NEW DELHI: One of the world's most iconic fresh-water fish found only in the country's Cauvery Basin is on the "brink of extinction" due to pollution, sand extraction and hydel power projects, a study has claimed.

The paper published by Adrian Pinder of Bournemouth University in the UK and Rajeev Raghavan of St Albert's College in Kerala said that the fish known as 'humpback Mahseer' is now believed to be so endangered that it may be "extinct" in the wild within a generation.

The fish known to anglers around the globe as "one of the largest and hardest fighting freshwater fish in the world," the paper said.

"With its (fish) distribution having always been limited to South India's River Cauvery basin, this fish is now believed to be so endangered it may be extinct in the wild within a generation," a statement by Raghavan said.

Both the scientists have been studying the ecology, taxonomy and conservation status of 17 species of Mahseer which populate rivers throughout south and southeast Asia since 2010. Four of these species are already listed as 'Endangered' on the IUCN (International Union for Conservation of Nature) Red List.

"The paper acknowledges that many pressures are placed upon the fish of India's rivers, including pollution, poaching (using dynamite and poisons), sand and gravel extraction.

"...low river flows due to abstraction and India's continuing thirst for electricity, which has resulted in dozens of hydro-electric which restrict the ability of fish to migrate to their spawning grounds," the statement said.

Against this backdrop of threats, the research suggests that the introduction of non-native Mahseer has acted as the catalyst which has had a "catastrophic" effect on the numbers of endemic Mahseer remaining in the River Cauvery and its tributaries, it said.

"As large monsoonal rivers are extremely difficult to survey and angling was banned in all protected areas in India in 2012, I started to look for alternative data sources and discovered that the Galibore Fishing Camp (one of three former angling camps in the Karnataka jungle) had kept detailed angler catch records.

"This not only allowed us to analyse the temporal trends in population size over the previous 15 years but also form a detailed understanding of how the type and species of Mahseer had changed over time," Pinder said in the statement.

He said that the study shows that the blue-finned Mahseer despite not being native to the River Cauvery, over the last two years have shown that they are now one of the most abundant fish in the river.

"Without a doubt, their success has been at the expense of the humpbacked Mahseer that historically occurred throughout the entire river catchment. Despite the positive intention of conservationists, this is clearly a conservation programme which has backfired.

"The state of confusion surrounding Mahseer taxonomy means the humpback Mahseer currently lacks a valid scientific name and could potentially go extinct before being named," he said.

He said that his current priority is on sourcing specimens of the endemic humpbacked Mahseer.

"If we are not already too late, obtaining DNA from this animal will allow us to name the fish and, based on our data, get it classified as 'critically endangered' on the IUCN Red List.

"When you consider that the iconic Giant Panda and tiger are classified as 'endangered' this puts things in context and demonstrates the urgency to act in sourcing native fish for culturing in local hatcheries," he said.