Parasitism of Riggia paranensis (Crustacea, Cymothoidea) on populations of Cyphocharax gilbert (Teleostei, Curimatidae) of Northern Rio de Janeiro

Abstract

Cyphocharax gilbert is an abundant species of fish in lagoons and rivers of northern Rio de Janeiro State, been important to the low-income populations of Campos dos Goytacazes city and adjacent regions. The present study shows the prevalence and the intensity of infestation of Riggia paranensis on C. gilbert from de Cima lagoon and Feia lagoon and from Itabapoana River, tests if the parasite affects the body size of infested fish, and evaluates if the parasitism affect the fish market activities. The results show that the prevalence of infestation was higher in Itabapoana River (between 49% and 64%), lower in the de Cima lagoon (between 2.6% and 2.8%) and intermediate in Feia lagoon (3.3% and 3.7%). Most of host fish presented only one parasite. Fish with two parasites were observed at Itabapoana River in 10% of the infested fish. The infested females were significantly bigger (P â"°¤ 0.05) than the no infested ones. Only in the Itabapoana River the consumers reject the infested fish. The high frequency of R. paranensis in C. gilbert population from the middle Itabapoana River might be a secondary impact of the exotic fish species introduction.