Goliath catfish spawning in the far western Amazon confirmed by the distribution of mature adults, drifting larvae and migrating juveniles

Abstract

We mapped the inferred long-distance migrations of four species of Amazonian goliath catfishes (Brachyplatystoma rousseauxii, B. platynemum, B. juruense and B. vaillantii) based on the presence of individuals with mature gonads and conducted statistical analysis of the expected long-distance downstream migrations of their larvae and juveniles. By linking the distribution of larval, juvenile and mature adult size classes across the Amazon, the results showed: (i) that the main spawning regions of these goliath catfish species are in the western Amazon; (ii) at least three species—B. rousseauxii, B. platynemum, and B. juruense—spawn partially or mainly as far upstream as the Andes; (iii) the main spawning area of B. rousseauxii is in or near the Andes; and (iv) the life history migration distances of B. rousseauxii are the longest strictly freshwater fish migrations in the world. These results provide an empirical baseline for tagging experiments, life histories extrapolated from otolith microchemistry interpretations and other methods to establish goliath catfish migratory routes, their seasonal timing and possible return (homing) to western headwater tributaries where they were born.

Unmasking continental natal homing in goliath catfish from the upper Amazon

“…Although resident behaviour was not observed among the 18 B. rousseauxii from the upper Madeira analysed in Duponchelle et al (2016), it is likely that a larger sample size would have revealed this behaviour in some individuals as well. Indeed, this species is known to spawn both during the highest river discharge (high-water season) and during the receding waters (dry season), including within the same river basin (García-Vasquez et al, 2009;Cañas & Pine, 2011;Van Damme et al, 2011;Agudelo et al, 2013;Cella-Ribeiro et al, 2015;García-Dávila et al, 2015;Barthem et al, 2017). Reproducing during the receding water period, when the river returns to its natural bed, probably reduces the risk of eggs and larvae being lost in the adjacent floodplains and therefore maximises their chances to reach the estuarine nursery area thousands of km downstream (García-Vasquez et al, 2009).…”

“…A case in point concerns the Amazonian goliath catfishes of the genus Brachyplatystoma in the Amazon Basin, undertaking the largest known freshwater migrations between breeding areas in the Andean piedmont of Bolivia, Colombia, Ecuador, and Peru, and their nurseries in the lower Amazon and estuary in Brazil (Barthem & Goulding, 1997;Duponchelle et al, 2016;Barthem et al, 2017). As migrations of goliath catfishes can span over several international boundaries, addressing fisheries management and conservation challenges requires understanding their homing behaviour.…”

Genetics and telemetry indicate unexpected movements among structured populations for Brachyplatystoma platynemum in the Amazon

“…The catfish Brachyplatystoma platynemum Boulenger 1898 undertakes a large‐scale migration in the Amazon Basin, as do three other Brachyplatystoma Bleeker 1862 species: Brachyplatystoma rousseauxii (Castelnau 1855), Brachyplatystoma juruense (Boulenger 1898) and Brachyplatystoma vaillantii (Valenciennes 1840) (Barthem et al, ). The general life‐history patterns of these species are similar, with the spawning areas of B. rousseauxii , B. vaillantii and B. juruense in the western Amazon Basin and the nursery areas in the eastern Amazon Basin (Barthem et al, ; Duponchelle et al, ; Hermann et al, ). However, the larval size distribution indicates that the spawning areas of B. platynemum are neither exclusively in the far western Amazon Basin nor are their nurseries restricted to or mostly in the eastern Amazon Basin (Barthem et al, ).…”

“…The general life‐history patterns of these species are similar, with the spawning areas of B. rousseauxii , B. vaillantii and B. juruense in the western Amazon Basin and the nursery areas in the eastern Amazon Basin (Barthem et al, ; Duponchelle et al, ; Hermann et al, ). However, the larval size distribution indicates that the spawning areas of B. platynemum are neither exclusively in the far western Amazon Basin nor are their nurseries restricted to or mostly in the eastern Amazon Basin (Barthem et al, ). The peculiar life‐history patterns of this catfish might be explained by the occurrence of more than one population, with each one presenting their own spawning and nursery areas.…”

Genetic Applications in the Conservation of Neotropical Freshwater Fish

“…The larvae, which are less than 6 mm in length, develop along the route that can reach 11,600 km. Their destination is the rich ecosystem of the Amazon River estuary [41]. Neotropical fish may also be responsible for the proliferation of plant species due to their migratory behaviour.…”