Infection of Acanthocephalan Parasite Acanthogyrus sp. in Nile Tilapia Oreochromis niloticus Collected from Agusan Marsh, Philippines

Abstract

Infection of the acanthocephalan parasite Acanthogyrus sp. in Nile Tilapia Oreochromis niloticus from Agusan Marsh, Philippines, was carried out last December 2019 – January 2020 in a semi-purposive sampling in municipalities surrounding Agusan Marsh, Caraga Region, Philippines. A total of 180 O. niloticus individuals were collected from Bunawan, San Francisco, Rosario, Talacogon, La Paz, and Loreto. Prevalence of infection among various sampling sites were significant (p<0.05). Acanthocephalan infection, particularly Acanthogyrus sp. in San Francisco, was reported highest 76%, followed by Loreto (53.3%), Talacogon (50%), La Paz (40%) and Rosario (30%) while Bunawan (20%) recorded lowest. Juveniles exhibited low prevalence (23.9%), while adults recorded highest 71.1%; (p < 0.05). Moreover, the prevalence rate was higher in females (49%) than in males (39.7%) but not significant (p > 0.05). This study confirms that O. niloticus in Agusan Marsh are definitive hosts of Acanthogyrus sp. Moreover, results showed that Acanthogyrus sp. had a highly aggregated distribution pattern in O. niloticus (p <0.05; k =0.43, variance = 16.99 > mean =2.49). The aggregated distribution of the parasite has implication on the regulation of host population. This study provides baseline information for future investigation on the ecology and infection dynamics of acanthocephalans in fish in the area.