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

Abstract

assessment of Prochilodus nigricans (Actinopterygii: Characiformes: Prochilodontidae) using two distinct algorithms, in the context of a small-scale Amazonian fishery. Acta Ichthyol. Piscat. 49 (4): 373-380. Background. Despite the importance of inland fishery, assessments of exploited inland stocks have relied on datadeficient databases, mainly in developing countries. In this paper, we employed two distinct analytical methods to evaluate the stock status of Prochilodus nigricans Spix et Agassiz, 1829, the most important fish in the Amazonian freshwater landings. In this study, we intended to test the sustainability of small-scale fisheries comparing two different methods. Materials and methods. The population dynamic of P. nigricans was studied using length and weight data for fish caught in Manacapuru Lake and the lower stretch of the Solimões River. Estimates of maximum sustainable yield and corresponding fishing mortality for 2012 and 2013, using Beverton-Holt curve, indicated an overfishing status for both years. At the same region, fishers were interviewed and their knowledge on the P. nigricans stock status was assessed using a stock assessment methodology based on fishers' knowledge, known as ParFish. Results. Both yield per recruit curves employed to assess the stock status of P. nigricans in 2012 and 2013 and ParFish approach indicate an overfishing status, but ParFish also found a high uncertainty level around 47%. Conclusion. The use of ParFish algorithm and traditional knowledge can provide qualitatively similar results to conventional models, such as the Beverton-Holt approach. The ParFish approach shows the advantage including confidence intervals to its estimates.

Stable mean trophic level and decreasing fish size in Central Amazonian fishery landings

“…Recently, in the Amazon, declining stocks of some commercially important species, such as tambaqui ( Colossoma macropomum ) and curimatã ( Prochilodus nigricans ), has been identified using traditional stock assessment methods that analyze each stock individually (Campos et al., 2015; Catarino et al., 2019). In this study, we did not find a decline in mean trophic level, possibly due to high diversity of fish in the Amazon region (Dagosta & de Pinna, 2019; Oberdorff et al., 2019).…”

“…Since the 1960s, with the introduction of technological innovations in fishing, some commercially important fish stocks, such as the pirarucu ( Arapaima gigas ), tambaqui ( Colossoma macropomum ), curimatã ( Prochilodus nigricans ), jaraqui ( Semaprochilodus spp. ), piramutaba ( Brachyplatystoma vaillantii ), and dourada ( Brachyplatystoma rousseauxii ) are showing signs of overfishing (Campos et al., 2015; Castello & Stewart, 2010; Catarino et al., 2019; Prestes et al., 2022). In addition to spatial and temporal constraints of stock assessment studies of these traditional fishery, all have focused on individual species, so the effects of intense fishing pressure on mixed‐species are unknown (Goulding et al., 2019; Pereira et al., 2023).…”

Effects of climate‐driven hydrological changes in the reproduction of Amazonian floodplain fishes

“…In addition, T. angulatus is an important seed disperser (Weiss et al, 2016) whose reduction in body size can lead to a reduction of seed dispersal function, once small individuals are usually less capable of dispersing seeds and can destroy seeds by mastication (Correa et al, 2015). Effects of fishing and droughts on fish size are very poorly known in the Amazon, Fabré et al (2017) found that in drought years the fishing landed is composed mainly by small fish, and Catarino et al (2019) reported overfishing growth effect by a highly fished species ( Prochilodus nigricans ); however, no other study considered demographic and life‐history changes.…”