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The rockfish (Sebastes schlegeli) and striped beakperch (Oplegnathus fasciatus) were released in marine ranching areas in Korea, Japan, and China to maintain fishery resources in coastal areas. To estimate the density and biomass of fishery resources, the target strength (TS) of target marine organisms is needed to scale integrated volume backscattering coefficients. In this study, the target strength–length (TS–L) relationship for live rockfish and striped beakperch was derived using ex situ methods at a frequency of 200 kHz. The TS-L function for rockfish and striped beakperch can be expressed as TSAvg. = 20logTL − 69.25 (R2 = 0.35) and TSAvg. = 20logFL − 67.01 (R2 = 0.31), respectively. These results can be used to assess the growth, density, and abundance of the two species using acoustics. [ABSTRACT FROM AUTHOR]

Background: Medication adherence after percutaneous coronary intervention (PCI) is essential to preventing the risk of restenosis. Even though Type D personality and depression have been known to affect medication non-adherence, their combined influence on PCI patients remains unclear. Aim: We aimed to identify how both Type D personality and depression were associated with medication non-adherence for 3 months after successful PCI. Methods: This prospective cohort study included 257 PCI patients, who took 3 or more cardiac medications, at a university hospital. We measured sociodemographic and clinical variables, Type D personality, depression, and medication non-adherence using face-to-face interviews and medical record reviews. Results: The total prevalence of medication non-adherence at the one- and three-month follow-ups was 14% and 16%, respectively. At one month, the prevalence of those with a combination of Type D personality and depression (23.4%) and depression alone (24%) was significantly higher than other groups. At three months, the prevalence of the Type D personality-only group (39.1%) was the highest. Type D personality increased the risk of medication non-adherence 5.089 times at three months, while depression increased it 2.6 times at one month. However, the risk of medication non-adherence was not increased in patients with combined Type D personality and depression. Conclusions: Individual assessments of Type D personality and depression are required. Therefore, psychological interventions focusing on personality and depression are crucial. Longitudinal follow-up studies must explore the interaction or individual impact of Type D personality and depression on medication non-adherence and other negative outcomes.

In this study, acoustic, sighting, trawl, and marine environmental surveys were used to determine the vertical distribution and density of giant jellyfish that have been observed in Korean waters over the past 3 years. From 2020 to 2022, annual surveys were conducted in May and July in the East China Sea and waters adjacent to South Korea. The acoustic data were processed by identifying and eliminating all signals considered as noise while excluding those suspected to be jellyfish signals. Subsequently, a single target detection method was employed. Giant jellyfish are distributed mostly in the middle and low layers. In May 2021, the average population density of giant jellyfish was recorded as 11.6 (ind./ha), which was the highest density. In July 2022, this value decreased to 1.7 (ind./ha), marking the lowest density. The sighting survey, which allows for the identification of jellyfish distributed in the surface layer, exhibited a difference of approximately 0.13 times compared to the acoustic survey conducted in the middle and low layers in 2020. In 2021 and 2022, this difference was approximately 0.11 times and 0.24 times, respectively. The average of this difference was 0.16 times or greater. [ABSTRACT FROM AUTHOR]

Antarctic silverfish (Pleuragramma antarcticum) play a crucial intermediary role in connecting top predators and krill in the food web of the Antarctic Ocean. Despite their crucial role, research on their abundance is lacking. In this study, we estimated the abundance of juvenile Antarctic silverfish as foundational data for predicting their abundance. The density of juvenile Antarctic silverfish was estimated using an acoustic backscattering theoretical model. The mean volume backscattering strength was used to investigate the vertical and horizontal distributions of juvenile Antarctic silverfish in the Antarctic Ross Sea. The survey area was located near Cape Hallett, Antarctica, where Antarctic krill (Euphausia superba), ice krill (E. crystallorophias), and Antarctic silverfish coexist. The survey was performed four times using the Korean Antarctic research ship, RV Araon (R/V, 7507 GT). Frame trawls were conducted to identify the length and weight of the target fish species in the survey area. Captured Antarctic silverfish captured measured 3–9 cm. The maximum target strength (TS) was −92.93 dB at 38 kHz, −86.63 dB at 120 kHz, and 85.89 dB at 200 kHz. The average TS was −100.00 dB at 38 kHz, −93.00 dB at 120 kHz, and −106.90 dB at 200 kHz. Most juvenile Antarctic silverfish were found at a depth of 100 m and were distributed closer to sea ice. Between nearshore and polynya waters, the fish demonstrated a proclivity for polynya waters. [ABSTRACT FROM AUTHOR]

The supply of feed has a significant effect on fish growth and operation costs, making it a critical factor in aquaculture. Owing to the repetitive nature of feed supply, feeding techniques have undergone a shift from manual feeding to systems allowing operators to set feed quantities and timing, reducing labor efforts. However, unlike manual feeding, automatic systems cannot adjust the amount of feed supplied according to the feeding activities of fish, potentially resulting in overfeeding or underfeeding. Such overfeeding causes marine pollution and increases operational costs, whereas underfeeding hinders fish growth. In this study, we present an intelligent feeding system that observes the depth-specific feeding behavior of red seabream during the feeding process and determines whether feed supply must be continued. The performance of the feeding algorithm is evaluated by comparing the feed loss rate measured during a feeding experiment at a red seabream sea cage farm with that of the traditional manual feeding method. The results reveal that the feed supply per unit time of the manual method and the developed intelligent feed supply system is at an equivalent level. Moreover, the difference in the average feed loss rate is a negligible 1.16%, confirming that the new system is slightly more advantageous. [ABSTRACT FROM AUTHOR]