• Journal of Fisheries and Marine Sciences Education
• /
• v.13 no.2
• /
• pp.146-167
• /
• 2001

Korea and China are two opposite countries located aside Yellow Sea and co-utilize the East China Sea. The two countries are close together from geological point of view, however, the competitive development of resources was more emphasized than the cooperative development of resources between the two countries because the special policy relationship. Additionally, after the communist government of China was founded in 1949, the political conception between the two countries was quite different. Therefore the establishment of appropriate international fisheries co-operation was impossible, and the international management problems of fisheries resources in Yellow Sea and East China Sea were let alone. UN convention on the Law of the Sea came to force in 1994, Korea and China adopted the exclusive economic zone system in 1996. On the other hand, Fisheries Law in Korea was enacted in 1953 in order to management of fisheries resources, and also China was enacted fisheries law in 1986. The two countries control the fisheries effort through fisheries license system, meanwhile through prohibition fishing area, prohibition fishing period, limitation of net size, and limitation of body length to conserve and manage the fisheries resource. The serious management methods of resource management in the two countries are similar such as the creation of promptly decreased species and those species that have commercial value, discharge of fish seedling stock, settlement of artificial reef and clean of fishing ground. Therefore, the two countries should consider not only the improvement of formal law system, but also how to recover the fisheries resources in circumference water zone and how to improve the efficiency of fisheries resource management. Specially the settlement and management of artificial reef should be chosen in the area that have the highest benefit to two countries, and should establish the common management system of discharge of fish seedling stock. And the two countries should adopt the same criteria through technical management and limitation of net size, limitation of body length, and prohibition area of special fisheries to ensure the highest fisheries benefit of fisherman in the two countries and the highest efficiency of fisheries resource management.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.53 no.1
• /
• pp.98-102
• /
• 2020

We examined the comparative spawning ecology of daggertooth pike conger Mureanesox cinereus and common pike conger M. bagio in the South Sea of Korea from May 2018 to December 2019. In the South Sea of Korea, the mean total length (TL) of M. cinereus was significantly smaller than that of M. bagio. The sex ratios of both species were skewed toward females. The spawning period of M. cinereus was from June to October, while the spawning period of M. bagio was from August to October. The lengths at 50%, 75%, and 97.5% sexual maturity of M. cinereus females were estimated as 54.6 cm, 60.4 cm, and 74.1 cm TL, respectively. It was not possible to estimate lengths at sexual maturity for M. bagio in the South Sea of Korea due to the absence of immature stages.

• The Korean Journal of Malacology
• /
• v.25 no.1
• /
• pp.23-28
• /
• 2009

Samplings have been monthly collected in Jeju Island, Korea, using ser nets. A total of 759 individuals were sampled from June to November 2006. We analyzed mantle length distribution, monthly changes in maturity stages, maturation size and sex ratio. Mean Mantle length of the female specimens ranged from 6.7 to 50.3 cm and that of the male specimens ranged from 6.7 and 50.0 cm. The spawning period was November. The Mantle length at 50 % group maturity was estimated to be 17.1 cm. Sex ratio was 1 : 1.3 (male : female), suggesting the female population may be predominant.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.53 no.1
• /
• pp.50-56
• /
• 2020

Determination of the precise size at sexual maturity is very important for science-based stock assessment and fisheries resource management. In this study, two different models, (1) a visual method and (2) a gonadosomatic index (GSI) method, were employed to estimate length at sexual maturity of the small yellow croaker Larimichthys polyactis in the Yellow Sea of Korea. The visual method is a common qualitative method using visual gonadal identification. Conversely, the GSI method is a quantitative method using the GSI, which can be easily and precisely collected. We compared results from these methods to determine the best approach, and to examine the practicality of the GSI method. Logistic regression of the maturity ogive was conducted using a general linear model (GLM) with the R statistics program. Also, the bootstrapped 95% confidence intervals of all estimates were calculated. The best-fit model was the visual method (R_Mc²=0.805, AUC=0.989, L₅₀=15.1). Among models using the GSI method, the model computing GSI_ref=0.94 was the best-fit model (R_Mc²=0.792, AUC=0.989, L₅₀=15.2). There was no significant difference between the two models, evidencing the effectiveness and accuracy of the GSI method.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.55 no.4
• /
• pp.392-401
• /
• 2019

This study describes how the illustration book of Korean coastal and offshore fishing boats was published. The illustration book provides information on fisheries which need boats for their fishing operation. The book contains 25 fishing boats belonging to 15 offshore fisheries and six boats belonging to five coastal fisheries totalling 31 boats belonging to 20 kinds of fisheries. Until now, no books were available in Korea on fishing boats which provided illustrated descriptions of their use in fishing. We carried out field and literature surveys of fishing boats for three years (2016-2018) and the results were compiled into three-dimensional modeling images with schematic drawings of fishing boats, along with text explanations. The particulars and technical drawings of lines, general arrangement (GA), fishing gears and methods are collected and summarized. All fishing boats are modeled with 3D color graphics. The particulars and names of the main items of the fishing equipment are presented besides structural parts. In addition the fishing gear, fishing season and grounds, number of crews and target species for each boat are correctly described. The illustration book of Korean coastal and offshore fishing boats will contribute to understanding the current status of fishing techniques in Korea and will assist in developing new types of fishing boats.

• Journal of Fisheries and Marine Sciences Education
• /
• v.17 no.3
• /
• pp.340-360
• /
• 2005

Fishery resource rents(i.e. windfall gains or excess profit), which tend to lead a variety of important economic, social, political problems, have been a fundamental cause of unbalance between fishery resource use and management. Thus, there may exist several sorts of optimal level of resource utilization such as economic maximum sustainable yield, biological maximum sustainable yield, social optimum production, socio-political optimum yield, etc. The fishery resource use level seems to a large extent to be determined by the characteristics of fishermen's rent seeking structure. As well known, fishery resources as common properties have a characteristic of being difficult to establish private property rights. Therefore, their use rights are controlled by the permit and/or the license system. As a result, absolute or differential rents are formed by the changes in institutional arrangements. Rent problems are often transformed into serious socio-political issues when the rent in a given industry is much higher to a socially unacceptable extent than the average of other industries. However, individual fishermen or fishermen's groups tend to behave aggressively to change the existing fishery institutions towards maximizing fishery rents. These rent-seeking behaviors often tend to nullify fishery management schemes. The larger is the relative rent difference between fisheries and other industries, the more aggressive tend to be the rent-seeking behaviors in fisheries.

• The Journal of Fisheries Business Administration
• /
• v.50 no.1
• /
• pp.17-37
• /
• 2019

The purpose of this study is to estimate the resource recovery effect and the economic effect of the fishermen by the fisheries vessel buy-back program. First, this study standardizes the fishing efforts of coastal gill net, coastal trap, and coastal composite fisheries using Gavaris general linear model. Second, the resource evaluation is performed by using vessel buy-back program data, and also the CYP model based on exponential growth function is applied. In order to derive the effect of the vessel buy-back program, the MSY with the vessel buy-back program is compared with the MSY without the vessel buy-back program. Finally, we compare and analyze producer surplus under the equilibrium of the MEY and the OA using bioeconomic model. In conclusion, the vessel buy-back program has shown an increase in resource growth and economic improvement for the remaining fishermen. The result shows that the remaining fishermen are able to obtain an increase in producer surplus of about 53% due to the vessel buy-back program under equilibrium levels of the open access and the maximum economic yield.

• Fisheries and Aquatic Sciences
• /
• v.26 no.3
• /
• pp.216-223
• /
• 2023

Pacific yellowtail emperor, Lethrinus atkinsoni Seale, 1910, is one of the most targeted reef fish species in Southern Sulawesi, Indonesia. Therefore, assessing its stock is important to understand the condition of the population, providing valuable inputs for sustainable fisheries management in the area. Here we assess the stock condition of L. atkinsoni in Southern Sulawesi, Indonesia, using the length-based spawning potential ratio model. A total of 4,887 individuals were collected from commercially small-scale fishers from January to October 2022. The total length, sex, and gonad maturity of the individuals were examined. We observed that the fish length ranged from 10.5 to 39.5 cm, with an average length of 23.3 cm. The sex ratio was equal (1:1.2) between male and female individuals. Length at first maturity and length at first capture were 23.4 and 19.6 cm, respectively. In addition, we observed a growth coefficient of 0.45/year, with an asymptotic length of 41.14 cm and natural mortality of 0.6/year. Based on these life history parameters, we observed the spawning potential ratio (SPR) value of 12%, indicating an unsustainable fishery level (SPR of < 30%). Further concerns related to the sustainability of the species and strategy to rebuild stock of the L. atkinsoni in Southern Sulawesi are of utmost importance.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.41 no.3
• /
• pp.188-198
• /
• 2005

This study was conducted to survey the catches of vertical bottom longline fisheries in the sea mount of central northern Pacific($30^{\circ}-42^{\circ}N$, $170^{\circ}-175^{\circ}E$), during the period of July 1 to August 25,2004 by commercial fishing vessel. The number of 57 test fishing was carried out in the central northern Pacific during 43 days and the total catches were 21,092.4kg as 19 fish species, CPUE/day and catches/day were 185 baskets and 490.5kg, respectively. Main fish species caught from the experimental fishing were Squalus mitsukurii (66.3%), Coelorhyrchus asperocephaius (11.7%) and Helicolenus avius (9.8%) and, average inside diameter for fish mouth was 4.0cm over. Catch ratio according to each fishing ground was the order of F, D, J, B and C. Catch ratio fur water depth was the order of 450-500m, 350-400m, 300-350m, 400-450m, 1000-1100m and 500-550m and, main species by water depth was Squalus mitsukurii for 300-400m, Etmopterus lucifer for 300-550m, Coelorhyrchus asperocephaius far 1,000m over. Catch ratio according to the kind of hooks was higher at the hook no.6 for Squalus mitsukurii and no. 5 for Etmopterus lucifer and, catch ratio by baits was higher at squid for Squalus mitsukurii, saury and eel for Helicolemus avius and saury for Etmopterus lucifer. Accordingly, it is thought that the extension of fishing hours is needed with the reduction of damage and loss for fishing gears during fishing operation.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.52 no.2
• /
• pp.173-179
• /
• 2019

We investigated the ecological characteristics and proximate composition of Muraenesox cinereus off the southern coast of Korea. Anal length distribution, sex ratio, condition factor of M. cinereus individuals caught by costal complex (longline) fisheries were investigated from June to October 2018. The mean anal length was 23.5 cm, which was less than $L_{50}$, indicating that the individuals were mostly immature. Sex ratio is 9:1, we captured 382 females and 29 males, which produced a significantly different ratio (P<0.05). Condition factor remained constant over the study period. The proximate composition of M. cinereus individuals was analyzed from July to October 2018. No significant differences in moisture, crude lipid, crude protein, and ash content were observed between individuals caught in summer and those caught in fall.