278 
Fishery Bulletin 108(3) 
Table 4 
Number of fish caught per species (No.), number of fish alive at time of hauling (no.), range of size per species (lower jaw fork 
length for billfish and swordfish, and fork length for other species in cm), maximum survival time per species, percentage of 
individuals alive at time of hauling, and percentage alive eight hours after hooking. 
Common name 
Species 
No. 
no. 
Length 
(cm) 
Maximum 
survival 
time 
(hours) 
Alive at 
time of 
hauling 
(%) 
Alive 
after 
8 hours 
(%) 
Swordfish 
Xiphias gladius 
389 
76 
93-242 
14 
19.5 
8.4 
Bigeye tuna 
Thunnus obesus 
86 
42 
65-160 
14 
48.8 
26.7 
Albacore 
Thunnus alalunga 
79 
3 
105-113 
8 
3.8 
1.2 
Yellowfin tuna 
Thunnus albacares 
66 
23 
99-150 
14 
34.8 
13.6 
Common dolphinfish 
Coryphaena hippurus 
48 
32 
83-120 
14 
66.7 
8.3 
Oceanic whitetip shark 
Carcharhinus longimanus 
17 
7 
120-151 
14 
41.1 
23.5 
Blue shark 
Prionace glauca 
92 
45 
150-240 
14 
48.9 
29.3 
Indo-Pacific sailfish 
Istiophorus platypterus 
7 
3 
?-163 
4 
42.8 
— 
Indo-Pacific black marlin 
Makaira indica 
3 
3 
238-240 
2 
100 
— 
Indo-Pacific blue marlin 
Makaira mazara 
2 
0 
— 
— 
0 
— 
Pelagic stingray 
Pteroplatytrygon violacea 
12 
5 
— 
2 
41.2 
— 
0 % to 40% on the hooks increased CPUE, but that 
the effect was not increased beyond this threshold. In 
contrast, blue shark had an increase in CPUE when 
the proportion of lightsticks was increased. Beyond an 
interest in understanding the influence of lunar perio- 
dicity and operational factors on the behavior of large 
pelagic fishes, these potential mechanisms are also of 
interest to fishermen, and our results also have impli- 
cations for current and future fishing practices. 
Frequency (%) 
0 5 10 15 20 25 
Figure 7 
Pooled data from the time-depth recorders located on the 
mainline in the middle position between two consecutive floats 
during experimental sets (n = 284) in the domestic Reunion 
Island longline fishery. 
Adjustments of fishing strategy 
and future research needs 
This study may help fishermen to modify fishing opera- 
tions and select a fishing strategy to increase economic 
benefits and reduce the impact of bycatch mortality. Cap- 
tains would be able to switch fishing practices to target 
one species or another according to lunar phase. More- 
over, shifting from expensive squid to cheaper mackerel 
bait to catch albacore could reduce the operational 
costs during trips in October and November when 
albacore CPUE is seasonally highest. 
We suggest that shortening the soak time dur- 
ing the fishing operation should be beneficial be- 
cause the major portion of the catch occurred in 
the first few hours of the operation (presumably 
bait decreases in quality with time and there is 
an increase in bait loss) (Lokkeborg and Pina, 
1997). Hook-timers and direct observations indi- 
cated that swordfish could escape for several hours 
after capture. Many triggered hook-timers were 
retrieved without a fish (1301 cases) and they 
may have been triggered for a variety of reasons, 
such as being triggered during deployment or re- 
trieval operations, being activated by squids, or 
may have been triggered by the escape of fishes or 
turtles. Although we cannot assume that high es- 
cape rates have occurred, we had the opportunity 
to film a swordfish escaping during the hauling of 
the gear. It succeeded in unhooking itself at the 
surface but sank immediately from exhaustion. 
Therefore, even if the fate of the escaped animal 
was unknown, we assumed that a large propor- 
tion of swordfish might die from ingestion of the J 
hooks. In addition, long soaking periods in warm 
temperatures increase the degradation of flesh. 
