PRODUCTION OF THE EUPHAUSIID NYCTIPHANES SIMPLEX IN VIZCAINO BAY, WESTERN BAJA-CALIFORNIA

Production of the euphausiid Nyctiphanes simplex Hansen in Vizcaino Ba y was 1,736 mg m(-2) yr(-1) as determined from size-class distribution s through 9 sampling periods during 1966. The production:biomass (P:B) ratio for this period was 17.0. Production due to growth was 74.7%, e xuviae 23.4%, and only 1.9% due to eggs. Most reproduction was in the fall. Maximal recruitment and spawning female aggregations (containing > 50 ind m(-2)) occurred in September, with a mean batch fecundity pe r spawner of 46 eggs. Maturation time for the eggs was estimated at 30 days, and 3 spawning events seem to be the usual quota per female. Th e reproductive pattern during fall in Vizcaino Bay seemed to be relate d to local eddy development in which adults were retained.