Efficiency and selectivity of a trap and truck fish passage system in Brazil

Paulo Dos Santos Pompeu,Carlos Barreira Martinez

doi:10.1590/s1679-62252007000200011

Paulo Dos Santos Pompeu, Carlos Barreira Martinez

Open Access

https://doi.org/10.1590/s1679-62252007000200011

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Abstract

The construction of fish passages has been one of the strategies adopted by the Brazilian energy sector in order to diminish the effects of barriers on fish communities. However, studies of the efficiency of these mechanisms are scarce. The present study evaluated the efficiency and selectivity of the first trap and truck fish passage system in Brazil, installed in Santa Clara Dam, Mucuri River. The species composition in the Santa Clara Dam fish lift was compared to the original composition of Mucuri River fish fauna and with the populations that gather downstream of the dam during the reproductive season. The proportion of previously tagged individuals translocated by the lift was used to estimate its efficiency. During the 2003/2004 reproductive period, 67,841 individuals of 32 species passed through the lift, which corresponds to 66% of the lower Mucuri river fish richness. Less than 0.5% died or were injured during the passage. When compared to the river's population, less representative captures of smaller individuals and marine species were observed. However, the composition and structure of the community in the fish lift was quite similar to those downstream of the dam during the reproductive season. The estimated efficiency of the fish lift ranged from 0.2% for Pogonopoma wertheimeri to 16.1% for Leporinus conirostris reaching an average of 7% for all migratory species.

Highlights

In Brazil, the main emphasis in the management of reservoir fisheries seems to be on the rehabilitation of the fish species affected by the formation of dams
We evaluated the efficiency and selectivity of the first trap and truck fish passage system in Brazil, installed in the Santa Clara Power Plant, Mucuri River
While four migratory species (P. vimboides, L. conirostris, B. ferox and S. steindachneri) were found in great abundance during the two events, Pogonopoma wertheimeri was considerably more abundant in the captures conducted in the tailrace, and the lambaris (Astyanax spp.) were only recorded in the fish lift

Summary

Introduction

In Brazil, the main emphasis in the management of reservoir fisheries seems to be on the rehabilitation of the fish species affected by the formation of dams. The environmental legislation made fish stocking and the control of fisheries the main, and in some cases, the only strategy for the conservation of these species (Agostinho et al, 2007). These policies continue to be pursued throughout the country, studies are lacking that determine their efficiency in the recuperation of species and threatened populations, as well as their cost-benefit ratio and their role in the sustained management systems of fish populations (Vieira & Pompeu, 2001). The low fishery yield in reservoirs located in the South and Southeast regions of Brazil, with a significant reduction of migratory species (CESP, 1996; Agostinho et al, 1994) clearly indicates that this strategy is not satisfactory (Agostinho et al, 2004; 2007)

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