• The Korean Journal of Malacology
• /
• v.27 no.2
• /
• pp.143-148
• /
• 2011

Even though ark shell, Scapharca broughtonii is commercially important species, its artificial seed production is not yet fully developed. This study was carried out to understand the effect of three microalgal species on gonadal development and sex maturation of S. broughtonii in terms of broodstock management and food organism. Isochrysis galbana, Phaeodactylum tricornutum and Tetraselmis tetrathele were supplied to S. broughtonii broodstock in single or mixed. And condition index, gonadal development, sexual maturation and survival of the broodstock were analysed. After 45 rearing days, frequency of ripe stage of gonadal phases, rate of induced sexual maturation and survival of S. broughtonii broodstock fed mixed diet with 3 microalgal species or single diet of T. tetrathele were the highest.

• Journal of Fisheries and Marine Sciences Education
• /
• v.12 no.1
• /
• pp.11-21
• /
• 2000

Most of artificial reefs in the examined areas were normally established except for some lower parts demersed slightly, and some to function. 1) Twenty species of fish were captured by fishing gear, and 10 species were observed by scuba in the examined areas. 2) Five algal and five fisheries animal species were observed as fouling organism. 3) C.P.U.E of trap, long liner and gill netter in the examined areas was respectively 2.12, 10.23, and 4.93, where as that in contral was established as 1.41, 4.43 and 2.86. 4) Species composition by the fishing gear the trap, long liner and gill netter in the examind areas was respectively 94, 85 and 118, where as that in control was established as 58, 37 and 62. Accordingly, The fishing effects in the artificial reefs installation sector was two times higher than comparative sector.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.11
• /
• pp.682-687
• /
• 2018

This study investigated the food value of Paracyclopina nana for flounder Paralichthys olivaceus larvae in two feeding stages, rotifer (for 12 days) and Artemia (for 16 days). In the rotifer feeding stage, survival and growth of flounder larvae in the only P. nana (nauplii) feeding experiment were higher than in the only rotifer feeding experiment on 12 DAH (days after hatching). In the Artemia feeding stage, the growth of flounder larvae in the only P. nana (C4-adult) feeding experiment and mixture feeding experiment (P. nana+Artemia) were higher than in other experiments on 30 DAH, but the survival of flounder larvae did not differ significantly among experiments. The n-3 HUFA contents of nauplius and C4-adult were 4.0% and 5.4%, respectively. Overall the results of this study indicate that the brackish water cyclopoid copepod, P. nana, is an effective live food organism for larval seedling production of marine fish.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.1
• /
• pp.119-126
• /
• 2021

In this study, the variability in paralytic shellfish poisoning (PSP) by the toxic dinoflagellate Alexandrium catenella (Group I) was analyzed under a variety of water temperatures and salinities. This dinoflagellate experienced optimum growth at temperatures and salinities of 20~30℃ and 20~30 psu, respectively. These findings indicate that A. catenella is an eurythermal and euryhaline organism. High toxin contents and toxicities were observed at low temperatures (10 and 15℃), where they were associated with low growth rates; salinity did not have any significant impact on toxicity parameters. Therefore, it is likely that A. catenaella contributes to the rapid intoxication of commercial bivalve when temperatures are ≤15℃. To better estimate PSP caused by A. catenalla, we suggest that the influence of various environmental factors controlling PSP should persist with other A. catenella stains and commercial bivalves.

• Proceedings of the Microbiological Society of Korea Conference
• /
• 2001.11a
• /
• pp.39-45
• /
• 2001

Extremophiles are unique microorganisms that are adapted to survive in ecological niches such as high or low temperatures, extremes of pH, high salt concentrations and high pressure. These unusual microorganisms have unique biochemical features which can be exploited for use in the biotechnological industries. Due to the high biodiversity of extremophilic archaea and bacteria and their existence in various biotopes a variety of biocatalysts with different physicochemical properties have been discovered. The extreme molecular stability of their enzymes, membranes and the synthesis of unique organic compounds and polymers make extremophiles interesting candidates for basic and applied research. Some of the enzymes from extremophiles, especially hyperthermophilic marine microorganisms (growth above $85^{\circ}C$), have already been purified in our laboratory. These include the enzyme systems from Pyrococcus, Pyrodictium, Thermococcus and Thermotoga sp. that are involved in polysacharide modification and protein bioconversion. Only recently, the genome of the thermoalkaliphilic strain. Anaerobranca gottschalkii has been completely sequenced providing a unique resource of novel biocatalysts that are active at high temperature and pH. The gene encoding the branching enzyme from this organism was cloned and expressed in a mesophilic host and finally characterized. A novel glucoamylase was purified from an aerobic archaeon which shows optimal activity at $90^{\circ}C$ and pH 2.0. This thermoacidophilic archaeon Picrophilus oshimae grows optimally at pH 0.7 and $60^{\circ}C$. Furthermore, we were able to detect thermoactive proteases from two anaerobic isolates which are able to hydrolyze feather keratin completely at $80^{\circ}C$ forming amino acids and peptides. In addition, new marine psychrophilic isolates will be presented that are able to secrete enzymes such as lipases, proteases and amylases possessing high activity below the freezing point of water.

• The Journal of Fisheries Business Administration
• /
• v.54 no.3
• /
• pp.69-92
• /
• 2023

The 'Japanese Useful Fisheries Classification Table', published in advance before the publication of the "Useful Fisheries of Japan", is the first data to classify and introduce fisheries animals and plants in a single table. Therefore, it had received public attention immediately. However, The academy of animal studies at that time quickly pointed out that this classification table was a mixture of traditional and modern classifications, and that there were too many errors. However, Yoshio Tanaka, who was in charge of revising Yamamoto Arikatana, that wrote the classification table, was not an adherent of traditional taxonomy, nor was he ignorant of modern taxonomy. Nevertheless, the classification table, which was quite different from the well-known zoological classification at that time, was prepared. For example, the top classifications of marine organism are not at the same level, but rather a mixture of phylum and class, while the water insect contains several phylums, including Arthropoda, Echinodermata, Mollusca, and Coelenterata. As such, the method of classification of animals in the classification table was hard to understand in the zoological academy at that time. The reason for this unusual taxonomy was that the classification table showed classification of useful fisheries products, not intended to convey academic classification. In other words, it is not for the purpose of academic classification of all fishery products, but for the purpose of presenting standards that can be easily understood by those engaged in the collection, manufacture, and aquaculture of fishery products. This principle of 'Useful Fisheries of Japan' is also ascertained in the "Fishing Methods of Japan" and "Fishery Products of Japan". Regarding the collection and processing of marine products, it could have shown how to catch whales, which are mammals, and how to dismantle whales and obtain oil and meat, according to academic classifications. However, the first appearances in the book include dried squid, abalone, shark fins, and sea cucumbers. In other words, the most important fishery products at that time are presented first. The contents of the classification table, which is considered somewhat bizarre, show where the purpose to compile Useful Fisheries of Japan.

• Fisheries and Aquatic Sciences
• /
• v.9 no.2
• /
• pp.57-63
• /
• 2006

A bacterial strain capable of hydrolyzing carrageenan was isolated from the coast of Busan in Korea. The isolated strain (HS5322) is aerobic, gram-negative, rod-shaped, and motile. Comparison of the 16S rDNA of the isolate with that of known Pseudomonas sp. showed that sequence similarity was at most 95%, implying that the isolate is a new Pseudomonas species. The organism grew optimally at NaCl concentrations of 2.0 to 2.5%. The optimum temperature and pH for carrageenase production in a 72-h flask culture containing 1% carrageenan was $20^{\circ}C$ and pH 8.5, respectively. Of the synthetic substrates tested, the highest enzyme activity was obtained with p-nitrophenyl ${\beta}$-D-galactopyranoside.

• Korean Journal of Environmental Biology
• /
• v.35 no.1
• /
• pp.1-5
• /
• 2017

A native species to the European ocean, the tunicate Ciona intestinalis now appears worldwide, from sub-Arctic to tropical regions. C. intestinalis generally occurs as an opportunistic fouling organism on artificial substrates in harbors or aquaculture. This study focused on estimating the early growth pattern of C. intestinalis under various temperature conditions. Adults were collected from the Guryungpo harbour in November 2016, and their artificially inseminated eggs were used for the study. The growth of the C. intestinalis was investigated at 8 constant temperatures, ranging from $12^{\circ}C$ to $26^{\circ}C$, at 30 psu. Results indicate that the growth of C. intestinalis increased with increasing temperature. The growth was sluggish at $12^{\circ}C$, and decreased at $26^{\circ}C$. The optimal temperature for growth of C. intestinalis was therefore estimated to be between $20^{\circ}C$ and $24^{\circ}C$.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.102.1-102
• /
• 2003

A bacterial strain YC4963 with antifungal activity against Colletotrichum orbiculare, a causal organism of cucumber anthracnose was isolated from the rhizosphere soil of Siegesbeckia pubescens (Siegesbeckia pubescens Makino；Family：Compositae) in Korea. Based on physiological and biochemical characteristics and 16S ribosomal DNA sequence analysis, the bacterial strain was identified as Pseudomonu aureofaciens. The bacteria also inhibited mycelial growth of several plant fungal pathogens such as Botrytis cinerea, Fusarium oxysporum and Rhizoctonia solani on PDA and 0.1 TSA media. The antibiotic activity was found from the culture filtrate of TSB(tryptic soy broth) and its active compounds were quantitatively bound to XAD adsorber resin. The antibiotic spectrum was broad and growth of C. orbiculare and F. oxysporum, B. cinerea were inhibited at very low concentration. The chemical data from various chromatographic procedures showed that active fraction consisted of at least two phenazine derivatives. However, the metabolites had no inhibitory effect on Pythium ultimum which was reported to be sensitive to phenazine antibiotics. The compounds responsible for the activity are now under investigation.

• The Korean Journal of Malacology
• /
• v.21 no.1
• /
• pp.19-24
• /
• 2005

This study was undertaken with the intent to describe the influence of water temperature and food concentration on the filtration rates of the Asiatic clam, Corbicula fluminea. The clams were collected at Lake Geumho near Yeongsan river, during March 2001. Food organism, Scenedesmus sp. (KMCC FC-34), was indoor-cultured in f/2 medium, and was used to measure the filtration rate of the clams. Filtration rate of the clams was measured by indirect method. Cell concentrations of food organisms were determined by direct counting cells using the hemacytometer under the light microscope. The filtration rate of the clams increased with water temperature up to circa $25^{\circ}C$. Above this temperature, the filtration rate decreased rapidly. The minimal filtration rate of the clams was recorded at $5^{\circ}C$. Thermal coefficient, $Q_10$ values at low temperature range were much higher than those at high temperature range. These results indicate the asiatic clam is more sensitive in cold water like most of marine bivalves. There was a strong reversed correlation between filtration rate and food concentration. Filtration rate of the clams was reduced as food concentration was increased.