Abstract
Ninety-two samples taken during four oceanographie cruises (January/February, April, August, October/November, 1972) provided material to study the bionomics and life history of Umbrina canosai. As many as 1477 specimens were examined to determine individual total length and weight, age (through otoliths readings) sex and maturity. A certain number of ovaries was examined to estimate their fecundity and determine spawning periodicity. Spatial distribution pattern of the species was obtained graphically for the different seasons using demographic isolines. Salinity, temperature and oxygen content of the bottom waters and depth related to the number of individuals caught by unit effort provided information to conclude that U. canosai migrates seasonally under the influence of the displacement of Subantarctic waters along the Southern Brazilian coast. A rather different spatial distribution was observed between immature and mature individuals. Spawning occurs throughout August/November and individuals spawn more than once during each spawning season. The recruitment of young specimens occurs during summer-autumn. There is no significant difference in the growth rate for both sexes. The weight/length relationship was significantly different for female and male values. It seems that U. canosai is closely associated with the presence of cold waters (below 16oC).
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