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 Bahia Vizcaino, south of Punta Abreojos and in front of Bahia 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 Bahia Vizcaino to the Golfo de Ulloa. Daily N. simplex growth production (Pg) values in Bahia Vizcaino and South Punta Abreojos were 0.215 and 0.440 mg dw m(-3) day (-1)respectively. In Bahia Magdalena the Pg value (0.014 mg dw m(-3) day (-1)) was lower. Larvae (organisms less than or equal to6 mm) showed the highest percentage of Pg. The Pg values recorded here, are nearly 3-fold the values registered previously in Bahia Vizcaino, and correlate well with those reported before at Bahia Magdalena. The region off Punta Abreojos 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 Bahia Vizcaino and Punta Abreojos contribute to maintain these important biological activity centers.