Olive flounder and other flatfish species are important aquaculture species in East Asia. Their benthic lifestyle, sensitivity to water quality, and variable slaughter methods create a distinct set of welfare considerations.
Flounder welfare is poorly studied relative to salmonids, yet the species shows clear stress responses to crowding, poor water quality, and handling. Their benthic lifestyle means that tank design significantly affects welfare outcomes: tanks without adequate bottom space relative to fish density create crowding that flatfish experience differently from round fish — they cannot school vertically to utilise water column space. Rapid changes in dissolved oxygen — common in intensive recirculating systems — cause acute respiratory distress. Disease outbreaks, particularly viral disease in intensive Korean systems, cause substantial mortality and the suffering of acute infection before death. Slaughter welfare for flounder remains largely unaddressed: the flatfish body plan creates specific challenges for stunning that have received little research attention compared to salmonids. Consumer and regulatory pressure in East Asian markets is beginning to raise welfare awareness, but changes in production practice have been slow.