• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.1
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• pp.41-48
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• 1993

Using the eight-year-working diaries($1984{\sim}1991$) of the fishing co-operative in Tonggui-ri, Cheju-do, as well as the records of consignment sale in the fish trust market as the corporate body in Aewol-up, the results have been analyzed as follows. 1. The monthly catch of Turbo cornutus was high from September through December, representing $58.2\%$ of the annual total catches. The maximum sustained yield(MSY) of this stock was estimated to be 2.5 tons. 2. The maximum sustained yields of Haliotis spp. and Sulculus sp. were estimated to be 800kg and 750kg, respectively. 3. The maximum sustained yields of Stichopus sp. and Octopus sp. were 500kg and 2, 500kg, respectively. 4. The total yield of Hizikia fusiforme has been decreasing a little and that of Gelidium sp. has been increasing. The total yield of Gelidium sp. in 1984 was about 5 times greater than that in 1990. 5. The daily catchability by divers have been high at thirties, and the individual mean working day of divers was 101 per year. 6. The consignment sale rates were $100\%$ each for Turbo cornutus, Hiziki fusiforme and Gelidium sp., $25.5\%$ and $61.1\%$ for Haliotis sp. and Stichopus sp. respectively, and $0\%$ each for Sulculus sp. and Octopus sp.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.1
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• pp.44-52
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• 1996

Humic substances of 17 organic fertilizers available on the market were the objects of study. The list of ingredients for formulation of them comprised fish meal. bone meal, oil-cakes, brewer's grains, peat, sawdust, wood bark, zeolite, soil conditioner, live-stock droppings, amino acid fermentation byproduct, chaff, limestone and others. Humic and fulvic acids were isolated from those substances and given chemical and spectroscopic analyses. Nutritional values of the organic fertilizers showed big diversity. Humification of organic matter was incomplete for some of the fertilizers as indicated by a high C/N ratio. Extractable humic acid percentage was higher, in general, than that of fulvic acid. Also the relative content of humin increased with advanced humification. Total acidity was closely related to phenolic hydroxyl groups. Relationships between carboxyl and hydroxyl groups. and carboxyl and alcoholic hydroxyl groups were very significant. Ultraviolet and visible light absorption spectra of humic and fulvic acids were substantially similar. The types of humic acids were B. P, and Rp. Two humic acids of the 17 samples belonged to B type. 3 to P type and all the rest to Rp type.

• Journal of Aquaculture
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• v.20 no.3
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• pp.160-167
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• 2007

Embryonic and pre-leptocephalic larvae development of the eel, Anguilla japonica, are described following natural fertilization in the indoor tank of $23^{\circ}C$ water temperature. Following a routine hormone treatment technique for the brood stock, female eels were artificially matured by weekly intramuscular injections of salmon pituitary extracts (SPE) at a dosage of 20 mg/kg body weight (BW) for a total of 10-14 doses to induce ovarian maturation, while male eels received weekly intramuscular injections of human chorionic gonadotropin (HCG) at a dosage of 1 IU/g BW for a total of 6-10 doses to induce testicular maturation in a separate aquarium and induced natural spawning. Fertilized eggs of about 1.0 mm in diameter were pelagic and showed a typical discoidal cleavage. Hatching occurs 38 hrs after fertilization at a water temperature of $23^{\circ}C$. The newly hatched larvae measured about 3.0 mm in total length and the number of myomeres averages 42. Their mouths and anuses were opened at 4.5 days and the yolk sacs of the pre-leptocephalic larvae were almost absorbed at 6.5 days after hatching. Pre-leptocephalic larvae survive for 14.5 days. At this time they are $5.87{\pm}0.25mm$ in total length and have about 98 myomeres. However, morphological characterization of embryonic and pre-leptocephalic larvae were not different between natural fertilization and artificial fertilization by the dry method.

• Korean Journal of Ichthyology
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• v.20 no.4
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• pp.272-278
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• 2008

Optimum concentration of alizarine complexone (ALC) for staining of otoliths for Pacific cod was determined by examination of stained quality, growth and survival rates. Small juveniles ($34.1{\pm}1.8mm$ TL, $mean{\pm}SD$) were immersed in four different concentrations (20, 40, 60, 80 mg/L) and large ones ($73.8{\pm}1.2mm$ TL, $mean{\pm}SD$) in five different concentrations (1, 5, 10, 20, 40 mg/L) of ALC for 24 hrs. The fish were then reared and observed for 14 days. The stained quality of otoliths was evaluated by dividing them into four grades by the presence of fluorescent stains on the otoliths under G-excited UV light. The small juveniles stained with the different ALC concentrations had 100% staining success, and their growth rate and body weight did not differ significantly between treatments. Optimal ALC concentration for the smaller juveniles was 20 mg/L in the present experiment. On the other hand, distinct fluorescent rings were confirmed on otoliths of larger juveniles in the 10 mg/L treatment with high survival rate. These results suggest that ALC staining at concentrations of 10 mg/L with larger juveniles will be helpful for release-recapture experiments for stock enhancement of Pacific cod.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.44 no.4
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• pp.282-293
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• 2008

In order to develop the substitutive materials for natural baits of swimming crab pots, the attracting effects of swimming crab such as the preference of baits which were made of the by-products of marine and stock raising through the water tank experiments and fishing experiments. On the investigation of mean entrapped catch number to the pot by the baits after putting the 4 kinds of baits, mackerel(M), mackerel with grinded mackerel s internals($MM_I$), mackerel with tuna s internals$MM_I$) and makerel with grinded krill(MK) each in one pot by turns, $MM_I$ and MK were entrapped mean 3.9(13.0%) and they were a little more comparing to M, and $MT_I$ is least with mean 2.1(7.0%)(F=12.913, P < 0.05). Otherwise, on the preference investigation of swimming crabs by the baits after putting the 4 kinds of baits in the 4 pots each, M was entrapped mean 3.0(10%), but $MM_I$, $MT_I$ and MK were mean 1.2(4.0%), 1.0(3.3%) and 1.5(5.0%) each and they were only 30-50% of M(F=13.398, P < 0.05). On the preference investigation of swimming crabs by the 5 kinds of baits, mackerel(M), and krill(K), manila clam($M_C$), pig s fat($P_F$) and chicken s head($C_H$) which were used in substitutive baits, M was entrapped mean 3.2(10.7%), but K was about 50% of catch of M with mean 1.6(5.3%), and $M_C$, $P_F$ and $C_H$ were very few with mean 0.1-0.2(0.3-0.7%)(F=89.186, P < 0.05). On the preference investigation of swimming crabs by the pots which were put each the 3 kinds of baits, original krill(K), grinded krill with gluten and soybean oil cake($K_GGS$) and grinded krill with gluten, soybean oil cake and glycine($K_GGSG_L$) in the blue fluorescent hexahedral plastic bait cages(BF), and which were put the mackerel(M) in the non-fluorescent hexahedral red plastic bait cage($RF_N$), it was entrapped mean 3.0(10.0%) in the pot which was put the mackerel in the $RF_N$, and the same level in the pots which were put the K and $K_GGSG_L$ in the BF, but it was mean 2.0(6.7%) in the pots which was put the $K_GGS$ in BF and it was decreased by 30% of catch comparing to $RF_N$(F=3.750, P < 0.05). On the preference investigation of swimming crab by the pots which was put grinded tuna with gluten, soybean oil cake and glycine($T_IGSG_L$) in the blue fluorescent hexahedral plastic bait cage(BF), and which was put mackerel(M) in the nonfluorescent hexahedral red plastic bait cage($RF_N$), it was entrapped mean 3.3(11.0%) in the pot which was put mackerel in $RF_N$, and mean 2.7(9.0%) in the pot which was put $T_IGSG_L$ in BF and it was about 15% less comparing to use bait M(t=1.387, P < 0.05). As a results of fishing experiments, a plan for enhancing catching efficiency of $T_IGSG_L$ will be required because catching efficiency of $T_IGSG_L$, alternative bait, was half of fish catching efficiency of natural bait using mackerel. Fishing experiments were conducted 3 times using reinforced substitutive artificial bait that is reinforced attractive effect of $T_IGSG_L$ and composed of tuna intestine, grinded mackerel, gluten, soybean cake, glycine and alanine($T_IM_GGSG_LA$). Catching efficiency of $T_IM_GGSG_LA$ was about 80% of that of natural bait made of mackerel.