Ctenoplusia agnata (Lepidoptera: Noctuidae) is a polyphagous pest that damage on crops belonging to the Fabaceae and Brassicaceae, and it is known as a migratory pest. In this study, we investigated pattern of occurrence to trace invasion characteristics using sex pheromone traps and conducted genetic analysis of captured individuals while also exploring their correlation with air currents. Our findings suggest that C.agnata exhibits an annual occurrence of four generations in Korea, with the second or third generation, primarily active from July to September, posing a significant threat to soybean. Genetic analysis revealed the presence of 17 haplotypes, and trajectory modeling confirmed the influence of air currents from Kyushu, Japan and Zhejiang, China etc. These results are expected to be used as a comprehensive management of C.agnata and other migratory moth species.

The speed of vertical migration and the volume backscattering strength of the scattering layers during the evening and morning transitions between day and night were measured in November 1990-1992 in thermally stratified waters of the East China Sea. Acoustical measurements were carried out using a scientific echo-sounder operating at t재 frequencies of 25 and 100kHz, and using an echo-integration system connected with a micro-computer. Biological sampling was accomplished by bottom trawling to identify fish species recorded on the echo sounder, and the species and length compositions were determined. The values of scattering strength were allocated to group of fishes according to the fish traces on the echo recording paper and the species composition of trawl catches. The vertical velocities of migration derived from the changes in the depths and the values of peak scattering strength of the dense layer vertically migrating toward the bottom or toward the surface. The trawl data suggest that snailfish and fishing frog were the most abundant fishes in all research stations. As sunrise approached, the fish formed a strong concentration just above the thermocline. The the highest values of scattering strength in the entire water column appeared in the depth strata above the thermocline just before the begining of downward migration. As soon as the fish began to migrate downwards across the thermocline, the values of the scattering strength in the depth strata above the thermocline rapidly decreased, while the values for the scattering layer moving slowly toward the bottom gradually increased. During the 1992 surveys, the speed of the vertical migration was estimated to be 0.38m/min in the upward migration and 0.32m/min in the downward migration, respectively. That is the rate of vertical migration was slightly higher at dusk than at dawn. Similar migration patterns were observed on different stations and under different weather conditions during the surveys in 1990.

This study described the characteristics of the upstream migration of salmon (Chum salmon, Oncorhynchus keta) along Yeon-gok Stream in the eastern coastal region of Korea from October 24 to November 9, 2018 using radio tag and data storage tag loggers for the detection of the locations of tagged salmon and measurement of water temperature. Tracking experiments were conducted and classified into four types (case 1 to case 4) depending on the release time and the number of salmon tracked. Experiments from case 1 to case 3 were classified depending on the number of salmon tracked into cases in which a single tagged salmon was tracked (case 1), a pair of tagged salmon was tracked (case 2), and salmon were tracked by different sex ratios (case 3). Experiments from cases 1 to 3 were conducted between 10 AM and 1 PM, and case 4 was conducted after 3:30 PM. Salmon moved and spawned in the downstream region of the Yeon-gok, where water temperature is higher than in other rivers and salmon return in Canada, Russia, Japan, and the U.S.A. Most of the radio-tagged salmon swam in deep and shaded areas during the day but actively moved upstream close to sunset, regardless of the release time. Females showed relatively more active movements than males during upstream migration.

Migration is defined as the movement of people between residential places, and represents interactions between regions. Changes in migration involve changes in both the number of migrants toward/from regions and migration patterns across regions. However, most migration studies have focused only on the change in migrants, while no empirical study captures changes in migration patterns. In this paper, I present a function using the cosine similarity to measure changes in migration patterns, and apply it to 2001-2016 migration data of Korea. The results show that the migration patterns of Korea shifted in 2007, resulting in two distinct clusters. Local areas experienced various migration pattern changes despite few changes in the number of migrants.

초고령화된 한국 농촌에서 다양한 교육 및 직업 배경을 가진 중장년층 귀농인구의 유입은 고령화 문제에 대한 대안의 하나로 부각되고 있다. 본 연구는 농가 고령화에 대한 귀농인구의 잠재적인 기여도 측면에서 귀농인구의 지역별 유입 유출 패턴을 분석하였다. 분석에는 로그선형모형과 총합레퍼런스코딩을 사용하였고, 분석자료는 통계청의 2013년 귀농 통계이다. 분석결과에 의하면, 귀농인의 절반 정도가 수도권에서 비수도권 지역으로 이주한 인구이고, 이들을 제외하면 귀농인의 대부분은 원 거주지가 있던 도 내에서 이동하고 있다. 귀농인의 귀농 전 대비 귀농 후 지역 내 오즈비(odds ratio)는 지역별로 차이가 있으며, 귀농인의 성별과 연령에 따라서도 지역별 유입 유출패턴이 다르다. 이는 귀농인 유입의 긍정적 효과를 높이기 위해서는 지자체별 차이를 반영한 특화된 정책이 필요하다는 것을 의미한다.