An Assessment of the Primary Productivity of Two Freshwater Aquaculture Ponds at Hajipur, Vaishali, with Reference to Physicochemical Parameters

Abstract

The variation of primary productivity in terms of NPP, GPP and CRV of water was studied at two fresh water aquaculture ponds named as Pond A, a manually managed pond (surface area 6 acre) with the application of lime and fertilizers and Pond B (surface area 4 acre), a natural pen culture pond recovered from a part of swamp located at Hajipur, Vaishali, Bihar. In both ponds, a comparatively high density of plankton was recorded in the monsoon season of the study period, with a luxuriant growth of Microcystis aeruginosa during late monsoon to early autumn in Pond A. The differences in water temperature between the two studied aquaculture ponds are not well marked; however, the water temperature of Pond B is always observed to be lower than that of Pond A. The water of Pond A is found to be more alkaline than that of Pond B. A normal range of fluctuation in DO, FCO₂, TA, and TH of water in both ponds is maintained throughout the study period. During the investigation period, the experimental values of GPP, NPP, and CRV show more or less a normal trend where GPP and NPP of the studied ponds indicate a bimodal pattern of increase, showing lower values in the rainy monsoon season and higher values during pre-monsoon summer months. The CRV of Pond A shows two prominent winter and autumn peaks followed by a lean period in summer and monsoon, whereas Pond B does not show a prominent peak but exhibits the lowest profile in June of the investigation period.