NASHIK: A small species, which migrate upstream to spawn (breed), was recently photographed at Borgad Conservation Reserve recently. They are record-breaking climbers, reaching mountain peaks where no other fish is able to reach. The fish is identified as Garra species, and they make their journeys to the high-altitude cascading seasonal streams in monsoon.
Garra secretively swim in masses without getting noticed much as they are the blade runners of this altitudinal migration marathon. The Western Ghats or ‘Sahyadris’ are home to unique flora, fauna and fungi. Sahyadri’s freshwater ecosystem and biodiversity are highly diverse, supporting livelihoods, providing invaluable ecosystem services and sustaining more than 400 million people in the world’s highest concentration of humans in a biodiversity hotspot.
Fish species have evolved differently for life and adapted to different aquatic habitats ranging from marine to brackish to freshwater ecosystems and form a critical link in the food chain of these ecosystems. Freshwater fish live in a variety of habitats such as rivers, streams, ponds, lakes, wetlands, swamps and marshes. They form a big share of the food consumed by man and also offer aesthetic pleasure as aquarium pets.
Globally, about 15,000 freshwater fish species are recorded, including brackish water species. In India, there are about 760 freshwater fish species, of which 73 are in cold freshwaters, 544 are in warm freshwaters, and 143 are in brackish waters. The Western Ghats harbour 332 fish species that are endemic (60%).
Some major threats to freshwater fishes
Pollution of freshwater habitats, construction of dams and other structures that alter the natural flow of a water body, thereby restricting migration of fishes for breeding, over-exploitation for food, and increasingly from alien invasive fish and crustacean species.
More than 1/3rd (37%) of freshwater fishes are threatened with extinction, and more than 50% of endemic species are threatened with extinction in the Western Ghats. Indian freshwater fishes have evolved to all sizes and shapes and show an array of diversity in form. Some species undertake seasonal movements in rivers, travelling short or long distances upstream or downstream and back to spawn or feed. Some species among them literally climb hills, as they spawn exclusively in streams at mountain tops.
-Pratiksha Kothule, Nature Conservation Society of Nashik