• 수산해양기술연구
• /
• 제51권1호
• /
• pp.16-25
• /
• 2015

Visual census and hydro-acoustic survey was carried out at Ulju small scale marine ranching area (MRA) to estimate demersal fish aggregations on September and November 2013. In this hydro-acoustic survey, the authors combined an image sonar with a scientific echo sounder to monitor an underwater situation and compare two acoustic data. Consequently, visual census survey was useful to estimate fish species composition for hydro-acoustic survey, because it is easy to identify aggregated fish species and overcome limits on a fishing depth and ability of an conventional fishing gear like a bottom gill-net or a fish trap at marine ranching area. Mean fish density was estimated as $0.757g/m^2$ on September and $0.219g/m^2$ on November and Fish abundance was finally calculated as 1.51ton (coefficient of variation, CV=13.1%) on September and 0.44ton (CV=47.7%) on November, respectively. Hydro-acoustic survey combined with the image sonar was useful to monitor fish aggregations and estimate fish stocks around artificial reefs at shallow coastal MRA. We were able to easily identify the underwater structures like an artificial reef and a fishing rope as well as fish aggregations from image sonar data. Therefore, the method was effective to separate unwanted echo signals in acoustic data of scientific echo sounder.

• 한국수산과학회지
• /
• 제46권2호
• /
• pp.111-118
• /
• 2013

The Norwegian coastal area is the most efficient region for fishery production in the world's oceans, the Norway is the world's top 10 fisheries countries through efficient fishing and fishing aquaculture technology and its scientific management of fisheries bio-resources, with Norwegian salmon having attained the world's highest level. In the late 1980s, fisheries resources were depleted due to overfishing and fish diseases, resulting in a crisis in the fishing industry that lasted until the early 1990s. Since the national fishery emergency, people involved in the fishing industry, including fishermen, research scientists, and government officers, have tried to overcome the challenges facing the industry and identify an appropriate management model for fisheries bio-resources in the Norwegian coastal area. First, research vessels were used to monitor water and sediment conditions and fishery species, with the long-term aim of predicting fishery resources in real time and collecting information on species diversity, abundance, and distribution. Second, a "Healthy Fish Project" was promoted to counter natural disasters and fish disease problems with the development of vaccines against viruses and bacteria, eventually allowing for a decrease in the use of antibiotics and the production of notably healthier fish in the 2000s. Third, a systematic management model was developed to help with preparations for decreases in the total number of fishermen and increases in the proportion of elderly fishermen in the fishery industry using the development of automatic fishing aquaculture systems and short-chain systems. We could learn from the Norwegian model of fisheries bio-resources, management and could adopt it for the preparation of fishery bio-resources management policy for South Korean coastal areas in the near future.

• Journal of Microbiology and Biotechnology
• /
• 제24권10호
• /
• pp.1346-1353
• /
• 2014

In the present study, an anthraquinone derivative, questinol was successfully isolated from the broth extract of the marine-derived fungus Eurotium amstelodami for the first time. The structure of questinol was determined based on the analysis of the MS and NMR spectral data as well as comparison of those data with the published data. Moreover, the anti-inflammatory effect of questinol in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells was investigated. The results showed that questinol did not exhibit cytotoxicity in LPS-stimulated RAW 264.7 cells up to $200{\mu}M$. Questinol could significantly inhibit NO and $PGE_2$ production at indicated concentrations. Questinol was also found to inhibit the production of pro-inflammatory cytokines, including TNF-${\alpha}$, IL-1${\beta}$, and IL-6. Furthermore, the western blot analysis showed that questinol suppressed the expression level of iNOS in a dose-dependent manner. However, questinol could slightly inhibit the expression of COX-2 at the concentration of $200{\mu}M$. Therefore, our study suggests that questinol might be selected as a promising agent for the prevention and therapy of inflammatory disease.

• 수산해양기술연구
• /
• 제53권4호
• /
• pp.430-436
• /
• 2017

The most frequent occurring and the serious marine casualties in fishing vessels are the collision in statistics from Korea Maritime Safety Tribunal (2008-2015). Collisions are is given a great deal of weight in all marine casualties, and the main cause of collisions is the negligence of watching. From this point of view, this study deals with the collision and its immediate cause, the negligence of watching which are main factors on the indirect causes. Basic analyzing data was gathered from the questionnaire made by experts of sea service part, and analyzed by using the fault tree analysis (FTA). From the result of the study, the occurrent probability of the negligence of watching in the collision due to the indirect causes occupied 64.9%, and its probability caused by the man factors was less than the other factors; i.e. the media factors and the management factors. For the reduction of the negligence of watching in the collision from this study, it needs an effort to remove not only the man factors, but also the media factors and management factors.

• 수산해양기술연구
• /
• 제47권2호
• /
• pp.139-145
• /
• 2011

Hydro-acoustic survey was carried out to estimate a fish distribution at marine ranching area and aggregated fish schools at artificial reef area in Oeyeondo, Korea. The survey system was set up with DGPS system, scientific echo sounder (EK60, Simrad Co.), and ECDIS (Mecys. Co. LTD). A track survey and a random survey was respectively applied to the marine ranching area (474.4ha) and to the artificial reef area (within a radius of 300m). As the result, fish distribution and MVBS values in marine ranching area showed that created fisheries resources didn't come to be abundant yet as to appear fish distribution in all of the area. In the artificial reef area, it was, however, able to detect many fish school signals on the top of and around artificial reefs and to confirm the luring effect of artificial reefs.

• Fisheries and Aquatic Sciences
• /
• 제17권2호
• /
• pp.215-222
• /
• 2014

To explore marine microorganisms with medical potential, we isolated and identified marine bacteria from floats, marine algae, animals, and sponges collected from Jeju Island, Korea. We isolated and identified 21 different strains from the marine samples by 16S rRNA analysis, cultured them in marine broth, and extracted them with ethyl acetate (EtOAc) to collect secondary metabolite fractions. Next, we evaluated their anti-oxidative and anti-inflammatory effects. Among the 21 strains, the secondary metabolite fraction of Bacillus badius had both strong antioxidant and anti-inflammatory activity, and thus was selected for further experiments. An antioxidant compound detected from the secondary metabolite fraction of B. badius was purified by preparative centrifugal partition chromatography (n-hexane:EtOAc:methanol:water, 4:6:4:6, v/v), and identified as diolmycin A2. Additionally, diolmycin A2 strongly inhibited nitric oxide production. Thus, we successfully identified a significant bioactive compound from B. badius among the bacterial strains collected from Jeju Island.

• 한국어병학회지
• /
• 제21권3호
• /
• pp.241-246
• /
• 2008

The effects of temperatures on pearl oyster, Pincdata fucata were studied by evaluating some functional immune responses of the haemocytes. Water temperature is one of the most important factors in bivalve immune defense. Haemocytes comprise a primary line by inflammation, encapsulation and phagocytosis. These phagocytic abilities of haemocytes were observed in different temperatures. The number of the circulating haemocytes by migratory assay, phagocytic activities by MTT assay and reactive oxygen species production of haemocytes by CL assay were measured at different temperatures. Results showed that pearl oyster maintained at 20℃ and 25℃ displayed significantly higher values for all the measured immune parameters in comparison to maintained at 10, 15, and 30℃.

• Journal of Ecology and Environment
• /
• 제31권2호
• /
• pp.107-113
• /
• 2008

We measured a set of 37 morphological characteristics in 97 specimens of adult Korean chub, Zacco koreanus, trapped in the Milyang River, Korea, in May and October of 2005. Twelve out of thirty-seven morphometric measurements were significantly different between the sexes. In particular, both the pectoral fin length and the direct distance between the insertion of the dorsal fin and the insertion of the anal fin were highly significant (p < 0.001). This sexual dimorphism may reflect the outcome of sexual selection in this species.

• 한국해양바이오학회지
• /
• 제1권1호
• /
• pp.34-39
• /
• 2006

Molecular biology and microalgal biotechnology have the potential to play a major role in improving the production efficiency of a vast variety of products including functional foods, industrial chemicals, compounds with therapeutic applications and bioremediation solutions from a virtually untapped source. Microalgae are a source of natural products and have been recently studied for biotechnological applications. Efficient genetic transformation systems in microalgae are necessary to enhance their potential to be used for human health. A microalga such as Chlarella is a eukaryotic organism sharing its metabolic pathways with higher plants. This microalga is capable of expressing, glycosylating, and correctly processing proteins which normally undergo post-translational modification. Moreover, it can be cultured inexpensively because it requires only limited amount of sunlight and carbon dioxide as energy sources. Because of these advantages, Chlarella may be of great potential interest in biotechnology as a good candidate for bioreactor in the production of pharmaceutical and industrial compounds for human functional foods. Here, we briefly discuss recent progress in microalgal transgenesis that has utilized molecular biology to produce functional proteins and bioactive compounds.

• 한국미생물·생명공학회지
• /
• 제47권4호
• /
• pp.581-584
• /
• 2019

In this study, the carbon monoxide (CO)-fermenting acetogen, Clostridium sp. AWRP was subjected to chemical mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine (NTG) to generate a CO-resistant mutant. Among the 26 colonies obtained, the highest alcohol production was observed in one isolate, named C1. Compared to the wild-type strain, the C1 strain exhibited 1.5- and 3.4-fold higher CO consumption rate and alcohol selectivity, respectively. The total CO consumption of strain C1 could be further enhanced by increasing the content of metal ions, such as nickel and iron. The highest ethanol titer (5.7 g/l) was achieved by 5-fold increase in the iron concentration.