Nutrients and anti-nutrients in leaf litter of four selected mangrove species from the Sundarbans, Bangladesh and their effect on shrimp (Penaeus monodon, Fabricius, 1798) post larvae

The release of nutrients and anti-nutrients from mangrove leaf litter plays an important role in the biogeochemical cycling in aquatic environments and directly or indirectly affects water quality and food availability to shrimp. In this study, we assessed nutrient and anti-nutrient loss during decomposition of leaf litter at a concentration of 1 g/L for four mangrove species (Avicennia officinalis, Heritiera fomes, Sonneratia apetala, Sonneratia caseolaris) to monitor water quality and to estimate how leaf litter influences shrimp post larvae (PL) growth and survival. There were significant differences (P < 0.05) between the studied species in terms of mass loss of the leaf litter during the investigation period. There were also significant differences (P < 0.05) between the studied species in terms of loss of nutrients and anti-nutrients in the shrimp PL rearing tank during the four-week experimental period. Decomposing mangrove leaves stimulated availability of natural food for shrimp PLs. There was a strong positive correlation between mass loss and PL production. At the concentrations of leaf litter used, the anti-nutritional factors did not affect the PLs. PL survival with mangrove leaf litter was 75-82%, whereas all the PL died without any leaf litter. PL weight gain ranged from 0.83-3.33 mg/d where S. apetala leaf litter resulted in the highest PL growth rate, followed by A. officinalis, S. caseolaris and H. fomes, in that order (P < 0.05). Overall, mangrove leaf litter had a positive effect on shrimp performance in terms of growth and survival and this effect was highest for S. apetala leaf litter.