http://scholars.ntou.edu.tw/handle/123456789/20315 Wed, 08 Apr 2026 10:23:49 GMT 2026-04-08T10:23:49Z https://scholars.ntou.edu.tw:443/retrieve/5171/15_LIFE_ON_LAND.png http://scholars.ntou.edu.tw/handle/123456789/20315 http://scholars.ntou.edu.tw/handle/123456789/22218 標題: Effects of Environmental Factors on Suspended Sediment Plumes in the Continental Shelf Out of Danshuei River Estuary 作者: Liu, Wen-Cheng; Liu, Hong-Ming; Young, Chih-Chieh 摘要: The effects of environmental factors on suspended sediment plumes in the continental shelf out of the Danshuei River estuary were numerically investigated using an unstructured-grid three-dimensional hydrodynamic model (SCHISM) together with a suspended sediment (SS) module. The coupled model (SCHISM-SS) was calibrated and validated against the in situ measurement data in 2016. Consistent with the observation results, the model simulations satisfactorily reproduced the water levels, velocities, salinities, and suspended sediment concentrations. The model was then applied to explore the role of various environmental factors in the dynamics of suspended sediment plumes from the estuary to the adjacent coastal seas. These factors include tidal forcing, salinity, river discharge, and wind stress. Analysis and comparisons of different scenario results indicated that the suspended sediment plume was greatly affected by tides, e.g., a longer plume distance resulted from a larger flux under tidal motions. A higher sediment concentration in the plume in the offshore area was also found during the neap tide, relative to that observed during the spring tide. In addition, salinity affects the movement of density currents and the spread of the sediment plume, i.e., the plume distance is longer due to the residual circulation when a salinity difference is present. Further, an extreme river flow could occur during typhoon periods and would discharge a greater water volume into the coastal region, causing the suspended sediment plume to expand from the near shore. Finally, the directions of prevailing winds can slightly influence the sediment plumes. Thu, 01 Sep 2022 00:00:00 GMT http://scholars.ntou.edu.tw/handle/123456789/22218 2022-09-01T00:00:00Z http://scholars.ntou.edu.tw/handle/123456789/22197 標題: Effects of decadal climate variability on spatiotemporal distribution of Indo-Pacific yellowfin tuna population 作者: Wu, Yan-Lun; Lan, Kuo-Wei; Evans, Karen; Chang, Yi-Jay; Chan, Jui-Wen 摘要: Spatial variations in tuna population and abundance are strongly linked to large-scale climate fluctuations, such as the Pacific decadal oscillation (PDO) and Atlantic multidecadal oscillation (AMO). However, the mechanisms underlying the association of climate indices with yellowfin tuna (YFT) abundance and habitat preference remain unclear. We analysed long-term longline fishery data for YFT and oceanic climate variability index data for 1971-2018. The standardized catch per unit effort (CPUE) of Indo-Pacific Ocean YFT was higher during negative AMO and positive PDO phases. In tropical Pacific Ocean, the trend of YFT habitat preference exhibited seesaw patterns because of the distinct environmental factors influenced by the PDO phase. The PDO changed the environmental parameters throughout the tropical Indian Ocean such that the habitat preference of YFT remained consistent throughout. However, the variations in habitat suitability did not correspond to the distribution or standardized CPUE of YFT throughout the Pacific Ocean during AMO events. Moreover, the changes in habitat suitability had a positive periodicity of 8-16 years with AMO in the Indian Ocean, but revealed opposite trends with the distribution or standardized CPUE of YFT. Our results provide sufficient information to distinguish the variations between PDO phase changing and YFT standardized CPUE/ habitat preference. Furthermore, the AMO phase shift period 60-100 years longer than that of the PDO (20-30 years), and models employing time series of fishery and environmental data must be extended the time period of our study to make the AMO match the fishery data more complete. Fri, 12 Aug 2022 00:00:00 GMT http://scholars.ntou.edu.tw/handle/123456789/22197 2022-08-12T00:00:00Z http://scholars.ntou.edu.tw/handle/123456789/22185 標題: Investment Feasibility Analysis of Large Submersible Cage Culture in Taiwan: A Case Study of Snubnose Pompano (Trachinotus anak) and Cobia (Rachycentron canadum) 作者: Lan, Hsun-Yu; Afero, Farok; Huang, Cheng-Ting; Chen, Bo-Ying; Huang, Po-Lin; Hou, Yen-Lung 摘要: Onshore farming for premium aquaculture is under scrutiny and criticism partially due to possible causes of adverse environmental impacts on other resource users and the surrounding environment. The best alternative to preventing or minimizing these impacts is to utilize open seawater by large submersible cage culture. The current operation in Taiwan has demonstrated that the culture operation is technically feasible but economically demanding because of high capital and operating costs. Therefore, this study conducted an economic analysis of the expansion of large submersible cage culture by selecting two premium species of snubnose pompano (Trachinotus anak) and cobia (Rachycentron canadum) and examined the profitability of large submersible cage culture investment. This study found that the current operation of four-unit cages highlighted a negative net present value and internal rate of return with a payback period of over ten and six years, respectively. Large submersible cage culture can be financially profitable when its operation unit expands from 8 to 24 units. Increasing unit cages to eight incurred a gross margin of 17.09%, BCR 1.21, with a payback period of 5.36 years. Expanding the operation to 24-unit cages was a potentially lucrative investment with a gross margin of 18.51%, BCR 1.23, PI 2.15, internal rate of return of 20.84%, and a payback period of 3.55 years. Sensitivity analyses revealed that market price and survival rate significantly impact the profitability of large submersible cage culture. Finally, it is suggested that producers could invest in 8-unit cages and maintaining the survival rate of snubnose pompano and cobia at 80% and 40%, respectively. Mon, 01 Aug 2022 00:00:00 GMT http://scholars.ntou.edu.tw/handle/123456789/22185 2022-08-01T00:00:00Z http://scholars.ntou.edu.tw/handle/123456789/22115 標題: The Effects of Cryopreservation on the Cell Ultrastructure in Aquatic Organisms 作者: Narida, Arah; Tsai, Sujune; Huang, Chih-Yang; Wen, Zhi-Hong; Lin, Chiahsin 摘要: This review provides an update on the current state of cryopreservation studies coupled with ultrastructural observation. Research in these fields has evolved and advanced since its inception in the 1950s. Different techniques have different advantages, but the researcher's technical proficiency is also necessary to derive a sound conclusion. Sperm samples are the most widely studied specimen because they are less sensitive to freezing and have high fluidity in the membrane and low water content. Some studies have also investigated oocytes, embryos, larvae, and algae from aquatic species. Cryopreservation studies have formulated a method applicable to every species of interest to preserve their biodiversity and prevent extinction. However, the avoidance of cryoinjury because of intracellular ice formation is a species-specific challenge. More comprehensive studies on ultrastructural observation can assist in understanding the underlying mechanisms of failed cellular responses to cryopreservation. Thus, optimizing protocols and increasing the survival rates of thawed samples can improve current cryopreservation techniques. Nevertheless, investigations into the effects of freezing on organisms' ultrastructure remain limited, especially regarding aquatic organisms. Fri, 01 Apr 2022 00:00:00 GMT http://scholars.ntou.edu.tw/handle/123456789/22115 2022-04-01T00:00:00Z