RESUMO
In aquatic invertebrate (e.g., daphnids and Artemia sp.) and zebrafish cultures, in ecotoxicological bioassays, or when addressing complex population-level experimental designs, the counting of an organism's progeny is often required. This counting process is laborious, repetitive, and time-consuming, potentially posing health hazards to the operators, and necessarily entailing a higher likelihood of human error. We present an experimental evaluation of a computer-based device for counting neonates (Daphnia magna, Daphnia longispina, and Ceriodaphnia sp.), nauplii (Artemia salina and Artemia franciscana), and zebrafish (Danio rerio) eggs. Manual counts by an experienced technician were compared with the corresponding automated counts achieved by the computer-based counting device. A minimum of 55 counts/species was performed, with the number of counted organisms being up to a maximum of 150 neonates of Ceriodaphnia dubia, 200 neonates of D. magna and D. longispina, 200 nauplii of A. franciscana and A. salina, and 500 zebrafish eggs. Manual and automated counts were both performed in culture medium solutions of 50 ml of volume. Automated counts showed a mean relative acccuracy of 98.9% (97.9%-99.4%) and a relative standard deviation of 1.72%. The results demonstrate that the computer-based device can be used for accurately counting these aquatic organisms. This computer-based counting might be extended to other organisms of similar size, thus facilitating reproduction and life-cycle ecotoxicity tests. Environ Toxicol Chem 2022;41:1451-1458. © 2022 SETAC.
