Identification and distribution of gill monogeneans from Nile tilapia and red tilapia in Thailand

Abstract

ill monogeneans are pathogenic effects on the freshwater, brackish water and Gill monogeneans are pathogenic effects on the freshwater, brackish water and marine fishes. Intensive culture can cause the abundant of parasites; especially gill monogeneans. Therefore, the aim of this study was to study the morphology and display the distribution of gill monogeneans collected from moribund Nile tilapia and red tilapia in Thailand. The investigation for gill monogeneans from 57 moribund fish specimens (Nile tilapia, Oreochromis niloticus and red tilapia, O. niloticus x O. mossambicus) in 14 provinces was carried out during June, 2008 to March, 2009. The results revealed all fish examined (18.0 ± 3.8 [7.6-28.0] length, 209.1 ± 119.2 [20.0-540.0] weight) was infested gill monogeneans. Five species of gill monogenean were discovered. (i.e., Cichlidogyrus tilapiae, C. halli, C. sclerosus, C. thurstonae, and Scutogyrus longicornis). The overall prevalence of these gill monogeneans was 22.8%, 66.6%, 91.2%, 54.4%, and 49.1%, respectively. The highest diversity occurred in Loei, Nakhon Ratchasima, and Nakhon Sawan province. Mean abundance of which was 2.8, 5.3, 13.7, 7.4, and 3.4, respectively. The results of this study display 5 species of gill monogeneans can be found in Thai waters. Cichlidogyrus halli and C. sclerosus were the most widely distributed parasites, while C. sclerosus was found in the highest number. In addition, the taxonomy and distribution of these gill monogeneans from Nile tilapia and red tilapia in fourteen provinces were documented in Thailand for the first time.