Assessing the sustainability of lepidophagous catfish, Pachypterus khavalchor (Kulkarni, 1952), from a tropical river Panchaganga, Maharashtra, India

Abstract

Background

The Western Ghats of India, one of the global biodiversity hotspots and freshwater eco-regions, harbors several fish species which not just form the important part of the world’s freshwater biodiversity yet in addition are the vital segment of livelihood of the neighborhood population. The rate of fish decline in the Western Ghats is alarming. The absence of organized study and data scarcity on basic biology and life history traits of several species could be one reason behind the decline, and thus it is difficult to execute conservation action/s. This is especially true, particularly for data-deficient species for which definite data related to distribution, population size, and trend is not available. The present study deals with the detailed investigation of population dynamics of catfish species, Pachypterus khavalchor, which is data-deficient species inhabiting the Western Ghats of India and forms an important component of freshwater inland fishery, providing nutritional and financial security to the local community.

Methods

Specimens for the present study were collected monthly for a period of 1 year from the River Panchaganga and length–frequency data were analyzed using FiSAT II software.

Results

Length–weight analysis of pooled (male + female) data suggested the fish exhibited higher exponent than expected under isometry, indicating the positive allometric growth of P. khavalchor in the Panchaganga River. The asymptotic length (L∞) and the growth rate (K) were estimated as 149.63 mm and 0.71 year⁻¹ respectively. Potential longevity (t_max) and length at first capture (Lc) were estimated as 4.22 years and 73 mm respectively. The total (Z), natural (M), and fishing mortality (F) were estimated as 2.23 year⁻¹, 0.88 year⁻¹, and 1.35 year⁻¹ respectively. The current exploitation rate (E_cur = 0.60) was found to be almost 90% that gives the maximum relative yield per recruit (E_max = 0.67). Recruitment pattern revealed two peaks, suggesting the fish have two spawning bouts each year.

Conclusions

The stock of P. khavalchor in the Panchaganga River may be in near full exploitation under the current harvesting strategy, with a high chance of recruitment failure in the future. Additional studies on the reproductive biology of P. khavalchor would be particularly welcome for the imposition of the seasonal closure for effective conservation of stock.