||Abstract of "Investigations on environment parameters at sea cage and oyster culture area": 1. "Monitoring of the environmental factors of marine cage fish farming: study of the optimal cage farm scale" : 本計畫為科技保密計畫，故不引入相關資訊，請另參照細部計畫期末報告紙本。 2. "Environmental monitoring and optimal spat harvest timing in oyster farming area" : Oyster cultivation has long been an important fishery economic activity in the western coastal area of Taiwan, annual production can reach NTD 3.0 billion. Currently, the wild oyster larvae are the main spat source of Taiwanese oyster cultivation, the main oyster spat collecting area is located in the coastal waters of Tai-Hsi in Yun-Lin County, yield about 80% oyster spat in Taiwan. Traditionally, the forecast of optimum oyster spat harvesting period is followed the solar terms of Chinese lunar calendar, but recently, such forecast by the solar terms often obtained inaccurate predictions. This situation not only causes investments losses of oyster spat collector, but also affects the need of spat for following oyster farming. To investigate the instability of oyster spat catch in the waters off Yun-Lin, in this study, we first monitored the environmental conditions as well as temporal and spatial distribution of oyster larvae in the adjacent waters, and then constructed a 2D particle tracking model to simulate oyster larvae distribution patterns in several marine environment conditions, to provide references for oyster spat harvester.