Standing stock of Nyctiphanes simplex in the southern region of the California current system

On the west coast of Baja California, Nyctiphanes simplex is by far the most abundant euphausiid species. To determine its importance in terms of growth production (Pg), and its relation to physical changes in the southern region of the California Current System, a survey was made along the Baja California peninsula including intensive sampling areas on Bahía Vizcaíno, south of Punta Abreojos and in front of Bahía Magdalena during February 1994. The results show high values for zooplanktonic volumes, chlorophyll a concentrations, and abundance of N. simplex along the peninsula associated to inshore areas from Bahía Vizcaíno to the Golfo de Ulloa. Daily N. simplex growth production (Pg) values in Bahía Vizcaíno and South Punta Abreojos were 0.215 and 0.440 mg dw m^-3 day^-1 respectively. In Bahía Magdalena the Pg value (0.014 mg dw m^-3day^-1) was lower. Larvae (organisms 6 mm) showed the highest percentage of Pg. The Pg values recorded here, are nearly 3-fold the values registered previously in Bahía Vizcaíno, and correlate well with those reported before at Bahía Magdalena. The region off Punta Abrejos proved to be the most important in terms of Pg of N. simplex for February 1994. Seasonal hydrographic conditions along the Baja California peninsula during winter may explain higher Pg values in South Punta Abreojos. The secondary production values of N. simplex produced in Bahía Vizcaíno and Punta Abreojos contribute to maintain these important biological activity centers.