BIOLOGICAL INDICATIONS OF ACTIVE UPWELLING IN THE NORTHWESTERN INDIAN OCEAN IN 1964 AND 1979, AND A COMPARISON WITH PERU AND NORTHWEST AFRICA.

When surface properties of the northwestern Indian Ocean observed during the southwest monsoon of 1964 are compared with those of 1979, the area of upwelling around Ras Hafun showed the clearest similarity in the two years. Major dissimilarities between 1964 and 1979 were observed in the vertical distribution of temperature and nitrate near 5 degree N, which suggested that upwelling there in August 1964 was less intense than in July 1979. The intensity of upwelling near 5 degree N probably reached a peak in July both years, implying a relatively stable annual cycle for the upwellings off Somalia. The relationship of primary productivity and chlorophyll a observed off Somalia is very similar to that observed off Peru, and standing stocks of net zooplankton are also similar, but both are quite different from northwestern Africa. Refs.