Upstream dam impacts on gilded catfish Brachyplatystoma rousseauxii (Siluriformes: Pimelodidae) in the Bolivian Amazon

Abstract

This paper explores the effects of two run-of-river dams (Jirau and Santo Antônio) built in cascade in the middle Madeira River (Brazil) on the interruption of long-distance migration routes of the gilded catfish (Brachyplatystoma rousseauxii). A participative monitoring system was set up to compare capture by commercial fishers approximately 1500 km upstream of the dams in Bolivia, before (1998-2007) and after (2015-2017) dam closure. A significant decrease in gilded catfish catches and in catch per unit effort was observed after dam closure, whereas no significant difference in mean weight was found. Back-estimation of age suggests that the few individuals remaining after dam closure in 2009 are a mixture of old homers that returned upstream before dam closure, and residents hatched after dam closure and trapped in the upper Madeira. Unless fishways in the Madeira River dams improve their efficiency, the gilded catfish might become rare and in danger of regional extinction in the upper Madeira basin in the next few years, negatively affecting river fisheries.

From Amazon Catfish to Mekong Money Fish: Size‐based Assessment of Data‐Limited Commercial Inland Fisheries

“…Mean length of Dourada increased systematically upstream, with a corresponding increase in estimated SPR. This is assumed to reflect ontogenetic migration of large fish, although Van Damme et al (2019) suggested an influence of diminished upstream migration of small individuals due to dams. One solution to such spatial heterogeneity in size structure may be to calculate an average SPR from a fish sample collected throughout the river, to ensure a representative population size distribution.…”

Conservation of migratory fishes in the Amazon basin

“…For long‐distance migrants, such as goliath catfishes and other longitudinal migrants, any dam on their migration routes will interfere by isolating their breeding areas from feeding and nursery areas (Agostinho, Pelicice, & Gomes, 2008; Ribeiro et al, 1995), depleting resident populations above the dams, with unlikely long‐term chances of persistence (e.g. for B. rousseauxii in the Madeira; Hauser, 2018; Van Damme et al, 2019). Large catfish fisheries usually decline upstream and downstream of dams, as was observed above the Tucuruí dam on the Tocantins River (Ribeiro & Petrere, 1988; Ribeiro et al, 1995).…”

FISHING PRODUCTION OF <i>Pinirampus pirinampu</i> AND <i>Brachyplatystoma platynemum</i> CATFISH HAS BEEN AFFECTED BY LARGE DAMS OF THE MADEIRA RIVER (BRAZILIAN AMAZON)

“…Currently, one of the main problems for the sustainability of large migratory catfish fisheries in the Amazon basin is the construction and operation of hydroelectric dams along the main channels of its largest tributaries, restricting the reproductive and trophic migrations of fish species that live in or utilize the flood basin's aquatic environments as a migratory route (Gubiani et al, 2011;Winemiller et al, 2016). Recent records indicate a decrease in the amount of fish able to cross these barrages (Hauser et al, 2019), which is reflected in the decrease seen in records of fish production reported in the fishery landing sites, especially in upstream regions of these enterprises (Damme et al, 2019). This has been a direct source of harm to small-scale fisheries, which are traditionally responsible for maintaining the supply of animal protein in the riverine communities of the study area (Fearnside, 2013;Lima et al, 2017;Santos et al, 2018).…”