Ecologia e pesca da piramutaba (brachyplatystoma vaillantii)

Abstract

The catfish piramutaba (Bracyplatystoma vaillantii, Pimelodidae) is the most important export fish of the Amazon basin and estuary and was the third ranked export fish of Brazil in 1987. There are two kind of fisheries exploiting this species: traditional and industrial. The traditional fishery use gillnet with mesh 14- 22 cm. It is responsible for about 30% of landed catch, which is sold in the regionional market. This method catches fish in the Amazon river ando estuary with minimum fork length 44.9 cm and age 3.75 y. The industrial fishery uses trawl-seines with two trawlers. It is responsible for about 70% of all landed catch, which is sold on the international market. This method catches fish only in the Amazon river with minimum fork length 18.1 cm and age of 0.95 Y and result in discarding up to 56% of the catch. The relation between yield per recruit (VIR) anel fishery mortality (F) was estimated forboth fisheries. The total mortality (Z) was 1.18 and 0.94 years-1, in 1984 and 1985, based on the sample landed by the traditional fishery. The natural mortality (M) was 0.5 years-1, indirectly estimated. ... Note: The complete abstract is available with the full electronic digital thesis or dissertations