272 
Fishery Bulletin 108(3) 
Table 1 
Variables, indices, and types of analyses performed during our study to elucidate the direct and indirect effects of lunar cycle and 
other operational factors affecting fishing performance, fish behavior, capture time, and fish survival for the domestic Reunion 
Island longiine fishery. 
Database 
Scale 
Variable 
Index 
Type of analyses 
1 Logbook 
Set (day) 
Number of fish (7 species, 
3 broad groups) number 
of hooks 
CPUE (number of fish per 
1000 hooks) 
Between classes analysis, 
Permutation test, 
Nonparametric loess 
regression 
2 Experiments with 
hook timers (HT) 
Hook (hour) 
Setting time 
Capture time 
Elapsed time after setting 
as capture time index 
(0-4 h, 4-7 h, 7-10 h, and 
>10 h) 
Multiple correspondence 
analysis 
3 Experiments with 
lightsticks 
Set (day) 
Number of fish (7 species, 
3 broad groups) 
Number of hooks 
Lightstick density 
Lightstick density and 
CPUE 
Catch composition 
(percentage of fish per 
species 
Centered principal 
component analysis (CPCA) 
Factorial correspondence 
analysis (FCA) 
4 Environmental 
Set ( day) 
Lunar day 
Lunar day (1 to 30) and 
lunar phase index (new 
moon, first quarter, full 
moon, last quarter) 
Hook (hour) 
Angle of elevation of the 
moon tide characteristics 
Lunar illumination index: 
low illumination intensity 
(angle <45°), high 
illumination intensity 
angle (45°-90°) and dark 
(new moon) 
Tide phase index (ebb, 
high, flood and low) 
univ-lyonl.fr/ADE-4, accessed January 2000) was used 
to perform calculations and graphical displays for be- 
tween-group analyses. 
Results 
Effect of the moon at a large scale 
Time series covered by logbook data The CPCA indi- 
cated that lunar day represented only 13.3% of the 
total variability, although the influence of the lunar 
day on CPUE was highly significant (permutation test, 
PcO.Ol). The first two axes explained 71% and 17% of 
the between-lunar-day variability and illustrated the 
effect of lunar days on CPUE (Fig. 3). Albacore CPUE 
reached maximum values during the full moon (between 
the 13 th and 19 th day of the lunar cycle), whereas CPUE 
was less important during the new moon (between the 
25 th and 6 th day of the lunar cycle). 
Swordfish was the unique component of the second 
axis (Fig. 3) and the projection of lunar days on this 
axis indicated that the highest CPUE occurred mainly 
during two short periods of time within the lunar cycle, 
between the 7 th and 9 th day and between the 23 rd and 
26 th day. None of the other four species analyzed ap- 
peared to be affected by the lunar day (Fig. 3). 
Case study of albacore and swordfish For albacore, 
LOESS regression confirmed that the highest CPUE 
was obtained during the full moon (Fig. 4A). In contrast, 
there was no apparent influence of tidal fluctuation (Fig. 
4C). The situation for swordfish was more complex. 
Variation of CPUE according to lunar cycle provided 
less contrast than that for albacore. LOESS regression 
confirmed that the highest CPUE was obtained during 
the first and last quarter of the moon as characterized 
by the lowest tidal ranges. Nevertheless, the relationship 
between swordfish CPUE and lunar intensity was not 
consistent because the CPUE progressively decreased 
