The relationship between water quality and prevalence of ectoparasites on cultured Nile tilapia at two reservoirs in Central Java, Indonesia

Abstract

Besides environmental impacts, climate change is likely to cause a profound disruption to aquatic organisms. Therefore, parasitic infections could become more detrimental to host fish due to climate change in the future. This study aims to assess the relationship between the prevalence of ectoparasites Gyrodactylus spp., Dactylogyrus spp., and Trichodina spp. on cultured Nile tilapia and the water quality parameters of the Gajah Mungkur and Cengklik reservoirs. The standard parasitological procedure was used to determine the prevalence of these ectoparasites species. The water quality parameters conductivity, pH, dissolved oxygen, transparency, ammonia level, and temperature were measured. The results showed a high prevalence of 73% recorded by protozoan Trichodina spp followed by 30.1% and 25.3 % for Dactylogyrus spp., and Gyrodactylus spp., respectively. Furthermore, the findings showed that the prevalence of ectoparasites correlated with water quality in different ways in each reservoir. The presence of ectoparasites in the Gajah Mungkur reservoir was primarily influenced by ammonia level and temperature. Besides, in the Cengklik reservoir, ectoparasites were the most influenced by water pH. There was no fish mortality recorded despite the parasitic infection. The water quality parameters were within the recommended range for tilapia culture under cage systems.