Sousa R.,Direcao de Servicos de Investigacao e Desenvolvimento das Pescas DSIDP |
Henriques P.,University of Madeira |
Biscoito M.,Estacao de Biologia Marinha do Funchal |
Pinto A.R.,Direcao de Servicos de Investigacao e Desenvolvimento das Pescas DSIDP |
And 4 more authors.
Turkish Journal of Fisheries and Aquatic Sciences | Year: 2014
Life history traits of Plesionika narval were studied in the Northeastern Atlantic, Madeira archipelago including growth, age, sexual maturity, recruitment pattern and mortality. A total of 28262 specimens were sampled over a period of 8 years comprising two time series from 1991 to 1995 and 2004 to 2008. The relative growth pattern showed a negative allometric nature of growth for combined sexes, males, females, non ovigerous and ovigerous females. Estimated asymptotic carapace length (CL∞) and growth coefficient (K) showed higher values in females (CL∞=30.21 mm, K=0.450 year-1) comparatively to males (CL∞=28.61 mm, K=0.430 year-1), resulting in better overall growth performance in females. The maximum life span (tmax) was estimated at 6.81 years for combined sexes, 6.97 for males and 6.66 for females, however 99.95% of the individuals were younger than 3 years. Although a seasonal spawning season was evident from late summer to late autumn, reproduction may be prolonged throughout the year since ovigerous females are present in all months and achieving sexual maturity at 14.61 mm. The recruitment pattern was continuous throughout the year with a major peak occurring in spring. The total mortality (Z) and fishing mortality (F) were higher in females than in males while natural mortality (M) was similar between groups. © Published by Central Fisheries Research Institute (CFRI) Trabzon, Turkey.