Polovina and Mitchum: Recruitment of Panulirus marginatus relative to sea level in NW Hawaiian Is 



491 



Based on the comparison of FFS-Midway sea level 

 with the available puerulus settlement data from 

 MacDonald (1986) in the same year, the FFS-Midway 

 sea level correlates positively with mean puerulus 

 catches at Kure Atoll (r 0.78, P 0.11) and shows no 

 significant correlation with mean 

 puerulus catches at FFS (r 

 -0.37, P>0.25) (Fig. 11). 



ment differs between Necker I. and Maro Reef. At 

 Maro Reef, large-scale oceanographic features appear 

 to control the abundance of late-stage larvae, which in 

 turn results in interannual variation in recruitment to 

 the fishery. 



Discussion 



The research and commercial 

 catch and effort data presented 

 here show that the recruitment 

 of 3-year-old spiny lobster to the 

 fishery has varied considerably 

 at Maro Reef but has remained 

 stable at Necker I., 670km to the 

 southeast. Fishing effort is not 

 considered sufficiently heavy to 

 explain a decline in recruitment, 

 especially a decline at one bank 

 and not the other. The relation- 

 ship between recruitment to the 

 fishery at Maro Reef and the 

 FFS-Midway sea level advanced 

 by 4 years suggests that environ- 

 mental factors impacting the lar- 

 val stage are responsible for the 

 recruitment variation. The Geo- 

 sat data suggest that the FFS- 

 Midway sea level measures the 

 sec. Hence the SCC strength or 

 location dictates recruitment 

 strength to the fishery 4 years 

 later. Consistent with this hy- 

 pothesis is the mean age of lob- 

 sters in the commercial catches 

 as well as the correlation be- 

 tween puerulus settlement at 

 Kure Atoll and FFS-Midway sea 

 level. The lack of correlation be- 

 tween puerulus settlement at 

 FFS and sea level is consistent 

 with the observation that recruit- 

 ment at the lower end of the 

 NWHI is not linked to the same 

 pattern of variation as Maro 

 Reef. Annual variation in both 

 SCC strength and position has 

 been observed in the western 

 Pacific (White and Hasunuma 

 1982). In summary, the temporal 

 pattern of spiny lobster recruit- 



D 



o 

 ? 



■g 



I 



CO 



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Quarter of year 



Figure 10 



Overlay of 3-quarter moving average of French Frigate Shoals (FFS)-Midway sea level 

 advanced by 4 years (D), with a 3-quarter moving average of the ratio of Maro Reef 

 to Maro Reef plus Necker I., spiny lobster landings ( + ). 



