• • Fourteen functional groups were categorized according to their catch availability and diet information.

• • The basic inputs for functional groups are biomass, Production/Biomass ratios (P/B) estimations, Consumption/biomass (Q/B) and diet matrix. The biomass of each functional group is one of the key input parameters and is expressed in t/km².In a mass-balanced model, the Ecotrophic efficiency (EE), which denotes a “proportion of a group’s production utilized within the system” is the balanced indicator.

• • In an unbalanced condition, the EE always exceeds 1, indicating a higher energy demand than the total production of the system.

• • Based on the diet preference of functional groups, the highest preference or electivity index (0.999) was achieved by zooplankton towards the phytoplankton; also, the zooplankton was one of the most preferred foods for major carps, grass carp, exotic carps, omnivore, planktivore and benthos group.

• • Eichhornia was found to be the most avoided functional group of the ecosystem as the electivity index value was -1 for all groups. These macrophytes contribute more towards detritus inflow, which is affecting negatively the system maturity as well as the cycling process of the matter in the wetland.

• • The system is found to be an immature or a developing system, as its total primary production per total respiration (TPP/TR) value is 10.845.

• • The bird group was found as the keystone species. Owing to grass carp stocking for controlling the macrophyte infestation of this wetland, virtually we have created a mass-balanced model to know the optimum grass carp stocking required for sustainable production.
• • This Ecopath-based wetland management strategy would be an example of sustainable fish production through a cleaner approach without adding any external food to the system rather than utilizing the natural resources of the system to maximize production.

 

Ecopath model of Beledanga wetland.