Table 5.— Average number of larval skipjack under 10 m.- of 

 ocean surface for the inner, middle, and outer 75-mile sections 

 of the of shore surveys. 

 (Numbers of samples on which the averages are based are in parentheses] 



Larval skipjack had been found to be widely dis- 

 tributed in the northeastern part of French Oceania 

 previous to the series of cruises in this report. Fig- 

 ure 4 illustrates the locations around the Marquesas 



» LARVAL SKIPJACK 

 • OTHER LARVAL TITNAS 



• r 



■*ll\IAR0UES.4S 

 .ISLANDS I 



^.TAHITI t * 



MS" W0« 



-10' 



135° 



130° W. 



Figure 4.— Stations in northeastern French Oceania where 

 larval tunas were collected on cruises earlier (1952-57) than 

 those covered by this study. (Data from Matsumoto, 

 1958, and Strasburg, 1960.) 



Islands where larval tunas were collected during 

 cruises of vessels of the Bureau of Commercial 

 Fisheries prior to those listed in table 1 . 



ABUNDANCE OF LARVAL TUNAS 

 AND INVERTEBRATE PLANKTON 



Relations between the abundance and distribution 

 of invertebrate plankton and of larval tunas, if any 

 exist, are obscure. If the plankton volumes and 

 abundance of larval tunas are averaged for each of 

 the offshore surveys, an obvious positive correlation 



Figure 5. — Average abundance of zooplankton, larval tunas, 

 and tuna schools for the offshore surveys. 



can be seen (fig. 5), but in individual samples no 

 significant correlations (Spearman rank correlation) 

 were found. High and low measures of abundance 

 of larval tunas were found in high as well as in low 

 volumes of plankton. Strasburg (I960) reported 

 that high catches of larval tunas came from samples 

 of low and moderate volumes of plankton, while the 

 samples with lowest and highest plankton volumes 

 contained smaller numbers of larval tunas. 



ABUNDANCE OF LARVAL 

 AND ADULT TUNAS 



Strasburg (1960) found a tendency for larval 

 tunas to occur in larger abundance where there were 

 more adults of the same species although the correla- 

 tion was statistically nonsignificant. Similar com- 

 parisons by species were not possible with our data. 

 Schools of adult tunas were located by sighting the 

 associated bird flocks. Because of the necessity of 

 covering a certain distance of the offshore surveys 



LARVAL TUNAS IN MARQUESAX WATERS 



