Ecological status of a freshwater tectonic lake of the indo-burmese province: Implications for livelihood development

Abstract

Tectonic lakes are among the most geologically fascinating and environmentally versatile hydrobiological systems found on the earth's surface. We conducted a study on the limnology of Tasek Lake, a tectonic lake located in the Indo-Burma Province of the South Asian region. Physico-chemical parameters of the lake's water along with its plankton were considered for the study. Their relationship was analysed by understanding their seasonal variations and through linear regression models. The water quality index (WQI), plankton diversity indices and canonical correspondence analysis (CCA) were computed. The ichthyofaunal diversity was also studied to get an insight into the lake's fishery potential. A preliminary assessment on the economic feasibility of converting Tasek Lake into a fishery was also completed. Results indicate moderate eutrophication in the lake and the plankton population is observed to be rich and abundant. The WQI value confirms the water to be of "very poor" quality. The CCA was done to analyze the relationships of physico-chemical parameters with months and seasons, and the relation between seasons and plankton assemblages. Results corroborate the results of WQI. Identified fish population suggest ample fishery potential of the lake. The economic assessment reveals that in order to maintain the ecological sustainability of the lake, it should be transformed into a recreational fishery, following a catch-and-release model. The study calls for urgent restoration of the lake so that not only its pristine ecology is survived but also its fishery potential is sustainably harnessed and local livelihood is improved.

Fig 1

Study area (a- Map of India; b: Map of Meghalaya; c: Map of Tasek Lake).

Fig 2

a. Monthly variation of phytoplankton population. b. Monthly variation of zooplankton population.

Fig 3

a. Diversity indices for phytoplankton (Winter). b. Diversity indices for phytoplankton (Pre-Monsoon). c. Diversity indices for phytoplankton (Monsoon). d. Diversity indices for phytoplankton (Retreating Monsoon).

Fig 4

a. Diversity indices for zooplankton (Winter). b. Diversity indices for zooplankton (Pre-Monsoon). c. Diversity indices for zooplankton (Monsoon). d. Diversity indices for zooplankton (Retreating Monsoon).

Fig 5

a. CCA biplot showing the relationship between environmental parameters and months in a year. b. CCA biplot showing the relationship between environmental parameters and seasons in a year. c. CCA biplot showing relationship between the phytoplankton species and seasons in a year. d. CCA biplot showing relationship between the zooplankton species and seasons in a year.