324 
Fishery Bulletin 106(3) 
O 
06 
0.5 -0 
0.4 
0.3 
0.2 
01 - 
0 
0 
□ = Octopus 06 
A = Other o.5 
• = All species combined o .4 H 
" 0 3 
I) 
a 
£3 A — B- 
u 
0.2 i 
0.1 
0 
A 
- a- r a 
C(t)= ab + a(t-b)e 
0 10 20 30 40 50 60 70 80 90 100 
Days after deployment (t) 
A 
i t B □ 
10 20 30 40 50 60 70 
Days after deployment (t) 
80 
90 100 
Figure 4 
Octopus trap catch rates (mean number per trap) over time. Inset figure is 
the fitted catch model of Zhou and Shirley (1997) with a = 3.8576, b = 0.0318, 
and c = 2.292. 
1 7 14 27 35 43 55 71 89 
Days after deployment (t) 
Figure 5 
Murejona catch rates (C) (mean number per trap) over time. Mean ±SE (stan- 
dard error) number of fish and octopus per trap, and the predator-to-prey 
ratio. Predators were conger eel ( Conger conger), forkbeard (Phycis phycis), 
Mediterranean moray eel ( Muraena Helena), and common octopus ( Octopus 
vulgaris ), whereas prey were all other finfish species. Inset figure is the 
fitted catch model of Zhou and Shirley (1997) with a = 1.5397, b = 0.5669, 
and c = 0.1101. 
region of Portugal) with licenses for fishing with traps. 
Of these, 13 boats had to be excluded from the survey 
because traps had not been used during the past year. 
Thus, questionnaire surveys were completed for 71 fish- 
ing boats that had been used to fish with traps. The 
results of the questionnaire survey are summarized in 
Tables 1 and 2. 
All skippers surveyed that had fished with octo- 
pus traps had the particular type of small trap (covo) 
used to catch octopus. However, some of the boats also 
possessed other types of traps, generally of a larger 
size that were used to target other species. Thus, 16 
(22.5 %) of the skippers interviewed had also used 
larger traps, mostly to catch cuttlefish, and two (2.8 
%) of the skippers from the western area (Barlaven- 
to), had used murejona wire fish traps to capture 
fish, especially sea breams. These results confirmed 
the relative importance of covo-style traps as a gear. 
