Squire. Aerial monitoring of abundance of pelagic fishes 



349 



Species included in this study are the northern an- 

 chovy Engraulis mordax, Pacific sardine Sardinops 

 sagax, Pacific bonito Sarda chiliensis, chub mackerel 

 Scomber japonicus, jack mackerel Trachurus 

 symmetricus, and bluefin tuna Thunnus thynnus. These 

 species, along with market squid Loligo opalescens, 

 are the primary targets of the commercial purse-seine 

 fleet based in San Pedro, California. Most are also 

 fished by the southern California sportfishing fleet. 

 The species are members of a complex interacting 

 coastal and oceanic ecosystem that crosses interna- 

 tional boundaries (Sette 1969). 



Methods 



Procedures for collection and tabulation 

 of data 



Since the fall of 1962, fish-spotter pilots have been 

 directed to complete a flight logchart at the termina- 

 tion of each spotting flight. These pilots were instructed 

 to draw their flight track on the chart and record the 

 locations of all schools of fish species observed, along 

 with their best estimates of tonnage observed. These 

 data were recorded either as total tonnage of fish in 



123° 



122* 



121* 



SAM FRANCISCO Ba 



M 



118° 



116* 



34° 



33° 



32' 



117' 



116' 



115' 



Figure 1 



Block areas designated for sampling from off central California to Mexico, grouped in 18 zones, A to T. (Zones Q and S were originally 

 used on flight logs; however, no flights were recorded for these zones. ) 



