FISHERY BULLETIN: VOL. 69, NO. 4 



3. Stations greater than 250 km from the 

 coast were classified as offshore (stations 

 15, 24, 33, 46, 38, 73, 84, and 88). 



Transect 1-B was made at a time when the 

 Davidson Current is usually developed (Bolin, 

 1964). The inshore station (CalCOFI 3) was 

 occupied during an oceanic phase of the Mixed 

 Period, and subsidence is evidenced by the down- 

 ward trend of the isotherms and nitrate iso- 

 pleths (Figures 2, 8, and 9). Surface temper- 

 atures were comparatively high and nitrate 

 concentrations low. The Davidson Current was 

 developed at stations 3 and 14, and the transition 

 from Davidson to California Current Water oc- 



curred between stations 14 and 12 with a surface 

 divergence probably located between stations 5 

 and 12. Station 8, the outermost station, was 

 in the California Current proper. 



SURFACE PRIMARY PRODUCTIVITY 

 AND STANDING CROP 



During the July-August transects, when coast- 

 al upwelling dominated the hydrographic regime 

 of the California Current system, phytoplankton 

 productivity and chlorophyll-a concentrations 

 decreased markedly with distance from land 

 (Figure 10). Inshore, productivity and chlo- 

 rophyll ranged from 6.62 to 61.6.5 mgC m^^ hr~' 

 and from 0.8 to 11.5 mg m~^, respectively. Pro- 



15 24 33 46 38 73 84 88 

 Offshore 



Figure 10. — a. Inshore-offshore variations in surface netplankton (  ) and nannoplankton ( □ ) productivity 

 (mpC m~5 hr~') during tlie .July-August transects and the Novcmljer tran.scct (inset), b. Inshore-offshore 

 variations in surface netplankton and nannoplankton chlorophyll-a (mg m~^). 



810 



