Effects of mangrove leaf litter on the water quality, growth, and survival of tiger shrimp (Penaeus monodon Fabricius, 1798) post-larvae

This research aims to determine the effects of mangrove (Rhizophora mucronata and Avicennia alba) leaf litter on the water quality, growth, and survival of tiger shrimp, Penaeus monodon post-larvae (PL-60). Three levels of mangrove leaf litter, 0.125 g/L LS, 0.25 g/L LS, 0.5 g/L LS; 0.125 g/L TD, 0.25 g/L TD, and 0.5 g/L TD, were placed directly (LS) and placed in separate aquariums (TD) during post-larvae rearing. The post-larvae-fed pellets constituted 20% of the total biomass, with two daily frequencies. Ammonia, nitrite, total organic matter (TOM), phosphate, Vibrio, and total bacteria in water and sediment, as well as chlorophyll-a, were monitored every 10 days during a 1-month study. The highest ammonia was detected in the 0.5 g/L LS R. mucronata and A. alba leaf litter, whereas nitrite was detected in the 0.5 g/L TD R. mucronata and 0.125 mg/L LS A. alba leaf litter. TOM concentration > 25 mg/L in all the treatments. The highest phosphate coincided with the highest chlorophyll-a on day 20. The lowest total Vibrio in the water was found in the 0.5 g/L LS R. mucronata and A. alba leaf litter, whereas the sediment was found in the control treatment. The total bacteria in the sediment reached 10⁶ CFU/mL in the R. mucronata and A. alba leaf litter. A high tannin concentration was detected in the treatment where the mangrove leaf litter was directly placed, and it had a significant effect (p < 0.05) on post-larvae growth, survival, and production. The lowest post-larvae growth was found in the 0.5 g/L TD R. mucronata treatment. The lowest survival rate for post-larvae was found in 0.5 LS R. mucronata treatment.