226 
Fishery Bulletin 115(2) 
Table 2 
Results of the permutation (perm) tests for statistical comparison between catch in number (CPUEn) 
and weight (CPUEb) per unit of effort (per 1000 hooks) and mortality (MPUE) per unit of effort (per 
1000 hooks) by species and species groups caught by 2 different leader materials, 2.5-mm monofila¬ 
ment nylon and 1.2-mm multifilament stainless wire, during experimental longline sets conducted in 
the southwest Indian Ocean between November 2013 and March 2014. 
CPUEn MPUE CPUEb 
Group and species 
Perm test 
P 
Perm test 
P 
Perm test 
P 
Billfish 
Istiompax indica 
0.00 
1.00 
0.02 
1.00 
-0.31 
1.00 
Makaira nigricans 
0.02 
1.00 
-0.02 
0.99 
6.87 
0.48 
Kajikia audax 
0.10 
0.58 
0.10 
0.46 
4.85 
0.24 
Istiophorus platypterus 
-0.07 
0.44 
-0.10 
0.12 
-2.88 
0.32 
Tetrapturus angustirostris 
-0.10 
0.29 
-0.10 
0.22 
-8.94 
0.36 
Xiphias gladius 
0.56 
0.57 
1.45 
0.05 
65.26 
0.24 
Total billfish 
0.51 
0.62 
1.36 
0.08 
64.85 
0.27 
Tuna 
Thunnus alalunga 
0.12 
0.35 
0.07 
0.37 
2.57 
0.25 
Thunnus obesus 
-0.19 
0.15 
-0.02 
1.00 
-8.90 
0.13 
Thunnus albacares 
0.07 
0.66 
0.05 
0.73 
0.69 
0.90 
Total tuna 
0.00 
1.00 
0.10 
0.51 
-5.64 
0.59 
Other bony fishes 
Alepisaurus brevirostris 
0.00 
1.00 
-0.05 
0.62 
- 
- 
Alepisaurus ferox 
-0.39 
0.13 
-0.24 
0.27 
- 
- 
Sphyraena spp 
-0.12 
0.12 
-0.10 
0.12 
- 
- 
Centrolophidae 
-0.02 
1.00 
-0.02 
1.00 
- 
- 
Coryphaena hippurus 
-0.12 
0.79 
-0.05 
0.86 
1.60 
0.65 
Gempylus serpens 
-0.34 
0.30 
-0.27 
0.35 
- 
- 
Lampris guttatus 
-0.02 
0.99 
-0.02 
0.99 
- 
- 
Lepidocybium flavobrunneum 
-0.34 
0.15 
-0.19 
0.08 
-2.18 
0.45 
Mola spp. 
0.02 
1.00 
- 
- 
- 
- 
Ruvettus pretiosus 
0.05 
0.68 
-0.02 
1.00 
- 
- 
Regalecidae 
-0.02 
1.00 
- 
- 
- 
- 
Acanthocybium solandri 
-0.07 
0.44 
-0.07 
0.36 
-0.14 
0.75 
Total other bony fishes 
-1.36 
0.04 
-1.04 
0.03 
-0.65 
0.88 
Sharks 
Prionace glauca 
-2.49 
0.03 
-0.48 
0.28 
-233.52 
0.00 
Alopias superciliosus 
0.19 
0.05 
0.10 
0.21 
- 
- 
Manta sp. 
-0.02 
0.99 
- 
- 
- 
- 
Carcharhinus longimanus 
-0.15 
0.07 
-0.05 
0.50 
- 
- 
Pteroplatytrygon violacea 
-0.02 
1.00 
- 
- 
- 
- 
Lanina nasus 
-0.05 
0.51 
- 
- 
- 
- 
Pseudocarcharias karnoharai 
-0.02 
1.00 
- 
- 
- 
- 
Mobula sp. 
0.02 
0.99 
- 
- 
- 
- 
Isurus oxyrinchus 
-0.05 
0.82 
-0.02 
1.00 
-1.84 
0.85 
Sphyrna sp. 
0.02 
1.00 
- 
- 
- 
- 
Sphyrna zygaena 
-0.07 
0.23 
-0.07 
0.23 
- 
- 
Total sharks 
-2.64 
0.02 
-0.53 
0.27 
-235.37 
0.00 
Turtles 
Caretta caretta 
-0.02 
0.99 
- 
- 
- 
- 
Total turtles 
-0.02 
0.99 
- 
- 
- 
- 
Total overall 
-3.53 
0.03 
-0.12 
0.92 
-179.38 
0.04 
(2008), who found the same number of species caught 
with both leader types, and those observed by Vega 
and Licandeo (2009), who found that monofilament 
gear caught more species. Theoretically, monofilament 
nylon leaders may be more difficult than wire leaders 
of the same diameter to be visually detected, but are 
also more easily severed than wire leaders. One pos¬ 
sible reason for the different results may be related to 
differences in availability of species in the study areas, 
as well as their relative ability to bite through a leader. 
However, it should also be noted that other gear char¬ 
acteristics, such as hook style and size can also influ- 
