Abstract

This study aimed to identify monogenean parasites in Asian seabass (Lates calcarifer) and to assess infection rates in the host fish in an earthen pond culture during crop production, in Surat Thani province, Thailand.One hundred fish were examined for parasite infections from July to November, 2017. Two species of monogeneans, Laticola paralatesi and Laticola seabassi, weredetected on gillfilaments. The highest 75% prevalence was observed in September.The highest mean intensity ofL. paralatesiwas recorded in September (5.8 parasites per fish). L. seabassiwas detected atthe highest mean intensity in November (2.6 parasites per fish), which was significantly differentamong the five months (p<0.05). Moreover, the fish size was not significantly correlated with L. paralatesi, but there was a significant positive correlation between the weight of fish and the number of L. seabassi(r = 0.928; p<0.05).This study corroborates that Laticola spp. is commonly found in Asian seabass, with parasite transmission from fish to fish, and the larval stage from wild infected fish live in natural water sources and is spread to fish ponds. The present work reveals monthly profiles of infestations by monogenean parasites in earthen pond culture, and the results can be applied in fish health management. This is the first report on monogenean parasite infections in Asian seabass, in earthen pond cultures in southern Thailand.

Keywords:Lates calcarifer, Monogenean parasite, Laticolaspp.,Earthen pond culture