• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.145-158
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• 2008

To assess the source of oyster (Crassostrea gigas) and clam (Ruditapes phillippinarum), phytoplankton community structures in the water column and sediment, including the composition of phytoplankton in oyster and clam digestive organs were investigated bimonthly from December 2006 to June 2007 in the Taeahn coastal waters. During the sampling period, water temperature and salinity varied from 7 to 23$^{\circ}C$ and 34 to 35 PSU, respectively. Total phytoplankton abundances at St. O in the water column were higher than those at St. J, whereas total phytoplankton abundances at St. O in the sediment were lower. In addition, total phytoplankton abundances in the water column and sediment were observed to be relatively higher in February and April 2007. Among the diatoms, Paralia sulcata was always dominant, accounting for 41$\sim$87% of total phytoplankton, except St. J for February 2007 during the sampling period. The following phytoplankton compositions observed in the digestive organs of oyster and clam appeared: diatoms such as genus Paralia, Navicula, Melosira and Coscinodiscus, Silicoflagellate Dictyocha, dinoflagellates Prorocentrum and Dinophysis. Phytoplankton compositions observed in the digestive organs of oyster and clam corresponded relatively well with the species composition appeared in the water column and sediments of each season. A significant relationship was found between individual weight of oyster or clam and their digestive organs weight, while there was not a close correlation with total phytoplankton amount. We suggest that P. sulcata always dominated as one of important the food source of oyster and clam in the marine ranching ground of Taeahn coastal waters.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.143-150
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• 1984

A field survey and experiment on aquaculture in Costa Rica including Nicoya Gulf was carried out for a month, December $2{\sim}28$, 1981. 1) Air temperature was $27{\sim}32^{\circ}C$, water temperature, $28{\sim}29.5^{\circ}C$ and salinity, $20{\sim}28.5\%$ both in the surface and 5 m layer on December 22, 1981. 2) Dissolved oxygen plentiful, $7.3{\sim}9.95\;ml/l$. 3) Mean precipitation for the past ten years in Nicoya Gulf area was $1298.6{\sim}2196.3$ mm near Puntarenas area and rainy days a year was 137.7, Most rainfalls was concentrated from May to November, the rainy season. 4) Precipitation in main oyster farms near Chungmu, Korea was 1836.0mm a year and it was similar to that of Costa Rica. 5) Diatoms were 16 species belonged to 13 genera and dinoflagellates, 3 species belonged to 2 genera. Standing crops was $639{\sim}130,211\;cells/l$ and dominant species were Chaeteocros curvisetus, Chaetoceros decipiens, Nitzschia serata. Thalassiothrix mediterranca, a tropical esturary species, was found. 6) Nicoya Gulf has the good environmental factors in the water temperature, salinity, dissolved oxygen and planktons, and it is desirable to experiment and culture the oyster (Crassostrea rhrizophorae).

• The Korean Journal of Mycology
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• v.13 no.2
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• pp.105-109
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• 1985

Isolates of the different species groups of Trichoderma from the mushroom culture beds were identified according to Rifai's classification and influence of antibiotics produced by them against the oyster mushroom was examined. Trichoderma islolates were identified as Trichoderma hamatum, Trichoderma viride and Trichoderma koningii. Among the Trichoderma isolates, fungistatic action of Trichoderma viride was found to be most remarkable. Pleurotus ostreatus and Pleurotus sajor-caju were the most susceptable of the edible mushrooms tested, followed by Lentinus edodes, Flammulina velutipes and Auricularia auricula. A needle-shaped crystal gained from the chloroform extract of the culture filtrate of Trichoderma viride repressed distinctively the mycelial growth of the oyster mushroom. The grade of repression of the crystal at 500ppm and 1/10 aequ­ous solution of the chloroform extract against the oyster mushroom, seemed equal to that of cycloheximide at $100{\sim}200ppm$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.1
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• pp.23-30
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• 2021

To examine the optimal temperature, light intensity, and shell-type for shell-living conchocelis production, we tested the shell infiltration of free-living conchocelis fragments under various environmental conditions. Under a combination of various temperatures (10, 15, 20, 25 and 30℃) and light intensities (1, 5, 10, 20, 40, and 80 μmol m-2 s-1), the optimal infiltration conditions of the evaluated three Pyropia species were 20-25℃ and 5-80 μmol m-2 s-1 for P. yezoensis, 20-30℃ and 20-80 μmol m-2 s-1 for P. seriata, and 20-25℃ and 20-80 μmol m-2 s-1 for P. dentata. The infiltration efficiency of free-living conchocelis for different shell types was greater in Korean and Chinese oyster Crassostrea gigas shells than that in scallop Argopecten irradians and clam Meretrix lusoria shells. These results suggest that oyster shells are suitable substrates for shell-living conchocelis production. In conclusion, the present results for optimal infiltration conditions for free-living conchocelis of the three examined Pyropia species will contribute significantly to the production of stable shell-living conchocelis.

• Animal Systematics, Evolution and Diversity
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• v.27 no.3
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• pp.239-245
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• 2011

We describe and illustrate two pontoniine shrimps, Cuapetes grandis and Periclimenes ornatus, for the first time in Korea. C. grandis was collected in an artifical reef of Dadae, Geojedo Island by SCUBA diving in 15-20 m depth. This species was found in an oyster within an artificial reef and appeared to be free-living. P. ornatus was collected from Seongsanpo, Jejudo Island by SCUBA diving in 10 m depth. This species had a symbiotic relationship with sea anemone. This record extends their previously known range from southern Japan to the Korean peninsula and the number of known pontoniine species in Korea to four.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.1
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• pp.27-33
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• 1979

In early August 1978, a huge red tide occurred off Chilcheon Is, , at the mouth of Jinhae Bay. It expanded rapidly into the central part and then soon covered all the bay except the innermost part of the bay. After staying for a week it disappeared, and thereafter several small scale red tides partially occurred and disappeared untill the end of August. It differed from the red tides hitherto recorded from this bay in respect of the dominant plankter, the geographical extent and the severe damaging effect to local oyster resources. During the red tide period, nevertheless, no oyster damage was found. In September, however, oyster mortailty was found from all rafts and longlines in the bay. Except the inner most part of the bay the oyster farms were completely destroyed. Of the oyster Production in the winter 1978, $96\%$ of an estimated yield of 5,879 tons (shucked meat) was lost and it was estimated to be 2,275 million won, equivalent to $US\$$ 4.55 million. The dominant species was a dinoflagellate, Ceratium fusus and it constituted about $45\%$ of the total phytoplankton. Cell count showed $7.0\times10^4\;cells/\iota$ and chlorophyll-a, $50mg/m^3$ during red tide peak. No oxygen was found ill the bottom waters in September. Sulphides in bottom waters and in the superficial mud increased to 15 and 8-fold respectively in September compared with July ana August. Precipitation from January to May of 1978 was about a third in comparison with the past ten years average but rainfall ill June was two and half-fold more than normal year, and thereafter drought persisited till September Air and water temperatures were also higher, and sunny days continued for a long time without strong winds. Therefore, water was calm for a long time after the red tide extinguished. The result indicated that the occurrence of the Ceratium red tide occurred in that year which was characterized by the combination of the formation of almost anoxic bottom water before the red tide occurrence, high air temperature and the calmness after a great quantity of rainfall in June. The mass mortality of oysters was presumed not to be directly related with the red tide but with the depression of dissolved oxygen in the environmental waters at the bottom due to settling of the red tide organisms.

• The Korean Journal of Mycology
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• v.27 no.1 s.88
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• pp.1-9
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• 1999

For the practical using of liquid spawn we carried out selection test of nutrient sources, cultural methods and cultural apparatus for liquid spawn production of oyster mushroom(ASTI 2001, ASTI 2018, ASTI 2072, ASTI 2016, ASTI 2070, ASTI 2180, ASTI 2183, ASTI 2042). The optimal temperature and pH range for mycelial growth of Pleurotus species were $25^{\circ}C\;to\;30^{\circ}C$ and 5.5 to 6.5, respectively. The effect of carbon sources, nitrogen sources and mineral salts on the mycelial growth was studied using petridish culture. Generally, the disaccharides and polysaccharides showed good effect for mycelial growth of Pleurotus species, and the polysaccharides were superior to the other classes of carbon sources for mycelial growth. For the mycelial growth of the 8 oyster mushroom stains, soybean flour was superior to the other kinds of nitrogen sources. On the other hand, addition of mineral salts did not affect, and even poor under certain mineral salts, the mycelial growth of the 8 oyster mushroom stains. The brown sugar selected out the carbon source of the agricultural medium. Also the soybean flour selected out the nitrogen source of agricultural medium. In the medium selection, we selected out agricultural optimum medium composed of brown sugar 3%, soybean flour 0.3%, potassium phosphate 0.05%, magnesium sulfate 0.05%. Under the 250 ml erlenmeyer culture, the effects of such factors as the inoculum rate, the working volume, cultural method and flask shapes on the mycelial growth were examined. The optimal inoculum rate and working volume on the mycelial growth of oyster mushroom was 2 mycelial disk (diameter 6 mm) and 100 ml, respectively. The shake flask culture was enhanced the mycelial growth than at the erlenmeyer flask. Pulp form growth of mycelium in the erlenmeyer flask culture was obtained in the culture with glass rod of length 50 mm, diameter 10 mm.

• The Korean Journal of Mycology
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• v.37 no.2
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• pp.144-149
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• 2009

The occurrences of the major diseases and the densities of air-born microbes were surveyed in the cultivation facilities for oyster mushroom (Pleurotus ostreatus), king oyster mushroom (Pleurotus eryngii), and enoki mushroom (Flammulina velutipes) in different areas of Korea. Green mold disease was most often developed in oyster mushroom bed cultivation with the disease incidence rate of approximate 10% while the disease incidences from bottle and plastic envelop cultivation were less than 1~2%. In the bed cultivation, the major air-born microbes in the growth room were Aspergillus, Penicillium, Trichoderma, and Curvularia with the total fungal population density of 567~1,297 CFU/$m^3$ . However, only Trichoderma and Penicillium were detected in the growth rooms and innoculation rooms of bottle and plastic envelop cultivation with the densities of 350~700 CFU/$m^3$ and 160~260 CFU/$m^3$, respectively. The bacterial diseases become evident in the growth rooms of bottle and plastic envelop cultivation with the approximate incidence rate of 10%. The identified bacterial species were Brevibacillus levelkil, Rhizobium radiobacter, Brevundimonas vesicularis, Pseudomonas mosselii, Microbacterium testaceum. Sphingomonas panmi, Sphingomonas yabuuchiae, Paracocus dinitrificans, Curtobacterium flaccumfaciens pv. flaccumfaciens and some unidentified bacteria with the densities of 40~6,359 CFU/$m^3$ in the growth rooms and 9 CFU/$m^3$ in the inoculation room. This study indicated that the green mold disease by fungal strains was the major mushroom disease in the bed cultivation and suggested that the contamination of bacteria and fungi together in the growth media could result in severe production loss. The plastic envelope and bottle cultivation were evidenced to be less susceptible to such contaminations.

• Mycobiology
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• v.31 no.2
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• pp.74-80
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• 2003

Isolates of Trichoderma spp. collected from Pleurotus ostreatus and P. eryngii beds, which included loosened substrate compactness and development of green colour, were grouped into three species. The occurrence of different species of Trichoderma was as T. cf. virens(70.8%), T. longibrachiatum(16.7%) and T. harzianum(12.5%). The conidia of Trichoderma spp. were ellipsoidal, obovoid and phialides were bowling pins, lageniform and the length of phialides was $3.5{\sim}10.0{\times}1.3{\sim}3.3{\mu}m$. Phialides of T. cf. virens and T. harzianum were tending clustered, but it was solitary disposition in T. longibrachiatum. T. cf. virens was characterized by predominantly effuse conidiation, sparingly branched, and fertile to the apex and it was penicillate type. RAPD analysis could detect variability amongst three different species of Trichoderma using two newly designed URP-primers. However, intra-specific variation could not be detected in all the isolates except for rDNA sequence data classified Trichoderma isolates into three distinct groups representing three species. The profiles of rDNA sequences of isolates representing a species showed high similarity in T. cf. virens and T. harzianum. However, there was a variation in rDNA sequences of isolates representing T. longibrachiatum. The results of present study reveals that molecular techniques of RAPD and rDNA sequencing can greatly aid in classification based on morphology and precise identification of fast evolving species of Trichoderma.

• Parasites, Hosts and Diseases
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• v.55 no.4
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• pp.399-408
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• 2017

A survey was performed to know the recent infection status of digenetic trematode metacercariae in clams and oysters from 4 sites in western coastal regions of the Republic of Korea (=Korea). Four species of clams (Mactra veneriformis, Ruditapes philippinarum, Cyclina sinensis, and Saxidomus purpuratus) were collected from Taean-gun, Chungcheongnam-do (Province), Buan-gun (County) and Gochang-gun, Jeollabuk-do, and oysters, Crassostrea gigas, from Shinan-gun, Jeollanam-do were transferred to our laboratory on ice and examined by the artificial digestion method. The metacercariae of Himasthla alincia were detected in 3 species of clams, M. veneriformis, R. philippinarum, and C. sinensis from the 3 surveyed areas. The positive rate and the mean density per clam infected were 98.9% (30.8 metacercariae) in M. veneriformis, 60.0% (5.0) in R. philippinarum, and 96.0% (28.4) in C. sinensis. The positive rate (mean density) of Acanthoparyphium tyosenense metacercariae in M. veneriformis was 50.0% (2.1) from Taean-gun and 70.0% (2.8) from Gochang-gun. The metacercariae of Parvatrema spp. were detected in M. veneriformis and R. philippinarum from Taean-gun and Gochang-gun; the positive rate (mean density) was 63.3% (4,123) and 50.0% (19) in M. veneriformis, and 6.7% (126) and 100% (238) in R. philippinarum from the 2 regions, respectively. The metacercariae of Gymnophalloides seoi were detected in all 30 oysters from Shinan-gun, and their average density per oyster was 646. From the above results, it has been confirmed that more than 3 species of metacercariae are prevalent in clams from the western coastal regions, and G. seoi metacercariae are still prevalent in oysters from Shinan-gun, Jeollanam-do, Korea.