Abundance of young-of-the-year migratory Characiforms in floodplain areas of the middle Solimões-Amazon River at flooding 2007/2008

To test the influence of the largest Central Amazon fish consumption centre on the potential fish population recruitment, young-of-the-year (YOY) abundances of matrinxã Brycon amazonicus (Spix and Agassiz, 1829), jaraquis Semaprochilodus insignis (Jardine and Schomburgk, 1841), S. taeniurus (Valenciennes, 1821) and tambaqui Colossoma macropomum (Cuvier, 1818) were estimated in two floodplain areas of the middle Solimões-Amazon River – one near the city of Manaus and the other 500 km from Manaus – in the 2007–2008 flooding. Matrinxã presented the highest abundance among the four species, with 87.8% of captured individuals. The difference was significant in the representation of YOY matrinxãs between the two studied areas, with the input more significant in the last months of flooding in the area 500 km from Manaus. Jaraquis represented 12.1% of captures and showed no difference between areas. Tambaqui abundance was shown to be critical in both areas, with the capture of only 28 YOY (0.1%), and with no differences between the two floodplains. Matrinxã and jaraquis are more likely to present stabile stocks in the middle Solimões-Amazon River; on the other hand, matrinxã requires attention due to differences in the YOY input between the two areas and in their low input in the Upper Amazon River, near Manaus. Based on the present work and on the landing history in Manaus, tambaqui is still considered as under strong overexploitation, showing some of the characteristics of overfishing recruitment in the middle Solimões-Amazon.