First Report on Argulus and Aeromonas hydrophila Infestations Affecting the Cultivation of the Endangered Fish Species, Chitala lopis

Abstract

This study aims to examine the environmental factors that promote the proliferation of the ectoparasites Argulus and Aeromonas, as well as the impact of infestation on Chitala lopis. Fish rearing was conducted in the ponds that are 20×30×2.5 m3. Feeding with cyprinidae seeds and fresh vanamei prawns occurs ad libitum daily and was sustained for 60 days. DNA samples were obtained from the liver, gills, spleen, and kidneys of fish that died by Argulus disease. The study's test parameters included weight, survival rate, and fish health indicators (erythrocyte, hemoglobin, hematocrit, and glucose levels). The assessed water quality parameters were temperature, pH, dissolved oxygen (DO), conductivity, and total dissolved solids (TDS). A decrease in relative growth rate (-0.8±12.3%) and survival rate (84.3±11%) were observed. Positive DNA electrophoresis bands were observed in the liver and spleen. Erythrocytes, hemoglobin, hematocrit, and glucose were all within the normal range and did not decrease at all. However, the leucocyte value decreased to 125,291±77,929 ×103/mm3 at the end of the study. The water quality was within a suitable range for cultivation, except for low DO values (3.5±1.5mg/L), which might facilitate the development of pathogens. To avoid and safeguard Chitala lopis from attacks by Argulus and Aeromonas, it is imperative to implement periodic water quality optimization and quarantine of fry fishes outside the nursery.