SOME OBSERVATIONS ON THE PELAGIC DECAPOD PASIPHAEA-SEMISPINOSA HOLTHUIS 1951 IN THE BENGUELA UPWELLING SYSTEM

Information on vertical and horizontal distribution patterns, abundanc e and morphology of the decapod Pasiphaea semispinosa in the Benguela upwelling system is presented. P. semispinosa is the dominant pelagic decapod in the system, occurring between 19 and 32-degrees-S along the mid and inner shelf in concentrations of 10-100.m-2. Although it is m ore abundant during abated than during active upwelling in the norther n Benguela, it would appear to be equally abundant during both upwelli ng scenarios in the southern Benguela. In the southern Benguela, repro ductive females are present during winter and juveniles dominate durin g active upwelling, but juveniles appear to be more common during abat ed upwelling in the northern Benguela. The estimates of abundance of P . semispinosa presented in this study are subject to sampling biases a ttributable to their vertical migratory behaviour and net avoidance ca pabilities.