FISHERY BULLETIN: VOL. 83, NO. 3 



Figure 5. -Lunar phase relationships of settlement 

 and fertilization dates for French grunts. Data repre- 

 sent the totals obtained from Figures 2 and 3 summed 

 with reference to the days before and after full 

 moons. The settlement data are the sum of peak 

 numbers of PL-l's on all census sites. Actual settle- 

 ment rates (maximum rate of influx) were maximal 2 

 to 3 d before the figured peaks. The fertilization data 

 clearly reveal weaker weekly periods of spawning (see 

 text for details). 



3 



O 



C 



CO 



3 



o 



_l 

 < 

 > 

 cc 



< 



2000 



1500 



1000 



500 



SETTLEMENT 



CO ^ 



O 14 



^ 100 I- 

 u. 



O 



CC 

 UJ 



50 



10 



10 14 



n FERTILIZATION 



I 



5 



T 







(-) 14 10 5 5 10 



DAYS FROM FULL MOON 



14 (+) 



should be unimportant. This condition would prevail 

 because the tidal states (springs, neaps, intermediate 

 conditions) change phase relative to the lunar cycle 

 as the year progresses (Fig. 6). In contrast, if a par- 

 ticular state of the tide served as a primary trigger 

 for fertilization and/or settlement then the moon's 

 state would be unimportant. To test for the impor- 

 tance of tidal and lunar state the data were analyzed 



using a log likelihood statistic (g-test, Table 3) by 

 grouping the 22 settlement and 26 fertilization peaks 

 into the 9 possible combinations of tidal and lunar 

 state (e.g., spring, neap, and intermediate tides and 

 full, new, and quarter moons). Clearly both the lunar 

 cycle and tidal state have significant effects on 

 settlement and fertilization, but their interaction, 

 although large, is nonsignificant. Because 60 to 80% 



Table 3. — Summary of comparisons of lunar cycle and tidal state for fer- 

 tilizations and settlement pulses of Frencfi grunts during 1980. Data from 

 Table 2. Log likelihood test from Sokal and Rohlf (1981). 



g-value and associated chi-square 



Category 



Settlement data 



Fertilization data 



Total G' 



Moon alone' 

 Tide alone' 

 Moon-tide' 



36.7 



11.3 

 18.0 



>x' 



001(8) 



.01(2) 



> X' .001(2) = 1 3.8 



7.4 ns < x' .05(4) 



= 26.1 22.5 > x' 01(8) = 20.1 



= 9.9 7.3 > x' 05(2) = 6.0 



10.2 > x' .01(2) = 9-9 



= 9.5 4.9 ns < x ' 05(4) = 9.5 



'Single classification of all categories. 



'Single classification of moon or tidal state alone. 



'Two-way classification, moon phase versus tidal state. 



420 



