The fish species most commonly observed by the commercial 

 fish-spotters while operating off central and southern California, 

 and northern Baja California, Mexico, are the northern anchovy, 

 Engraulis mordax; jack mackerel, Trachurus symmetricus; Pacific 

 bonito, Sarda chiliensis; Pacific mackerel. Scomber japonicus; 

 Pacific sardine, Sardinops sagax cderulea; and bluefin tuna. Tlutn- 

 nus thynnus. Other species such as Pacific barracuda. Sphyraena 

 argentea, yellowtail, Seriola lalandei. white seabass, Atractoscion 

 nobilis, and albacore, Thunnus alalunga, are observed by the 

 pilots, and are sometimes caught by the commercial fleet with the 

 aid of aerial spotters. Other animals such as the basking shark, 

 Cetorhinus maximus, mammals (whales and porpoise), and inver- 

 tebrates (squid — Loligo opalescens), have been observed and 

 recorded. A total of 20 species of fish have been observed and 

 recorded by the spotter pilots (Squire 1972). 



METHODS 



Commercial aerial fish-spotters have recorded flight tracks and 

 fish school tonnage estimates for the program since the fall of 1962: 

 1963. however, was the first complete year of data. The pilots in the 

 program are full-time professional commercial fish-spotter pilots. 

 Participating pilots under contract were advised that all sightings of 

 schooling fish were to be reported. A total of 15 pilots have partici- 

 pated in the program. Observation quality has remained relatively 

 stable since the pilots who have made the major contributions to the 

 program have participated in it throughout its 16-yr period. There 

 has been no attempt to intercalibrate the pilots. The only data gap in 

 the program is for the second half of 1970 (July through Decem- 

 ber), when contracts for observation data were cancelled. 



For a review of the methods and procedures for obtaining and 

 processing the flight log observation data, and for results of the 

 program for the period 1963-69, see Squire (1972). Caruso : 

 described by details of computer coding of the aerial observations 

 for future analysis. The general procedure for recording fish sight- 

 ing observations on flight log charts has not changed from that 

 described by Squire (1972). In 1974 flight log charts were added to 

 cover the northwest coast of Baja California, Mexico. With the 



2 Camso, J. 1479. Aerial marine resources monitoring system. Data Coding Man- 

 ual. Admin. Rep. U-79-9, 99 p. Southwest Fisheries Center La Jolla Laboratory. 

 NMFS. NOAA. La Jolla. CA 92038. 



addition of charts for the area south of the United States-Mexico 

 border, pilots recorded observation sighting data for summer flights 

 in search of bluefin tuna. The borders of 10' longitude x 10' lati- 

 tude "block areas" and associated "block numbers" were printed 

 on the charts to expedite data coding. The "block areas" referred to 

 are identical to the California Fish and Game statistical grid sys- 

 tem. The area from Half Moon Bay, Calif., to Cedros Island, Baja 

 California, Mexico, has six flight log charts. Divisions of this area 

 into "block areas," which were later combined into larger grouped 

 "zones" lettered A through T, are shown in Figure 1 . 



Pilots recorded their flight paths and school sightings on the 

 appropriate charts. Aerial spotter data was analyzed by using sum- 

 maries of the number of block areas entered into by the pilots as a 

 measure of observation effort and tonnage estimates offish. 



Approximately 40,000 flight hours of observations were 

 recorded. A total of 164,753 block areas or portions of block areas 

 were surveyed: 1 10.375 (67%) during the day and 54,378 (33%) 

 during the night (Table 1). A graph of each year's day, night, and 

 total observation effort is given in Figure 2. 



From 1962 to 1978, no natural changes in the survey area 

 occurred that could be classed as atypical. However, one unusual 

 event did occur that had a severe local impact and affected the 

 observation of near-surface pelagic species. In late January 1969. a 

 large release of crude oil occurred in the Santa Barbara Channel 

 area. The oil release continued in varying quantities for some 

 months afterward, and affected fishing and aerial fish-spotting 

 operations in the eastern half of the Santa Barbara Channel and 

 around the Channel Islands. Since this was an area where concen- 

 trations of anchovy, jack mackerel, and Pacific bonito were previ- 

 ously observed by the aerial spotters and fished by commercial 

 seiners, the oil contamination resulted in a temporary cessation of 

 fishing. During the months when the surface crude oil spill was a 

 problem, however, frequent aerial surveys of the Santa Barbara 

 Channel and Islands area were made by the Union Oil Company, 

 using an aerial spotter pilot who was participating in the NMFS 

 program. Data from these observations were recorded in the same 

 format as the NMFS pelagic fish program and made available to the 

 NMFS for analysis. 



Flight log data represent a sample estimate of the apparent abun- 

 dance of pelagic species schooling in the near-surface layers of the 

 areas surveyed. The selection of flight tracks was nonrandom. 



Tabic 1 



-Observation effort off California for pelagic commercial fish (day/night) in units 

 of block area overflights by zone. 



Zone 



1962-65 



1966-69 



1970-73 



1974-78 



Total 



A 



443/310 



1.271/38 



14/0 



22/0 



1.750/348 



B 



.148 Win 



2.025 113 



21S4S 



180/53 



3.571/814 



C 2.098/2.207 



6.020 2. 053 



10.508/3.151 



6.213 3.475 



24.839/10.886 



D 



.043 1.190 



5.023/1.921 



5.075/1,503 



4.659/3.801 



15.800/8.415 



E 



151 427 



336/287 



124.122 



743/298 



1,354/1.134 



F 



40/181 



166/316 



123/732 



381/472 



710/1.701 



G 



.329 1,512 



3.583/3.206 



4.222/3.899 



7,974/8.369 



17.108/16.986 



H 



.041/967 



1.829. 1 .556 



1.612/2.001 



3,156/2,595 



7.638/7.119 



1 



.238 510 



2,585/1.215 



1.178/1,298 



3.356/1.026 



8.357/4.049 



J 



.599/626 



3.538/749 



4.208/211 



5.353/726 



14.698/2.312 



K 



35/0 



315/52 



932/72 



1.796/38 



3.078/162 



L 



0/0 



0/0 



1 .287/47 



5.157/202 



6.444/249 



M 



0/0 



0/0 



:: 3 



43/0 



65/3 



N 



0/0 



0/0 



878/0 



3.094/165 



3.972/165 



O 



0/0 



0/0 



0/0 



0/0 



0/0 



P 



0/0 



0/0 



212,0 



618/35 



830/35 



Q 



0/0 



0/0 



0/0 



0/0 



0/0 



R 



0/0 



0/0 



0/0 



161/0 



161/0 

 1 10.375/54.378 



