Tiny, circular “fishing floats,” attached to baited lines, bob on the water like wayward mini-beach balls. Plastic lawn chairs scrape against the concrete floor, as would-be fishermen shift and wait for the slightest tug. Tinny Mandarin music accompanies the bubbling of large water filters. But the most evocative sound reverberating through Taiwan’s catch-your-own shrimp bars is the sizzle of prawns on the grill.