Response of Prochilodus nigricans to flood pulse variation in the central Amazon

Abstract

The influence of the flood pulse on fish populations has been posited, but infrequently tested or quantified. Here, we tested the effect of habitat on population size, using Prochilodus nigricans as a case study species. Floodplain habitat was based on the littoral zone area occupied by P. nigricans to feed. The magnitude of this habitat in each hydrological year, the moving littoral (ML), was expressed as the sum of daily littoral areas during the advancing flood pulse, using satellite-based passive microwave data. Annual population size was estimated by age class, using a dynamic age-structured model (MULTIFAN-CL) based on catches, effort and fish length frequencies from the Manaus-based fishery over 12.75 years. The principal null hypothesis was that the ML, using three lag times, had no effect on population size of a single age class of P. nigricans. The population size at 29 months of age was positively related (p = 0.00030) to floodplain habitat (ML) earlier in the same year, when the fish were 21–27 months old. The result implies a density-dependent relationship for the population with respect to its feeding habitat. Potential mechanisms governed by flood pulse variation and habitat quality for this and other species using floodplain habitats are discussed.

Ecologia alimentar de Hassar affinis (Actinopterygii: Doradidae) em dois lagos de uma zona úmida de importância internacional no Nordeste do Brasil

“…The aquatic systems of the Baixada Maranhense are mainly regulated by the rains that occur in the region, and in such environments, in certain months of the year, there is a decrease in river flow, drastically modifying the environments, characterizing the so-called dry season (Gonçalves, 2005). Bayley et al (2018) studying biological, ecosystem and fishery data for Prochilodus nigricans in the central Amazon reports that the abundance of P. nigricans at the age of two was positively related to the breadth of the coastal zone and indicated that the population can be regulated by dependence density in relation to their main feeding habitat. Castello et al, (2019) analyzing the effect of floods on the abundance of fish of the species Colossoma macropomum describes that these flood patterns can influence food and development stages, since the availability of food and habitat are determined by interactions between flood events, availability of nutrients, cycling and biotic production processes, since these environments due to their dynamics are areas that present a high biological production and are widely exploited by fish from main channels and lakes.…”

Tracking the resource pulse: Movement responses of fish to dynamic floodplain habitat in a tropical river

“…Floodplain inundation greatly increases the area of available aquatic habitat and can provide access to abundant terrestrial and aquatic prey and other food sources, such as fruit and epiphytic algae (Correa, Costa‐Pereira, Fleming, Goulding, & Anderson, ; Douglas, Bunn, & Davies, ; Winemiller & Jepsen, ). The dynamism of habitat and food availability across the flood cycle strongly influences food web structure and ecosystem productivity on floodplains (Bayley, Castello, Batista, & Fabré, ; Warfe et al, ; Winemiller, ) and creates complex spatial patterns of species distribution and primary productivity (Pettit et al, ; Tonolla, Wolter, Ruhtz, & Tockner, ). The periodicity of floodplain inundation may also vary greatly among climatic regions, ranging from highly predictable, seasonal floods to unpredictable, arrhythmic events driven by stochastic climatic factors (Jardine et al, ).…”

Stock assessment of Prochilodus nigricans (Actinopterygii: Characiformes: Prochilodontidae) using two distinct algorithms, in the context of a small-scale Amazonian fishery

“…Prochilodus nigricans Spix et Agassiz, 1829, locally known as curimatã, is very abundant and widespread in the Amazon Basin. Its adult population size is strongly correlated with floodplain habitats (Bayley et al 2018), feeding on detritus composed of fine organic particulates and algae. Prochilodus nigricans is a migratory species and large schools of this fish migrate to spawn at the floodplains adjacent to Amazonian large rivers (Araújo-Lima et al 2003, Granado-Lorencio et al 2005.…”

“…The presently reported study found a lack of fishing pressure on the younger age groups but with the caveat that the available data do not permit a complete stock assessment. And Bayley et al (2018) studied the relation between P. nigricans abundance and the flood pulse.…”