FISHERY BULLETIN: VOL. 84, NO. 3 



(Fig. 4). The alongshore distribution of larvae below 

 the starting point was quite uniform, and the lower 

 larval concentrations had reached the southern 

 border of the modeled region (CalCOFI line 120). 

 Dispersal offshore was minimal, and a majority of 

 the larvae lay in a band near the coast with about 

 equal proportions inshore and offshore of the start- 

 ing point; 92% of the larvae were on or inshore of 

 CalCOFI station 37.5. After initial southeasterly 

 transport, some larvae were transported in an off- 

 shore, southwesterly direction. 



Extensive downshore transport also occurred to 

 northern anchovy larvae begun at location C, and 

 in fact only 3% of the larvae remained at or upshore 

 of the starting location after 30 d of drift (Figs. 3C, 

 4). The larvae begun at point C were also concen- 

 trated in a narrow band along the coast, but unlike 

 those started at point B most of the larvae begun 

 at C moved inshore of the starting location after 30 

 d of drift. 



Northern anchovy larvae begun at the offshore 

 location D showed much less extensive downshore 

 transport than those begun at B or C (Figs. 3D, 4). 

 Only 10% of the larvae remained at or upshore of 

 the starting point, but 86% of the total remained 

 at or between CalCOFI line 92.5 (location C's line 

 coordinate) and line 102.5, a span of 222 km. Most 

 larvae were inshore of location D, and the cross- 

 shore distribution was slightly more uniform than 

 those begun farther inshore. Starting point D's 

 distance from the coastline permitted the slightly 

 broader cross-shore distribution. 



Larvae begun at location A showed an alongshore 

 cumulative percentage distribution after 30 d of drift 

 which was similar to that of larvae that begin drift 

 at point D, although it was displaced farther upshore 

 (Fig. 4). Location A produced the greatest percent- 

 age of larvae remaining at or upshore of the start- 

 ing location, and there is a small patch of high 

 (10 _1 ) larval concentrations present at the starting 

 location (Fig. 3A). This reduced dispersal of larvae 

 begun at A also produced the strongest cross-shore 

 gradient of larvae. A majority of the larvae were 

 again on or inshore of the starting location after 30 

 d of drift. 



In summary, the distributions of northern anchovy 

 larvae that began drift at locations A through D and 

 that were produced by March currents were formed 

 as relatively strong cross-shore gradients, so that 

 the 30-d distributions were bands (ca. 100 km wide) 

 parallel to the coast. The results of starting larvae 

 at locations A, C, and D were that more than 85% 

 of the larvae were inshore of the starting location 

 after 30 d of drift. Larvae that began drift at loca- 



STATION 



120 105 90 75 60 45 30 

 100- 



120 115 110 105 100 95 90 85 80 75 70 



LINE 



Figure 4.— Cumulative percentages of northern anchovy larvae 

 after 30 d of drift, progressing offshore (increasing CalCOFI sta- 

 tion number) and downshore (increasing CalCOFI line number), 

 for the four starting locations under March current conditions. 

 Cross symbols are at the starting location's corresponding 

 CalCOFI line or station coordinate. Distance between tic marks 

 on the abscissae is equivalent to a distance of 111 km. Note that 

 a steep curve implies a compact distribution of larvae, while more 

 gradual slopes imply more widely dispersed larvae. 



tions B and C were extensively carried downshore 

 of the starting location. Most of the larvae that 

 started at points A and D also moved downshore 

 from those locations, but the bulk of the larvae were 

 not as widely dispersed from the starting location 

 as those begun at points B and C. 



Effects of Seasonal Current Fields 

 on Larval Distribution 



The distributions of northern anchovy larvae 

 started at the same location but using different 

 seasonal current regimes appear very different to 

 the eye (Figs. 3, 5-7). Part of this effect is real, but 

 part is also due to displacement of the contours for 

 the lower larval concentrations (e.g., 10~ 7 ), which 

 represent few larvae. The cumulative percentage 

 plots (Fig. 8) indicate that, when summarized on a 

 model-wide basis, the overall cross-shore distribu- 

 tions of larvae begun at locations B, C, and D were 

 not greatly different when currents from the four 

 seasonal periods were used in the simulations. A 

 fixed distance offshore there were some large differ- 

 ences in the cumulative percentages among seasons 



592 



