RECORD OF THE URVAE OF THE PACIFIC MACKEREL 

 ( PNEUMATOPHORUS DIEGO ) , 1956 



Pacific mackerel larvae are reported by size in table VI. The size 

 classes are identical to those used for jack mackerel (cf. p. 51). The data 

 are further summarized in text table 9. The distribution and abundance of 

 Pacific mackerel larvae in 1956 are shown in figure 6. The categories of 

 abundance, given in an insert on the chart, are identical to those used in 

 other charts in this report. The values at individual stations represent the 

 cumulative standard haul total for all occupancies during 1956. 



Pacific mackerel larvae constituted only 0.37% of the larvae collected 

 in the regular CCOFI survey area in 1956. Larvae of this species were much 

 more abundant in collections made in the Gulf of California. As noted earlier, 

 the Gulf results will be reported in a separate publication. 



On the outer coast, Pacific mackerel larvae were taken between Dana Point, 

 off southern California, and Magdalena Bay, off southern Baja California (lines 

 90-143). There were only three occurrences off California (in June and July). 

 The largest numbers of larvae were obtained off upper central Baja California 

 (lines 110-120), especially in Sebastian Viscaino Bay. Most of the larvae were 

 collected during a five-month period, April through August. 



Pacific mackerel larvae were not taken over as wide an area in 1956 as 

 in 1955. This is quite evident by comparing the distribution charts for the 

 two years (fig. 6 in this report, with fig. 6 on p. 68 of Ahlstrom and Kramer, 

 1956). Pacific mackerel larvae were taken in only 40 hauls in 1956, as com- 

 pared to 92 hauls in 1955. The 40 occurrences in 1956 were taken at 32 separ- 

 ate stations, while the 92 occurrences in 1955 were taken at 68 separate sta- 

 tions. These data are summarized in the following tabulation: 



1956 1955 



Total 40 32 1,519 92 68 1,950 



It is interesting to note that the stations at which Pacific mackerel lar- 

 vae were taken on more than one cruise in 1956 were all within Sebastian Vis- 

 caino Bay. In contrast, most multiple occurrences in 1955 were offshore 

 from Cedros Island on lines 117 to 123. 



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