Korean marine authorities have shifted from daily monitoring to responding to public sightings of Bukangi, a dusky shark named after the North Port waterway in which it was found, after monitoring teams failed to spot it for four consecutive days, officials said Friday. The shark had spent more than a month in an artificial waterway at Busan’s North Port Waterfront Park. The National Institute of Fisheries Science said it had suspended routine field monitoring around the port and assembled a standby team to investigate sightings reported by the public. With the shark roaming farther and spending longer underwater, tracking its movements had become increasingly difficult for the small monitoring team, the institute said. The roughly 3-meter-long female was first discovered in the park’s waterway on Sept. 18. Authorities made three attempts to guide it toward open water, concerned that the narrow channel was unsuitable for a prolonged stay. Following the third attempt on Oct. 21, Bukangi slipped through a barrier back into the waterway and continued circling near its entrance. Officials