FISHERY BULLETIN: VOL. 71, NO. 3 



the coastline or offshore beyond the bounds of 

 the plume. Their distribution showed a closer 

 correlation with temperature than salinity. 

 Plots of larval abundance, which ranged from 

 <1 to 62/1,000 m3, 210 to 451/1,000 m3, and 14 

 to 252/1,000 m3 in positive tows in deep bongo, 

 shallow bongo, and MN samples respectively in 

 June, are in Figure 3. Larvae were associated 

 with water >14°C which agrees with Ahl- 

 strom's (1959) findings off California. Plots of 

 abundance (2 to 840/1,000 m3 and <1 to 4,493/ 

 1,000 m3 in deep and shallow bongo samples) 

 for July-August (Figure 4) again show larvae 

 concentrated in water >14°C. Upwelling was 

 prevalent at that time with colder water near 

 shore. The Columbia River plume was not 

 clearly distinguishable although the warm 

 waters offshore were probably a result of the 

 plume (Pearcy and Mueller, 1969). After the 

 July-August cruise, fewer larvae were taken 

 and distribution was scattered throughout the 

 area sampled. 



Small anchovy larvae were concentrated in 

 surface waters which agrees with Ahlstrom's 

 (1959) results on vertical distribution of ancho- 

 vies off California. 



I I M I I I I I I I I I I I I I I I I I M I I I I I u p- I I I 



Enqraulis mordax 

 18 JUN-2 JUL 1969 



SAMPLE TYPE 

 • BONGOS, SHALLOW 

 O BONGOS , DEEP 

 A METER NET 



INDIVIDUALS / 1000 m 

 '///, < I 

 i%i% I-IOO 

 i^?^ >I00 



I I I I I I M I I I I I I I I I I I I I I I I I I I I I) g» I I I 



En q raulis mordax 

 31 JUL -12 AUG 1969 



I I I I"' 



I I ' I [ I tl I I I I I I 



Figure 3. — Distribution of Engraulis mordax larvae and 

 surface temperature, June 1969. 



Figure 4. — Distribution of Engraulis mordax larvae and 

 surface temperature, July-August 1969. 



Results of meristics and blood genetics studies 

 have indicated at least three distinct anchovy 

 subpopulations exist off Oregon, California, and 

 Baja California (Vrooman and Smith, 1972). 

 The present results together with previous 

 studies offer support for the existence of a 

 separate stock off Oregon. Anchovy larvae were 

 abundant in Columbia River plume waters in 

 the upper 10 to 20 m in 1969. Waters of the 

 Columbia River plume have a strong vertical 

 density gradient and a shallow mixed layer 

 depth (Owen, 1968). Anchovies spawn mostly 

 in the upper 10 m at temperatures >14°C (Ahl- 

 strom, 1959). Adult anchovies were reported in 

 unusually large concentrations near the coast of 

 northern California and Oregon in 1969 (Frey, 

 1971). The adults were probably spawning. 

 CalCOFI (California Cooperative Oceanic 

 Fisheries Investigations) sampling has indica- 

 ted a high abundance of anchovy larvae off 

 southern California with a substantial drop in 

 abundance from southern to northern California. 

 In 1949 and 1950, anchovy larvae were found in 

 moderate abundance off Oregon (Ahlstrom, 

 1968). Thus, a separate spawning stock of an- 



708 



