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Stock assessment of the Brazilian sardine, Sardinella brasiliensis, of the southeastern Coast of Brazil
M.C. Cergole

Stock assessment of the Brazilian sardine has been carried out based on analysis of length frequency composition. The data were collected from commercial catches throughout the Brazilian southeastern coast between 1977 and 1992. Age length keys were obtained by otolith ring counting and used to transform the length frequency data into age composition. Growth parameters and instantaneous mortality coefficients were estimated using age and length data. The growth parameters were: L= 271 mm TL and K= 0.59 year-l. The mortality coefficients were: Z= 3.60 year-l, M= 0.96 year-l and F= 2.64 year-l. Stock size was estimated by Virtual Population Analysis. It was possible to define two periods: one from 1977 to 1986 showing a relative steady state; the other from 1986 on, indicating a sharp decline in recruitment(R) and spawning stock biomass (SSB) and an increase in the fishing mortality coefficient (F). In the equilibrium period, the stock size (B), SSB and R values were estimated as 668 thousand tons, 255 thousand tons and 12.0 x 109 fishes, respectively; on the other hand, in 1989, these estimatives were 213,000 tons, 100,000 tons and 3.0 x 109 fishes. The decrease was related to a combination of environmental and fishing events, the last being the predominating factor.

Keywords: Growth, mortality, recruitment, biomass, Sardinella brasiliensis, Brazil: Southeastern coast.
Contents of this volume Sci. Mar. 59(3-4) : 597-610 Back PDF
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