Hatchability and Survival of Lamproglena clariae Fryer, 1956 Exposed to Increasing Concentrations of Aqueous Aluminium

The effect of increased aluminium concentration on the hatchability and survival of Lamproglena clariae is unknown. During October 2019 and October 2020, infected C. gariepinus were collected from the Vaal River and transferred to a controlled aquarium room. Parasite infection was established on acclimated C. gariepinus. Adult female parasites (F2 and F3 generation) on live fish were inspected for egg strings. Viable egg strings were removed, leaving females attached to produce more eggs. Bioassays were performed in varying concentrations of Al (control, 5 µg/L, 30 µg/L, 60 µg/L, and 120 µg/L). Egg development was monitored. In situ physical and chemical water quality parameters were measured, and water samples were collected every 24 h for metal analysis using inductively coupled mass spectrometry. The experiment terminated when all juveniles perished. Five percent of exposed eggs did not hatch in the control solution, compared to 26% in 120 µg/L Al. Hatchability and survival of L. clariae were negatively affected by increased Al concentrations. By removing this ectoparasite from living fish, the need to euthanise the host organism is eliminated, emphasising the usefulness of L. clariae as a bioindicator for metal pollution.