Effects of the parasite <i>Argulus ambloplites</i> (Wilson, 1920) on welfare and mouthbreeding eggs capacity of <i>Oreochromis niloticus</i> (Linnaeus, 1758) females

Abstract

Declines in the reproduction performance of Oreochromis niloicus fish have been observed for two decades in the fish farms located on the edge of the Aby lagoon. Research on the causes of these reproductive drops has led to a series of experiments with pathogens harvested from these spawners in a preliminary study in 2012 that found the parasite Argulus ambloplites in abundance. Thus, the aim of this study was to know the effects of the two forms of the parasites A. ambloplites on the welfare and mouthbrooding eggs capacity of the fish O. niloticus. As a method, fish spawners were exposed to an artificial infestation with naupli parasites as treatment one and adult parasites as treatment two in a total randomised design experiment containing three groups triplicated. Fulton’s condition factor K, mouth infestation intensity, number of mouthbrooding eggs, and the relationship between mouth infestation intensity and number of mouthbrooding eggs were biological parameters followed and determined. K values were lower in infested fish. Females of control group presented inside their mouth 601 eggs for incubating per female, against 0 egg inside the mouth of females parasitised fish. A strong nonlinear and negative correlation has been established between the absence of eggs in incubation in females and the intensity of mouth parasite infestation. The welfare and eggs mouthbrooding capacity of O. niloticus females were negatively affected by the parasite A. ambloplites infestation.