• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.4
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• pp.196-200
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• 1989

Fishery production of topshell in Cheju-do has been rapidly decreased in the last few years. To investigate the origin of this problem and estimate maximum sustainable yield (MSY) and catch per unit effort (CPUE) of topshell in Cheju-do, a survey has been done ysing the statistical data for 19 years (1968-1986) of topshell production in Cheju-do and data for 3 yea.5 (1984-1986) from an fishery village, Tonggui-ri, Pukcheju-gun, Cheju-do. Maximum sustainable yield of topshell in Cheju-do assumed to be 2,500-2,800 metric tons(M/T) per year. The annual fishery productions of topshell from 1982 to 1986 were 3,368, 3,649, 3,308, 3,136, and 1,400 M/T, respectively. These results show that topshell had been over-fished during 1982 to 1985. Because of the over-fishing, production sharply decreased down to 1,400 M/T in 1986. Total annual production of topshell in Tonggui-ri is a little less than one Percent of that of Cheju-do. To achieve this production, over the half of resistered diving women in this village have been worked. To estimate catch per unit effort of topshell in Cheju-do, it seems better to use the data which is the number of diving women who have been worked for certain period of time than the number of working days in the same period of time.

• The Journal of Fisheries Business Administration
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• v.45 no.1
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• pp.109-119
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• 2014

This study aimed to examine the applicability of a portfolio approach to the ecosystem-based fisheries management targeting the large purse seine fishery. Most fisheries are targeting multispecies and species are biologically and technically interacted each other. It enables a portfolio approach to be applied to find optimal production of each species through expected returns and risk analyses. Under specific assumptions on the harvest quota by species, efficient risk-return frontiers were generated and they showed a combination of optimal production level. Comparisons between portfolio and actual production provided a useful information for targeting strategy and management. Results also showed the possibility of effective multispecies fisheries management by imposing constraints on each species such as total allowable catch quotas.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.4
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• pp.342-350
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• 2021

Although Korea operates various systems and policies for the management of fisheries resources, it is judged that a more systematic resource management policy is needed due to the continuous decrease in the production of coastal and offshore fisheries. In this study, the catch capacity was analyzed using the DEA technique for coastal and offshore fisheries. As a result, despite the decrease in the amount of fisheries resources and the number of fishing vessels, there was a trend of increasing fishing capacity. As of 2019, the total maximum catch of offshore fishery was estimated at 820,007 tons. The actual catch was 548,159 tons and the CU was measured to be about 66.8%, which was analyzed to be an excess of about 33.2% of the catch. The total maximum catch of coastal fisheries was estimated at 187,887 tons. The actual catch was also the same value and the CU was measured to be about 100.0%. Thus, it was analyzed that there was no excess in catch. For the management of fisheries resources, it is necessary to manage the fishing capacity. To this end, policies such as scientific TAC should be promoted as well as expanding the reduction of fishing vessels.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.4
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• pp.327-336
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• 2017

Fishing dredge in Jeollabuk-do began to become widespread in the 1960s and has continued to catch diverse kinds of shellfish in the productive fishing grounds around Dongjin River, Mangyeong River and Geum River estuaries. Since the 1970s, the construction of various large-scale industrial complex and the implementation of Saemangeum reclamation project have resulted in a decrease in main fishing areas and a sharp decline in shellfish production. As a result, dredge fishery has faced many difficulties. Dredge fishery in Jeollabuk-do is carried out with a total of 30 fishing permits as of 2016. Surf clams, hen clams, bladder moon snails, and common orient clams were mainly caught before the construction of Saemangeum dike while comb pen shells, purple whelks and ark shells are mainly caught afterwards. Inside the Saemangeum dike, most fish species have disappeared due to low water level and low salinity, and littleneck clams are caught using a jet pump type of fishing dredge. Outside the dike, the diversity of shellfish species has been reduced; comb pen shells are mainly caught. In this process, a lot of friction occurs due to the use of a reformatted dredge. Therefore, a lot of research needs to be conducted in the near future.

• Journal of the Korean Data and Information Science Society
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• v.17 no.1
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• pp.63-76
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• 2006

Marine production forecasting in fisheries is a crucial factor for managing and maintaining fishery resources. Thus this paper aims to generate a forecasting model of total marine production. The most generally method of time series model is to generate the most optimal single forecasting model. But the method could induce a different forecasting results when it does not properly infer a model To overcome the defect, I am trying to propose a single forecasting through multiple time series model. In other word, by comparing and integrating the output resulted from ARIMA and VAR model (which are typical method in a forecasting methodology), I tried to draw a forecasting. It is expected to produce more stable and delicate forecasting prospect than a single model. Through this, I generated 3 models on a yearly and monthly data basis and then here I present a forecasting from 2006 to 2010 through comparing and integrating 3 models. In conclusion, marine production is expected to show a decreasing tendency for the coming years.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.835-842
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• 2022

Several countries are establishing management systems for aquaculture environment, and fishery environment assessment is one of them. The fishery management law amended in 2013 stipulates that a fishery environment assessment should be performed when a fish cage farm's license is extended. The purpose of the fishery environment assessment is to promote sustainable fishery, increase the fishery production capacity, and increase the fishermen incoming by implementing evaluation and improvement measures through scientific methods. The analysis items of fishery environment assessment include the Benthic Health Index (BHI), which is a biological index based on the macrobenthic polychaetes community, and total organic carbon (TOC), and the two items are scored and used for evaluation as a single grade. This study explains the selection process of BHI and TOC, which are evaluation items for fishing ground, and ecological significance of the calculated evaluation grades.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.1
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• pp.136-145
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• 2015

A large number of divers that are engaged in a diving apparatus fishery (DAF) have been experienced a decompression sickness. This study has two purposes. One is measurement of the diving patterns and respiration rate. The other one is to research the institutional improvement plan of the DAF. In the experiments, the diving depth, the diving time, the total ascent time and the ascent rate were about 12.4 m, 22 min, 28 s and 28.1 m/min, respectively, in Tongyeong. In the case of Geoje the diving depth, the diving time, the total ascent time and the ascent rate were about 20 m, 64 min, 17 min and 1.3 m/min, respectively. In a questionnaire survey, the diving depth was 20~29 m (56.4%) in Tongyeong and Geoje, the diving time was 50~59 min (42.9%) in Tongyeong and 70~79 min (35%) in Geoje and all of the divers experienced decompression sickness. In the investigation related to a institutional issue, both of the diving apparatus fisheries had adopted the share system. And the laws and the system for the safety of the divers were not enough in Korea. This study suggests that the license and the diving time for diver of the DAF are needed and diver protection for decompression sickness is needed in the law. And the wage payments should change from full sharing to partial sharing included a regular pay to enhance the safety of the divers.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.7
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• pp.1001-1006
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• 2011

To determine the efficiency of copper (Cu) supplementation, a feeding experiment was carried out with 240 day old broiler chicks (vencobb-100). Birds were divided into four dietary treatments: i) C - no additives, ii) $T_1$-75 mg inclusion of Cu/kg diet, iii) $T_2$-150 mg inclusion of Cu/kg diet, iv) $T_3$-250 mg inclusion of Cu/kg diet. The present study was carried out in the Department of Animal Physiology, West Bengal University of Animal and Fishery Sciences, Kolkata, India for a period of 42 days (6 weeks). Growth performance was measured in terms of live weight gain, cumulative feed intake and feed conversion ratio at the end of $21^{st}$ and $42^{nd}$ day of the experiment and the result was found to be encouraging for commercial enterprises when the chickens were fed at 150 mg Cu/kg ($T_2$) of their diet. Excess dietary copper more than 150 mg/kg reduced the haemoglobin (Hb) concentration in blood and resulted in the accumulation of copper in the liver with decreased blood Hb concentration and packed cell volumes (PCV). Copper supplementation increased the total erythrocyte count (TEC) as copper is involved in erythropoiesis. But, from the result it is indicated that the dietary copper concentration could not alter the total leukocyte count (TLC). In case of different leucocytes count (DLC), there were no significant differences observed among the different treated groups. Statistical analysis showed significant (p<0.01) difference in plasma concentration of copper, zinc, ferrous and cholesterol among the different copper treated groups. The result indicates that supplementation of copper is an effective way of improving the production performance and haematological parameters in broiler chicken.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.4
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• pp.356-363
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• 2016

To suggest more efficient fishing operation, it was analyzed using five years (2011~2015) catch data of six Korean-flagged tuna purse seiners (with 1000 mt of haul capacity) operating in the western and central Pacific Ocean. In terms of annual total catch, it presented a two-year cycle of variation on catch, showing that catches of 2012, 2014 and 2015 were high, whereas those of 2011 and 2013 were low. The proportions on fishing effort of associated set were around 21.9~30.8% having 21.5~45.0% of total catch. In this study, there was no significant difference between catches of unassociated set and associated set. When considered having good fishing conditions, fishing activities were concentrated in the areas of Papua New Guinea (PNG) and Kiribati, while it showed that fishing ground spreaded out to the areas of not only PNG and Kiribati but also Federated States of Micronesia (FSM), Tuvalu and Solomon islands. The average number of fishing days was 271 with a range of 246~285. As restriction on fishing operation such as reduction of fishing days and higher fishing fee are expected to strengthen, the result of this study will be helpful to select more efficient fishing methods for purse seine fishery based on fishing conditions.

• Journal of Fisheries and Marine Sciences Education
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• v.18 no.1
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• pp.19-30
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• 2006

For fishery stock assessment and optimum sustainable yield of anchovy in Korea, surplus production(SP) models and a maximum entropy(ME) model are employed in this paper. For determining appropriate models, five traditional SP models-Schaefer model, Schnute model, Walters and Hilborn model, Fox model, and Clarke, Yoshimoto and Pooley (CYP) model- are tested for effort and catch data of anchovy that occupies 7% in the total fisheries landings of Korea. Only CYP model of five SP models fits statistically significant at the 10% level. Estimated intrinsic growth rates are similar in both CYP and ME models, while environmental carrying capacity of the ME model is quite greater than that of the CYP model. In addition, the estimated maximum sustainable yield(MSY), 213,287 tons in the ME model is slightly higher than that of CYP model (198,364 tons). Biomass for MSY in the ME model, however, is calculated 651,000 tons which is considerably greater than that of the CYP model (322,881 tons). It is meaningful in that two models are compared for noting some implications about any significant difference of stock assessment and their potential strength and weakness.