• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.38 no.3
• /
• pp.196-204
• /
• 2005

The horizontal and vertical distribution of yellowfin tuna, Thunnus albacares (Bonnaterre) and bigeye tuna, Tunnus obesus (Lowe) in relation to oceanic conditions such as thermal structure produced during El Nino/La Nina episodes were analyzed on the basis of data sets for the catches and efforts from the Korean tuna longline fishery and for the oceanographic observations from the NOAA during 1982-2002 in the tropical Pacific. The high density of fishing ground appeared in the western Pacific ($5^{\circ}N-5^{\circ}S,\;160^{\circ}E-180^{\circ}W$) for yellowfin tuna and in the eastern Pacific ($5^{\circ}N-15^{\circ}S,\;130^{\circ}W-100^{\circ}W$) for bigeye tuna. yellowfin and bigeye tunas were mainly distributed at the 110-250 m layer and 245-312 m layer, respectively, in the western Pacific. However, in the eastern Pacific, they were mostly caught at the 116-161 m and 205-276 m layer for yellowfin tuna and bigeye tuna, respectively. It can be suggested that bigeye tuna be distributed in the deepest layer among tunas and show a vertical size stratification. It was observed that during the El Nino events the main fishing ground of yellowfin tuna shifted from the western Pacific toward the eastern Pacific. In the eastern Pacific which showed a higher density of bigeye tuna, the vulnerability of bigeye tuna caught by deep longline increased during the El Nino events due to deepening of thermocline layer and a more intensively distribution of the fish schools in the lower layer of thermocline during the El Nino events.

• Journal of Environmental Science International
• /
• v.29 no.3
• /
• pp.273-282
• /
• 2020

Residence time is defined as the time taken for a material in a system to leave the system. The residence time characteristics in shellfish aquaculture determine the dispersion of excretion from aquaculture farms, along with the supply of food by seawater exchange. In this study, we estimated the spatial distribution of average residence time in the shellfish farming area using a particle tracking model. As a result, a relatively short average residence time of about 20 days or less was calculated in most areas, but an average residence time of more than 40 days was calculated in the inner areas. Relatively long average residence times were calculated along the west coast compared to the east coast, with the longest average residence time of more than 50 days in the northwestern areas. It can be inferred that the disturbance of the benthic ecosystem caused by shellfish farms is likely to be large because of the relatively weak dispersion of excrement from shellfish farms located on the west coast, especially in the northwest region. This distribution of average residence time is important for understanding the potential effects of seawater exchange on the environmental sustainability of shellfish farms, along with the seawater circulation characteristics of Jaran Bay.

• The Journal of Fisheries Business Administration
• /
• v.42 no.1
• /
• pp.19-35
• /
• 2011

This paper tries to show the appropriate estimation method of oil pollution damage for mariculture fisheries. The International Oil Pollution Fund 1992(also known as the IOPC Fund 1992) has made up the Claims Manual to assist claimants by giving a general overview of the Fund's obligation to pay compensation. Section III of the Manual provides more specific information to assist claimants in presenting their claims concerning about economic losses in the fisheries, mariculture and fish processing sectors. The paper tries to suggest reform proposals for current etimation method of damages of maricluture fisheries contaminated by oil spillover using the population biology of living resources charaterized with age distribution.

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2001.05a
• /
• pp.267-268
• /
• 2001

Chlorobenzenes (CBs) are ubiquitous hydrophobic chlorinated organic compounds in the environment. These compounds are used as de-ordants, solvents and pesticides, as well as byproducts of agro- or petro-chemical related manufacturing processes, such as PCBs and pentachlorophenol, or of biodegradation of lindane (Newhook and Meek, 1994). Unlike some organochlorine (OC) compounds, including polychlorinated biphenyls (PCBs) and various pesticides, CBs are not banned from production or use in any country. (omitted)

• Korean Journal of Ichthyology
• /
• v.5 no.2
• /
• pp.217-225
• /
• 1993

A study on the distribution and mortality of eggs and larvae of anchovy. Engraulis japonica, was carried out on the basis of data collected from ichthyoplankton survey in the southern coastal waters of Korea from June to August in 1990. Egg and larval distribution areas were shifted from the adjacent waters of Namhae Is, to the eastern waters of Goeje Is, while eggs and larvae were developed in June. However, high densities of eggs and larvae of anchovy and were found near Goeje Is. in July. Anchovy eggs and larvae were correlated significantly with zooplankton in July, and were not in June and August. It is likely that the low instantaneous mortality coefficients in eggs and high values in the larvae during June and high values in eggs and low values in the larvae during July were affected by the distribution pattern of zooplankton.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.47 no.3
• /
• pp.283-291
• /
• 2014

This study assessed dominant fish species, and the characteristics and spatio-temporal distribution of fish schools using acoustic and catch data in the marine ranching area (MRA) of Yeosu in July and August 2013. Acoustic data were collected using a 200-kHz dual beam transducer, and catch data were analyzed through auction data generated by a set net installed in the MRA. More fish schools were detected by acoustic methods in July than in August. The temporal distribution of fish schools differed between July and August, but, many schools demonstrated a high mean volume scattering strength (SV) around artificial reefs. Additionally, the characteristics of fish schools detected by echograms and the species caught by set nets differed between July and August. The dominant fish species were Engraulis japonicus, Pampus argenteus, Scomberomorus niphonius, and Pampus echinogaster in July, and approximately 85% of the catch in August consisted of Scomberomorus niphonius. Therefore, hydro-acoustic tools are useful for estimating fish school characteristics in large areas over a short period. To determine species, it is important to conduct net sampling surveys during the acoustic surveys. However, if a database of fish school characteristics organized by species is constructed through continuous study, it could be possible to identify fish species through acoustic methods alone.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.21 no.3
• /
• pp.139-144
• /
• 1988

The vertical distribution of eggs and larvae of anchovy. Engraulis japonica were studied based on ichthyoplankton and the temperature distribution in the southwestern part of the Sea of Japan off Korea during the summer of 1985 and 1986. Thermoclines occurred at the surface layer in the coastal area and at the sub-surface layer in the offshore area in the early summer of 1985. However, they occurred at the surface layer throughout the summer of 1986. Anchovy eggs and larvae were abundant in the offshore in 1985 and in the coastal area in 1986. It seems that the spawning ground of anchovy in 1985 shifted to the offshore owing to the sloping of thermoclines. According to the distribution layer of anchovy eggs by developmental stage, the eggs in the early developmental stage were abundant at $0\~30m$ layer about 06:00. But the eggs in the late developmental stage were abundant at $30\~100m$ loom layer about 24 : 00. These results suggest that anchovy spawn at the $0\~30m$ layer at night and eggs tend to sink to the $30\~100m$ layer in the course of development.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.46 no.4
• /
• pp.458-465
• /
• 2010

Hundreds of Steller sea lions, Eumetopias jubatus, migrate from Sakhalin and the northern Kuril Islands to Hokkaido every winter. During this migration, they may use their roaring sounds to navigate and to maintain their groups. We recorded the roars of wild Steller sea lions that had landed on reefs on the west coast of Hokkaido, and those of captive sea lions, while making video recordings. A total of 300 roars of wild sea lions and 870 roars of captive sea lions were sampled. The fundamental frequency ($F_0$), formant frequency ($F_1$), pulse repetition rate (PRR), and duration of syllables (T) were analyzed using a sonagraph. $F_0$, $F_1$, and PRR of the roars emitted by captive sea lions increased in the order male, female, and juvenile. By contrast, the $F_1$ of wild males was lower than that of females, while the $F_0$ and PRR of wild males and females did not differ statistically. Moreover, the $F_0$ and $F_1$ frequencies for captive sea lions were higher than those of wild sea lions, while PRR in captive sea lions was lower than in wild sea lions. Since there was a linear relationship between body length and the $F_0$ and $F_1$ frequencies in captive sea lions, the body length distribution of wild sea lions could be estimated from the $F_0$ and $F_1$ frequency distribution using a regression equation. These results roughly agree with the body length distribution derived from photographic geometry. As the volume of the oral cavity and the length of the vocal cords are generally proportional to body length, sampled roars can provide useful information about a population, such as the body length distribution and sex ratio.

• Journal of Fisheries and Marine Sciences Education
• /
• v.27 no.5
• /
• pp.1343-1351
• /
• 2015

Though the history of fisheries business administration education has it's own uniqueness, the research or study of that still insufficient. And in spite of the structural shift of society and environmental diversity, there's few research that analyzing or examining the curricular constitution and change recently. The process of this research was implemented with investigating the objective and content domains concerning marine education in the fisheries and marine curriculum and changes of them. The changes of fisheries business administration education reviewed and analyzed in the view point of construction of the textbook, contents of the each changes and recency comparison of tables and figures of the high school textbook of the fisheries business administration general. The results show that most of the changes have been reflected by the demands of the society including fisheries related law, policy and distribution networks. But there are still some errors and necessity of improvements in data and descriptions. The results of this study would help develop sustainable curriculum design for further changes and give more effective guidelines for identifying the core of fisheries business administration education.

• The Journal of Fisheries Business Administration
• /
• v.47 no.4
• /
• pp.31-44
• /
• 2016

The purpose of this study is to analyze the climate change exposure of fisheries and fish species in the southern sea of Korea under the RCP climate change scenarios. The extent of exposure was calculated through weighted sum of the sea temperature forecasted by National Institute of Fisheries Science, and the weight were obtained from the time-space distribution of each fisheries or species, based on the micro-data for the fishing information reported by each fisherman. Results show that all the exposed sea temperature of RCP8.5 is higher than that of RCP4.5 in year 2100 as well as in near 2030, therefore it is thought to be very important to reduce the GHG emission even in the short term. The extent of exposure was analyzed to be comparatively high especially in the fisheries such as anchovy drag nets and species like cod, anchovy and squid. Meanwhile the method of this study is considered to be excellent to obtain the accurate extent of exposure under RCP scenarios, and therefore it is applicable on assessing the vulnerability of climate change in fisheries.