Fishery, biology, aquaculture and conservation of the threatened Asian Sun catfish

Abstract

We summarize the research on Asian Sun catfish, Horabagrus brachysoma (Günther), an endemic and threatened freshwater catfish from Western Ghats of India, and provide a comprehensive review of its taxonomy, distribution, biology, population, conservation and aquaculture. Although described in 1864, the taxonomy of H. brachysoma, particularly its familial affinities, continues to be in flux. The species, originally described from the erstwhile ‘state of Cochin’ in present day Kerala State, India, has a current distribution ranging from southern Kerala (8°N) to southern Maharashtra (16°N), where they are found in lowland westward-flowing rivers, as well as natural freshwater lakes and backwaters. As a much relished food fish, H. brachysoma is exploited throughout its range, predominantly through an unmanaged artisanal fishery. Although there are no scientific estimates of either the status or trends in overall population of this endemic catfish, anecdotal evidence and fisher-knowledge suggests drastic declines of several local populations. The fishery for H. brachysoma in the Periyar and Achenkovil rivers in the State of Kerala has been documented to be unsustainable. As a result of an overall population decline of 35 % due to overharvest and habitat loss, H. brachysoma is assessed as ‘Vulnerable’ on the IUCN Red List of Threatened Species™. Primary research on various aspects of feeding, reproductive biology and demography has generated a wealth of information on the species, but this knowledge is yet to be utilized for the development and implementation of in situ conservation or management plans. In view of its high consumer demand, efficient biological and eco-physiological characteristics, as well as the availability of a captive breeding technology, H. brachysoma is considered an emerging species for small-scale aquaculture. Priorities for scientific research to address knowledge-gaps, as well as strategies for effective conservation of this threatened freshwater catfish are discussed.