ESR 28:11-17 (2015)  -  DOI: https://doi.org/10.3354/esr00673

ABSTRACT: The Western Ghats region of India is an area of exceptional freshwater biodiversity and endemism. Mahseer of the genus Tor are considered prized sport fishes of great cultural significance; nevertheless, they are threatened as a result of increasing anthropogenic stressors. In the River Cauvery, the mahseer community comprises a ‘blue-finned’ and an orange-finned, ‘hump-backed’ fish. Whilst it is not yet known whether these are distinct species or 2 different phenotypes, evidence suggests that the hump-backed phenotype is endemic to the river, whereas the blue-finned phenotype was introduced in the 1980s. Angler-catch data from a managed fishery on the River Cauvery, gathered between 1998 and 2012 and comprising 23620 h of fishing effort, revealed that captured individuals ranged in size from 0.45 to 46.8 kg, with the blue-finned phenotype comprising 95% of all captured fish and the remainder being hump-backed. The catch per unit effort (CPUE) of the blue-finned phenotype significantly increased over the study period, while the mean weight of individual fish significantly declined. By contrast, the CPUE of the hump-backed phenotype declined significantly over the period, with individual mean weights significantly increasing. These data suggest a recent recruitment collapse in the hump-backed phenotype resulting in an ageing population that may be headed towards extinction. The introduced blue-finned phenotype, however, continues to recruit strongly, suggesting that the mahseer community of the River Cauvery has undergone considerable shifts in the last 30 yr.

KEY WORDS: Western Ghats · Tor khudree · Tor mussullah · Catch and release · Endemic · Recruitment · Recreational fisheries

Full text in pdf format

Cite this article as: Pinder AC, Raghavan R, Britton JR (2015) The legendary hump-backed mahseer Tor sp. of India’s River Cauvery: an endemic fish swimming towards extinction? Endang Species Res 28:11-17. https://doi.org/10.3354/esr00673 Export citation Share:    Facebook - - linkedIn