• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.1
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• pp.107-123
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• 2018

The global impact of climate change on agriculture is now increasing. The purpose of this study was to investigate the effect of climate change on livestock productivity. The variables that have the greatest influence on climate change factors were examined through previous studies and expert surveys. We also used the actual productivity data of livestock farmers to investigate the relationship with climate change. In order to evaluate the climate for changes in livestock productivity, national representative data (such as bullocks, dairy, pigs, laying hens, and broilers) were surveyed in Korea. Also, to select and classify evaluation indexes, we selected climate change factor variables as prior studies and studied the weighting factor of climate variable factors. In this study, the researchers of industry, academia, and farmers in the livestock sector conducted questionnaires on the indicators of vulnerability to climate change using experts, and then weighed the selected indicators using the hierarchical analysis process (AHP). In order to verify the validity of the evaluation index, was examined using domestic climate data (temperature, precipitation, humidity, etc.). Correlation and regression analysis were performed. The empirical relationship between climate change and livestock productivity was examined through this study. As a result, we used data with high reliability of statistical analysis and found that there are significant variables.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.5
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• pp.539-546
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• 2019

The major cultured marine fishes in sea off the coast Gyeongsangnam-do Province, South Korea, were assessed and included 9.3% rockfish Sebastes schlegelii, 7.8% red seabream Pagrus major, and 2.1% rock bream Oplegnathus fasciatus. The number of insurance payments related to disease mortality in cultured fish in 2017 was fourfold that in 2016. Economic loss in aquaculture due to disease in cultured fish is high and represents an important inhibitory factor affecting marine fishery productivity. In 2018, diseases led to severe production losses in several aquaculture species: 40.0% in rockfish, 11.4% in olive flounder Paralichthys olivaceus, 10.0% in filefish Thamnaconus modestus, and 9.3% in red seabream. Fish-parasitic pathogens such as Microcotyle sebastis, Alella spp., and Dactylogyrus spp. enter mainly via the gills and skin surface. Among bacterial pathogens, Vibrio species were most common, with Vibrio harveyi being the dominant species causing infections in these fishes. The bacterium Lactococcus garvieae is thought to exhibit host specificity in fish. The fish species in the present study exhibited a higher tendency for infection by heterologous pathogens than by a single pathogen; therefore, it is necessary to devise new strategies for treating diseases in cultured fish.

• The Journal of Fisheries Business Administration
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• v.32 no.2
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• pp.51-72
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• 2001

This study intends to review the development of Squid Angling Fisheries of Korea and Japan and subsequent changes in the fisheries regime as well as management conditions and to examine reorganization directions. Although catches and productivity are all increasing in Korea and Japan as the squid resource in the East Sea is improving, the number of fishing vessels and the conditions of fisheries management are showing a symmetrical relationship. The former is increasing in Korea and decreasing in Japan while the latter is aggravating in Korea and rather stable in Japan. And while the competition between the two countries for more fishing grounds and catches are not that serious since the resource is relatively increasing, the catch and price competition with other domestic fisheries is a more significant problem. Furthermore, even though light restriction is implemented in both countries in order to suppress over-competition, it is adopted as a means to curtail management costs and block over-investment rather than to adjust international or inter-fisheries circumstances. Japan has been implementing the TAC system on squid resources since 1998. However, it has a different meaning than as a resource management method in its original sense because it is based on the highest catch level of the past and takes into consideration the fishermen's management conditions. In case of Korea, it is necessary to establish a plan to strengthen its fisheries management competence to address its shrinking catch in the Japanese waters. The developments mentioned so far have appeared amidst the increase of squid resources, and if such conditions disappear, problems such as international allocation of catches and fishing seasons, access to fishing grounds, and domestic conflicts among different fisheries will emerge.

• Korean Journal of Ecology and Environment
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• v.44 no.3
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• pp.303-313
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• 2011

Field observations and culture experiments have been carried out during the rainy season (on the 6th, 8th and 27th July 2009) to examine changes in the primary productivity and associated plant pigments in the estuary of the Seom-jin River. Primary productivity was determined at four sampling stations along the salinity gradient. On 6th July (before heavy rain) primary productivity ranged from 689~1,169 mgC $m^{-2}$ $d^{-1}$. On the 8th, just after more than 216.5 mm of precipitation, euphotic layers at all stations were reduced to very shallow water because of the high concentration of suspended solids in the water. This resulted in dramatically decreased primary productivity down to as low as 12~32 mg C $m^{-2}$ $d^{-1}$. However, after the rain, primary productivity on the 27th ranged from 266~999 mgC $m^{-2}$ $d^{-1}$, demonstrating a fast recovery in the upper stream water to similar productivity levels to those before the rainy season. Concentration of fucoxanthin in the water was highest on the 6th July. Before the rain, concentration of the zeaxanthin, increased as the salinity decreased. Immediately after the heavy rain, the Chl b (Chlorophytes) concentration was higher at all sites than before the rainy season. The concentration of fucoxanthin decreased after the heavy rain. At the downstream site, peridinin (Dinoflagellates) were found. During the rainy season, the diatoms contributed to the primary productivity at all sites. However, after the rainy season, Chl b (Chlorophytes) and Peridinin (Dinoflagellates) increased, demonstrating the enhanced contribution of those species in addition to diatoms.

• Journal of Marine Bioscience and Biotechnology
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• v.8 no.2
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• pp.54-66
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• 2016

Productivity of Saccharina japonica was evaluated by water layers in Gijang and Wando sea area to find the suitable farming areas for mass production of biomass. For this, S. japonica was cultivated at various depths (0.5, 1, 2, 3 m), respectively. As the result, the growths in Gijang were 225.1-261.5 cm in length, 18.5-21.3 cm in widths, 396.0-537.7 g in weights, 14.3-17.8 kg/cluster in biomass, and those in Wando were 332.0-435.7 cm in lengths, 24.6-32.5 cm in widths, 766.0-1,232.9 g in weights, 16.4-24.3 kg/cluster in biomass. It showed that the growths of blades in Wando were faster than those in Gijang. The growth rates of blades by the depths were faster at 0.5-1 m depth from January to June. After June, however, as the growth rates of blades were lower than the shedding rates of blades, it showed that the growth of S. japonica decreased at all depth conditions except 2 m depth. Productivity of S. japonica was better in Wando which is lower in the water temperature and nutrients than Gijang.

• The Journal of Fisheries Business Administration
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• v.52 no.4
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• pp.45-63
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• 2021

The purpose of this study is to analyze the structure, status and economic ripple effects of the fisheries processing industry in Korea using interindustry analysis. Five input-output tables published over the past twenty years have been reclassified with a focus on the fisheries processing sector. Through these multi-period tables, we analyzed changes in the inducing effects in production, value added and employment as well as the backward-forward linkage effects. As a result of the analysis, it was found that the industrial scale of the fisheries processing industry is very small compared to other food manufacturing industries. The backward linkage effect of the fisheries processing industry was greater than that of other industries, but the forward linkage effect was rather low. This means that the fisheries processing industry can be greatly affected by industrial depression of the downstream industries such as fishery and aquaculture. Production and employment-inducing effects of the fisheries processing industry have shown a decreasing trend in recent years. This reflects the reality that intermediate inputs are gradually being replaced by imports from domestic production due to the expansion of market opening and the depletion of fishery resource. In the future, it is necessary to prepare a strategy to increase the value-added productivity of the fisheries processing sector and foster it as an export industry.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.898-906
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• 2018

To investigate the effect of yellow dust on phytoplankton, a field survey and physiological experiments were carried out in the waters near Taean Peninsula from April 22 to 26, 2006, when yellow dust occurred. Phytoplankton populations during the yellow dust period were in the range of $26{\sim}290{\times}10^3cells{\cdot}L^{-1}$, a somewhat low standing crop. An increase in diatoms (a main taxonomic group), especially benthic diatoms such as Paralia sulcate, a typical species for active mixed sea water areas, was also remarkable. In addition, the Chl-a concentration after yellow dust exceeded the Chl-a concentration change range according to the tide before yellow dust. As the concentration of yellow sand increased in a yellow sand treatment experiment, primary productivity decreased, and the maximum assimilation number showed the same tendency. In the 48h culture experiment, primary productivity of the test group was lower than that of the control group at the early stage (T0) of yellow sand treatment, but after 48 hours (T48), the test group showed higher primary productivity than the control group. In particular, the primary productivity of the test group significantly increased to 321 % after 48 hours. Therefore, strong physical environment accompanied by yellow dust may temporarily inhibit the growth of phytoplankton in the waters adjacent to China in the early stage of yellow dust, but the formation of stable water mass has also been identified as a potential factor promoting the growth of phytoplankton.

• Fisheries and Aquatic Sciences
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• v.24 no.7
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• pp.260-275
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• 2021

Aquaponics is a cultivation system that combines aquaculture and agricultural hydroponics. This study investigated the productivity of leafy vegetables cultivated in the hybrid biofloc technology-aquaponics (HBFT-AP) using Japanese eel fed two kinds of diets (Mash, commercial powdered feed and extruded pellet [EP]) and hydroponics (HP).The mash was fed to the fish in a type of a dough mixed with water for 6 weeks (Exp1) and switched to the EP containing 2.7% monobasic potassium phosphate (MKP) for subsequent 6 weeks (Exp2). Leafy vegetables of 8 cultivar were employed in the experiment and water quality [dissolved oxygen (DO, mg/L), pH, water temperature (℃), electrical conductivity (EC; ㎲/cm), turbidity (NTU), TAN (NH₃ + NH₄⁺) (mg /L), NO₂-N (mg/L), NO₃-N (mg/L) and PO₄-P (mg/L)] was measured 6 times a week. Leafy vegetable productivity (HBFT-AP vs HP) was compared in respective experiment, which was similar or somewhat higher in HBFT-AP. During the 12-week feeding trial, concentrations of nitrite (NO₂-N) and phosphorus (PO₄-P) were kept low in variability while total ammonia nitrogen (TAN) and NO₃-N levels increased with time in HBFT-AP. At the end of two feeding trials, values of weight gain (WG, %), feed efficiency (FE, %), specific growth rate (SGR, %) and protein efficiency ratio (PER) were higher in Exp2 than in Exp1. As well, higher values in hematocrit (PCV, %), plasma K (mEq/L) and inorganic phosphorus (mg/dL) were found (p < 0.05) in Exp2 where fish were fed the EP (EP: 38.60%, 2.80 mEq/L and 7.04 g/dL; Mash: 33.20%, 1.95 mEq/L and 5.50 g/dL). Leafy vegetables in HBFT-AP using Japanese eel fed the EP with MKP 2.7% had a productivity similar (4 kinds of cultivar) or somewhat higher (4 kinds of cultivar) compared to those in HP. Also, Japanese eel fed the EP showed higher values of Pi (m/dL) and K (mEq/L) in plasma compared to those fed commercial powder diet.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.671-676
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• 2011

To determine the optimum light intensity for mass culture of the brackish-water cyclopoid copepod Paracyclopina nana, survival, growth, and productivity of the copepod were examined at several light intensities (0, 10, 100, 500, 1,000 lx). The survival rate of P. nana from nauplius to adult decreased with increasing light intensity. The highest survival rate was found under the dark condition, with 61.7% surviving; no significant difference was observed between 0 and 10 lx (51.7%) and the lowest survival rate was with 100 lx (26.7%). Survival rates at 500 and 1,000 lx were significantly lower in comparison with other conditions. The developmental period from nauplius to copepodid (5.8 days) and to adult (11.8 days) at 10 lx was significantly shorter than in the other treatments. Daily mean nauplius production of adult females over 7 days at 0, 10 and 100 lx was significantly higher than at 500 and 1,000 lx. In the 1,000 lx treatment, 99% of the adult females died on the $14^{th}$ day. The optimum light intensity for the mass culture of P. nana could be 10 lx, which had no adverse effects on survival, development, or reproduction.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.4
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• pp.984-993
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• 2016

This study aims to analyze the aquaculture farmers awareness of aquafarm management system influenced by socio-economic, environmental, and other factors using ordered logit model focused on aquafarm resting system. The survey data were obtained from 94 aquaculture farmers in Gyeongsangnamdo and Jeollanamdo province as a cross sectional data in 2015. This paper estimates the impact of socio-economic, environmental, and other characteristics, such as region, working period, productivity, environmental condition of fishing field, expected effectiveness of the system, and subject of responsibility on fishing field management. Based on the result, lastly, it suggests some implications to promote aquaculture farmers perception and participation in aquafarm resting system. The main results are as follows; the aquaculture farmers consciousness of the system is not affected by working period, productivity, and environmental condition of fishing field. But it is influenced by region, expected effectiveness of the system, and subject of responsibility on fishing field management. While it has a positive relationship with expected effectiveness of the system, it has a negative relationship with object who has responsibility on fishing field management.