Rapp. Comm. int. Mer Médit., 36,2001
309
Material and methods
In the framework of the project “Selectivity of fi
xed gears in
Mediterranean” the Sepia officinalis(cuttlefish) ‘metier’has been studied
in Greek waters. Sampling took place during April 1996 and April 1997 on
a professional small scale fishery vessel in Patraikos Gulf. The duration of
each mission was one week and 17 stations were sampled. The depth of the
stations ranged from 2 to 12 m. A trammel net with nominal mesh size of
the inner net 60 mm and nominal mesh size of the outer net 240 mm was
used (full mesh). The twine of the inner net was multifilament PA 210/2
and of the outer net was multifilament PA 210/4. The height of the net was
2.5 m. The fishing practice consisted on setting the nets on the bottom 2
hours before sunset and hauling them 2 hours after sunrise (soaking time
about 17.5 hours). The Catch Per Unit of Effort is expressed as number or
weight of the catch per 1000 fathoms of netting.
Results
A total of 1794 specimens were caught belonging to 45 species. Sepia
officinaliscomposed 30.85% or 31.15% of the total catch in terms of num-
bers and weight respectively (Fig. 1). Dominant by catch species was
Symphodus tincawhich composed 31.99% by number and 22.77% by
weight of the catch. Other important species were Scorpaena porcusin
terms of number (9.85%) and Octopus vulgarisin terms of weight
(11.59%).
Fig. 1. Combined catch composition in cuttlefish metier (Patraikos Gulf
96-97).
Cuttlefish,S. tincaandS. porcuswere caught in all stations, whereas O.
v
u
l
g
a
r
i
spresented a frequency of occurrence of 64.7% (Table 1).
Cuttlefish presented the highest mean CPUE by weight (4.11 Kg/1000
fathoms), while by number, it ranged second (22 specimens/1000 fathoms)
with a small difference from S. tincacoming first (23 specimens/1000 fath-
oms).
The lengths of cuttlefish ranged from 85 to 235 mm (ML) in 1996 and
form from 85 to 205 mm in 1997. In both years, the mode appeared at 105
mm (Fig. 2). The lengths of S. tincaranged between 175 and 265 mm
(mode at 215 mm) and between 115 and 285 mm (mode at 205 mm) in
1997.
Table 1.Mean CPUE (number and Kg per 1000 fathoms of netting) and
frequency of occurrence of main species in cuttlefish metier.Numbers
inparentheses
show the Standard Deviations.
The commercial/total catch ratio in 1996 was high both in terms of num-
ber and of weight (0.79 and 0.82 respectively), but in 1997 it was lower
(0.48 and 0.62 respectively). The difference between the two years was due
to the decrease of the catch of cuttlefish and to the increase of that of S.
tinca during the second year.
In the middle part of the panel of the net, 100% of cuttlefish, 90% of S.
tincaand 28% of S. porcuswere caught, whereas in the lower part, 10% of
S. tincaand 72% of S. porcus. Cuttlefish and S. porcuswere mainly caught
entangled (97% and 71%, respectively) whereas S. tincagilled (71%).
Discussion
Cuttlefish metier can be considered species selective since the 5
more abundant species composed about 80% in terms of number and
weight of the total catch. Moreover the marketable part of the catch
composed a high proportion comparing with bottom trawl fishing (1),
whereas it was similar to the sole trammel net metier and hake gill net
metier (2). The main non commercial species was S. tincawhich was
mainly caught gilled opposing to cuttlefish that was caught entangled.
Subsequently, the discarded part could be reduced, without important
losses in the commercial part, by a small increase of the mesh size.
References
1 - Tsimenidis, N., (ed.) 1998. Analysis of trawls' discards operation in
Central and Eastern Mediterranean. Final Report, IMBC.
CUTTLEFISH TRAMMEL NET ‘METIER’IN GREECE
G. Petrakis and C.-Y. Politou*
National Centre for Marine Research, Helliniko, Greece - Gpetr@ncmr.gr, c-y@ncmr.gr
Abstract
The cuttlefish metier was studied in Greek waters with observations on a professional vessel during 1996-1997. Trammel nets with mesh
size of 60 mm in the inner net and of 240 in the outer net were used. Cuttlefish composed 31% by number and weight of the catch.
Symphodus tincawas the dominant by catch species (32% by number and 23% by weight). Cuttlefish presented the highest mean CPUE
(4 Kg/100 fathoms of netting) with ML ranging from 85 to 235 mm. Most cuttlefish were entangled in the middle part of the net. The
commercial/total catch ratio was about 0.80 by number and weight in 1996 and 0.48 by number and 0.62 by weight in 1997.
Keywords : cuttlefish, trammel nets, Greek waters
Species
By NumberBy WeightOccurrence
(%)
Sepia officinalis
22.27 (18.50)4.11 (3.16)100
Symphodus tinca
23.08 !21.05)3.00 (2.51)100
Scorpaena porcus
7.11 ( 6.90)0.77 (0.65)100
Octopus vulgaris
0.94 ( 0.85)1.53 (1.52)64.7
Fig. 2. Length
frequency
distribution
of the two
more abun-
dant
species in
the cuttlefish
metier.
