“…However, competition in olive flounder farming is gradually declining due to an increase in the incidence of various diseases, deterioration of water quality due to environmental pollution, and labor and production costs. Moreover, the increase in breeding density to reduce production costs has affected the growth rate, feed intake rate, productivity, and survival rate of fish ( Refstie, 1977 ; Rowland et al., 2006 ; Kim et al, 2015 ; Seo, 2020 ). In particular, mass mortality and diseases have been observed in fish due to the stress caused by an increase in breeding density ( Holm et al, 1990 ; Björnsson, 1994 ; Noble & Summerfelt, 1996 ).…”