Fig. 4
Redundancy analyses (RDA) showing the statistical association between the number of ectoparasite species of the Nile tilapia Oreochromis niloticus (L.) and the environmental and management variables of the farms. The acronyms for the parasite species were as follows: Cs, Cichlidogyrus sclerosus; Ct, Cichlidogyrus tilapiae; Cd, Cichlidogyrus dossoui; Cl, Cichlidogyrus longicornis; Cq, Cichlidogyrus quaestio; Ci, Cichlidogyrus sp.; Ch, Cichlidogyrus halli; Gy, Gyrodactylus cichlidarum; Tr, Trichodina sp.; Vo, Vorticella sp.; En, Enterogyrus malmbergi. Codes for management and environmental variables (in bold) are as follows: Fd, Fish density per tank; Nw, Number of workers; Qa, Quarantine; NO 2 −, Nitrites; Ba, Bathrooms; NH 4 +, Ammonium; We, Water exchange. The numbers associated with the circles and squares are the farm reference numbers in Table 3