Effect of unmanaged harvests for the aquarium trade on the population status and dynamics of redline torpedo barb: A threatened aquatic flagship

Abstract

The freshwater aquarium trade provides economic and livelihood opportunities to the rural poor, but has been implicated in biodiversity loss through population declines and local extirpation of high†value endemic species. Previous observations on population declines are largely based on anecdotal data, however, and there are no studies on the population dynamics or stock assessment of freshwater fish species collected for the aquarium pet trade. To understand how wild collection of endemic and threatened species for the aquarium trade could affect their populations, the sustainability of collecting the endangered redline torpedo barb (Sahyadria denisonii), and its evolutionarily distinct lineages (henceforth RLTBs), from the Western Ghats region (part of the Western Ghats–Sri Lanka biodiversity hot spot) for the aquarium trade was studied to provide baseline data to inform conservation action. Local populations of RLTBs at the five commercial collection sites showed high mortality rates, and fish were exploited before they attained sexual maturity. The unmanaged fishery has led to unsustainable levels of exploitation, and populations of RLTBs at three sites are vulnerable to an impending collapse. Endemic and threatened freshwater fish species used in the aquarium pet trade are exposed to local extirpations and global extinctions unless management plans and legislative controls are implemented and strictly enforced. Management plans and conservation actions to help guide the responsible fisheries of RLTBs are suggested, and the wider implications of unmanaged exploitation of endemic aquarium fisheries are discussed.