Materials and Method
Sharavathi estuary (Lat 14.211894º to 14.304110ºN Long 74.421160º to 74.675575ºE) is situated towards the centre of South Indian west coast, in Honavar taluk of Uttara Kannada. Originating in the central Western Ghats region of Shimoga district in Karnataka, the river runs through a rugged mountainous terrain before plunging into a deep gorge at Jog, creating one of the most majestic waterfalls of India. From there on it flows westward through landscapes of rocky precipices, evergreen forests, spice gardens and rice fields and merges with the Arabian Sea in the vicinity of the coastal town of Honavar forming an estuary at the confluence.
The observations on fish diversity and salinity were carried out for one year from June 2011 to May 2012. Cast-net catches were monitored from three fish landing stations namely Honavar, Malkod and Balkur (Fig-1), situated closer to the river mouth, mid and upstream estuary respectively, for one day every month. During each sampling day, station-wise, fish species caught by fishermen from five consecutive hauls of the cast-net were examined. In addition fishermen were interviewed regarding the availability of fishes in different seasons.(Pre monsoon, monsoon, post monsoon) Fish specimens collected for identification were preserved in 70% alcohol and kept in the Kumta field station of the Centre for Ecological Sciences of the Indian Institute of Science, Bangalore. Standard keys by Jayaram (1984), Day (1889), Talwar & Jhingran (1991), Munro (2000), and fish base website (www.fishbase.org) were used for identification. Monthly monitoring of surface water salinity, during high tide, was monitored using digital salinity meter.
Figure - 1: Sharavathi estuary and locations of sampling stations
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