This study was performed to estimate biomass and provide management guidance through population ecological characteristics, including growth parameters, instantaneous coefficients of natural and fishing mortalities, and age at first capture of the starry flounder, Platichthys stellatus and olive flounder, Paralichthys olivaceus of Korea. For describing growth of this species, a von Bertalanffy growth model was adopted. The von Bertalanffy growth parameters estimated from a non-linear regression for starry flounder were L∞=48.25 cm, K=0.16/yr, and t0=-1.48, respectively and those for olive flounder were L∞=86.46 cm, K=0.26/yr, and t0=-0.29, respectively. Biomass of Platichthys stellatus was estimated by direct biomass estimation method was 2.6 M/T, that was estimated by indirect method was 13.4 M/Tt. Those of Paralichthys olivaceus were estimated as 10.1 M/T, 19.3 M/T, respectively. An yield per recruit analysis showed that the current yield per recruit on Platichthys stellatus was about 48.2 g with F=0.646/yr and the age at first capture (tc) 1.35yr, that on Paralichthys olivaceus was about 167.6 g with F=1.121/yr and the age at first capture (tc) 1yr.

Flounder was selected as one of the 10 strategic export aquaculture products for seafood export expansion in 2013. The flounder aquaculture industry has promoted export market diversification and product diversification from live to processed goods as a it’s main strategy. The purpose of this study is to find an improvement plan for export expansion to the United States, as it emerged as a new target export market for the flounder. A summary of the key findings is as follows. First, the western region of the United States prefers to consume live and fresh flounder, whereas the eastern region prefers to consume fresh flounder. Second, because of it’s high quality, Korean flounder is favored in the western region of the United States despite it’s high price, whereas in the eastern region of the United States, where production volume is high, Korean flounder has to compete with US flounders because of it’s high price. Third, according to the survey results, US consumers tend to enjoy seafood, as well as flounder cuisines. Fourth, the main consumption place of flounders by US consumers are restaurants, and they prefer to consume them in the form of sashimi and sushi. Fifth, 70% of US consumers expressed willingness to consume flounder when eating out. which shows great market potential. However, the high price of Korean flounder and limited size of the live fish market act as major obstacles to expanding export volume. To expand exporting Korean flounder, continuos efforts such as price reduction, exporting highly fresh fish , the co-development of processed food with the US are needed.

This study is to analyse the timing of the structural change of price volatility and the asymmetry of price volatility during the period before and after the timing of the structural change of price volatility using Jeju Farming Olive Flounder’s production area market price data from January 1, 2007 to June 30, 2013. The analysis methods of Quandt-Andrews break point test and Threshold GARCH model are employed. The empirical results of this study are summarized as follows: First, the result of Quandt-Andrews break point test shows that a single structural change in price volatility occurred on May 4, 2010 over the sample period. Second, during the period before structural change, daily price change rate has averagely positive value which means price increase, but during the period after structural change daily price change rate has averagely negative value which means price decrease. Also, daily volatility of price change rate during the period before structural change is higher than during the period after structural change. This indicates that price volatility decreases after structural change. Third, the estimation results of Threshold GARCH Model show that the volatility response against price increase is larger during the period after structural change than during the period before structural change. Also the result shows the volatility response against price decrease is larger during the period after structural change than during the period before structural change. And, irrespective of the timing of structural change, price increase has an larger effect on volatility than price decrease. This means volatility is asymmetric at price increase.

해양에서 이산화탄소 증가에 따른 해양산성화가 넙치 치어의 성장에 미치는 영향을 조사하기 위하여 현장 메조코즘 실험을 실시하였다. 동해 남부에 위치한 기장군 장안읍의 사질저질에서 실험군(이산화탄소 주입)과 대조군의 실험장비를 설치하여 43일 동안 총 447개체 (실험군 223개체, 대조군 224개체)를 대상으로 실시하였다. 실험군의 pH는 평균 7.63±0.13, 이산화탄소 (fCO2)농도는 평균 1660±540 μatm로 2100년도에 예상되는 수준으로 (IPCC 2007) 유지하였으며, 대조구는 현재 기장군 장안읍 해역의 해양환경으로 유지하였다. 실험기간동안 사망률은 실험군과 대조군 사이에서 큰 차이를 나타내지 않았고 시간이 지남에 따라 감소하는 경향을 나타내었다. 넙치 치어의 체장과 체중은 대조군에서 더 큰 증가양상을 나타내어, 그 결과 대조군에서 더 큰 성장률(specific growth rate)을 보였다. 결론적으로 본 연구는 해양에서 이산화탄소 농도의 증가는 넙치 치어의 초기 성장에 영향을 줄 수 있는 가능성을 제시하였다.

본 연구는 고온미생물인 Bacillus coagulans를 이용하여 발효시킨 탈피대두박(fermented soybean meal; FS)을 어분대체 단백질원으로서 10%, 20% 및 30% 수준별로 첨가한 배합사료를 급여하여 넙치의 성장 및 육질에 미치는 영향을 비교 조사하였다. 사육실험은 평균체중 123 g의 넙치를 원형수조에 50마리씩 실험구별로 3반복으로 수용하면서, 대조 배합사료(control)와 실험배합사료(FS10, FS20, FS30)를 8주간 사육하였다. 수분과 조단백질 함량은 대조 배합사료를 공급한 넙치의 등근육과 실험 배합사료를 공급한 넙치의 등근육에서 유의적한 차이를 보이지 않았으나, 조지방 함량은 실험배합사료 FS20, FS30을 공급한 넙치 등근육에서 유의적으로 높은 값을 나타내었다. 18:2n-6의 함량은 실험배합사료 FS10, FS20, FS30을 공급한 넙치 등근육에서 대조 배합사료를 공급한 넙치 등근육보다 유의적으로 높게 나타났다. 모든 시험구에서 넙치 등근육의 유리아미노산 중 taurine, leucine, alanine, lysine이 공통적으로 높은 함량을 나타내었고, 공급한 사료에 따라 넙치 등근육의 유리아미노산에는 유의적인 차이는 없었다. 핵산관련물질 중 AMP의 함량은, FS20 및 FS30을 공급한 넙치 등근육에서 대조 배합사료를 공급한 것보다 유의적으로 높은 함량을 나타내었다. 이상의 결과로부터, 본 실험 사료조성으로 넙치 치어를 사육하였을 때 어분대체 단백질원으로서 발효대두박을 어분 단백질 함량기준으로 30%까지 대체 가능할 것으로 생각되었다.

Antibiotic Detection Kit (Combination I), a lateral flow immunoassay (LFIA) developed for the detection of antibiotic residues in milk, was utilized for the analysis of antibiotic residues in the muscle tissue of olive flounder. After 60-min treatment by dipping in water dosed with ampicillin (200-g/ton water), the residue depletion of ampicillin was investigated in 25 cultured olive flounder (Paralichthys olivaceus). Muscles of fish were sampled on the 1st, 2nd, 3rd, 4th and 5th day after drug treatment. The concentration of ampicillin in the muscle was determined by LFIA. The absorbance ratio of the sample to the control blank (Bs/Bo) was employed as an index to determine the muscle residues in olive flounder. To investigate the recovery rate, standard solutions were added to muscle samples to give final concentrations in the muscle of 4 and 8 ng/ml. The recovery rates of all spiked samples were > 96% of the spiked value. Ampicillin was detected in the muscle of fish treated with the drug until the 2nd day of the withdrawal period. The present study showed that the LFIA can be easily adopted to predict ampicillin residues in tissue of farmed fishes.

Physical characteristics of net filament were investigated to test the fishing capacity of gill nets due to the flexibility difference between nylon and biodegradable nets (PBS 95%+PBAT 5% and PBS 80%+PBAT 20%). In addition, a total of 16 fishing experiments were conducted in the coastal waters of Jeongja, Ulsan, from August 10 to October 20, 2011 and from September 11 to November 3, 2012. The test results showed that nylon net filament exhibited more flexibility than biodegradable net filament when they were wet. Accordingly, the longer submerged time, the more fishing capacity the nylon gill nets demonstrated in comparison with the biodegradable gill nets. A total of 16 species were caught in 2011 with the nylon gill nets (1,323 fishes, weighing 342,885g) and the biodegradable gill nets (958 fishes, weighing 236,857g). 15 species were caught in 2012 with the nylon gill nets (1,582 fishes, weighing 448,360g) and the biodegradable gill nets (1,431 fishes, weighing 406,590g). Thus catch weights and the number of fish caught produced by the nylon nets were 1.45 times and 1.38 times higher than those of the biodegradable nets produced in 2011, and 1.1 times and 1.11 times higher in 2012. A test on the target species, pointhead flounder (Cleisthenes pinetorum) has similar results. The flexibility of a net was proved to be related to the fishing capacity, and as a result, it is concluded that the higher flexibility, the higher fishing capacity.

나프탈렌(Naphthalene)과 같은 다환방향족탄화수소류(Polycyclic aromatic hydrocarbons, PAHs)는 수계에 유입되어 해양생물들에게 영향을 미치게 된다. 나프탈렌은 유류속의 PAHs 내에서 함량이 가장 높으며, 독성이 강하다. 본 연구에서는 대조구(0 μg/L), 1000, 1800, 3200, 5600, 10000 μg/L의 6개 나프탈렌 농도구를 설정하고 넙치 치어에 대한 나프탈렌의 24시간 반수치사농도(24h-LC50)을 구했으며, 아가미, 간, 신장, 근육내의 나프탈렌 농도를 분석하였다. 넙치 치어의 24h-LC50은 Large 그룹에서 2410.76 μg/L, Small 그룹에서 2230.67 μg/L을 나타내었다. 각 조직에서의 나프탈렌 농도는 간 및 신장에서 아가미 및 근육보다 높았다.

There are many studies of the biodegradable net for fishing to prevent marine pollution in Korea and the snow crab gill nets is developed effectively. Recently, the biodegradable gill net for fishes is being developed. This study is the experiment of the catch characteristics for the biodegradable flounder gill net. The 8 experiments were carried out using the nylon gill net and the biodegradable gill net in from August to October, 2011 in the southern East Sea. The results obtained from the above approaches are summarized as follows; A total of 16 species was caught with most dominant species of Cleisthenes pinetorum followed by Liparis tanakai, Glyptocephalus stelleri, Buccinum striatissimum and Dasycottus setiger. A total of catch of the nylon net was 342,885g and that of the biodegradable net was 236,857g. Thus catch of the nylon net was 1.45 times more than that of the biodegradable net. The length composition of Cleisthenes pinetorum, caught by the biodegradable net was very similar to that of nylon. As a result of analysis on the effect of submerged time, small fish escaped more easily than large fish as the submerged time is getting longer. And catches of the biodegradable net was less than the nylon net's as higher as wave height. Wave height was more influential factor for fishing capacity than submerged time based on the results of a comparison between catch difference of two kinds of gill nets and catch characteristics.

넙치, Paralichthys olivaceus 수정란의 부화율을 이용하여 중금속(Pb, Cr, As)의 독성 영향을 조사하였다. Pb, Cr, 및 As (0, 10, 100, 500, 1,000, 2,500, 5,000 ppb)에 수정란을 48 h 노출시킨 후, 정상 부화율을 백분율로 나타내었다. 중금속을 포함하지 않는 대조구에서는 정상 부화율이 80% 이상을 나타냈으나, 중금속 농도가 증가할수록 정상 부화율은 급격히 감소하였다. 정상 부화율은 Pb, Cr, 및 As에 대해 농도 의존적으로 감소하였으며, 각각 100, 100, 500 ppb 이상의 농도에서 유의한 차이를 나타내었다. P. olivaceus의 정상 부화율에 대한 Pb, Cr 및 As의 반수영향농도(EC50)를 이용한 독성은 Cr¤As¤Pb 순으로 나타났다. Pb와 As의 NOEC와 LOEC 각각 100 ppb와 500 ppb로 유사한 값을 나타냈으며, Cr에 대한 NOEC는 10 ppb, LOEC는 100 ppb를 나타내었다. 이들 결과로부터 자연생태계 내에서 Pb과 As의 농도는 100 ppb, Cr 농도는 10 ppb를 초과할 경우 P. olivaceus 수정란의 정상 부화율은 독성 영향이 나타날 것으로 판단된다. 본 연구 결과를 바탕으로, P. olivaceus의 정상 부화율을 이용한 생물학적 평가방법은 중금속과 같은 유해물질에 대한 해양생태계의 영향을 판단하기 위한 시험방법으로 유용하게 이용될 수 있을 것으로 판단된다.

넙치(Paralichthys olivaceus) 수정란의 부화율에 대한 중금속(Cd, Cu, Zn)의 급성독성을 조사하였다. Cd, Cu 및 Zn (0, 10, 100, 500, 1000, 2500, 5000 ppb)에 수정란을 48h 노출시킨 후, 정상 부화율을 백분율로 나타내었다. Cd, Cu 및 Zn을 포함하지 않는 대조구에서는 정상 부화율이 80% 이상을 나타냈으나, 중금속 농도가 증가할수록 정상 부화율은 급격히 감소하였다. 정상 부화율은 Cd, Cu 및 Zn에 대해 농도 의존적으로 감소하였으며, 각각 1000, 100, 100 ppb 이상의 농도에서 유의적이 차이를 나타내었다. P. olivaceus의 정상 부화율에 대한 Cd, Cu 및 Zn의 반수영향농도(EC50)를 이용한 독성은 Zn¤Cu¤Cd 순으로 강한 것으로 나타났으며, 이들 중금속에 대한 EC50는 각각 584, 1015, 1282 ppb를 나타내었다. Cd에 대한 NOEC는 500 ppb를 나타냈고 LOEC는 500 ppb를 나타내었다. Cu와 Zn의 NOEC와 LOEC 각각 100 ppb와 500 ppb로 유사한 값을 나타내었다. NOEC와 LOEC 결과로부터 자연생태계 내에서 Cu와 Zn 농도는 100 ppb, Cd 농도는 500 ppb를 초과할 경우 P. olivaceus 수정란의 정상 부화율은 감소할 것으로 판단된다. 본 연구결과를 바탕으로, P. olivaceus의 정상 부화율을 이용한 생물학적 시험은 중금속과 같은 유해물질에 대한 해양생태계의 영향을 판단하기 위한 시험방법으로 유용하게 이용될 수 있을 것으로 판단된다.