Evaluation of the growth and mortality of the oysters (Crassostrea gigas, thunberg, 1795) in the sea farm in Arraial do Cabo, RJ

Abstract

This study, carried out during 7 months, evaluated the growth and mortality of oyster Crassostrea gigas cultured at long-lines in Arraial do Cabo/RJ at 3 initial stocking densities 500; 1,000 and 1,500 oysters/floor), maintained the pattern of density larger, medium and smaller throughout experiment. Lowest stocking density of all months displayed significant difference of greater growth than other densities. From June to September was the most representative phase of growth (11.4 ± 5.2 mm to 51.1 ± 11.8 mm). In October and November had low growth rate suggesting natural reduction in final stage of development. The high mortality was observed in July and October when it presented rates of 31% and 36%. The reduction in mortality as population stoking density increases was recorded only in August and September, suggesting that density was not a factor limiting in other months. Although the low upwelling events in the region this period, a satisfactory growth was reached.