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

Md Iftakharul Alam,Md Nazmul Ahsan,Adolphe O Debrot,M.C.J Verdegem

doi:10.1016/j.aquaculture.2021.736865

Md Iftakharul Alam, Md Nazmul Ahsan + Show 2 more

Open Access

https://doi.org/10.1016/j.aquaculture.2021.736865

Copy DOI

Abstract

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.

Highlights

Mangroves form a highly productive ecosystem, showing high pri mary and secondary productivity in intertidal coastal regions of the tropics and subtropics (Nagarajan et al, 2008)
No significant differences (P > 0.05) between freshly fallen senescent leaves of mangrove species were found for ash free caloric value (MJ/kg dry matter (DM)), tannin or phytate content (% DM) but there were significant dif ferences (P < 0.05) among the species in terms of crude fibre, ash, organic matter (OM), carbon (C), nitrogen (N), phosphorus (P) and saponin content (% DM) (Table 1)
Heritiera fomes leaf litter was the highest in crude fibre (33% DM), OM (96%DM), C (48%DM), tannin (1.8%DM) and saponin (1.6%DM) content, whereas S. apetala was lowest for all those parameters except for tannin

Summary

Introduction

Mangroves form a highly productive ecosystem, showing high pri mary and secondary productivity in intertidal coastal regions of the tropics and subtropics (Nagarajan et al, 2008). Considering the ecological importance of mangroves as well as the economic value of shrimp culture, mangrove-based shrimp culture (Silvo-aquaculture) is practiced in numerous countries, not to the extend needed to conserve or restore mangrove biotopes. In aquatic waterways the culture of sea weeds, molluscs (Rejeki et al, 2020) and fish in cages is possible adja cent to or between mangroves (Primavera, 1993) while in intertidal mangrove areas different types of silvo-aquaculture can be explored (Bosma et al, 2014; Primavera et al, 2007; Primavera, 2000). As mangrove leaf litter is an important influencer of shrimp productivity in silvo-aquaculture, its net effect on shrimp production (either positive or negative) needs to be quantified

Objectives

Methods

Results

Discussion

Conclusion