done. Thus, skipjack spawiing can be inferred to 

 occur throughout the year in these waters. Yoshida 

 (1965) hkewise concluded from a study of skipjack 

 ovaries that skipjack spawn year-round in the 

 Marquesas. 



Yoshida also concluded that spawning is greatest 

 from Novemlier through April. Although the 

 seasonal distribution of larval skipjack (fig. 3) is 

 consistent with Yoshida's results, the data do not 

 permit a comparison for all seasons. 



Table 8. — Months, years, and cruises during wliich Uirnd skiii- 

 jack hare been captured in northeastern French Oceania. Ital- 

 icized cruises sampled the Marquesan offshore survey area. 



[Data prior to October 1957 from Matsumoto (1958) and Strasburg (1960)] 



SUMMARY 



1. The results of a study of the distribution of 

 larval tunas in IMarquesan waters are presented. 

 Data were collected in 1957 and 1958 on repeated 

 transits of a standardized offshore survey pattern 

 and on repeated visits to a single station where diel 

 variability of larval abundance was studied. 



2. Larval tunas were sorted and counted from 

 113 plankton samples from the offshore surveys and 

 92 from the diel variability station. Larval abun- 

 dance is expressed as the number of larvae under 

 10 m.= of ocean surface down to a depth of 140 m. 



3. Duplicability of larval catches by oblique 

 tows taken at niglit or day was demonstrated. 



4. Greater abundance of larval skipjack during 

 darkness was evident at the diel variability station 

 in December 1957 and March 1958 and of larval 

 yellowfin in January 1958. Greater abundance of 

 larval skipjack at twilight was found in April and 

 .June of 1958. Results of attempts to determine 

 whether larvae were below 140 m. were inconclusive. 



5. Data from the offshore surveys indicate 

 greater abundance of larval tunas during the Mar- 



quesan summer and fall (January to April) than 

 during other months. 



G. Larval skipjack have been collected through- 

 out the area of northeastern French Oceania bounded 

 by long. 130° W. and 147° W. from the Equator to 

 lat. 18° S. 



7. High and low catches of larvae occurred in 

 samples of high as well as of low plankton volume. 



8. Average abundances of zooplankton, larval 

 tiuias, and tuna schools for the offshore surveys were 

 lowest during CHG-35 (Oct.-Nov. 1957), highest 

 during either HMS-43 (Jan.-Feb. 1958) or CHG-38 

 (Mar.-Apr. 1958), and intermediate during HMS-45 

 (May 1958). 



9. According to records of the localities of the 

 capture of larvae and juveniles, skipjack spawn 

 throughout the tropical and subtropical zones of the 

 Pacific Ocean. In northeastern French Oceania, 

 skipjack appear to spawn throughout the year. The 

 data are consistent with the conclusion reached from 

 a study of skipjack ovaries that the spawning of 

 skipjack in northeastern French Oceania is most 

 active from November through April. 



LITERATURE CITED 



Austin, Thom.\s S. 



1957. Summary, oceanographic and fishery data, Mar- 

 quesas Islands area, August-September, 1956 (EQUA- 

 PAC). U.S. Fish Wild!. Serv., Spec. Sei. Rep. Fish. 

 217, v-|-186pp. 



King, Joseph E., Thomas S. Austin, and M.\xwell S. Doty. 



1957. Preliminary report on expedition EASTROPIC. 

 U.S. Fish Wildl. Serv., Spec. Sci. Rep. Fish. 201, 

 iv-|-155 pp. 



King, Joseph E., and Joan Demond. 



1953. Zooplankton abundance in the central Pacific. 

 U.S. Fish Wildl. Serv., Fish. Bull. 54: 111-144. 

 Klawe, Witold L. 



1963. Observations on the spawning of four species of 

 tuna {Neothunnus macropterus, Katsuwonus pelamis, 

 Auxis thazard and Euthynnus lineatus) in the eastern 

 Pacific Ocean, based on the distribution of their larvae 

 and juveniles. Inter-Amer. Trop. Tuna Comm. Bull. 

 6(9): 449-540. 

 1\I.\RR, John C. 



1948. Observations on the spawning of oceanic skipjack 

 {Katsuwonus pelamis) and yellowfin tuna {Neothunnus 

 macropterus) in the northern Marshall Islands. In 

 Schaefer, Milner B., and John C. Marr, Contributions 

 to the biology of the Pacific tunas, pp. 201-206. U.S. 

 Fi.sh Wildl. Serv., Fish. Bull. 51. 

 Matsumoto, Walter M. 



1958. Description and distribution of larvae of four 

 species of tuna in central Pacific waters. U.S. Fish 

 Wildl. Serv., Fish. Bull. 58: 31-72. 



LARVAL TUNAS IN MARQUESAN WATERS 



