• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.3
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• pp.230-238
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• 2003

An effect on the enhancing production of hollow 'jumbo' structures and the condition of artificial reefs (dice and hollow jumbo structure) by side scan sonar were described. The experiment of the capture of fish in the jumbo structures and control site (non-artificial site) by trammel net and traps was done twice every year from 1998 to 2000. The relative catches by trammel net between in the jumbo structure and in the control site was significantly different in number and in weight at 5% level and also that by traps significantly different in weight. The t-test of the catch of finespotted flounder showed that the hollow jumbo structure was regarded as a breeding field because the average size of the flounder in the jumbo site was smaller than that in the control site. The search on the condition of the artificial reefs (dice and hollow jumbo structure) was performed by side scanning sonar which showed various phase of it such as accumulated, dispersed, scouring and partly buried. The result implied that in the area of sand bottom with strong tide like the western sea of Korea, the current criterion for constructing artificial reef should be modified because of the sand moving on the bottom.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.3
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• pp.241-248
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• 2002

The combined hydroacoustic and demersal trawl surveys to investigate the distribution characteristics of fish schools in the Yellow Sea and the East China Sea were carried out during the spring of 1997 by the training ship "Nagasaki Maru" of Nagasaki University. Fish samples were collected by bottom trawling from 9 trawl stations randomly selected in the survey area, and the species and length compositions of trawl catches are examined. Hydroacoustic data were collected by using a Furuno FQ-50 scientific echo sounder operating at 50KHz and the data stored in field were later processed in the laboratory. The results obtained can be summarized as follows ：1. In the 9 trawl surveys conducted in the Yellow Sea and the East China Sea, 78 species including 80 species of fishes, 4 species of Cephalopoda and 6 species of Crustacea, were identified. The most abundant species in these stations were swimming crab(Portunus trituberculatus), Japanese horse mackere(Trachurus japonicus), redlip croaker(Larimichthys polyactis) and the catch per one hour in each station ranged 7.7 to 182.5 kg/hour. 2. The mean volume backscattering strength for the entire water column and the bottom layer of the 0-10 m from bottom friction were -74.6 ㏈ and -68.2 ㏈, respectively. That is, the mean volume backscattering strength for the bottom layer was 6.4 ㏈ higher than that for the entire water column 3. In the surveys during the spring of 1997, the geographical distribution characteristics of fish schools suggests a trend of decreasing fish abundance toward the coast area of Korea and the highest demersal concentrations appeared in waters between the Cheju Island and the Tsushima Island 4. The distribution density of fish school in the East China Sea and Yellow Sea during the 1997 acoustic survey were estimated to be 6.65$\times$10$^{-5}$ kg/㎥ in the entire water column and 2.86$\times$l0$^{-4}$ kg/㎥ in the bottom layer, respectively.pectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.4
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• pp.390-402
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• 2011

A preliminary study on species composition of a Korean purse seine catch landed at cannery was conducted in April 2011. In the cannery, all tuna catch are sliding through a sorting grid panel that filters and drops fish in the buckets by size class (above 9kg, 3.4-9kg, 1.8-3.4kg, 1.4-1.8kg and below 1.4kg). In cannery processing, species sorting was made for skipjack tuna and yellowfin tuna only from catches greater than 3.4kg during filtering but not for bigeye tuna because of difficulties in species identification between bigeye tuna and yellowfin tuna under frozen state. As no species identification was carried out for catch groups less than 3.4kg in the cannery process, this study focused on sorting out skipjack tuna and yellowfin tuna from these groups and then identifying bigeye tuna from all size groups of yellowfin tuna. Using the mixture rate of species obtained from the samples taken, species composition of the landed catch was estimated. As results, cannery research showed 95% for skipjack tuna, 3% for yellowfin tuna and 2% for bigeye tuna in species composition, while vessel logbook data represented 96%, 3% and 1% for skipjack tuna, yellowfin tuna and bigeye tuna, respectively. The proportion of bigeye tuna identified in the cannery was slightly higher than shown in logbook data by 1%.

• 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 Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.341-348
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• 1983

The Relationship between the distribution of the fishing grounds of anchovy and the oceanographic conditions in the Korean Waters are investigated by using the data of the catch of anchovy by the gill net fishery (Fisheries Research and Development Agency, 1969-1982) and the oceanographic observation data (Fisheries Research and Development Agency, 1979). The main fishing ground of anchovy by the gill net fishery was five fishing areas located in the adjacent seas of Sockcho, Kuryong-po, Kijang, Keoje island and Chungmu, the area of which occupies no more than $20\%$ of all fishing grounds, and it appeared that about $80\%$ of mean catches of fourteen years was concentrated in this area. The main fishing periods were from April to June and October to November. The coefficient of variation of the catch for the main fishing ground were from 0.3 to 0.6 and the condition of all fishing ground was generally stable. The mean CPUE was 81.2 kg/set at the main fishing ground. The annual mean catch of anchovy by the gill net was the smallest in February and the largest in May through a year. It was found that the fluctuation is related to the expansion and reduction of the isothermal line of $10^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.4
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• pp.219-227
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• 1970

The shrimp fishery for Penaeus japonicus on the Koje-Do coast commences in May and continues to October. The best catches are made twice a year, namely June and September. Modal carapace length for the female is $51\~55\;mm$ in May, $51\~60\;mm$ in June occupying about 80 percent of the total catch. There is conspicuous mode in July and $46\~50\;mm$ in August. Modal carapace length for the male is $41\~45\;mm$ in May, $46\~50\;mm$ in June, $41\~45\;mm$ in July and August. The stock of p. japonicus can be divided into two groups, namely, spring and fall groups. Among samples of p. japonicus during the period from May through August the sex ratio consisted of about 33 percent females and 67 percent males, showing wide departure from a 1:1 ratio. The relationships between carapace length ($\iota$), body length (L) and body weight (W) are expressed by the following formulae : $$L=2.9418{\iota}+2.0166$$, $$W:1.449{\iota}^{2.2858}$$ (Mayssample) $$L=2.5551{\iota}+4.2986$$, $$W=1.528{\iota}^{2.2595}$$ (June sample) $$L=2.6738{\iota}+3.4037$$, $$W=1.341{\iota}^{2.3598}$$ (July sample) The relatlonship between carapace length ($\iota$) and ovary weight (W) is shown as follows: $W=2.695\times10^{-3}\iota^{4.2973}$ for May, June and July Samples.

• Korean journal of applied entomology
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• v.40 no.2
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• pp.97-103
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• 2001

The rate of gerbera (Gerbera jamesonii Bolus.) leaf damaged by Liriomyza trifolii larvae was lower than that by adults. The adults began to be attracted to yellow sticky trap immediately after transplanting and increased gradually up to early August followed by low population density from middle to late August. In the second year, adults began to be attracted from late April after transplanting and increased abrubtly from middle May and the high density was maintained till early truly. The density decreased, however, from middle July, and then followed by the high density again early September and late October The seasonal fluctuations of larva and pupa were similar to that of adults and the peaks of pupa occurred one week later than that of larvae. Larva infected by parasitoid were observed 4 weeks after transplanting. Parasitism was 65% in average from early July to late August but decreased to 50% from early September. Number of trapped adults was the highest in the yellow sticky trap among the five different colour raps. Catches at 30~60 cm above soil surface were significantly greater than that at 90 cm.

• Korean journal of applied entomology
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• v.41 no.3
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• pp.183-189
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• 2002

Occurrence of scarabs at sweet persimmon (Diospyros kaki var. Fuyu) orchards was investigated by mercury light traps every one week interval in several areas in Gyeongnam province including, Jinju, Sacheon, Sancheong, and Gimhae, from April to September in 2000 and 2001. In addition, damage of persimmon by scarabs was observed every ten days interval at three orchards in Jinju and at one in Gimhae from late May to late October. Although sixteen species of 12 genera were attracted to the traps, species and number of catches were different according to orchards and years. Holotrichia morosa was most dominant in Jinju, Sacheon, and Sancheong. Total number of scarabs attracted to the traps was highest at the orchard surrounded by chestnut orchards in Sancheong. Fruits of sweet persimmon were not damaged by scarabs at the studied orchards. However, leaves and calyxes were slightly damaged by Adoretus tenuimaculatus. Maximum average numbers of the damaged leaves and calyxes throughout the year by A. tenuimaculatus were 0.33 leaves from 10 new shoots and 0.07 calyxes from 15 fruits. Gametis jucunda and Popillia mutans damaged flowers and calyxes. Maximum average numbers of damaged flowers and calyxes by these 2 species were the same as 0.03 from 15 flowers and 15 calyxes, respectively. These levels of damage suggest that the scarabs are not economically injurious to sweet persimmon fruits in Korea.

• Korean journal of applied entomology
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• v.43 no.3 s.136
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• pp.201-209
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• 2004

Overwintering ecology of the peach pyralid moth, Dichocrosis punctiferalis Guenee (Lepidoptera: Pyralidae) was studied in laboratory and in a chestnut orchard in 2001/2002 winter and 2003 spring. All twenty-four female and fourteen male moths were fruit-feeding type which were emerged from the larvae collected at the same chestnut orchard in 2003 winter. Periodical thermal treatment of overwintering larvae at $25^{\circ}C$ revealed that diapause termination of the larval population started from the end of January and was completed until April 20 in southern region of Korea. Pupation of diapause-terminated larvae started from early May and reached to $100\%$ at June 3 in chestnut orchard. Days to pupation of female larvae after diapause termination were 12.5, 8.9, and 7.5 at $20^{\circ}C,\;25^{\circ}C$, and $30^{\circ}C$, respectively. Those of male larvae were similar to those of females. Pupal periods of female were 14.7, 11.8, and 9.0 days at the three temperatures. Moths of the overwintered generation emerged from May 20 to June 28, and reached to $50\%$ emergence on June 8 to 9 under emergence cage. Attraction of the male moths of overwintered generation to sex pheromone traps showed that the date of $50\%$ catches to the traps were June 17, when data from 3 southern regions of Korea were pooled.

• Korean journal of applied entomology
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• v.49 no.2
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• pp.139-144
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• 2010

This study investigated the efficiency of mating disrupters for the control of Grapholita molesta(Busck) and Adoxophyes orana in pear orchards. G. molesta was shown 4 peak occurrence, which were different according to treatments. In conventional control, many moths were captured in mid and late April and peaks occurred in mid June, August, and early-mid September. In the non-control treatment, there were low populations in April. A. orana also appeared to 4 peak in 2007. Moths were rarely captured in mating disrupter treatment but many were captured in both the non-control and in conventional treatment. A. orana damage differed significantly between mating disrupter use and conventional control in 2006. Especially, the difference was significant between conventional control and mating disrupter to leaf damage in August, and there were similar results in the damage by G. molesta in the shoots and fruits.