JOHNSON: DISPERSAL OF LOBSTER LARVAE 



S'N 



Figure 3. — RW David Starr Jordan cruise 65 sta- 

 tion pattern in unit areas 1-6; 1-m net tow also made 

 at neuston stations. 



10° 



I4''S 



- <r 



n 



D I 





I 



I 



J* 



I • 



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100° 



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JORDAN 65 



Stations with ovailable 

 plankton samples: 



• 5'x5' net 



A midwater trawl 



n neuston net 



/ ptiyllosoma larvae token 



SOUTH EQUATORIAL CURRENT 



< 



SOUTH EQUATORIAL CURRENT 



PERU COASTAL CURRENT 



95° 



90° 



87°W 



coast of the Americas. Hence one is forced to 

 conclude that it most likely had drifted from is- 

 lands to the southwest where the genus is 

 known to occur. It should be mentioned here 

 also that a late larva of this genus was taken at 

 lat. 14°13.6'S, long. 126°00'W near the southern 

 limit of the most distant offshore stations of 

 EASTROPAC. Nothing is known regarding the 

 duration of the entire floating period of this 

 genus. 



Saisho (1962) included Pam6acus antarcticus 

 in his generalization stating that the free- 

 swimming life of scyllarids is shorter than for 

 palinurids. This was based on laboratory 

 studies of only the first three larval stages. 

 However, if the present observations of the two 

 late, but not yet the last, stage is characteristic 

 of the genus they suggest that, like Scyllarides 

 astori, the free-swimming life is not ab- 

 breviated. 



DISCUSSION 



This survey is of special interest in substan- 

 tiating the earlier findings of the EASTROPAC 

 survey relative to the far offshore drift of 

 planktonic stages of lobster larvae in the 

 Equatorial Current System. As in the earlier 

 survey, only species known to occur in the east 

 tropical area were found with one exception 

 (Parribacus sp.) referred to above. 



Assuming that the Galapagos Islands are the 

 main source of the larvae encountered, it is evi- 

 dent that the westward transport with the 

 South Equatorial Current involves at least a 

 distance of about 1,800 nautical miles. In 

 Townsend Cromwell cruise 51 larvae of each of 

 the prevailing species Panulirus penicillatus, P. 

 gracilis, and S. astori were netted in trawl tows 

 at the western-most stations at long. 

 121°32'-121°54'W between lat. 02°45'N and 



643 



