• 한국수산과학회지
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• 제57권3호
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• pp.292-301
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• 2024

It is challenging to simultaneously estimate parameters in a stock-recruitment relationship, steepness, and natural mortality rate with the other parameters within an age-structured assessment model even in a data-rich situation. Such a problem leads to uncertainty in estimates of management references such as maximum sustainable yield (MSY), which are affected by those components. The objective of this study was to evaluate the effects of those parameters on MSY by analyzing the process of estimating the MSY. For illustration, we used two data sets: The chub mackerel Scomber japonicus in the Korean waters and the yellowtail flounder Limanda ferruginea in the Southern New England-Mid Atlantic. As a result, the natural mortality rate influenced spawning stock biomass per recruit, yield per recruit, and MSY, while steepness affected MSY. A sensitivity analysis enabled us to estimate the natural mortality rate and steepness. The optimal set of steepness and natural mortality was 1.0 and 0.37 per year for the chub mackerel, and 0.35, and 0.8 per year for the yellowtail flounder, respectively.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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• pp.77-80
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• 2005

Recently illegal fishing is being committed as a result of changes in the economic and social framework of Korea, and its mainly due to a reduction of marine living resources, lack of a law-abiding spirit and alienation between related laws and reality. This paper suggests improved methods to fight illegal fishing by revising or enacting fisheries-related laws in an attempt to continuously develop our nation's fisheries industry, by establishing fishing control and fundamentally detering illegal fishing.

• 수산해양기술연구
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• 제56권4호
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• pp.347-360
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• 2020

In this study, the Bayesian state-space model was used for the stock assessment of the Blackfin flounder. In addition, effective measures for the resource management were presentedwith the analysis on the effectiveness of fisheries management plans. According to the result of the analysis using the Bayesian state-space model, the main biometric value of Blackfin flounder was analyzed as 1,985 tons for maximum sustainable yield (MSY), 23,930 tons for carrying capacity (K), 0.000007765 for catchability coefficient (q) and 0.31 for intrinsic growth (r). Also the evaluation on the biological effect of TAC was done. The result showed that the Blackfin flounder biomass will be kept at 14,637 tons 20 years later given the present TAC volume of 1,761 tons. If the Blackfin flounder TAC volume is set to 1,600 tons, the amount of biomass will increase to 16,252 tons in the future. Lastly, the biological effectiveness of the policy to reduce fishing effort was assessed. The result showed that the Blackfin flounder biomass will be maintained at 13,776 tons if the current fishing efforts (currently hp) level is set and maintained. If the fishing effort is reduced by 20%, it will increase to 17,091 tons in the future. The analysis on the economic effect of TAC showed that NPV will be the lowest at 1,486,410 won in 2038, 20 years after the establishment of 2,500 tons of TAC volume. If the TAC volume is set at 2,000 tons, NPV was estimated to be the highest at 2,206,522,000 won. In addition, the analysis on the economic effect of the policy to reduce the amount of fishing effort found that NPV will be 2,235,592,000 won in 2038, 20 years after maintaining the current level of fishing effort. If the fishing effort is increased by 10%, NPV will be the highest at 2,257,575 won even thoughthe amount of biomass will be reduced.

• 한국토양비료학회지
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• 제44권1호
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• pp.91-97
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• 2011

The objectives of this research were to investigate the system of rice intensification (SRI) on early growth, grain yield, and yield components under Chinese milk vetch residue-mulched no-tillage cropping systems at silt loam soil. The field was prepared as a split-plot design with three replications, main plots consisted of Dongjinbyeo, and Sobibyeo as a cultivar, and subplots consisted of $10{\times}10$ cm, $20{\times}20$ cm, and $30{\times}30$ cm as a planting density. Weed infestation during rice growing season was more severe in wider planting density $30{\times}30$ at 35 days after transplanting (DAT), and $20{\times}20$ cm at 95 DAT in both Sobibyeo and Dongjinbyeo. The maximum plant height was recorded in Sobibyeo compared with Dongjinbyeo, $10{\times}10$ cm and $20{\times}20$ cm planting density compared with $30{\times}30$ cm from 20 DAT until 60 DAT. Among the three planting densities, SPAD values were significantly greater in planting density of $20{\times}20$ cm both in Sobibyeo and Dongjinbyeo followed by $30{\times}30$ cm compared with closer planting density of $10{\times}10$ cm. The lowest grain yield was observed in wider planting density of $30{\times}30$ in both Sobibyeo and Dongjinbyeo due to lower number of panicle per unit area. Our findings suggest that optimum planting density for SRI in no-tillage paddy was $20{\times}20$ cm and it should be useful the systems to small-scale rice farmers in Korea as a sustainable farming system.

• 한국산림과학회지
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• 제103권2호
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• pp.264-269
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• 2014

본 연구는 아까시나무 군락에 대한 현재 생육지 분포면적의 파악과 임분수확량 및 탄소저장량을 구명하기 위하여 수행되었다. 아까시나무에 대한 분포면적은 1:5,000 임상도를 이용하여 추출하였으며, 임분수확량은 Weibull 직경분포모델을 이용하였고, 탄소저장량 및 흡수량은 임분수확량에 탄소배출계수를 적용하여 산출하였다. 임분수확량을 산출하기 위하여 임분 평균직경, 임분 흉고단면적, 최소 및 최대 직경 등 임분 생장인자에 대한 추정식을 산출하고 정확성을 검증하였다. 이 결과 모든 생장인자의 추정식이 분석에 이용할 수 있는 유의성을 가지고 있는 것으로 나타났다. 또한 임지의 생산력을 판정할 수 있는 지위지수를 도출한 바, 지위지수는 16~22 범위에 있는 것으로 나타났으며, 이들을 종합하여 임분수확표를 만들었다. 우리나라 아까시나무는 경상, 충청 및 경기도의 내륙에 주로 분포하는 것으로 나타났으며, 총 면적은 26,770 ha에 달하는 것으로 나타났다. 이를 탄소저장량으로 전환한 결과 2,517,598 tC 였으며, 연간 3.76 tC/ha를 흡수하는 것으로 계산되었다. 이는 탄소흡수량이 높은 수종으로 알려져 있는 참나무류와 유사하여, 추후 아까시나무가 기후변화 시대에 온실가스를 저장하는 수종으로서의 역할도 충분히 가능할 것이라 판단된다. 또한 본 연구에서 만든 임분수확표는 아까시나무 경영 및 관리정책에 도움을 줄 수 있을 것으로 사료된다.

• 수산경영론집
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• 제25권1호
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• pp.37-59
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• 1994

Many studies to cope with the present problems of Korean coastal and offshore fisheries has been performed, but these were done partly in necessities and general studies for Korean inshore and offshore fisheries are in early stage. Most of these studies adopted analytical way of approach for each fishery individually and they could not reflect the effect of correlated interaction among fisheries on the several common species/stocks, and thus optimal effort allocation was impossible. To consider general fisheries and optimal effort allocation among competing mixed species, a linear programming (LP) approach is applied in this study and introduced into 16 important inshore and offshore fisheries with 13 constraining species which were chosen by annual yield order. This study is not based on the biological interaction among species (i.e., prey - predator system) but the technological interaction between species and fishing efforts. For the application of LP model in these fisheries, the standardization of fishing efforts through different fishing gears could not be successful and a new way of effort standardization through CPUE for vessel tonnage was originated. Total standardized fishing effort on a particular species i, Ei, is computed as the linear summation of standardized fishing effort generated by each fishery j. That is, (equation omitted) where $f_{j}$ is the total vessel tonnage of fishery j and aij is the coefficients contributing to the standardized fishing effort per ton for species i taken in fishery j. The total fishing effort level on species i due to both directed fishing and by - catch can thus be accounted in the aij's. Optimal effort allocation among the j fisheries may be considered a minimizing problem (minimize $\Sigma$ $f_{j}$), subject to the constraints that standardized fishing effort levels on particular species are maintained at, above, and below certain predefined levels. Fishing effort goals for individual species can be based on various biological and/or economic criteria, i.e., fishing effort level generating maximum sustainable yield and/or maximum economic yield. But in this study the $F_{0.1}$ criteria which was accepted as an approximate level for $F_{mey}$ by Outland and Boerema's (1973) study. The findings of this study are, (1) LP model can be applied to the Korean inshore and offshore fisheries giobally. (2) Through a new way of combining multiple different fisheries' efforts for a particular species together generating standardized fishing effort, Schaefer curve could be applied to the complex system successfully. (3) The results of this study for total reduction scale were mostly the same as those of prior studies, but different much from the individual scales of reduction. This study showed the necessities for exploitation of more concrete parameters to put into consideration of profitability of fisheries and social factors, and this model can be modified according to the actual constraints. Also, considering the age structure of stocks, this model can be developed into better one for better fisheries management.ent.

• 한국미생물·생명공학회지
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• 제51권4호
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• pp.449-456
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• 2023

Sugar or dextrose increases the cost of production of xanthan gum by Xanthomonas campestris. Brewers' Spent Grain (BSG) was chosen as a source of fermentable sugars. BSG is a significant industrial by-product generated in large quantities from the breweries. Primarily used as animal feed due to its high fiber and protein content, BSG holds great potential as an economically and ecologically sustainable substrate for fermenting biomolecules. This study explores BSG's potential as a cost-effective carbon source for producing xanthan, utilizing Xanthomonas campestris NCIM 2961. An aqueous extract was prepared from BSG and inoculated with the bacterium under standard fermentation conditions. After fermentation, xanthan gum was purified using a standard protocol. The xanthan yield from BSG media was compared to that from MGYP media (control). The fermentation parameters, including pH, temperature, agitation and duration were optimized for maximum xanthan gum yield by varying them at different levels. Following fermentation, the xanthan gum was purified from the broth by alcoholic precipitation and then dried. The weight of the dried gum was measured. The obtained xanthan from BSG under standard conditions and commercial food-grade xanthan were characterized using FTIR. The highest xanthan yields were achieved at 32 ℃, pH 6.0, and 72 h of fermentation at 200 rpm using BSG media. The FTIR spectra of xanthan from BSG media closely resembled that of commercial food-grade xanthan. The results confirm the potential of BSG as a cost-effective alternative carbon source for xanthan production, thereby reducing production costs and solid waste.

• 한국수산과학회지
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• 제25권4호
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• pp.282-290
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• 1992

한국근해 참조기의 지난 20여년 동안의 어획자료를 사용하여 잉여생산량 모델에 의해 추정된 MSY를 비교하여 보면, Shaefer와 Fox 모델에 의하여 추정된 값들은 각각 37,000mt와 33,450mt였고, Zhang 모델에 의하여 자원량과 순간어획사망계수를 적용시킨 MSY는 45,328mt, 자원량과 어획량 자료를 이용하는 방법에서는 40,160mt로 각각 추정되었다 이 현상은 이 모델들이 각기 독립된 다른 자료를 이용하여 MSY를 추정하였으나, 추정된 값은 거의 비슷한 결과를 보였다. 참조기자원을 가입당생산량 모델에 적용시킨 결과를 사용하여 자원관리 방안을 모색해 보면, 가능한 최대 가입당 생산량이 43g임에 비하여 현재의 $t_c=0.604, F=1.11$에서의 가입당생산량은 약 20g정도에 불과하다 여기서 $t_c$를 현재 상태로 고정시킨 후. 가입당생산량을 높이는 방안을 생각해 보면, F를 현재의 1.11에서 0.4 정도로 낮추어야 하나, 가입당생산량의 큰 증가는 없다. 즉, 현재의 20g에서 25g밖에 증가되지 않는다. 그러나, 현재의 어획강도(F)를 고정시키는 경우에는 $t_c$를 현재의 0.604세에서 3세 부근으로 조정하면 최대의 가입당생산량(43g)을 얻을 수 있고, 이 $t_c$ 값은 역시 $F_{0.1}$, 방법에서 추정된 적정어획체장을 연령으로 환산한 결과와 거의 일치함을 알 수 있다. Zhang모델을 이용한 자원의 회복 방안에서 참조기 자원의 최대생산가능 자원량$(B^*_{MSY})$를 유지시키려면 F를 약 0.5 수준으로 낮추어야 하고. 이 수준에서 약 8년 뒤에는 자원량이 적정 수준에 거의 접근하게 된다.-저층의 경우, 난류성 종인 E. russelli와 E. plana가 출현하며 수온이 $12^{\circ}C$이상인 제주도 서북방 해역이 난류의 영향을 받는 해역으로 나타났으며, 저온성 종인 C. abdominalis가 출현하는 진도 이북 해역이 황해 냉수괴인 것으로 나타났다. 하계 0-20m층의 진도부관 해역 및 20m- 저층의 진도 이북 해역에서 C. abdominalis가 출현하는 것으로 보아 냉수괴가 존재하는 것으로 나타났다.H와 온도에 대해서 복상어의 trypsin은 고등어의 두 trypsin보다 알칼리성측과 고온에 대해 안정하였으며, 저해제에 의하여서는 복상어 trypsin이 보다 예민하게 나타났다. 또한 BA-p-NA 합성기질에 대한 친화성에 있어서는 고등어의 두 trypsin이 복상어의 trypsin보다 높은 것을 알 수 있었다. 5. 아미노산 조성은 세 효소 모두 비슷하였으나, 고등어 trypsin B의 경우 arginine의 함량이 높은 특징을 보였다. 산성아미노산과 염기성아미노산의 비는 복상어 trypsin이 3.57, 고등어 trypsin A는 3.36, 그리고 고등어 trypsin B는 2.23이었다./TEX>에 의하여 저해를 받았으며, 그 저해의 정도는 고등어 trypsin-A와 B가 보다 심하게 받았다. 또 이들 효소들은 antipain, leupeptin, TLCK(to-syllysine chloromethyl ketone) 및 SBTI(soybean trypsin inhibitor)에 의하여 현저한 저해를 받았고, PMSF(phenylmethane sulfonylfluoride), DFP(diisopropyl fluorophosphate) 및 benzamidine에 의하여 어느정도 저해를 보여 모두 serine-계의

• 한국기후변화학회지
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• 제7권2호
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• pp.157-167
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• 2016

This study aims to evaluate the effect of shortened final cutting age by estimating future $CO_2$ absorption in each different scenarios based on each final cutting ages before and after shortening. We used $5^{th}$ Forest Type Map and Forest Yield Table to obtain information to estimate $CO_2$ absorption of forest. We also designed a simulated future scenarios from 2010 to 2100 which repeats cutting and reforestation according to respected each final cutting ages. As the result, number of cuttings and total amount of $CO_2$ absorption of forest were increased with shortened final ages. Total cutting times increased up to 2 in both minimum and maximum amount for Quescus spp. and Larix kaempferi. Maximum number of cutting of Pinus densiflora and minimum number of Pinus koraiensis increased by 1. Total $CO_2$ absorption increased 12％ for Quercus spp. which had the largest number of increase in cutting times, while total $CO_2$ absorption of Pinus koraiensis only increased by 1％. The result could be used to evaluate the changes in forest management plans and policies and then develop optimal final age for efficient sustainable forest management plans.

• 한국미생물·생명공학회지
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• 제51권3호
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• pp.257-267
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• 2023

The potential polyhydroxyalkanoates (PHA)-producing bacteria, Bacillus megaterium PP-10, was successfully isolated and studied its feasibility for utilization of pineapple peel waste (PPW) as a cheap carbon substrate. The PPW was pretreated with 1% (v/v) H₂SO₄ under steam sterilization and about 26.4 g/l of total reducing sugar (TRS) in pineapple peel hydrolysate (PPH) was generated and main fermentable sugars were glucose and fructose. A maximum cell growth and PHA concentration of 3.63 ± 0.07 g/l and 1.98 ± 0.09 g/l (about 54.58 ± 2.39%DCW) were received in only 12 h when grown in PPH. Interestingly, PHA productivity and biomass yield (Y_x/s) in PPH was about 4 times and 1.5 times higher than in glucose. To achieve the highest DCW and PHA production, the optimal culture conditions e.g. carbon to nitrogen ratios of 40 mole/mole, incubation temperature at 35℃ and shaking speed of 200 rpm were performed and a maximum DCW up to 4.24 ± 0.04 g/l and PHA concentration of 2.68 ± 0.02 g/l (61% DCW) were obtained. The produced PHA was further examined its monomer composition and found to contain only 3-hydroxybutyrate (3HB). This finding corresponded with the presence of class IV PHA synthase gene. Finally, certain thermal properties of the produced PHA i.e. the melting temperature (T_m) and the glass transition temperature (T_g) were about 176℃ and -4℃, respectively whereas the M_w was about 1.07 KDa ; therefore, the newly isolated B. megaterium PP-10 is a promising bacterial candidate for the efficient conversion of low-cost PPH to PHA.