• Journal of Fisheries and Marine Sciences Education
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• v.29 no.2
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• pp.513-525
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• 2017

In the estimation of the exploitable carrying capacity (ECC) in the Korean water of the East China Sea, two approaches, which are the ecosystem modeling method (EMM) and the holistic production method (HPM), were applied. The EMM is accomplished by Ecopath with Ecosim model using a number of ecological data and fishery catch for each species group, which was categorized by a self-organizing mapping (SOM) based on eight biological characteristics of species. In this method, the converged value during the Ecosim simulation by setting the instantaneous rate of fishing mortality (F) as zero was estimated as the ECC of each group. The HPM is to use surplus production models for estimateing ECC. The ECC estimates were 4.6 and 5.1 million mt (mmt) from EMM and HPM, respectiverly. The estimate from the EMM has a considerable uncertainty due to the lack of confidence in input ecological parameters, especially production/biomass ratio (P/B) and consumption/biomass ratio (Q/B). However, ECC from the HPM was estimated on the basis of relatively fewer assumptions and long time-series fishery data as input, so the estimate from the HPM is regarded as more reasonable estimate of ECC, although the ECC estimate could be considerd as a preliminary one. The quality of input data should be improved for the future study of the ECC to obtain more reliable estimate.

• Fisheries and Aquatic Sciences
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• v.27 no.4
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• pp.231-239
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• 2024

Geray Reservoir is home to some fish species including Varicorhinus beso, Cyprinus carpio, Carasius carasius, Oreochromis niloticus, and Tilapia randelli. The V. beso is among the top fish-farming species for the reservoir. However, this data on total fish catch showed that the fish population is declining as a result of overexploitation of the stock. The purpose of this study was to set some management measures for the Geray reservoir using some biometric data on the most commonly caught fish-V. beso. A total of 170 fish samples (102 females and 68 males) ranging from 21 to 40.2 cm in total length (TL) and 94.6 to 618.4 g in total weight (TW) were gathered between October 2022 and May 2022 using a cast net with a mesh size of 6 cm. Nonetheless, it is thought that the sampling period is sufficient because the fish were spawning more during the month when the data was collected because of the high concentration of nutrients during that time. The overall male-to-female sex ratio in the population was 1:1.5, which differed considerably from the real ratio of 1:1 (x² = 6.8; p < 0.01). V. beso in the Geray reservoir exhibited virtually an isometric growth (b = 3) considering the length-weight relationships of males (TW = 0.0122TL^2.993) and females (TW = 0.0114TL^3.0139). The V. beso had an absolute fecundity (AF) of 2,190 to 11,265 eggs. AF was significantly correlated with TL, TW, and gonad weight (p < 0.01). V. beso's reproductive season peaked between November and May, with the gonadosomatic index ranging from 0.02 to 20.12 for females and 0.03 to 5.67 for males. The average V. beso condition factors for both sexes were higher than 1, indicating that the fish in the reservoir had properly developed, which may be the result of favorable habitat conditions.

• Fisheries and Aquatic Sciences
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• v.27 no.4
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• pp.256-264
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• 2024

Small pelagic fish populations have long been exploited by various fishing gears in the Natuna Sea, and since the 1970s, purse seine exploitation has expanded to offshore fishing grounds. Various small pelagic fish species are exploited from these waters including spotted sardinella (Amblygaster sirm). This research was conducted for 22 months, from March 2019 to December 2020. The fish sample was taken from the purse seine fleet's catch in the fisheries management area (FMA) 711 Natuna Sea and Karimata Strait, which was brought to Pemangkat fishing port in the West Kalimantan Province, Indonesia. This paper aims to determine the exploitation status of spotted sardinella in the Natuna Sea as a recommendation material for management policies. The methods used in this analysis are estimated age, cohort, population parameters, and spawning potential ratio of spotted sardinella. The results show three primary cohorts of spotted sardinella in the Natuna Sea, with ages ranging from 9 months to 3.1 years and a maximum attainable age (longevity) of 4.3 years. The asymptotic value (L_∞) is 21.79 cmFL in length, with a growth rate (K) of 0.65 per year. The natural mortality rate (M) was 1.19, the total mortality rate (Z) was 2.19, and the fishing mortality rate (F) was 0.99. The exploitation rate (E) was 0.45 and the stock status was still in a sustainable condition. Therefore, the sardinella fisheries can be developed using a precautionary approach and focus on the ecosystem sustainability of FMA 711.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.3
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• pp.223-230
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• 2002

Investigations were made on catch composition, sex ratio, relationships between carapace length, body weight and fecundity and spawning season of major target shrimps (Acetes chinensis, A. japonicus) in the shrimp fishing areas of south-western coastal waters, accounting for about $45\%$ of annual shrimp landings in Korea. Catches were collected monthly in the fishing areas from March 2000 to February 2001, using single pocket-walled fishing gear, Total 59 species (shrimps 14, fishes 34, other crustaceans 8 and cephalopods 3 species) occurred. During the study period the bycatch-to-shrimp ratio of shrimp fishery was 2.42 in April 2000 and less than 1 for all months except for August 2000 and Febuary 2001. Compared with shrimp fishery of other areas and nations, these results indicate that effect of the fishing gear on catches of other species is minor, suggesting higher gear selectivity for shrimps. Of shrimps, there were two dominant species (A. chinensis, A. japonirus). Average sex ratio was 1.44 $\pm$ 0.42 for A. japonicus and 1,44 $\pm$ 0.43 for A. chinensis, which are dominant females in August. Average fecundity was 4,812 $\pm$ 1,511 for A. japonicus and 5,561 $\pm$ 1,900 for A. chinensis. In the two species mature females were found in the period from May to August. Similarly, the gonadosomatic index (GSI) was higher in July and August, with a peak in July, These results indicate that their main spawning season was summer.

• The Journal of Fisheries Business Administration
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• v.32 no.1
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• pp.15-39
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• 2001

The study, using the input-output analysis of 402 industrial sectors by Bank of Korea(BOK) and the resulting outcomes of price model, aims to evaluate the spillover effects the international fluctuations in crude oil prices have on the commodities prices and consequently, analyse the management and profitability of the offshore fisheries in Korea. At present, the fisher men are provided with tax-free oils for their fishing operations as specified under the Special Tax Treatment Control Law. However, the exhaustion of marine resources and new international fisheries agreements, which resulted in the loss of fishing grounds, made the stable catch even more unpredictable and the hike in the price of the international crude oil would have adverse effects on the fishing industry. The study revealed that the increasing rise in the price of crude oil would exert sweeping spillover effects on other industry sectors in general and accordingly, lead to a poorer performance by fisheries. The price spillover coefficients for the diesel oil was 0.6026, which would translate into the 42.6% increase in the prices of oil when the increase ratio of 73.3% for the base crude oil was applied based on the calculation methods employed in the study. This in turn increased the ratio of diesel oil required in the offshore fisheries from 23.3% to 16.6%, diminishing the ratio of current net profits to minus 2.0% from 4.2% otherwise. By fishing type, the Pair Trawl suffered current net profits loss most by ratio of minus 9.4% and other fisheries such as Coastal Stow Nets, Coastal Angling, Danish Sein also suffered ratio of 7% and more in the loss of current net profits. With the deteriorating fishing performance, coupled with the increasing international crude oil prices, it is urgently required that the authorities concerned deliberate in depth on such schemes as follows in efforts to secure stable fishing production. First, provision of large-scale storage facilities for oil is needed to timely adapt to the fluctuations in international crude oil prices. Secondly, in line with the stabilization of tax-free oil prices, duty levied on oils for fishing and tax collected from the refineries need to be tax-exempt. Thirdly, the beneficiaries from the provision of tax-free oil should be broadened, not limited to special fishing operation only. Fourth, investment in stabilization of the oil prices should be encouraged, possibly through funding from the formation of fisheries development funds underway.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.1
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• pp.9-16
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• 2005

This study was conducted in order to improvement of fishing gear and fishing operating system for anchovy boat seine by labor saving improved nets. Field experiments were carried out observe geometry of nets and fishing operating system by catcher boats. The obtained results are summarized as follows : The Vertical net opening of fore wing net, wing net, inside wing net, square, fore bag net, flapper, after bag net of the labor saving improved net according to the distance between catcher boats were varied in the range of 5.0${\sim}$7.8, 14.4${\sim}$21.1, 16.2${\sim}$21.2, 14.0${\sim}$17.3, 11.7${\sim}$13.9, 5.4${\sim}$6.9, 8.2${\sim}$9.8m respectively, varied in the range of 50${\sim}$78, 25${\sim}$36, 24${\sim}$31, 31${\sim}$38, 61${\sim}$73, 71${\sim}$91, 87${\sim}$104% of the actual ratio of net opening in each part. Labor saving improved net was performed instant net opening in fore wing net and maintained stable net opening and towing depth by means of attached net pendant. Also, it was minimized as net pocket phenomenon leading to guide anchovy for more catch by means of attached body net. The opening in accordance with distance between catcher boats and towing speed. The catch of labor saving improved net was increased than traditional net due to decrement of net resistance by improvement of bag net leading to increasement of towing speed and reduction of escape anchovy as well as improve nets of whole operation system.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.1
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• pp.78-91
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• 2021

This study analyzed the reproductive biology, fishing characteristics and changes in fishing business of Liparis tanakae, snailfish collected from September to March. It was the period when they were mainly caught from 2018 to 2020. The average length was generally small in September and October and was large in January and February. The average body weight was generally around 1,500 g and the average body weight in autumn was lower and in winter was higher. The sex ratio of male and female was 0.40:0.60 (��2 test, p < 0.05). The spawning period was estimated from October to February and the main spawning period was from December to February through the GSI. The egg diameter of matured staged female L. tanakae was 0.11-1.48 mm, which was the main spawning period and the relationship between body weight and fecundity was F = 1849TL0.1093 (r2 = 0.2401). The monthly catch of L. tanakae was high from November to February, the time of migrating to the coastal area. Coastal gillnet fishery showed the highest percentage of all fisheries catching Liparis spp. Liparis spp. were caught at a high rate in winter in Chungnam, Jeonbuk, Jeonnam and Gyeongnam region, and revenue and cost was increased since 2017. Assuming a situation where there is no catch of Liparis spp., the fishing profit that can be obtained was the highest in Gyeongnam region and the dependence on fishing of Liparis spp. by coastal gillnet fishery was high.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.4
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• pp.291-298
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• 2024

As an important fishing ground in the southern coast of Korea, Jinhae Bay is characterized by a high level of fisheries production. However, its marine-ecosystem has shifted owing to environmental changes such as industrial development and high water temperatures over the decades. This study analyzes the fisheries production, discards, mean trophic level, and fishing-in-balance index using annual fishing data from five regions surrounding Jinhae Bay for the period 2005-2022, as well as using additional forecasting trends by 2027 using ARIMA (Auto Regressive Intergrated Moving Average). The results shows, that the production in Goseong will decrease continuously by 2027, as compared with that in other areas. Additionally, byproduct management is considered necessary in Tongyeong. For the marine-ecosystem index, Tongyeong indicates stable catch ratio of large fish species and a fishing-in-balance exceeding 0. Finally, the annual catch variation for six pelagic fish species in Jinhae Bay by 2060 is estimated based on the IPCC climate-change scenario, in which the recent low level that decreased to approximately 20 thousand ton in early 2020 is projected to recover to approximately 40 thousand ton in the 2020s and 2040s, followed by an incremental decline by 2060.

• Management & Information Systems Review
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• v.22
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• pp.137-165
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• 2007

It seems high time to increase productivity by adopting e-business to overcome challenges posed by both external factors including the appreciation of Korean won, oil hikes and fierce global competition and domestic issues represented by disparities between large corporations and small and medium enterprises (SMEs), Seoul metropolitan and local cities, and export and domestic demand all of which weaken future growth engines in the Korean economy. The demands of the globalization era are for innovative changes in businessprocess and industrial structure aiming for creating new values. To this end, e-business is expected to play a core role in the sophistication of the Korean economy through new values and innovation. In order to examine business performance in e-business-adopting industries, this study analyzed the home shopping industry by closely looking into the financial ratios including the ratio of net profit to sales, the ratio of operation income to sales, the ratio of gross cost to sales cost, the ratio of gross cost to selling, general and administrative (SG&A) expense, and return of investment (ROI). This study, for best outcome, referred to corporate financial statements as a main resource to calculate financial ratios by utilizing Data Analysis, Retrieval and Transfer System (DART) of the Financial Supervisory Service, one of the Korea's financial supervisory authorities. First of all, the result of the trend analysis on the ratio of net profit to sales is as following. CJ Home Shopping has registered a remarkable increase in its ratio of net profit rate to sales since 2002 while its competitors find it hard to catch up with CJ's stunning performances. This is partly due to the efficient management compared to CJ's value of capital. Such significance, if the current trend continues, will make the front-runner assume the largest market share. On the other hand, GS Home Shopping, despite its best organized system and largest value of capital among others, lacks efficiency in management. Second of all, the result of the trend analysis on the ratio of operation income to sales is as following. Both CJ Home Shopping and GS Home Shopping have, until 2004, recorded similar growth trend. However, while CJ Home Shopping's operating income continued to increase in 2005, GS Home Shopping observed its operating income declining which resulted in the increasing income gap with CJ Home Shopping. While CJ Home Shopping with the largest market share in home shopping industryis engaged in aggressive marketing, GS Home Shopping due to its stability-driven management strategies falls behind CJ again in the ratio of operation income to sales in spite of its favorable management environment including its large capital. Companies in the Group B were established in the same year of 2001. NS Home Shopping was the first in the Group B to shift its loss to profit. Woori Home Shopping has continued to post operating loss for three consecutive years and finally was sold to Lotte Group in 2007, but since then, has registered a continuing increase in net income on sales. Third of all, the result of the trend analysis on the ratio of gross cost to sales cost is as following. Since home shopping falls into sales business, its cost of sales is much lower than that of other types of business such as manufacturing industry. Since 2002 in gross costs including cost of sales, SG&A expense, and non-operating expense, cost of sales turned out to have remarkably decreased. Group B has also posted a notable decline in the same sector since 2002. Fourth of all, the result of the trend analysis on the ratio of gross cost to SG&A expense is as following. Due to its unique characteristics, the home shopping industry usually posts ahigh ratio of SG&A expense. However, more than 80% of SG&A expense means the result of lax management and at the same time, a sharp lower net income on sales than other industries. Last but not least, the result of the trend analysis on ROI is as following. As for CJ Home Shopping, the curve of ROI looks similar to that of its investment on fixed assets. As it turned out, the company's ratio of fixed assets to operating income skyrocketed in 2004 and 2005. As far as GS Home Shopping is concerned, its fixed assets are not as much as that of CJ Home Shopping. Consequently, competition in the home shopping industry, at the moment, is among CJ, GS, Hyundai, NS and Woori Home Shoppings, and all of them need to more thoroughly manage their costs. In order for the late-comers of Group B and other home shopping companies to advance further, the current lax management should be reformed particularly on their SG&A expense sector. Provided that the total sales volume in the Internet shopping sector is projected to grow over 20 trillion won by the year 2010, it is concluded that all the participants in the home shopping industry should put strategies on efficient management on costs and expenses as their top priority rather than increase revenues, if they hope to grow even further after 2007.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.1
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• pp.69-77
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• 2010

We examined shrimp and bycatch species composition in the shrimp beam trawl fishery off Wan-do, Korea(in the major or fishing ground)from December 2004 to November 2005. We observed a total of 103, 072 individuals in 96 taxa. By densities of individuals, 96.97% were shrimps, 1.20% decapods, 1.10% fish, 0.30% cephalopods and 0.43% other species. By catch weight, 57.29% were shrimps, 26.33% fish, 6.82% decapods, 4.64% cephalopods and 4.92% other species. In spring, the dominant bycatch species by biomass were Okamejei kenojei, Lophiomus setigerus, and Charybdis bimaculata. In summer, the dominant species were Charybdis bimaculata, Muraenesox cinereus, and Paralichlhys olivaceus. In autumn, dominants were Okamejei kenojei, Conger myriasler, and Sefipinna tenuifilis, and in winter they were Okamjei kenojei, Chaeturichthys stigmatias, and Sillago japonica. Bycatch species composition and individual species abundances differed significantly among seasons, probably indicating that variations were related to the life history characteristics of bycatch species. The diversity index was highest in October (2.797) and lowest in July (1.012). The July dominance index (0.569) was much higher than in other months; evenness was highest in September (0.856) and lowest in July (0.374). During the study period, the bycatch-to-shrimp ratio of this fishery varied from 0.063 in February 2005 to 11.031 in May 2005, with a mean of 3.363 These temporal variations may be linked 10 variations in reproductive behaviors and migration patterns of the marine animals sampled.