Essays with traps for haevesting fishes and crustaceans at São Paulo State coast, Brazil

Abstract

During four research cruises with the Research Vessel Orion, 20 hauls were accomplished with seven different traps, in 1979 and 1981, in three kinds of environment at the coast of São Paulo State: vicinity of islands, oceanic areas on muddy bottom and on shoal. Three trap designs were used: truncate cone, cylinder, and rectangular parallelogram. The traps had some differences in the entrance funnels. The withdrawal stage is the most delicate of the management. The best way to operate the traps is by the side of the boat, but it spends more time. The fishing area in the vicinity of the islands presented bigger faunistic diversity than the other two analyzed areas. The best fish production/haul in number of fishes and weight was on the shoal area. However, the trap fishery is not indicated for this area because it may destroy the bottom substrate. The muddy bottom oceanic area apparently was the best for the fishery trap. The crustaceans caught by traps in São Paulo State coast seem not to be economically interesting because the valuable crustaceans occurred in a few number and the others, with the highest catches, had not an economic value yet. There was a relation between the production and the size trap to the fish catch, with the big one producing the best results. The mesh size increase had provided a catch selection with the fishes having more appropriate size to consumption. The model that offered the best production was the two juxtaposed funnels trap, probably because of a reduction in the occurrence of caught fish escape.