A Multi-species modelling approach to assess the influence of hydrological regime on commercial fisheries in a tropical river–estuary system

Abstract

Hydrological regime is the key determinant of fish species diversity and production in the river–estuary system; thereby it influences the catch dynamics of multispecies fisheries of the system. It is of significant importance to quantify the effect of the river hydrological regime on commercial fisheries in the river–estuarysystem, for developing strategic management plans. This article presents an analytical framework to accomplish the same for commercial fisheries of multiple species, including Macrobrachium rosenbergii, Mugil spp., Harpadon neherus, Wallago attu and Tenualosa ilisha, of a tropical river–estuary system. The prime tool of the framework is ‘Dynamic Factor Analysis’, which identifies the common trends in catch, and quantifies the influence of hydrological factors on multiple commercial fisheries. Annual hydrological and multispecies catch data of the Narmada river–estuary system for the period 1991 to 2013 have been used in the present study. The results reveal two significant trends: Trend 1, representing mainly the Tenualosa ilisha catch; and Trend 2, representing commercial fish catches of the remaining species. The annual observable flood level significantly influences the catch of all but Mugil spp. species. The annual sediment load significantly influences the catch of Tenualosa ilisha , Macrobrachium rosenbergii and Harpadon nehereus. This analytical approach has been effective in understanding the common catch trend patterns and the hydrological factors influencing them in the river–estuary system. The results can be used for formulating sustainable management plans for multispecies commercial fisheries in the river–estuary system.