Abstract: The purpose of this study is to detect chlorophyll-a front by using the Single Image Edge Detection (SIED) method and analyze the influence of the closest distance of chlorophyll-a front to the skipjack tuna catches. This study was conducted from June to August 2019. Data collecting was conducted by using survey method by following fishing operations in two research areas namely Barru Regency and Pinrang Regency, South Sulawesi, which is the representation of the fishing base area of skipjack tuna fishing in Makassar Strait. We collected skipjack tuna catches data and fishing ground positions (longitude and latitude).