본 연구는 서식 환경에 따라 구분된 3화기 미국흰불나방(Hyphantria cunea Drury)을 숙주로 하는 기생파리의 종과 기생률의 차이를 확인했다. 조사 기간은 2023년 10월 24일부터 29일까지로, 방제를 실시한 서천군 국립생태 원과 방제를 실시하지 않은 군산시 근린공원에서 숙주인 미국흰불나방의 유충을 채집하였다. 유충은 기주식물 인 수국을 급여하여 실내 개별 사육하였다. 각 조사지에서 미국흰불나방의 기주식물은 국립생태원에서 8종, 근린공원에서 6종이 확인되었다. 총 숙주 380마리 중 기생파리는 106개체로 총 27.9%의 기생률을 보였고(유충 92개체, 미동정 알 14개체), 기생률은 근린공원이(39.6%) 국립생태원(12.5%)보다 더 높았다. 성충의 우화율은 63.0%로, 동정 결과 4속 92개체가 나타났다. 전체 종과 가장 많은 개체가 확인된 Exorista japonica (Townsend, 1909)의 조사지에 따른 유충 생존율과 성충 우화율은 모두 근린공원이 더 높은 것으로 확인 되었다. 조사결과 E. japonica가 미국흰불나방의 생물적 방제제로 유효할 것이라 판단되며, 근린공원에서의 더 높은 기생파리 유충 생존율과 성충 우화율을 통해 인간에 의한 교란이 적은 환경에서 기생파리를 이용한 미국흰불나방 방제가 더 효과적일 것이라고 고려된다. 또한 숙주의 생존율과 기생파리의 우화율을 비교한 결과 해충 방제가 이뤄지지 않는 환경에서 천적 개체군이 유지될 가능성이 더 높다고 사료 된다.

The effect of oxidation time on the characteristics and mechanical properties of spent nuclear fuel cladding was investigated using Raman spectroscopy, tube rupture test, and tensile test. As oxidation time increased, the Raman peak associated with the tetragonal zirconium oxide phase diminished and merged with the Raman peak associated with the monoclinic zirconium oxide phase near 333 cm−1. Additionally, the other tetragonal zirconium oxide phase peak at 380 cm−1 decreased after 100 d of oxidation, whereas the zirconium monoclinic oxide peak became the dominant peak. The oxidation time had no effect on the tube rupture pressure of the oxidized zirconium alloy tube. However, the yield and tensile stresses of the oxidized nuclear fuel cladding tube decreased after 100 d of oxidation. The results of the scanning electron microscopy and transmission electron microscopy were represented with the in-situ Raman analysis result for the oxide characteristics generated on the cladding of spent nuclear fuel.

This study was conducted to evaluate the performance of the octopus pot according to mesh sizes. Entering behavior of Octopus minor and bait (Macrophthalmus japonicus) escape rate on the mesh sizes of the pots were investigated for six times in indoor tank. The sea trials for evaluating the performance of Octopus minor pot to different mesh sizes (22, 20 and 18 mm) were conducted for six times from 2017 to 2018 in the coastal sea of Deukyang Bay, the Republic of Korea. Behavior patterns of contact pot to leaved pot were more frequent than contact pot to bait search. When the octopus contacted to the pot, there was no clear search behavior to distinguish the mesh sizes. Total catch of 46% was accounted for 18 mm pots, followed by 34% at 20 mm and 20% at 22 mm (P < 0.05). Catch per unit effort was calculated as 30 g/pot at 22 mm, 44 g/pot at 20 mm and 59 g/pot at 18 mm. As a result of evaluating 50% selection of mantle length and weight on the mesh sizes, mantle length (mm) and weight (g) were 84.6 and 147.8 in 22 mm, followed by 20 and 18 mm.

The objectives of this study were to develop the optimal structures of recirculating aquaculture tank for improving the removal efficiency of solid materials and maintaining water quality conditions. Flow analysis was performed using the CFD (computational fluid dynamics) method to understand the hydrodynamic characteristics of the circular tank according to the angle of inclination in the tank bottom (0°, 1.5° and 3°), circulating water inflow method (underwater, horizontal nozzle, vertical nozzle and combination nozzle) and the number of inlets. As the angle in tank bottom increased, the vortex inside the tank decreased, resulting in a constant flow. In the case of the vertical nozzle type, the eddy flow in the tank was greatly improved. The vertical nozzle type showed excellent flow such as constant flow velocity distribution and uniform streamline. The combination nozzle type also showed an internal spiral flow, but the vortex reduction effect was less than the vertical nozzle type. As the number of inlets in the tank increased, problems such as speed reduction were compensated, resulting in uniform fluid flow.

The objective of this study is to develop education programs for cultivating smart aquaculture experts through a education demand survey of industries, high school students, university (graduate) students and field workers. The industry demand analysis was conducted as an in-depth interview on representives from seven companies. Education demand surveys were conducted on 96 students and field workers in the Jeonnam region. Results on the demand survey were analyzed using frequency analysis and cross-analysis. The company representatives responded that they want to participated in internship and retraining programs to proactively secure manpowers with convergence capabilities about smart aquaculture. Seven companies preferred manpowers with basic competencies on ICT (Information and Communications Technologies) or aquaculture. The most respondents in the demand survey want to participate in the education program for experience on advanced technology, self-development and enhancement of work capability. On the other hand, some respondents said that the education is time-consuming and that the education program does not fit their level. Thus, the education program should be developed in a way to minimize the spatial and temporal limitations of education targets and to improve understanding of non-majors by reflecting the demands of human resources in the industrial field.

The objective of this study is to establish a direction for smart aquaculture technology development in the Republic of Korea through patent analysis and a demand survey of experts and fishermen. The patent analysis was conducted using Wisdomain for patents in the Republic of Korea, the United States of America, Europe, Japan, and China from 2005 to 2016. This study conducted an analytic hierarchy process (AHP) survey of experts in the fields of fishery, marine, and ICT among others. Furthermore, it carried out a demand survey of 85 fishermen in Jeonnam and Jeju. The smart aquaculture technology market has moderately grown in the Republic of Korea until recently, and it is expected to expand further because of the expansion of national investment in the smart aquaculture field. The priority evaluation results for developing smart aquaculture technology show that land-based aquaculture has a higher priority than sea-based aquaculture. Of the fishermen that responded, 84% said that they need to introduce smart aquaculture technology to solve problems in the supply and demand of manpower, labor cost, and maintenance expenses. The direction of development should lie in developing biological and environment-based standard aquaculture models to spread high-tech systems and vitalize the aquaculture industry. This requires continual training of human resources in the smart aquaculture field.

The objective of this study was to investigate the growth rate and the optimal stocking density of sea cucumbers. Grow-out was studied in situ by conducting a follow-up survey using visible implant elastomer (VIE) tags. The rearing systems were made of polypropylene pipe for the frames and netting. The experiment ran for 70 days near Yeosu, Korea in the water depth of about 7 m. A total of 576 sea cucumbers which have three groups of body sizes (small: 5.15, medium: 12.34 and large: 23.26 g) were used. The five groups of stocking densities (150, 300, 450, 600 and 850 g/m2) in rearing system for sea cucumber were considered. Sea cucumbers were fed a mixed diet (mud, mineral, fish meal, etc.). The feed was supplied to 10% of their body wet weight once every 7 days. The survival rate (73%) of sea cucumber in 850 g/m2 was lower than those of other density groups (150 g/m2: 89%, 300 g/m2: 84%, 450 g/m2: 78% and 600 g/m2: 86%). The survival rate of medium size group was higher than those of small and large groups regardless of the density (P<0.05). Most of density groups have no significant difference except for 850 g/m2 (P>0.05). The growth rate of small size group (0.63% day-1) was higher than those of medium (0.38% day-1) and large (0.34% day-1) group regardless of the density (P<0.05). The threshold water temperature was 11.0°C for sea cucumber growth in winter season.

Abalone (Haliotis discus hannai) is a shellfish that feeds on kelp and, as a product, it can often achieve a high market value. However, the dissolved oxygen (DO) levels in coastal waters in Korea have been negatively impacted by pollution from many anthropogenic sources. Herein, a computational fluid dynamics (CFD) software package was used to analyze the distribution of the DO concentration within an abalone containment structure. A finite volume approach was used to solve the Reynolds-averaged Navier–Stokes equations combined with a k–ε turbulence model to describe the flow. The distribution of DO was determined within the control volume domain, and the transport equations of the pollutants were interpreted using a CFD model. The CFD analysis revealed that more than 60% and 30% of the relative oxygen concentration in one and two containers, respectively, was maintained when the flow acts along the six sheets of polyethylene plates. Therefore, it is clear that the abalone plate shelters should be placed parallel to the flow.

The common octopus, which has a high growth rate and high market price, is a prime candidate for commercial marine aquaculture operations. We evaluated the effectiveness of two types of shelters (pipe and tire types) for juvenile common octopus growing out in flow-through seawater tanks. Growth rates were evaluated in two experiments. The first experiment (Experiment 1) ran for 72 days, and the second (Experiment 2; replicated) ran for 46 days. Each trial included 40 octopuses fed a diet of frozen sardine (Sardinops melanostictus) and swimming crab (Portunustri tuberculatus) at 3–8% of body weight once every 3 days. In the two experiments, the respective specific growth rates were 0.3 and 0.04%/day in pipe-type shelters and 0.00 and 0.88%/day in tire-type shelters, while the respective percentage survivals were 80 and 80% in pipe-type shelters and 70 and 90% in tire-type shelters. Shelter type had little influence on the growth rate (P < 0.05).

The sea cucumber, Apostichopus japonicus, is becoming an important aquaculture species in China, Japan and Korea. The purpose of this study is to evaluate the biological performance of a tubular type of subsurface cage for sea cucumber grow-out by in-situ tests. The cage structure was constructed of PP (polypropylene) frames and PP tubes (ø130 mm×24 pieces). A set of tests were conducted at a depth of 15 m near Seosaeng, Ulsan, Korea for 295 days (23 July, 2012 to 13 May, 2013). A total of 155 sea cucumbers were used and fed a mixed diet containing mud, mineral, wheat, fish meal, etc (3% of their body weight). At the end of the experiments, sea cucumber showed a higher survival rate in feed shelter (77.14%) rather than no feed shelter (64.71%). The specific growth rate (SGR) of sea cucumbers in feed condition (0.04% day－1) was higher than that of no feed culture animals (－0.49% day－1) during total experimental periods. The result was able to find a no significance difference in survival rate but a significance difference in SGR under feed and no feed treatments.

The goal of this study is to examine case markers in Korean, i.e., i/ka and (l)ul, from a communicative perspective. In particular, this study seeks to explain what communicative functions the case markers hold in actual conversation. Based on the empirical analysis of the data, this study claims that the case markers in Korean are not only used for encoding the syntactic case of a given argument but they are also used as a linguistic cue to help focus the listener's attention on the processing difficulty and the informational importance that the given argument denotes. It further argues that speakers of Korean strategically use the case markers as a means of facilitating successful communication with the listener.