Growth parameters and mortality rate of the Scomber japonicus peruanus (Jordán & Hubb, 1925) along the Peruvian coast, South Pacific

The growth parameters and the mortality rates of the Scomber japonicus peruanus (Chub mackerel) were studied based on monthly data of frequency of fork length classes obtained from commercial landings off the Peruvian coast from 1996 to 1998. The asymptotic body length and growth rate values obtained by the ELEFAN I (Electronic Length Frequency Analysis) ranged from 40.20 cm to 42.20 cm and from 0.38 to 0.39, respectively. The oscillation amplitude was 0.60; the Winter point values varied from 0.50 to 0.60 and the performance index from 2.79 to 2.84. The total mortality rate of the Chub mackerel obtained by the linearized catch curve oscillated between 1.68 and 3.35. The rate of fishing mortality varied from 1.16 to 2.78 and the exploitation rate from 0.68 to 0.84. The annual rate of natural mortality estimated by the Pauly's method ranged from 0.52 to 0.53. The results obtained allow us to conclude that the longevity of the Chub mackerel was slightly over seven years.Os parâmetros de crescimento e as taxas de mortalidade de Scomber japonicus peruanus (cavalinha) foram estudados a partir de dados mensais de freqüência de classes de comprimento provenientes do desembarque comercial ao longo da costa peruana no período de 1996 a 1998. Os valores do comprimento furcal assintótico e da taxa de crescimento obtido pelo ELEFAN I(Electronic Length Frequency Analysis) variaram de 40,20 cm a 42,20 cm e de 0,38 a 0,39, respectivamente. A amplitude de oscilação foi de 0,60; os valores de Winter point variaram de 0,5 a 0,6 e os do índice de performance entre 2,79 e 2,84. As taxas de mortalidade total da cavalinha obtidas pela análise da curva de captura linearizada oscilaram entre 1,68 e 3,35, sendo as variações das taxas de mortalidade por pesca e explotação de 1,16 a 2,78 e 0,68 a 0,84, respectivamente. A taxa anual de mortalidade natural estimada pelo método de Pauly variou de 0,52 a 0,53. Os resultados obtidos permitem inferir que a longevidade da cavalinha foi de pouco mais de sete anos