In the Indian Subcontinent, 2500 species of freshwater fishes have been so far recognised of which 750 are freshwater species. There have been a number of descriptive accounts of fishes and morphological variety in fishes in a number of ancient Indian texts (Hora 1935) which talk of the classification of fish based on shape and structure. In more recent times, much of the study on the freshwater systems of the Indian subcontinent started with the works of British officers employed by the East India Company and who took great interest in the natural history of the region. Some of the most important contributions to the fishes of the Indian region were those of Francis Day with his treatise “Fishes of India” (1875-78). Other early contributions were those of Hamilton- Buchanan in 1822 in his book “Fishes of the Ganges” and by others like J. McClelland in 1839, Col. Sykes in 1839, and T.C. Jerdon in 1849. These were foundations on which modern fish taxonomists, most of whom were some of the first scientists working at the Zoological Survey of India, built upon later. Numerous literatures are available now on the identification and systematics of freshwater fishes of India, starting with Hora’s contributions between 1920- 1950s and most recent contributions by Datta Munshi and Srivastava (1988), Talwar and Jhingran (1991), and Jayaram (1999).  

The Western Ghats

The Western Ghats is a forested tract of relatively smooth, but very old, mountain ranges bordering the South Western coastline of India, starting from Central Maharashtra to the southern tip of Kerala. The Western Ghats, along with another range of smaller mountains - the Eastern Ghats, form a substantial percentage (approximately 10%) of the forested area of the Indian Subcontinent. The levels of endemicity seem to be very high over all the vertebrate taxa in this region. Of the 936 species of vertebrates recorded from this region, 335 (36%) are endemic. Endemicity is highest in species of amphibians where as much as 77% of the total 118 species known are endemic. Fishes also seem to have high levels of endemicity. Of the 218 species recorded, 114  (52%) are endemic to the Western Ghats and Sri Lanka (Daniels 2001a). Some studies on hill stream fishes have been conducted in Kerala and Tamil Nadu in the recent years. Some earlier works have been those of Silas (1951) on the fishes of the Anamalai and Nelliampathi Hill Ranges of Southern Western Ghats, and Rajan (1963) on the ecology of the fishes of the rivers Moyar and Pykara. Fish diversity and distribution in the Kerala part of the Western Ghats has been studied extensively by Shaji and Easa (1995, 1997 and 1998). Kerala has about 44 rivers and as many as 200 freshwater fishes, of which 25 have been reported as endemic. In addition to studying the systematics of the fishes of this region, their ranges and status have also been evaluated. Recently, studies on the fish communities of the Kaveri river basin were conducted as a part of a large project studying the various flora and fauna on the river system - along with studying the fish diversity (Jaayaram et al 1982), the link of the macroinvertebrate fauna on the fish food chain was also studied (Sivaramakrishnan et al 1995). In its entirety, the Kaveri system has 267 species of fishes, while the Kaveri basin by itself was reported to have 142 species (Jayaram et al 1982). In a more recent study, both diversity and endemism were reported to be very high in some of the rivers and streams in Central Western Ghats (Bhat 2003), where as much as 92 species (of which 25% are endemic) have been reported from 4 river systems. Studies have also been conducted in some parts of the Western Ghats with respect to fish assemblage structure and the association of microhabitat variables to species diversity and which seem to indicate that high habitat diversity is associated with high species diversity and abundance (Arunachalam 2000, Bhat in review).
However, large parts of the rest of the Western Ghats remain unexplored and the distribution status of many of the species needs to be updated.  Using species richness estimators, it has been predicted that while 288 species are so far recorded, about 350 species may be present in the Western Ghats (Dahanukar, Raut and Bhat, in press).

References

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