AHLSTROM: KIND AND ABUNDANCE OF FISH LARVAE 



southern portion of the Peru Current off Chile 

 at lat 34°S. They provide annotated identifi- 

 cations of 133 species. Although these transects 

 were south of the EASTROPAC area, many of 

 the species also occur in the EASTROPAC area. 



Parin (1971) reports on collections of mid- 

 water fishes of the Peru Current zone collected 

 on the fourth cruise of RV Akademik Kurchatov. 

 He lists about 150 species representing 33 fami- 

 lies. Collections were obtained between lat 5°N 

 and 30°S, in a broad coastal band, extending 

 offshore to long 90 °W, Distributions are illus- 

 trated for 24 species. 



In addition to the above, a number of ref- 

 erences dealing with particular species of genera 

 or families of eastern Pacific fishes are cited in 

 the body of the text, or were referred to in Ahl- 

 strom (1971). 



NUMBER OF FISH LARVAE OBTAINED 

 ON EASTROPAC II 



Fish larvae were obtained in all collections 

 (355) made with the 1-m plankton net on ETP 

 II; counts of larvae per haul ranged from 1 to 

 2,864, and averaged 347. Four collections con- 

 tained 10 or fewer larvae, and 22 collections 

 contained 1,000 or more specimens in each 

 (Table 6). 



Abundance of fish larvae according to latitude 

 and proximity to shore within the EASTROPAC 

 pattern is summarized in Table 7. The same 

 grouping of stations by latitude (5° except near 

 the equator) and longitude (inshore-oflFshore) 

 is used as in Table 4 (temperature summary 



table). Subtotals provide a rough separation 

 into quadrants. 



Larvae were taken in greatest abundance in 

 the northeast quadrant, particularly between 

 lat 5° and 10°N; in this latter area, with an 

 average surface temperature of 27.1°C, larvae 

 averaged 639 per haul. Larvae were less abun- 

 dant in the southeast quadrant, with numbers 

 decreasing southward and averaging only 118 

 larvae per haul between lat 10° and 15°S (av- 

 erage surface temperature, 18.1°C), 



Larvae were much less abundant offshore, in 

 the northwest quadrant, averaging slightly over 

 40% as many per haul as in the inshore (north- 

 east) quadrant. Surface temperatures, how- 

 ever, were quite similar. 



Near the equator (lat 2°N to 2°S), larvae 

 were moderately abundant inshore (434 per 

 haul), and the decrease in the abundance off- 

 shore was not as marked as in other areas (362 

 per haul). This is not surprising, since this 

 was an area of upwelling. 



In the southwest quadrant (lat 2° to 10°S, 

 long 110° to 119°W), there was a decrease in 

 abundance toward the south. However, this 

 quadrant was poorly sampled on ETP II. When 

 compared to inshore coverage of the same lat- 

 itude (lat 2° to 10°S), abundance of larvae per 

 haul averaged about 62% as many. 



Fish larvae averaged more per haul on ETP II 

 as compared with comparable coverage on ETP 

 I, 347.0 versus 231.9 larvae per haul; the in- 

 crease in abundance was reflected in all parts 

 of the EASTROPAC pattern. 



The majority of large collections of fish larvae 

 were made at stations with shallow thermo- 

 clines and relatively high mixed layer water 



Table 6. — Relative numbers of fish larvae obtained over the three vessel patterns oc- 

 cupied on EASTROPAC II; last column gives comparable counts for EASTROPAC I. 



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