• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.525-537
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• 2018

The Korean coast is divided into the West Korea Coastal zone (WKC), the South Coastal zone of Korea (SCK), the East Korea Coastal zone (EKC), and Jeju Coastal zone of Korea (JCK). Each coastal zone has different marine environment characteristics. This study analyzed zooplankton data of KOEM (Korea Environment Management Corporation) collected in the Korean coastal waters the spring and summer of 2015 and 2016. In spring, water temperature was lowest in the JCK, and gradually increased in the order of EKC, SCK, and WKC, while in summer lowest in WKC and increased in the order of EKC, SCK, and JCK. Salinity was lowest in WKC which had many rivers flowing inland, and increased in the order of SCK, EKC and JCK in spring. In summer it was lowest in JCK and increased toward WKC, SCK, and EKC. In summer, Chlorophyll-a concentrations were generally low, but was lowest in JCK in spring. In the study area, a total of 77 species occurred, of which 50 species did in spring and 65 species in summer. The number of species was lowest in JCK and highest in SCK in spring and summer, respectively. Paracalanus parvus s. l. was the most dominant species or the second dominant species in Korean coastal areas in spring, but it was predominant in summer. In addition, in spring Acartia hongi, Calanus sinicus, Oithona similis were predominant in WKC, Oithona similis and Corycaeus affinis in SCK, O. similis and Corycaeus sp. in EKC, C. affinis and O. setigera in JCK. In summer Corycaeus spp., O. similis, A. hongi, Tortanus forcipatus were predominant in WKC, C. affinis, Pseudodiaptomus marinus in SCK, O. similis, A. omorii, Corycaeus sp. in EKC, and A. steueri, A. pacifica, Oithona sp., C. sinicus in JCK. The copepod community in the Korean coastal areas were classified into four areas, WKC-western SCK, eastern SCK, EKC and JCK according to differences in environmental factors such as water temperature, salinity, Chl-a concentration, and suspended matter concentration of each coastal area.

• Korean Journal of Environment and Ecology
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• v.33 no.3
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• pp.266-279
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• 2019

We investigated the characteristics of fish communities and habitat status of endangered species Rhodeus pseudosericeus in Heuk Stream, a tributary of the Han River, from April to October 2018. During this period, we collected 47 species of 14 families from 10 survey stations using kick nets, cast nets, and long bag set nets. The dominant and subdominant species were Zacco platypus (37.6%) and Z. koreanus (13.8%), respectively. The next most abundant species were Squalidus gracilis majimae (11.1%), Pungtungia herzi (7.7%), Rhodeus pseudosericeus (5.0%), Microphysogobio yaluensis (4.3%), and Hemibarbus longirostris (3.0%). Among the fish collected, 19 species (40.4%) were Korean endemic species. Endangered species were R. pseudosericeus and Acheilognathus signifer while exotic species were Micropterus salmoides and Oncorhynchus mykiss, and land-locked species were Plecoglossus altivelis and Rhinogobius brunneus. The community analysis showed that the dominance and evenness indexes were mostly low and that the diversity and richness indexes were high. Moreover, the river health (index of biological integrity) was mostly excllent (1 site is good, 9 sites are very good). R. pseudosericeus inhabited widely from St. 3 to St. 9 in Heuk Stream, and its population size was large. Age groups for R. pseudosericeus estimated by the frequency distribution of total length in spawning season (April) indicated the 32~45 mm group as 1-year old, the 46~59 mm group as 2-years old, 60~69 mm group as 3-years old, and the 70~89 mm group as 4-years or older. Total length range of male and female was similar, and the sex ratio of female (426) to male (394) was 1 : 0.95. A. signifer, which had been released in Heuk Stream, inhabited from St. 4 to St. 5, but its population size was small. Lastly, this paper discusses a conservation plan for fish in Heuk Stream.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.122-131
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• 2023

This study was aimed to determine the effects of grow media on the mineral contents of the leaves and growth characteristics of strawberry grown under aquaponics system in a plant factory. For aquaculture, 12 fish (Cyprinus carpio) (total weight, 2.0 kg) were raised in an aquaponics tank (W 0.7 m × L 1.5 m × H 0.45 m, 472.5 L) filled with 367.5 L of water at a density of 5.44 kg·m^-3 and total 34 of strawberry seedlings were transplanted in the pots filed with 200 g of orchid stone, hydroball or polyurethane sponge in the growing bed (W 0.7 m × L 1.5 m × H 0.22 m) laid out with holly acrylic sheet (140×60 mm, Ø80) on the top of the system. The pH and EC of the aquaponic solution was ranged from 7.6 to 4.9 and 0.24-0.91 dS·m^-1, respectively. The concentration of NO_3-N was about 28% lower than that of the hydroponic standard solution, and K, Fe and B were 10, 27 and 3.8 times lower, respectively; however, the mineral contents of strawberry leaves were in the appropriate ranges with lower contents in the leaves grown with sponge media. The organic content (OM), nitrogen (N), phosphorus (P), and potassium (K) of the sludge were 61.5, 5.72, 8.92, and 0.24%, respectively. The leaf area, leaf number, and dry and fresh weights of shoot at 81 DAT were significantly higher in the hydroball, and the average number of fruits per plant was significantly higher in both the orchid stone and hydroball. There was no significant difference in the fresh and dry weights of fruits. Integrated all the results suggest that the orchid stone and hydroball media are more effective to utilize nutrients in solid particles of aquaponic solution, compared to the polyurethane sponge.

• Journal of Bio-Environment Control
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• v.33 no.1
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• pp.55-62
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• 2024

This study aimed to compare the nutrient uptake rate, growth and yield of strawberry grown under the aquaponic and hydroponic systems in a plant factory. For aquaculture, 12 of fish (Cyprinus carpio cv. Koi) were raised in an aquaponics tank (W 0.7 m × L 1.5 m × H 0.45 m, 472.5 L) filled with 367.5L of water at a density of 5.44 kg·m^-3. The 30 seedlings of strawberry were planted in ports filled with perlite substrate and then were placed on the bed (W 0.7 m × L 1.5 m × H 0.22 m) at the top of the aquaponics system, and the 30 seedlings were planted in net-pots and then placed on the holes of acrylic plates (140 cm × 60 cm, Ø80 mm) on the bed (W 0.7 m × L 1.5 m × H 0.22 m) at the deep flow technique (DFT)- hydroponics. The pH and EC of the aquaponic solution was ranged from 4.3 to 6.9 and 0.32 to 1.14 dS·m^-1, respectively, while those of hydroponics were ranged from 5.1 to 7.5 and 1.0-1.8 dS·m^-1, respectively. The NO₃-N and NH₄-N concentration of the aquaponic solution were higher about 3.6 and 2.2 me·L^-1 than those of the standard hydroponic solution for strawberry cultivation. The P, Ca, Mg, and S ions in the aquaponic solution were also higher about 0.76, 3.1, 0.8, and 0.9 me·L^-1 than those of standard hydroponic solution, respectively, while the K and Fe were lower about 0.8 me·L^-1 and 0.5 mg·L^-1, respectively. The mineral contents of the strawberry leaves grown on aquaponics did not differ from that of hydroponics, and K content in the leaves were in an appropriate range. Uptake rates of T-N and P between the 58 and 98 days after transplant (DAT) were 1.5 and 1.9-fold higher in the aquaponics than those of hydroponics, respectively with no significant difference in the uptake rate of K. The crown diameter, plant height, and leaf length and width in the 98 DAT were significantly higher in aquaponics. The number of fruits per plant was significantly higher in aquaponics than those in hydroponics, and the fresh and dry weights of fruit and length and width of fruit were significantly higher in hydroponics. The results suggest that plants in aquaponics continuously utilize fertilizer components of solid particles from fish and feed wastes.

• The Korean Journal of Malacology
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• v.32 no.3
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• pp.231-240
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• 2016

Techniques were developed for holding and conditioning of Pacific oysters, Crassostrea gigas, in a closed recirculating system. Experimental adults were used 500 oysters ( x two system, total 1,000 oysters) which were collected in $20^{th}$ March 2016 from long-line aquaculture farm at the south coast of Korea. During conditioning periods concentrated live microalgae as Isochrysis sp. $15{\times}10^7cells/mL$, Tetraselmis sp. $2{\times}10^7cells/mL$ and Pheaodactylum sp. $18{\times}10^7cells/mL$ were added 5 L every day, respectively which micro algae were functioned as diets and biological filter. Over all experimental periods total water exchange rate was 21.3% (daily 0.5%). Over 42 days conditioning, female and male oysters were maturated 90.9% and 94.4%, respectively. Survival rate was 98.7%. Mean shell hight (8.3 mm), total wet weight (19.2 g), meat wet weight (5.0 g) and shell wet weight (13.6 g) were significantly increased (P < 0.05). Water quality parameters including the water temperature ($22.1{\pm}0.4^{\circ}C$), salinity ($24.9{\pm}04$), dissolved oxygen (5.1-7.9 mg/L) and pH ($7.93{\pm}0.15$) were kept stable. Concentration of dissolved inorganic nutrient as ammonia (1.96-0.35 mg/L), nitrite (0.03-0.16 mg/L), nitrate (1.34-0.47 mg/L), DIP (0.42-0.03 mg/L) and silicate (3.83-0.00 mg/L) were significantly decreased throughout experiment except nitrite which was increased (P < 0.05), but nitrogenous components stayed below toxic levels (ammonia 0.0-5.5 mg/L, nitrite 0.0-460.0 mg/L) which indicated that closed recirculation system with microalgae based bio-filter could supply sufficiently environment condition to holding and conditioning of oyster.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.457-468
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• 1995

In order to develop a more practical culture system from the present running seawater tank system, two experiments of environmental factors, growth, survival rate and rearing density of olive flounder (Paralichthys olivaceus) were carried out for two consecutive years. Two groups of fish in initially averaging 7.5cm of total length, and 3.4g of body weight (EXP. I) and 5.0cm and 1.8g (EXP. II) were reared in the semi-closed recirculating seawater system equipped with the rotating biological contactors with the commercial culture scale. The dissolved inorganic nitrogen concentrations is EXP. I ranged 0,247-0.512 ppm of $NH_4-N$ (0.010-0.043 ppm of$NO_2-N$, and 0.108-0.342 ppm of $NO_3-N$, and those in EXP. II were 0.091-0.715 ppm, 0.002-0.045 ppm, and 0.007-0.277 ppm, respectively. Daily feeding rates of the fish were $0.67-2.41\%$ in EXP. I and $0.69-2.22\%$ in EXP_ II, and teed efficiency were $34.8-59.8\%\;and\;40.5-88.4\%$ in EXP. I and II, respectively. The average total ten說h and body weight were 40.0-42.8cm and 695.0-852.69g after 340 days culture in EXP. I, and 36.7-39.7cm and 552.4-706.4 g after 365 days culture in EXP. II, respectively. Survival rates of the fish at the end of EXP. I and II were $92.0\%\;and\;96.0\%,$ respectively. The ratio to body surface area of non-ocular side in all fish to bottom area of rearing tank, so-called covering rate, was used as an indicator of rearing density. The highest cowering rate and weight density of fish per $m^2$ of rearing tank at the end of experimental period were 2.2 and 34.1kg in EXP. I, and 2.6 and 36.3kg in EXP. II, respectively. For the commercial culture of olive flounder, the semi-closed recirculating seawater system was found to be more effective than the running seawater tank system in aspect to the fish productivity and protection of marine environment.

• Journal of Aquaculture
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• v.15 no.2
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• pp.95-101
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• 2002

During the periods from lily to October, 2000 in Hongseong and lucy to October, 2001 in Taean in the west coast of Korea, the following environmental conditions prevailed : water temperature : 22.0~26.817, salinity 27.23 ~30.80%, dissolved oxygen 4.12 ~6.26 ml/l, pH 7.89 ~8.09, phosphate 0.39 ~0.65 $\mu m$ , inorganic nitrogen 5.05~9.26 $\mu m$, suspended solid 5.4~20.8 mg/l and chemical oxygen demand 1.12~1.87 mg/l. The B-shaped veliger larvae of the Ark shell occurred in maximum number at $25^{\circ}C$ prevailing from mid-August at Hongseong and Taean. Full grown larvae reached maximum abundance from late August. To identify the effectiveness of the substratum for spat collection, raschel net were tested to Larval settlement. The most effective depth to collect the larvae in natural environment was the collectors suspended at 7~8 m depth. At these depths, about 49 to 94 spats were found on the collector (40$\times$50 cm), The growth of shell height (Y) to shell length (X), and total weight (W) to shell length (L) could be formulated as follows respectively: Hongseong: SH = 0.7168 SL -0.6466 ( $r^2$ = 0.9839), TW = $0.0001SL^{3.1705}$ ($r^2$ = 0.9882) Taean: SH = 0.736 SL -0.8824 ($r^2$ : 0.9899), TW : 0.00005 $SL^{3.3731}$ ($r^2$ : 0.9899)

• Journal of Food Hygiene and Safety
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• v.35 no.4
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• pp.291-303
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• 2020

Marine organism-derived toxins have negative effects not only on human health but also in aquaculture, fisheries, and marine ecosystems. However, traditional analytical methods are insufficient in preventing this threat. In this paper, we reviewed new rapid methods of toxin detection, which have been improved by adopting diverse types of nanomaterials and technologies. Moreover, we herein describe the main strategies for toxin detection and their related sensing performance. Notably, to popularize and commercialize these newly developed technologies, simplifying the process of pre-treating real samples real samples is very important. As part of these efforts, numerous studies have reported pretreatment methods based on the antibody-immobilized magnetic nanoparticles, and some cases have applied nanoparticles to enhance the sensing performance by utilizing the intrinsic catalytic activity. Furthermore, some reports have introduced fluorescent nanoparticles, such as quantum dots, to represent the lower detection limits of conventional enzyme-based colorimetric methods and lateral flow assays. Some studies using electrochemical measurements based on aptamer-nanoparticle complexes have also been announced. In addition, as the response to new toxins generated by changes in the marine environment is still lacking, further research on diagnostic and detection is also greatly needed for these kinds of marine toxins and their derivatives.

• Journal of Aquaculture
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• v.16 no.3
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• pp.190-195
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• 2003

Dietary optimum ratio of frozen raw fish and commercial compound meal (CCM) in moist pellet (MP) were investigated to improve the growth rate, and feed and economical efficiency in the flounder, Paralichthys olivaceus. Experimental fish (average body weight, about 48 g) were divided into 6 groups and each group was fed with raw fish (FRF), and MPs (ratio of raw fish and CCM=9:1, 8:2, 7:3, 6:4 and 5:5) for 10 weeks. The 9:1, 8:2, 7:3, 6:4, 5:5 groups showed no significant difference in weight gain as 203.5~217.3%, while the FRF group showed significantly low growth rate as 183.1%(P<0.05). The feed efficiency gradually increased with the increase in the ratio of CCM and was the highest in the 5:5 group as 89.7%. As a result of analysis of body composition after the experiment, moisture was significantly low in the 7:3 group (P<0.05) and crude protein was significantly low in the 9:1 group (P<0.05). The crude lipid increased as the ratio of raw fish increased, and it was the highest in the raw fish group (8.3%) and the lowest in the 5:5 group (4.6%). There were no significant difference in hepatosomatic index (HSI) and condition factor(CF) among the experimental groups. Visceralsomatic index (VSI) increased with the increase in the ratio of raw fish and was significantly high in the raw fish group as 5.49 (P<0.05). For the unit cost of feed, it was found that raw fish was economical when mackerel, a source of raw feed, was 400 won/kg, while the ratio of 5:5 was economical when it was more than 500 won/kg. Results of this study concluded that sole use of raw feed is not desirable in view of growth, environment and economy, and the 5:5 group showed highest effect under the least use of raw feed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.2
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• pp.166-172
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• 2002

The top shell, Omphalius pfeifferi capenteri meat vacuum-packed in can (diameter$\times$height, 74.1mm$\times$50.7mm) were heated at 115$^{\circ}C$ up to $F_0$ values of 5 min, 10 min, 15 min and 20 min, and the changes in food components were studied. After 14 days storage at 37$^{\circ}C$ and 55$^{\circ}C$, no growth of microorganism and panelling were recognized from the canned meats which were sterlized at 115$^{\circ}C$ with $F_0$ value of S min and over. In the case of proximate composition of the canned meats, the moisture content decreased with the increase of $F_0$ value, while crude protein increased. The increase of volatile basic nitrogen content, pH and degree of browning and the decrease of mineral, total amino acid, free amino acid, trimethylamine oxide, total creatinine contents and yields were observed during thermal processing, In sensory evaluation on color, texture and taste in the canned meats, no significant difference was observed among a boiled sample and the canned meats heated at re value of 10 min and below. But, in the canned meats heated at $F_0$ value of over 15 min, its sensory scores decreased with the increase of $F_0$ value. From these results, the reasonable $F_0$ value for preparation of the heat-treated top shell meats was in the range of 5$\~$10 min.