high light intensities were observed around the winter and summer solstices, respectively. Maximum light intesities around the winter and summer solstices were 19.7 and 47.3 mol/m2/day, respectively. The lowest and highest temperatures were observed around 2 and a half months after than the winter and summer solstices, respectively. The lowest and highest temperatures were 13.8 and 26.4°C, respectively. The lowest Ulva sp. growth rate (1.03 times/day) was obtained around the winter solstice and the highest growth (1.42 times/day) around 3 weeks after than the summer solstice.
In multiple regression analysis, a multiple regression coefficient of 0.74 was obtained. Partial regression coefficients between Ulva sp. growth rate and light intensity was 0.55 and that between Ulva sp. growth rate and temperature was 0.38. From these results, it was clarified that both light intensity and temperature affected the algal growth, suggesting larger influence of light intensity than temperature.View full abstractDownload PDF (577K) -
Izuru KAKUTA1996 Volume 44 Issue 4 Pages 419-426
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSFour test diets containing different levels of bovine lactoferrin (0.0001, 0.001, 0.01, 0.1%) were fed at 6% of fish body weight per day, that is, lactoferrin at 0.06 to 60 mg/kg B.W./day was orally administrated to goldfish, Carassius auratus, weighing about 5.6 g for 56 days. Growth and blood parameters were compared with those of the control fish fed with the same commercial diet without lactoferrin.
Growth was significantly enhanced in the groups fed diets with 0.001 to 0.1% lactoferrin after 28 days. However, little difference in body weight was found between the groups fed diets with 0.01 % and 0.1 % lactoferrin at day 56.
Lower values for plasma lactate and cortisol, and a slightly higher value for iron in the groups fed diets with 0.001 to 0.1% lactoferrin comparing with those of the control were found after 28 days. At day 56, concentrations of phosphate, calcium, iron and zinc in plasma from goldfish fed diets with 0.01% lactoferrin were higher than those of the control. Plasma bromine decreased at that time. No significant differences in plasma lactate and cortisol were also found between the group receiving 0.1 % lactoferrin diet and the control at day 56.
Oral administration of lactoferrin at 0.6 to 6 mg/kg B.W./day thus appears adequate to improve the nutritional and physiological conditions of goldfish.View full abstractDownload PDF (962K) -
Izuru KAKUTA1996 Volume 44 Issue 4 Pages 427-432
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe protective effect of bovine lactoferrin against experimental infection of goldfish Carassius auratus withIchthyophthirius multifiliis was studied at 20°C. The experimental infection was conducted by rearing uninfected fish which had been fed a lactoferrin-added diet, those fed with lactoferrin-free diet, and infected fish together in the same tank for 7 days. Oral administration of lactoferrin (80mg/kg body weight/day) to the fish for 3, 14 and 35 days resulted in decreased I. multifiliis infection and enhanced survival rates of goldfish. In lactoferrin-treated fish, increased mucus secretion on the body epidermis was also observed. These results suggest that (i) the lactoferrin has a protective effect against I. multifiliis infection in goldfish, and (ii) the increased mucus production constitutes an effective defense mechanism against I. multifiliis infection.View full abstractDownload PDF (658K) -
Riichi KUSUDA, Norihiko AKAMATSU1996 Volume 44 Issue 4 Pages 433-437
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSMTT (3- [4, 5-dimethylthiazol-2-yl] -2-5 Biphenyl tetrazolium bromide) colorimetric assay is developed to quantify the proliferation of mammalian cells. In this study, the MTT colorimetric assay was optimized for the measurement of proliferation and mitogenic response of yellowtail, Seriola quinqueradiatalymphocytes. Proliferative responses were assayed using the mitogen, concanavalin A (Con A) . A linear relationship between cell number and absorbance (OD) of MTT-formazan production was obtained up to a cell number of about 2.0×105 cells per well. Also, a positive correlation between viability and OD of MTT-formazan production of the yellowtail lymphocytes was observed. Optimum mitogenic response of yellowtail lymphocytes was obtained when 0.1 ml of 4.0×105 lymphocytes per well were used and incubated for 72 h after the addition of Con A at a concentration of 100μg per ml. From these results, it is suggested that the MTT colorimetric assay is useful for the measurement of yellowtail lymphocyte proliferation. The main advantages of the MTT colometric assay are it's rapidity, precision, and the lack of any radioactive material like 3H-thymidine.View full abstractDownload PDF (594K) -
Riichi KUSUDA, Norihiko AKAMATSU1996 Volume 44 Issue 4 Pages 439-443
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSA major route of signal transduction in the proliferation of mammalian lymphocytes is the phosphatidyl inositol (PI) pathway. This signaling pathway induces increase of intracellular Ca2+concentration and activation of protein kinase C (PKC) . This study investigated whether intracellular Ca2+and PKC are involved in the proliferation of yellowtail, Seriola quinqueradiatalymphocytes. Proliferative responses were assayed using the mitogen, concanavalin A (Con A) . Con A induced an increase of intracellular Ca2+concentration of yellowtail lymphocytes inducedby Con A. Proliferation of Con A-stimulated yellowtail lymphocytes was inhibited by the Ca2+channel blocker, Verapamil and PKC inhibitor, H-7. Furthermore, the calcium ionophore, A23187 and the PKC activator, TPA also stimulated yellowtail lymphocytes. From these results, it is apparent that the increase of intracellular Ca2+concentration and the activation of PKC are related with the proliferation of yellowtail lymphocytes as seen in mammals.View full abstractDownload PDF (572K) -
Satoru MATSUOKA, Yuji WADA1996 Volume 44 Issue 4 Pages 445-449
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSIn vitro drug sensitivity of 168 Edwardsiella tarda and 110 Streptococcus iniae strains against several kinds of chemotherapeutics were investigated by the standard agar plate dilution method. Bacterial strains were isolated from cultured Japanese flounder Paralichthys olivaceus in Ehime Prefecture from 1986 to 1995.
Most of the E. tarda strains tested were highly sensitive to oxytetracycline (OTC), oxolinic acid, flumequine, florfenicol and sodium nifurstyrenate (MIC, 0.1-1.56μg/ml) . However, OTC resistant strains (MIC, 50-100μg/ml) have been increasing in Ehime Prefecture since 1990.
All strains except 1 strain of Streptococcus iniae were highly sensitive to macrolides, OTC and doxycycline.View full abstractDownload PDF (438K) -
Sharmin Rumi ALIM, Kenji KAWAI, Riichi KUSUDA1996 Volume 44 Issue 4 Pages 451-456
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSPathogenic properties of Enterococcus seriolicida, a pathogen for yellowtail, were compared between substrains which have different virulence properties and antibody-mediated agglutination with the anti-serum against Enterococcus seriolicida type strain ATCC 19433. A virulent, nonagglutinating substrain {SS91-014 (N) } was significantly resistant to phagocytosis and intracellular killing by yellowtail peritoneal macrophages compared to an agglutinating, attenuated substrain {SS91-014 (A) } From adhesion assay, it was revealed that the number of adhered bacteria to yellowtail intestinal wall was higher in the virulent than in the attenuated substrain. The results indicate that the differences in the agglutination properties of the two substrains may contribute to their differences in resistance to phagocytosis and tissue attachment, which are the most important factors for virulence.View full abstractDownload PDF (658K) -
Shingo ITOH, Mamoru YOSHIMIZU, MUNG-JOO Oh, Shinichi HYUUGA, Kenichi W ...1996 Volume 44 Issue 4 Pages 457-463
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe effects of ozonized seawater on bacterial population and survival of cultured Japanese flounder (Paralichthys olivaceus) and barfin flounder (Verasper moseri) were investigated. The number of viable bacteria was reduced in more than 99.9 % and Vibrio sp. could not be detected after seawater was treated with total residual oxidants (TROs) of 0.5 or 1.0 mg/l, for 8.5 minutes. TROs showed toxicity for fish; barfin flounder died 16 and 2 hours at TROs of 0.1 and 0.5 mg/ l, respectively. However, Japanese flounder could be cultured in ozonized seawater after removed of the TROs by charcoal, showing similar survival rates as fish cultured in U. V.-treated or non-treated seawater. Therefore, ozonization of seawater seem an effective methods for disinfection of fish culture water.View full abstractDownload PDF (857K) -
Katsuya HATTORI, Masayuki MIZUNO, Masaya OCHIAI, Munehiko UEMURA1996 Volume 44 Issue 4 Pages 465-470
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSNon-spotted (HH) and spotted (NN) gynogenetic diploids were produced by suppressing the extrusion of the second polar body in the eggs from normal diploid non-spotted (HN) female rainbow trout. By crossing HH females with sex-reversed HH males, all-female HH were obtained. The all-female non-spotted fish could then be used as a broodstock for the production of non-spotted fish. The genetic variability of gynogenetic diploids, induced from F1 of non-spotted rainbow trout with another strain of rainbow trout, was estimated from electrophoretic analysis of isozymes. Heterozygosity of the gynogenetic diploids was reduced in comparison with the F1. The risk of inbreeding can be greatly reduced by crossing the all-female HH with other strains. Gynogenesis was found to be more effective than the traditional crossing/progeny test method for the production of non-spotted (HH) rainbow trout.View full abstractDownload PDF (808K) -
Kotaro KIKUCHI, Takeshi FURUTA, Isamu SAKAGUCHI, Yoshiaki DEGUCHI1996 Volume 44 Issue 4 Pages 471-477
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe nitrogenous excretion rates of starved and fed fish were compared among red sea bream of 11.6 to 37.0 g in body weight, puffer fish of 15.6 to 28.2 g, and scorpaenid fish of 7.5 to 15.1 g at 20°C. Fed fish were given on a pellet diet at about 1.5% of their body weight once a day in the morning.
The average ammonia excretion rates of the starved red sea bream and puffer fish were 19.3 and 16.1 mg-N/100 g fish/day, respectively, and were much higher than that of scorpaenid fish (4.3 mg-N, p<0.05) . The urea excretion rates of these 3 species were 3.8, 3.4, and 2.3 mg-N/100 g fish/day, respectively, and there was also a significant difference between scorpaenid fish and the others (p<0.05) .
The hourly rates of ammonia excretion of fed red sea bream and puffer fish increased immediately after feeding, reached a peak between 3-6 h after feeding, and declined thereafter. In contrast, the highest rate in scorpaenid fish was observed during the period of 6-12 h, and the rates through the 24 h experimental period were much lower than those of the other two species. The urea excretion after feeding also showed an increase and species-dependent patterns of change.
In red sea bream and puffer fish, about 33% of the consumed nitrogen was excreted as ammonia within 24 h after feeding. In the same period, the former and latter species excreted 5 and 7% as urea and 6 and 8% as feces, respectively. Lower values were obtained in scorpaenid fish in which about 16, 5, and 1% of the consumed nitrogen were excreted as ammonia, urea, and feces, respectively.View full abstractDownload PDF (669K) -
Tetsuya UMINO, Heisuke NAKAGAWA, Minoru TAKABA1996 Volume 44 Issue 4 Pages 479-485
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe effect of the ration size (6 % or satiation, 3 %, and 1 % of body weight per day) on biological characteristics and body constituents of young red sea bream were investigated. When fish were fed at 6 % BW/day for 42 days, their energy storage in the form of protein, lipid, and triglycerides was enriched. In contrast, when fish were reared with 3 % and 1 % BW/day, their energy accumulation was inhibited. In the fatty acid profile of muscle triglycerides, there was a tendency that total polyenes decreased with decreasing ration, size, while those of phospholipids were not affected by ration size. Condition factor, hepatosomatic index, and muscle ratio decreased with decreasing ration size. Additionally, body depth and intestinal length showed the same tendency. The result indicates that the ration size is influential factor affecting these indices of young red sea bream.View full abstractDownload PDF (630K) -
Effect of Triiodothyronine Injection of Broodstock Fish on Seed Production in Cultured Seawater FishMohammad Kalil EL-ZIBDEH, Katsunori TACHIHARA, Yasuo TSUKASHIMA, Masat ...1996 Volume 44 Issue 4 Pages 487-496
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSTriiodothyronine (T3) was injected intramuscularly at a dose of 20 mg/kg body weight to broodstock fish of both sexes in greater amberjack, Seriola dumerili and Japanese whiting, Sillago japonica, and to maternal fish in Japanese parotfish, Oplegnathus fasciatus, red sea bream, Pagrus major, and red spotted grouper, Epinephelus akaara. T3 levels in eggs and larvae were then determined by radioimmunoassay. Survival and growth were compared for parotfish, bream and whiting larvae from treated and non-treated eggs under hatchery conditions for 35 to 64 days. A significant elevation of T3 content was observed in the eggs of all species. The patterns of changes in egg T3 with time though varied between species. Slight changes in egg and oil globule diameter were detected after the treatment, but these were also species-dependent. Fertilization and hatching rates were not affected by the T3 treatment in all species. Survival of larvae was improved in parotfish (control (C) 3.1-5.6 %; T3-treated 6.2-10.5 %), but not in bream (C 4.3-5.0 %; T3 4.0-5.2 %) and whiting (C 12.1-12.2 %; T3 11.4-15.2 %) . Growth was unaffected by the treatment.View full abstractDownload PDF (869K) -
Isao YANO, Toni RUCHIMAT, Tatam SUTARMAT, TRIDJOKO, Samuel LANTE, Joh ...1996 Volume 44 Issue 4 Pages 497-502
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThis study examined the effects of moist pellets containing fish oil supplemented with vitamin E on maturation and spawning of cultured giant tiger prawn, Penaeus monodon. At the end of 10 days, 7 out of 10 females fed the 3 % vitamin E-supplemented diet were undergoing ovarian maturation compared with only 2 out of 10 females fed the 0.8 % supplemented diet. The 3 % vitamin E supplementation also resulted in spawning with production of a large number of viable larvae. These data indicate that a moist pellet containing fish oil supplemented with vitamin E induces and accelerates maturation in captive prawns, and allows spawning with production of viable larvae.View full abstractDownload PDF (563K) -
Kenzo YOSEDA, Masakazu ASHIDATE, Naoto MURAKAMI, Akio KANAZAWA1996 Volume 44 Issue 4 Pages 503-510
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe effects of initial diets on the growth and survival rate of P. japonicus from nauplius6 to postlarva1 under mass seed production were investigated. Four live foods: Chaetoceros gracilis (C.g.), Tetraselmis sp. (T.sp.), Brachionus plicatilis (B.p), Artemia sp. nauplii and a microparticulate diet were used as food. All four live foods and the microparticulate diet were fed in the control.
Four dietary treatments were compared in which the following live foods were removed from the control: 2) B.p., 3) B.p.+C. g., 4) B.p.+C.g.+T. sp., and 5) all four live foods. Treatments 2), 3), and 4) promoted higher survival rates than the control whereas the lowest survival rate was obtained in treatment 5) . These results indicated that a microparticulate diet may be used as substitute for C. gracilis, Tetraselmis sp., and B. plicatilis, but not for Artemia sp. nauplii in the mass production of P. japonicus from nauplius6 to postlarval.View full abstractDownload PDF (892K) -
Masaharu UKAWA, Kenji TAKII, Motoji NAKAMURA, Hidemi KUMAI1996 Volume 44 Issue 4 Pages 511-516
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSA 51-day feeding trial was conducted to evaluate the dietary utilization of soy bean meal (SBM), corn gluten meal (CGM) and meat bone meal (MBM) as a partial substitute for brown fish meal (BFM) in single moist pellet (SMP) for young tiger puffer, Takifugu rubripes. Fish with a mean body weight of 48.2 g were fed on the diets until satiation. Rearing water temperature during the feeding trial was 21.2-26.4 °C.
No remarkable differences were detected in weight gain, growth performances and, blood characteristics between the fish fed on SMP including 31.4 % of SBM and MBM. While, the fish fed on SMP including 31.4 % of CGM showed slightly poorer performances and characteristics than fish fed on other diets.
These results suggest that tiger puffer, as yellowtail and red sea bream, are able to utilize efficiently SBM and MBM in diet, and that the lower EAA index of the SMP including CGM result in poorer growth performances.View full abstractDownload PDF (693K) -
Yasurou ISHIZAKI, Toshio TAKEUCHI, Takeshi WATANABE, Naoto MITSUHASHI, ...1996 Volume 44 Issue 4 Pages 517-525
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe effect of docosahexaenoic acid (DHA) and vitamin E (VE) on the development of larval yellowtail Seriola quinqueradiatawas examined by feeding them rotifers enriched withEuglenasupplemented with DHA and different types and levels of VE (dl-α-tocopherol and dl-α-tocopheryl acetate) .
The crude lipid content and fatty acid composition of total lipids in rotifers were reflected by those levels inEuglena. A positive relationship was found between VE content inEuglenaand the incorporation of lipid in rotifer. Regardless of its type, VE was accumulated and incorporated VE acetate was not converted to free-type in rotifers. A maximum concentration of VE was obtained in rotifers fedEuglenasupplemented with VE acetate. However, VE was not detected in whole body of larvae in any of the groups, suggesting that larvae could not metabolize VE in rotifers derived fromEuglena, and it was not confirmed that the effect of VE on survival and growth of larval yellowtail.
Larvae fed rotifers enriched with fresh waterChlorellahave shown poor growth, low survival rate, and poor activity, indicating that DHA has strong effect on early larval development of yellowtail.View full abstractDownload PDF (963K) -
Yasurou ISHIZAKI, Toshio TAKEUCHI, Takeshi WATANABE, Ken SHIMIZU, Kein ...1996 Volume 44 Issue 4 Pages 527-535
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe effect of vitamin E (VE) on the development of larval yellowtailSeriola quinqueradiatawas examined by feeding them rotifers enriched with shark eggs containing different types and levels of VE (d-α-tocopherol, dl-α-tocopherol and dl-α-tocopheryl acetate) .
The VE content in both rotifers and larvae reflected its level in shark eggs and enriched rotifer, respectively. It was found that no VE acetate was converted to free-type in rotifer. In terms of VE incorporation, both d-type and free-type of VE were incorporated in rotifer and larvae more effectively than dl-type and acetate-type of VE, respectively. A positive relationship was found between VE content in rotifer and the incorporation of DHA in fish; a higher level of VE in rotifer resulted in a higher amount of DHA in fish.
The VE requirement of larval yellowtail was estimated to be 2-40 mg/100 g in rotifer on dry matter basis when DHA content in rotifer is about 1.1 % dry matter basis.View full abstractDownload PDF (917K) -
Kunihiko FUKUSHO1996 Volume 44 Issue 4 Pages 539-546
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSTo date, nearly one hundred species of marine finfish have been examined for larval rearing potential in Japan, of which nearly sixty species have become actual objective for intensive culture and ocean ranching (Saibai-Gyogyo in Japanese) . At present, nearly two hundred million juveniles are being produced per year (excluding salmon and trout under ocean ranching) . Red sea bream, Pagrus majorand flounder, Paralichthys olivaceusare the most important species, occupying almost 70% of total production. Artificially reared red sea bream and flounder juveniles are being stocked for ocean ranching (26-63% and 40-60%, respectively) . To achieve an effective contribution to ocean ranching, technology for the production of active and vigorous juveniles capable of acclimating to wild conditions is required. Diets, rearing technique, and evaluation methods under vigorous conditions are being intensively studied. Further development of intensive mariculture, establishment of fry production technology for bluefin tuna, Thunnus thynnus, amberjack, Serioal purpurascens, various groupers, Epinephelusspp., northern plaices, Verasper moseri, Limanda herzensteini, and L. schrenkiand halibut, Hippoglossus stenolepis, is being pursued currently. Several research subjects have been pointed out for further development of fry production technology and mariculture of finfish, i.e., 1) accumulation of biological information on larvae and juveniles, 2) development of complete microparticulated diets, 3) improvement of design and and structure of larval rearing tanks for intensive feeding of microparticulated diet, 4) protection against disease, and 5) integrative studies among various scientists and technologists of different fields. In order to develop techniques for genetic breeding and sex control, biotechnological studies are being attempted for fry production of marine finfish.View full abstractDownload PDF (878K) -
R. BILLARD, L. DABBADIE1996 Volume 44 Issue 4 Pages 547-560
Published: December 20, 1996
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSA large variety of technologies are involved in production and processing in fish culture. Some are engineering technologies dealing with all physical aspect of production and mechanics, others are dealing with biology, (the so called ‘biotechnologies) . There is a continuum in the complexity of technologies which is related to a continuum in the complexity of production systems and in the degree of domestication of the species. The most widely distributed production system is the extensive aquaculture in pond with fish feeding on the endogenous food produced by the aquatic ecosystem. It usually deals with simple technologies mostly based on know-how and domesticated species (carp for instance), and were empirically elaborated by generations of fish farmers based in trial-errors. Sophisticated technologies are more based on knowledge resulting from a strong research effort made by developed countries. In the North, imput of technologies resulted in successful complex intensive production systems and commodity chains; attempts of transfert to developing country often results in failures. Technologies have to be adapted to the local socioeconomic context, to the capacity of the social corpus to handle them, to availability of local expertise and to the degree of domestication of the cultivated species.View full abstractDownload PDF (3250K) -
Helge R. REINERTSEN1996 Volume 44 Issue 4 Pages 561-565
Published: December 20, 1996
Released on J-STAGE: December 10, 2010
JOURNAL FREE ACCESSSalmon and trout farming in Norway is based on cage technology, which will be further developed in the coming years to improve fish quality, reduce production costs and minimize environmental impact. Halibut is expected to be the first coldwater marine fish species in commercial production, but the technology for fry production and the ongrowing phase needs to be further improved.
The long-term challenge will be to meet the high demand for fish in the future. The production of freshwater species can be improved, but the freshwater resources are limited and the major increase in fish production will have to take place in brackish- and seawater. Most of the present candidates for seawater production are carnivorous species. Aquaculture currently uses 15% of the available amount of fish meal in the world, so a huge increase in fish production consider‘new’feed resources as well as marine production of herbivorous species.
We need to establish a biological and technological basis for:
—systematic increases in the production of natural systems, eventually in combination with sea ranching.
—systematic production of improved macroalgae and other organisms which can be used as feed or constitute a major component of the feed for cage-farmed herbivorous and carnivorous fish species improved by selective breeding.View full abstractDownload PDF (485K)
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