JOHNSON: DISPERSAL OF LOBSTER LARVAE 



the unit areas. Because of the scarcity of speci- 

 mens, no attempt is made to give figures based 

 on unit volume of water filtered. 



In unit area 1, 52% of 27 tows (other than with 

 the neuston or 1-m net) yielded a total of 87 larvae 

 in this 8° square area in the South Equatorial 

 Current. Nine neuston net tows caught no larvae. 



The three stations below 4°S were negative 

 and approach or fall into a large expanse of 

 water that yielded no larvae during the EAS- 

 TROPAC cruises (Johnson, 1971, Chart 12). 



Unit area 2 also in the South Equatorial Cur- 

 rent was less well sampled, but 36% of 11 tows 

 with the trawl and 5x5 foot net yielded a 

 total of 35 phyllosoma larvae and one scyllarid 

 postlarva (nesto). The five neuston tows were 

 negative. 



The large number of larvae caught by the 

 trawl in unit areas 1 and 2 when compared 

 with the more northern unit areas is striking in 

 indicating the tendency of the South Equatorial 

 Current to retain its load of phyllosoma larvae 

 in their long drift from the adult area. 



In unit area 3 overlapping into the North 

 Equatorial Countercurrent, which was well de- 

 veloped at the time (Williams, 1971), 20% of 15 



tows with the trawl and 5x5 foot net were 

 successful but yielded only seven larvae in 

 these nets. However five additional larvae were 

 caught in 2 of 11 neuston tows. 



Unit area 4 comprises only a 2° square area 

 within the North Equatorial Countercurrent. 

 Here two of three trawls and one of nine 5x5 

 foot net tows yielded 3 and 1 larvae respectively 

 while the neuston net caught a total of 10 lar- 

 vae in two of eight tows. The successful neuston 

 tows in this area and in unit area 3 were taken 

 during evening or nighttime tows. 



Unit areas 5 and 6 provided no phyllosomas 

 although both areas were comparatively well 

 sampled. 



The relatively large number of larvae taken 

 during these two cruises compared with the fol- 

 lowing cruises reflects more intensive sampling, 

 especially with the trawl, but a seasonality in 

 release of larvae in the adult area may also 

 have contributed. 



David Starr Jordan Cruise 60 

 6 Mar.- 11 Apr. 1971 



The stations occupied for plankton were more 

 scattered and very few larvae were caught, 



Table 1. — David Starr Jordan cruise 57 andTownsend Cromwell cruise 51. Types of gear, 

 total number of tows taken (the successful number of which is shown in parenthesis) and 

 the number nf larval species caught with different gear in unit areas 1-6. 



641 



