Fish bycatch of the laulao catfish Brachyplatystoma vaillantii (Valenciennes, 1840) trawl fishery in the Amazon Estuary

Abstract

This study aimed to analyse the composition and seasonal variation in the fish bycatch of the Brachyplatystoma vaillantii trawl fishery in the Amazon Estuary in 2009 by monitoring the trips of 48 vessels. The bycatch represented 29% of the catches, totalling 22,228 specimens and 52 taxa, distributed in 22 families (the principal families were Ariidae, Pimelodidae, and Sciaenidae). Brachyplatystoma rousseauxii, Plagioscion squamosissimus, and Sciades herzbergii together contributed 69% of the bycatch and were considered consistent bycatch species. Although a higher proportion of bycatch was captured during the rainy season, the seasonal difference was not significant. A multidimensional scaling (MDS) ordination analysis and an analysis of similarity (ANOSIM) indicated that the species composition of the bycatch was similar across the seasons. However, larger numbers of B. rousseauxii and P. squamosissimus were captured during the rainy season, whereas S. herzbergii predominated during the dry season. The marine migrants and estuarine species guilds showed the greatest richness, whereas freshwater migrants were the most numerous. Among the feeding guilds, the zoobenthivores were the most diverse, whereas the piscivores were the most abundant. The results indicate that fishing pressure primarily affects small- (20-30 cm) and medium-sized (30-50 cm) individuals, although the catch of P. squamosissimus was composed primarily of adults. However, the catches of both B. rousseauxii and B. vaillantii were composed primarily of juveniles.

<b>Jatuarana fishing dynamics <i>Brycon amazonicus</i> (Spix & Agassiz, 1829) of the upper and middle Madeira River Basin

“…Factors such as environment and fishing gears were the same in both areas and did not influence the difference in catch and follow the pattern of the fisheries in other regions of the Amazon, as reported by Barthem (1999), Batista and Petrere Jr. (2003) and Ruffino (2004) the capture of jatuarana in both studied areas was mainly realized in the channel rivers or on its banks, demonstrating the importance of this environment for the local fisheries. Goulding (1979) observed that the capture of many Characiformes in the Madeira River (including jatuarana) was performed mainly in mouths of tributaries, rivers and the lowland, with catches in rivers occurring mainly during reproductive migration when B. amazonicus was more vulnerable to fishing gear.…”

Diverse Early Life-History Strategies in Migratory Amazonian Catfish: Implications for Conservation and Management

“…Manaus (03°05'39.60''S, 60°01'33.63''W), is the largest city in the central Amazon, located at the confluence of the whitewater Solimões River with the blackwater Negro River. Belém (01°27'18.04''S 48°30'08.90''W), is situated on the banks of the Amazon estuary and is the main landing port of large migratory catfishes fisheries in Brazil [ 30 ]. Prior to otolith collection the total length (TL) and weight (W) of each fish was recorded: dourada: mean TL = 83.6 cm, mean W = 8.58 kg; piramutaba: mean TL = 67.6 cm, mean W = 3.34 kg; piraíba: mean TL = 186.6 cm, mean W = 86.6 kg.…”

“…Dourada ( Brachyplatystoma rousseauxii ) is a pelagic predator found throughout the whitewater and clearwater rivers of the Amazon and supports the largest fishery in the Amazon [ 27 , 29 ]. Piramutaba ( Brachyplatystoma vaillantii ) make up a second large export fishery and are found almost exclusively in the Amazon River mainstem, whitewater tributaries, and the estuary [ 30 – 32 ]. Piraíba ( Brachyplatystoma filamentosum ) is the largest of the migratory catfish, present in whitewater rivers throughout the Amazon basin.…”

From Amazon Catfish to Mekong Money Fish: Size‐based Assessment of Data‐Limited Commercial Inland Fisheries

“…Around 16,000 fishers participated in 2005, of which 50% were concentrated in the estuary, where the only industrial Amazon fishery takes place. The industrial fleet uses demersal pair trawls, and mainly targets juvenile Piramutaba, with a bycatch of small Dourada (Jimenez et al 2013). The small-scale fleet operates throughout the Amazon basin, using drifting gillnets (80%) or longlines (20%).…”