• Journal of Marine Bioscience and Biotechnology
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• v.3 no.1
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• pp.1-6
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• 2008

Angola has a coastline of about 1,650 km long. Two diverging current namely, the Angola current with its warm water from the north and the cold Benguella Current in the south create a strong up-welling with a high productive ecosystem for marine resources. The area from Lobito to the mouth of the Cunene River, also known as the Southern fishing zone is by far the most productive of Angola's fishing zones. In 1977, the total potential of its marine fisheries sector was estimated at more than 700,000 tonnes per annum. In 2003, the Total Allowable Catch (TAC) established for demersal species was 57,600 tonnes and 160,000 tonnes for pelagic species. The most important resources are various marine demersal and pelagic fish including pilchard and the Cape and Cunene horse Mackerel (Tranchurus capensis and T. trecae). Sardinellas (Sardinella aurita and S. maderensis) are fished in parallel with horse mackerel. The rest of the catches are mainly demersal spp. and some deep water crustaceans. The demersal sppecies consist of Hake (Merluccius polli and M. capensis) and the large eye dentex spp. Tunas are caught at certain times of the year whilst some marine shrimp are also harvested from the Angolan waters. Angola also has several high value freshwater fish species, exploited by about 255 fishers. Tilapia sp. is among the most important and abundant fresh water fish found in Angola. Other species include the catfish (Clarias gariepinus) and fresh water prawns (Macrobrachuin rosenbergii). Some aquaculture ponds have been established in the country side, but due to lack of investment, proper training and the impact of civil war have seriously limited developments in the sub sector.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.1
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• pp.34-40
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• 2009

In fresh water fish hatcheries and farms, Saprolegniales often cause serious mortality to the fish and their eggs. Malachite green is an effective antifungal agent, but is carcinogenic to fish and humans. Alternative antifungal agents are needed. Presently, we tested various concentrations of MBT-01108 (Opuntia ficus-indica extracts) alone and in combination with bronopol, formalin and sodium chloride (MBT-01108 mixture) on in vitro mycelial growth and in vivo remediation of adult eel, Anguilla japonica, infected with Saprolegnia sp. and fertilized eggs of chum salmon, Oncorhynchus keta, to evaluate the compounds' antifungal efficacy on eyed-egg and hatching rates. MBT-Oll08 mixtures incorporating bronopol and formalin at respective concentrations of 50 and 30 parts per million (ppm), and 100 and 20 ppm were most effective in controlling Saprolegnia in vitro and in vivo (P<0.05). Repeated daily exposures to 50 ppm and 100 ppm MBT-01108 were more effective than exposure every 2-3 days post-fertilization for the inhibition of Saprolegnia infection of rainbow trout, Oncorhynchus mykiss eggs as compared with control (0 ppm).

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.10
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• pp.1600-1605
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• 2007

This study was undertaken to investigate the effects of oxidative stress on growth performance, nutrient digestibilities and activities of antioxidant enzymes of weanling pigs. In the experiment, 24 male $Landrance{\times}Yorkshire $weanling pigs were allotted to three groups of 8 animals each. Pigs were fed individually. According to a single factorial arrangement, pigs received diets with 5% of either fresh (group 1 and group 3) or oxidized fish oil (peroxide value was 786.50 meq $O_2/kg$ before inclusion in the diet, group 2). At the beginning of the experiment, pigs in group 3 received an intraperitoneal injection of diquat at 12 mg/kg of body weight. The trial lasted for 26 d. A metabolism test was carried out during the last 4 days of the second week. The results showed that feeding diets containing oxidized fish oil or injection with diquat depressed the growth performance and nutrient digestibilities of weanling pigs, decreased activities of antioxidant enzymes and increased concentration of malondialdehyde in plasma and liver. Intraperitoneal injection of diquat would induce more serious oxidative stress than oral intake of oxidized fish oil in the diet. In conclusion, administration of oxidized fish oil or diquat could induce oxidative stress in weanling pigs, and oxidative stress could depress growth performance and impact anti-oxidative ability of young pigs.

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.375-380
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• 2003

For some decades eutrophication poses a great problem in water quality management in fresh-waters. To solve this problem, studies based on "bottom-up" hypothesis have been mostly carried out worldwidely unlike biomanipulation. This implies that not only fish but also fish stock playa key role down to other food web components in pelagic ecosystem. It is generally accepted that biomanipulation becomes a potent tool for eutrophication control. For a practical application of this, however, further development and understanding of the food web under the specific lake condition on a whole-lake scale are needed. The question is how can we maintain the positive effects resulted from biomanipulation (fortuitous or planned) for a long period.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.9
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• pp.1272-1275
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• 2001

Two hundred and forty post-larvae (PL) of fresh water prawn, Macrobrachium rosenbergii were distributed in eight treatment groups with three replicates each. Eight experimental diets were prepared by using squilla (Orato squilla nepa), squid (Sepia pharonis) and clam (katelysia opima) alone or in different combination as source of animal protein and compared to a control diet containing fish meal. Total crude protein content for all dietary treatments was around 32%. Total protein content of fish meal was replaced by an equal amount of protein from different animal protein sources on isonitrogenous basis. Diets were fed at 5% of the body weight of post-larvae twice daily. The experiment was conducted for a period of 60 days. It was found that all the above three protein sources could be used by completely replacing fishmeal except clam meal at higher level of inclusion (26%). A combination of squid and squilla meal at 14% each in the diet increased the growth performance of PL significantly (p<0.05) in terms of Specific growth rate (SGR) % (5.17), FCR (2.12) and PER (1.51). Squilla meal can be used to the maximum level of 38% without any growth depression.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.993-999
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• 1998

Aquatic raw materials easily undergo deteriorative changes, and thus it is very important to keep fish meats fresh during transport and processing. The $K_i$ value, biogenic amines, trimethylamine (TMA) and volatile basic nitrogen (VBN), which are reported fish freshness indices, were measured for 20 samples. The $K_i$ values were normally in the range of $7.8{\sim}43.6%$, except those for some fish including squid. The contents of biogenic amines were negligible, and a correlation (r=0.894) was found between the contents of TMA and VBN.

• Korean Journal of Animal Reproduction
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• v.18 no.3
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• pp.183-189
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• 1994

We examined early development in loach(Misgurnus mizolepis) embryos with parthenogenetic agents well-known in mammals. Female loach was superovulated with an intraperitoneal injection of 15 IU human chorionic gonadotrophin (hCG) per gram body weight. After 13 h of hCG injection, the oocytes were obtained from the abdomen. The oocytes were activated with 10% ethanol in tap water or fish Ringer's solution for 5, 10 and 15 minutes(eTW5, 10, 15 and eFRS5, 10, 15), respectively. The activation rates were 29% and 10% in eFRS10 and eFRS15, 5% and 6% in eTW10 and eTW15 by judging the cleaved blastomeres. Whereas, no parthenogenetic embryo was produced by tap water or fish Ringer's solution alone. The activation rate with the fish Ringer's solution was higher than that of tap water. No embryonic development was observed by calcium ionophore, A23187, at concentrations of 10, 20, 40 and 100$\mu$M when treated for 1, 2.5 and 5 minutes, respectively. The activation agents did not cause early development as in mammalian eggs. Therefore, the results suggest that fresh water fish may have a different egg activation pathway from that of mammals.

• Journal of fish pathology
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• v.21 no.3
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• pp.157-166
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• 2008

Streptococcal diseases are known as serious problems in fresh water and marine fish culture industry worldwide. Recently, the importance of the infection of Streptococcus parauberis has been increased among the streptococcicosis since severe outbreaks in cultured olive flounder (Paralichthys olivaceus) were recorded in Korea. The aims of the present study were to investigate immunomodulatory differences between S. parauberis and S. iniae. In this study, S. parauberis isolated from diseased olive flounder was investigated on the characteristics of morphological and immune responses. Immune response of the fish to the pathogen was characterized by bactericidal activity in the serum, phagocytic activity and reactive oxygen intermediaters (ROIs) production of olive flounder. The capsules of both bacteria, S. parauberis and S. iniae seem to be associated with the ability to resist killing activity of normal sera. Also, capsulated strains could survive in the phagocytes and induce to lower ROIs production.

• The Korean Journal of Ecology
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• v.12 no.1
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• pp.51-65
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• 1989

Some aspects of limno-biology of the five dammed lakes such as Tamyang, Changsong, Kwangju, Naju, and Youngsan Lake along the Yongsan River were investigated from June 1986 to July 1988 for the comparison on the lentic ecosystems in relation to the fish fauna. Sixty four fish species representing 48 genera and 21 families of fishes were collected in these dammed areas, which included 29 species of the family Cyprinidea and 40 speaies of the primary fresh-water fishes. Among, these, 12 species such as Rhodeus Acheilognothus yamatsutae, A canathorhodeus gracilis, Sarcocheilichthys nigripinis morii, S. variegatus wakiyae, Gnathopogon strigatus, Squalidus gracilis majimae, Microphysogobio yaluensis, Cobitis longicorpus sp, Liobagrus mediadiposalis and Odontobutis platycephala are enddmic to Korea. Leiocassis nitidus and Gasterosteus aculeatus which occur in these water areas take note of the zooge rographic study of Korea. The fish species in each of the dammed lakes is in proportion of the scale of the lakes such as 32 species in Thamyang, 40 species in Changsong, 24 species in Kwangju, 35 species in Jaju, and 52 species in Yongsan Lake. The dominant fish species of the 4 upper dammed lakes of Thamyang, Changsong, Kwangju and Naju Lake are Zacco platypus and Rhodeus uyekii, while those of Youngsan Lake are Hemiculter eigenmanni and Carassius auratus. This difference of fish species of those areas suggests that the upper damed lake differ from the lower dammed lakes in the habitable condition of fishes. The migratory fish species have significantly declined and will continue to decline in both population size and number of species in the dammed lakes in near future as a result of the dam construction barriers in the river estuary. The major migratory fishes of this water area are as follows; Anguilla japonica, Plecoglossus altivelis, Hypomesus olidus, Gasterosteus aculeatus, Konosirus Punctatus, Coilia ectens, Hemirhampus sajori, Mugil cephalus. Acanthogobius flavimanus, and Takifugu ocellatus.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.541-548
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• 2022

Biofloc technology (BFT) systems provides an additional protein source for fish by converting waste in microbial flocs. Therefore, we aimed to determine the difference in the protein levels of the diet of Far Eastern catfish Silurus asotus reared in BFT and FW systems. We applied a two-way (six protein levels × two aquaculture systems) ANOVA design. We formulated six experimental diets to contain different protein levels (CPs)- 20%, 25%, 30%, 35%, 40% and 45%-referred to as the CP20, CP25, CP30, CP35, CP40 and CP45 diets, respectively. We randomly distributed 900 fish into 36 (18 each for BFT and FW), 300 L tanks (25 fish/tank) with three replications of each diet for 4 weeks. The weight gain (WG) and specific growth rate (SGR) considerably improved as the dietary protein level increased in the formulated diets. The BFT fish showed higher growth performance with any experimental diet than the FW fish. The growth performance of the fish fed the BFT-CP35 diet was higher than that of the fish fed the FW-CP45 diet. In conclusion, the cultivation of Far Eastern catfish (S. asotus) in BFTs can be carried out under reduced dietary protein levels.