Age and growth of the Amazonian migratory catfish Brachyplatystoma rousseauxii in the Madeira River basin before the construction of dams

Abstract

The goliath catfish Brachyplatystoma rousseauxii has crucial economical and ecological functions in the Amazon basin. Although its life history characteristics have been studied in the Amazon, there is little information in the Madeira River basin, which holds genetically distinct populations and where dams were recently built. Using fish collected in Bolivia, Brazil and Peru, this study provides a validation of growth rings deposition and details the growth patterns of B. rousseauxii in the Madeira before the dams’ construction. Age structure and growth parameters were determined from 497 otolith readings. The species exhibits two growth rings per year and sampled fish were between 0 and 16 years old. In the Brazilian portion of the basin, mainly young individuals below 5 years old were found, whereas older fish (> 5 years) were caught only in the Bolivian and Peruvian stretches, indicating that after migrating upstream to reproduce, adults remain in the headwaters of the Madeira River. Comparing with previous publications, B. rousseauxii had a slower growth and 20 cm lower maximum standard length in the Madeira River than in the Amazon River. This study provides a baseline for future evaluation of changes in population dynamics of the species following dams closure.

Unmasking continental natal homing in goliath catfish from the upper Amazon

“…Data on population genetics(Carvajal-Vallejos et al, 2014), life-history traits(García-Vásquez et al, 2009;Hauser et al, 2018), and otolith microchemistry(Duponchelle et al, 2016;Hauser, 2018; current study) suggest the existence two main source populations of B. rousseauxii in the Amazon basin: one in the upper Amazon and the other in the other in the upper Madeira. Data on population genetics(Carvajal-Vallejos et al, 2014), life-history traits(García-Vásquez et al, 2009;Hauser et al, 2018), and otolith microchemistry(Duponchelle et al, 2016;Hauser, 2018; current study) suggest the existence two main source populations of B. rousseauxii in the Amazon basin: one in the upper Amazon and the other in the other in the upper Madeira.…”

“…The light blue and light pink rectangles correspond to the range of 87 Sr: 86 Sr values in waters of the Amazon (0.705-0.712) and Madeira (0.714-0.726), respectively. The juvenile then stays in the lower Amazon waters for a few years (see Hauser et al, 2018 for age validation). The juvenile then stays in the lower Amazon waters for a few years (see Hauser et al, 2018 for age validation).…”

“…(a) Natal homing behaviour of a fish hatched and caught in the Upper Madeira sub-basin (Bolivia), after a prolonged migration down to the lower Amazon River: on the otolith's transverse section, the hatching signature (c. 0.721), characteristic of the upper Madeira waters, quickly drops to a lower value typical of the lower Amazon River (c. 0.710), when the larvae are flushed down to the lower Amazon by the current at a mean size of c. 3.4 cm (Duponchelle et al, 2016). The juvenile then stays in the lower Amazon waters for a few years (see Hauser et al, 2018 for age validation). The 87 Sr: 86 Sr profile then starts rising again to come back approximately to the hatching value at the moment of the fish's capture in the upper Madeira subbasin (in the Ichilo River).…”

Population and reproductive parameters of the red-tailed catfish, Phractocephalus hemioliopterus (Pimelodidae: Siluriformes), from the Xingu River, Brazil

“…No specific legislation applies to the Xingu River, however, which is preoccupying for the preservation of local aquatic biodiversity. This information is useful to prevent overfishing and the depletion of natural stocks by defining an effective cut-off size for fishery exploitation (Trippel, 1995;Hauser et al, 2018). The red-tailed catfish presented a peak in reproductive activity (as indicated by the GSI values and the increased frequency of mature individuals) at the beginning of the filling period.…”

“…The adult fishes of this family vary considerably in body length, ranging from 20 cm to over two meters. Many of the larger pimelodid species are long-distance migrators (Godinho, Kynard, 2009;Hauser et al, 2018) that travel considerable distance to spawn, and are an important source of animal protein for many human populations throughout tropical South America. These fish are mainly species of the genera Brachyplatystoma and Pseudoplatystoma (Barthem, Goulding, 1997;Pérez, Fabré, 2018).…”