Pre‐impoundment stock assessment of two Pimelodidae species caught by small‐scale fisheries in the Madeira River (Amazon Basin – Brazil)

Abstract

The middle stretch of the Madeira River has supported an intensive commercial fishery for several decades. Developed in an area of rapids and waterfalls, this fishery focuses primarily on catfish stocks, mainly pimelodids. Data from fish landings collected in the years immediately prior to the start in operations of two large hydroelectric dams were used to estimate growth and mortality rates for Pirinampus pirinampu (Spix & Agassiz) and Brachyplatystoma platynemum Boulenger. In addition, stock assessment was carried out for both species, and the results used to evaluate the status of the fishery. Mean population parameters were L∞ = 80.85 cm (total length), k = 0.52 year−1, ϕ = 3.53, A0.95 = 6 year, M = 0.87, F = 1.41–1.64 and Z = 2.28–2.51 for P. pirinampu; and L∞ = 95.55 cm (total length), k = 0.28 year−1, ϕ = 3.40, winter point = 0.41, A0.95 = 11 year, M = 0.55, F = 0.16–0.35 and Z = 0.71–0.90 for B. platynemum. Yield‐per‐recruit analysis indicated P. pirinampu was overfished and that the stock of B. platynemum was under‐exploited. Moreover, overfishing of the P. pirinampu stock and the effects of fragmentation caused by the construction of the dam should be monitored.

Length-weight relationships of fish from Madeira River, Brazilian Amazon, before the construction of hydropower plants

“…The LWRs calculated for Pinirampus pirinampu ( a = 0.0271, b = 2.81, SL max = 74 cm) and Brachyplatystoma platynemum ( a = 0.0462, b = 2.67, SL max = 89 cm) were published in Sant'Anna et al. () using data from our samples. Most specimens captured in the Madeira River were adults and with a few juveniles.…”

“…Growth rates and length–weight relationships have been reported for six species in the Madeira River Basin on the Bolivian side: Prochilodus nigricans (Loubens and Panfili, ), Colossoma macropomum (Loubens and Panfili, ), Pseudoplatystoma fasciatum ( P. punctifer , García‐Dávila et al., ) and P. tigrinum (Loubens and Panfili, ), Piaractus brachypomus (Loubens and Panfili, ), Plagioscion squamosissimus (Loubens, ), Pellona castelnaeana (Le Guennec and Loubens, ); and on the Brazilian side: Pellona castelnaeana (Ikeziri et al., ), Roestes molossus (Torrente‐Vilara et al., ), Brachyplatystoma platynemum and Pinirampus pirinampu (Sant'Anna et al., ), however a complete list of LWRs for most of the Madeira River freshwater fish has not been reported previously.…”

2015 Snapshot of Water Security in the Nile, Mekong, and Amazon River Basins

“…; Sa‐Oliveira et al 2015). Pre‐impoundment studies have predicted declines of migratory fishes as a consequence of recently constructed dams on the Madeira River, a major tributary that drains the southwestern Amazon region and that historically has supported intensive commercial fisheries, dominated by migratory species that spawn in headwater regions now upstream from the Jirau and Santo Antonio dams (Sant'anna et al ; Cella‐Ribeiro et al ). Simply by restricting movement of migratory fishes, hydropower dams in the Amazon challenge preservation of ecosystems, and affect human food security and livelihoods and therefore human well‐being and socioeconomic development; all are components of water security in the Amazon Basin.…”

Limnology and Oceanography Bulletin Volume 25 Number 1 February 2016 1–28

“…; Sa-Oliveira et al 2015). Pre-impoundment studies have predicted declines of migratory fishes as a consequence of recently constructed dams on the Madeira River, a major tributary that drains the southwestern Amazon region and that historically has supported intensive commercial fisheries, dominated by migratory species that spawn in headwater regions now upstream from the Jirau and Santo Antonio dams (Sant'anna et al 2014;Cella-Ribeiro et al 2015). Simply by restricting movement of migratory fishes, hydropower dams in the Amazon challenge preservation of ecosystems, and affect human food security and livelihoods and therefore human well-being and socioeconomic development; all are components of water security in the Amazon Basin.…”