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Coastal aquaculture activities overlap with the habitats of various marine predators such as sea birds, seals, and dolphins (Schreiber et al., 2002; Kemper et al., 2003; Bearzi et al., 2009). In such areas, predatory species have been reported to interact with the aquaculture systems regularly (Methion & López, 2019). Such interactions seem to be associated with food resource availability. The establishment of aquaculture systems leads to the aggregation of wild fish, primarily because of the large quantities of unconsumed food originating from the facilities (Tuya et al., 2006; Fernandez-Jover et al., 2007). Consequently, considerable amounts of organic matter with high nitrogen and phosphate contents are found at the dumping sights which, in turn, attract prey species (Karakassis et al., 2000; Würsig & Gailey, 2002; Kemper et al., 2003).
Aquaculture is a major economic activity in Jeju Island, South Korea, especially with olive flounder (Paralichthys olivaceus), which is the flagship fish species and the second-largest export item in Jeju Island after semiconductors (Sohn et al., 2019). In a small village in the east of Jeju Island, Haengwon-ri, there is an inland aquafarm complex where 27 companies specializing in olive flounder aquaculture share an intake pipe and a sewer (Figure 1). The emitted content from the aquafarm complex reaches the open shore after two steps of outdoor systems: the sedimentary pool ^ Wondam ^ open water. The sedimentary pool connected to the complex is a fishing spot in Jeju Island filled with olive flounders emitted from the fish tanks. Adjacent to the sedimentary pools and outdoor filtering system of the aquafarm complex is a small basin called Wondam (Figure 2). Wondam, meaning "stone wall" in Jeju Korean dialect, is a traditional fishing method used throughout Korean waters. The Sejong Chronicles from the 15 th century describe the fishing method: stone walls built on the shore to trap fish via tidal action throughout the whole peninsula, including Jeju island (Lee, 2006; Hilty, 2011; Ril et al., 2020). Currently, the traditional fishing method is not widely used by the fishers, but the Wondam stone wall structures remain around the shoreline of Jeju Island. Herein, we report an unusual case of multiyear, repeated, and prolonged visits by an Indo-Pacific bottlenose dolphin (Tursiops aduncus) to a specific Wondam.
The Indo-Pacific bottlenose...