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Kolleru lake is one of Asia’s largest freshwater lakes, which has undergone tremendous changes in the water quality due to the sewage, pollution and development of aquaculture in its surrounding area. This study is undertaken to evaluate the present water quality scenario existing in Kolleru lake, which has been affected seriously due to the anthropogenic disturbances since long. Water samples were collected from ten sampling locations within the lake during pre and post-monsoon seasons of 2017-18. A total of 11 water quality parameters were analysed such as pH, temperature, EC, TDS, TSS, total alkalinity, total hardness, dissolved oxygen, salinity, COD, and nitrates. Parameters were estimated by using a standard protocol of APHA 2012. The spatial distribution maps of water quality were generated from pre and post monsoon data using Arc GIS software. Spatio-temporal variation of all parameters indicated that the water quality found was unsatisfactory within the Kolleru lake. The present study shows the better water quality in the post-monsoon season. The Inverse Distance Weighting (IDW) interpolation spatial mapping was also used for water quality mapping to observe the environmental variation for protecting the important freshwater ecosystem-Kolleru lake. The outcome of GIS analysis demonstrated the spatial visualization of the lodging evolution and geographical distribution trends of water quality parameters within the study area.

Aim: The present study is an attempt to analyze the land use pattern of Kolleru Lake in and around by using the techniques of remote sensing and GIS to detect the temporal changes of the Kolleru Lake. Methodology: The 1938 and 1967 years topographic sheets and Landsat-5 TM of 1997 and Resoucesat-2 LISS 4 of 2017 satellite images were used and analyzed by the latest version of Arc GIS 10.4 and ERDAS IMAGINE 2016 (Version 16.00). Unsupervised and supervised classification was done for 1997 and 2017 images, respectively. Results: It was estimated from the topographic map of 1938 that the total lake boundary area was 230.15 km2. Digital image processing of 2017 satellite data revealed that the lake area of 76.9 km2 (32.45%) only remained degraded, extensively colonized by macrophytes. The land use/land cover maps of 1997 and 2017 revealed that lake area was significantly occupied by aquaculture which amounted to 84 km2 (36.53%) and 56 km2 (24.35%), respectively, and no aquaculture activity was reported from 1938 and 1967 toposheets. Interpretation: The geospatial analysis data gives accurate and reliable information and associated factors. The spatio-temporal analysis data provide a significant foundation for monitoring activities in other lake systems, and are applicable to monitoring wetland use patterns in other sites of international importance. Key words: Eutrophication, Geospatial technology, Kolleru wetland, Macrophytes, Remote sensing

Background: Fishes of the family triacanthidae are highly diversified throughout the world, but studies on these fishes were very limited in India. Now a day’s catch of species belongs to this family increasing and showing new geographical distributions due to overfishing of top predators. Methods: Experimental fishing method was conducted by using the M.F.V Narmada-IV vessel of ICAR- Central Institute of Fisheries Education, Mumbai. The vessel operated with a demersal trawl net with a cod-end mesh size of 30 mm. Spatial distribution map of the family Triacanthidae was generated from previous literature using the IDW interpolation method in Arc GIS 10.4.Result: New distributional record of silver tripodfish, Triacanthus nieuhofii Bleeker, 1852 was recorded for the first time from the Mumbai waters, northwest coast of India. Spatial map showing that the species of the family Triacanthidae were highly diversified along the east coast than the west coast of India.

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