by Chrissi-Yianna Politou and Eugenia Lefkaditou, Maria Karkani, John Dokos & Costas Papaconstantinou
In the
53 hauls effected in the region of Argosaronikos (21 hauls) and the Ionian Sea
(32 hauls) during the Medits-GR
'99, 188 animal species were identified in the first region and 168 in the
second one. The majority of these species were fishes (121 and 106 species). 47
and 42 species were crustaceans, and 20 and 20 were cephalopods respectively
for the two regions. An analysis of the results concerning the most important and
the target species of the project is given below.
In the
Ionian Sea, the most important fishes in kg/kmē were Chlorophthalmus agassizii (53.61), Helicolenus dactylopterus (34.06), Mullus barbatus (28.90), Spicara
smaris (20,62), Lophius budegassa
(20.41), Galeus melastomus (19.88) Hoplostethus mediterraneus (19.70) and Squalus blainvillei (18.84). In
Argosaronikos, high biomass indices were obtained for Micromesistius poutassou (156.55), Merluccius merluccius (73.01), Capros
aper (71.44), Spicara smaris
(63.58), Argentina sphyraena (53.04),
Trigla lyra (42.42), Trachurus trachurus (38.84), Lophius budegassa (38.68), Raja clavata (32.12), Scyliorhinus canicula (29.95), Boops boops (27.90), Diplodus annularis (25.78), and Mullus barbatus (20.55).
A
detailed analysis concerning the target fish species is given below.
Aspitrigla cuculus
It was
caught in depths from 50 to 200 m in the Ionian Sea and from 50 to
500 m in Argosaronikos. The maximum of its abundance was observed in the
zone 100-200 m for both regions, however its biomass index was higher in
Argosaronikos (24.17 compared to 9.47 in the Ionian Sea). Its length ranged
from 6 to 23 cm in the Ionian Sea and from 4 to 29 cm in Argosaronikos.
A trend of increasing size with depth was evident mainly in Argosaronikos,
where a mode of small specimens (<11 cm) was the only present in the
zone 50-100 m, it was dominant in the zone 100-200 m and completely
absent in the zone 200-500 m.
Citharus linguatula
It
showed generally low biomass indices with the exception of the zone
50-100 m of Argosaronikos (27.91). It was present in depths between 10 and
200 m. Its length ranged from 6 to 22 cm in both regions showing two
length modes in almost all the zones where it was present.
Eutrigla gurnardus
It was
fished in very low abundance on the shelf of the Ionian Sea. In Argosaronikos
it was found in depths from 50 to 200 m with a maximum of 17.02 kg/kmē for
the zone 50-100 m. In the Ionian Sea, mainly small specimens (4-9 cm)
were present, whereas in Argosaronikos, its length ranged from 8 to 23 cm.
Galeus melastomus
This
species was caught mainly (Ionian Sea) or exclusively (Argosaronikos) in the
deepest stratum, where its biomass index was 84.19 in the Ionian Sea and 21.74
in Argosaronikos.
Helicolenus dactylopterus
It was
found in depths greater than 100 m. Its abundance was higher in the
deepest zone of both regions (145.12 kg/kmē in the Ionian Sea and
39.14 kg/kmē in Argosaronikos). Its length ranged from 4 to
33 cm in both regions with lengths increasing with depth.
Lepidorhombus boscii
It was
fished mainly (Argosaronikos) or exclusively (Ionian Sea) on the slope. Its
biomass index was low in the Ionian Sea and higher in the region of
Argosaronikos presenting a maximum in the zone 200-500 m (9.75). The
lengths ranged between 13 and 36 cm in the Ionian Sea and between 7 and 36
in Argosaronikos with the smaller individuals being generally more abundant.
Lophius budegassa
It was
found in all depths of both regions, but it was more abundant in Argosaronikos.
In both regions, it presented the highest biomass index in the shallowest zone
(71.57 in Argosaronikos and 35.98 in the Ionian Sea). In the Ionian Sea, the
lengths ranged from 6 to 64 cm, and in Argosaronikos, they ranged from 4
to 72 cm. Small specimens (<20 cm) were present in all depth
strata with the exception of the deepest one.
Lophius piscatorius
Few
large specimens were caught only in the zone 500-800 m of the Ionian Sea.
Merluccius merluccius
It was
found in all depths of both regions, but it was more abundant in the region of
Argosaronikos. In this region, very high biomass indices were obtained for the
depth zones 50-100 m (236.42) and 100-200 m (182.54), where young
specimens were present almost exclusively. In the Ionian Sea the highest
biomass index was observed in the zone 50-100 m, where specimens of length
ranging between 6 and 39 cm were present. Specimens larger than 40 cm
were found only on the slope of both regions.
Micromesistius poutassou
It was
found in low abundance on the slope of the Ionian Sea with a maximum biomass
index of 13.05 in the deepest zone. In Argosaronikos, it was present in depths
greater than 100 m and showed a particularly high biomass index in the
zone 100-200 m (533.39). Its length ranged from 9 to 38 cm in the
Ionian Sea and from 13 to 33 cm in Argosaronikos, and it increased with
depth.
Mullus barbatus
Abundant
in depths shallower than 200 m in the Ionian Sea and 100 m in
Argosaronikos, although fished down to depths of 500 m. The highest
biomass index was observed in the zone 10-50 m for both regions (150.37
for Argosaronikos and 50.93 for the Ionian Sea). The lengths ranged from 10 to
28 cm and the main bulk of individuals were between 12 and 18 cm for
both regions.
Mullus surmuletus
It was
scarce in the Ionian Sea. In Argosaronikos, it was found in depths shallower
than 500 m with worth mentioning biomass indices obtained in the zone
100-200 m (23.20) and 200-500 m (20.17). The specimens caught had
lengths from 11 to 29 cm.
Pagellus acarne
Found
mainly in the shallowest zone of both regions (81.66 kg/kmē in the Ionian Sea
and 193.81 kg/kmē in Argosaronikos) although present down to 500 m in the
Ionian Sea and in the zone 200-500 m of in Argosaronikos. Its length range
was between 8 and 18 cm.
Pagellus bogaraveo
It was
scarce in Argosaronikos. In the Ionian Sea, it was found mainly on the slope
with the highest biomass index observed in the deepest zone (28.53). The length
of the specimens caught ranged between 13 and 29 cm.
Pagellus erythrinus
It was
found on the shelf of both regions. It was generally more abundant in
Argosaronikos, where it showed the highest biomass index in the zone
50-100 m (82.50). In this zone the specimens caught were of size from 15
to 22 cm. In the shallower zone of this region, the biomass index was also
high (70.97) and an important presence of small individuals (8-15 cm) was
observed. More pronounced was the presence of small specimens in the shallower
zone of the Ionian Sea, where the maximum biomass index was obtained (40.98).
Phycis blennoides
It was
caught mainly on the slope of both regions with the highest biomass index
obtained for the deepest zone (39.79 for the Ionian Sea and 14.16 for
Argosaronikos). Its length ranged from 6 to 56 cm in the Ionian Sea and
from 7 to 43 cm in Argosaronikos with a dominance of small specimens (Ģ15 cm) for both regions.
Raja clavata
This
species was caught in all depth strata of both regions. It was more abundant in
Argosaronikos with higher biomass indices calculated for the zones
100-200 m (57.10) and 200-500 m (42.77). In the Ionian Sea, it was
not abundant and higher biomass indices were obtained in the zones
200-500 m (12.04) and 50-100 m (11.81). The length of the specimens
fished ranged between 10 and 68 cm.
Scyliorhinus canicula
In the
Ionian Sea, it was caught in very low quantities in all strata, and only in the
stratum 200-500 m its abundance was noticeable (14.43 kg/kmē). In
Argosaronikos, it was more abundant, and it was found in depths lower than
100 m with a maximum biomass index in the zone 200-500 m (62.28). Its
length ranged from 10 to 46 cm in both regions.
Solea vulgaris
It was
found only on the shelf of the Ionian Sea with a maximum of biomass index
(12.34) obtained for the shallowest zone.
Spicara flexuosa
It was
found only on the shelf of the Ionian Sea with a maximum of biomass index in
the zone 50-100 m (25.50). The specimens caught had lengths ranging from 8
to 18 cm.
Spicara smaris
In the
Ionian Sea, it was present on the shelf, and the highest biomass index was
obtained for the zone 50-100 m (67.13). Its length ranged from 10 to
19 cm. In Argosaronikos, it showed high biomass indices in the zones
10-50 m (307.03) and 100-200 m (115.63). Its length ranged from 7 to
20 cm.
Trachurus mediterraneus
It was
found on the shelf of both regions. It was more abundant in the Ionian Sea with
a biomass maximum in the zone 50-100 m (51.29 kg/kmē). In Argosaronikos,
its distribution was almost exclusively concentrated in the zone 50-100 m,
where it presented a biomass index of 17.19. In the Ionian Sea, the lengths
ranged mainly between 6 and 17 cm with small specimens (<10 cm)
being present mainly in the zone 100-200 m. In Argosaronikos, there was a
dominance of large individuals (16-21 cm).
Trachurus trachurus
It was
present in depths shallower than 500 m in both regions. It was more
abundant in Argosaronikos with a maximum of biomass index in the zone
100-200 m (129.94). In the Ionian Sea, higher biomass indices were
obtained for the zones 50-100 m (14.37) and 100-200 m (10.69). Most
specimens caught in both regions were juveniles.
Trigloporus lastoviza
It was
found on the shelf of both regions, however its abundance was very low in the
Ionian Sea. In Argosaronikos, it showed a maximum of 55.70 kg/kmē in
the shallowest zone. Its length ranged from 6 to 26 cm.
Trisopterus minutus capelanus
It was
fished in depths from 50 to 500 m of both regions. Its abundance was very
low in Argosaronikos, where almost only immature specimens were found
(<11 cm). In the Ionian Sea, its abundance was somewhat higher though
not exceeding 2.12 kg/kmē. In this region, the specimens caught were of length
from 5 to 22 cm.
Zeus faber
This
species was scarce in the Ionian Sea. In Argosaronikos, it was found in depths from
10 to 500 m, although it was more abundant in terms of weight in the zone
100-200 m (13.91 kg/kmē). A high presence of small individuals
(<20 cm) was observed.
Crustaceans
generally showed low total biomass indices in both regions. In the Ionian Sea
the following species were found by order of importance in kg/kmē: Aristaeomorpha foliacea (6.00), Parapenaeus longirostris (3.69), Plesionika martia (3.08), Liocarcinus depurator (1.51), Aristeus antennatus (1.37), Nephrops norvegicus (0.95), whereas the
biomass indices of the rest species caught were lower than 0.5. In
Argosaronikos, the most important biomass indices were obtained for the
following species: Parapenaeus
longirostris (8.40), Nephrops
norvegicus (8.33), Plesionika martia
(6.31), Munida intermedia (4.17) and Aristaeomorpha foliacea (2.12).
Concerning
the target species of crustaceans, a more detailed analysis follows.
Aristeus antennatus
It was
fished in the deepest zone of both areas, and its biomass index was estimated
5.98 for the Ionian Sea and 1.41 for Argosaronikos. Its carapace length ranged
from 26 to 54 mm in the Ionian Sea and from 29 to 56 in Argosaronikos. .
Aristaeomorpha foliacea
This
species was found in the deepest zone of both regions. In the Ionian Sea, it
was more abundant (26.23 kg/kmē compared to 6.11 kg/kmē of Argosaronikos). Its
carapace length ranged from 19 to 59 mm in the Ionian Sea and from 24 to
60 mm in Argosaronikos.
Nephrops norvegicus
It was
fished mainly on the slope. The highest abundance was observed in the zone
500-800 m of Argosaronikos (20.89 kg/kmē), whereas in the Ionian Sea it
did not exceed 2.69 kg/kmē (500-800 m). Most of the specimens caught had
carapace lengths from 29 to 50 mm.
Parapenaeus longirostris
This
species was fished almost in depths from 50 to 800 m of both regions, but
it was more abundant in depths from 100 to 800 m. Its maximum biomass
index was calculated for the zone 200-500 m of the Ionian Sea (10.46) and
for the zone 100-200 m of Argosaronikos (18.28). The carapace lengths ranged
from 8 to 36 mm in the Ionian Sea and from 7 to 41 mm in
Argosaronikos. In both regions, a mode of small specimens, which exists in the
shallower zones of the species distribution, does not appear in the deepest
stratum.
The most
important cephalopods in the Ionian Sea were in kg/kmē: Alloteuthis media (7.37), Octopus
vulgaris (6.76), Illex coindetii
(6.15), Eledone cirrhosa (3.36) and Loligo forbesi (3.23). In Argosaronikos,
Illex coindetii (32.23) showed a high
biomass index followed by Octopus
vulgaris (10.40), Eledone moschata
(8.59) and Eledone cirrhosa (7.01).
An
analysis by target species is given bellow.
Eledone cirrhosa
It was
fished in depths between 50 and 500 m in Argosaronikos. It showed an
exceptionally high biomass index (104,3 kg/kmē) in the stratum 50-100 m,
where relatively large individuals (VML: 6-18 cm) were caught. Smaller
individuals (VML: 1-5 cm) were present in the zone 100-500 m. In the
Ionian Sea, it was mainly caught down to 100 m of depth its biomass being
equally distributed and reaching the 7 kg/kmē in the two depth strata. The
ventral mantle length of the individuals caught ranged from 2 to 11 cm.
Eledone moschata
In the
Ionian Sea it was scarcely caught in depths between 10 and 100 m. In
Argosaronikos, its overall biomass index reached 8,59 kg/kmē, but it was more
abundant in depths down to 100 m. Its biomass index (21 kg/kmē) in the
zone 10-200 m was the highest observed among the Medits areas during the survey 99. Its mantle length ranged
between 4 and 14 cm. The larger individuals (VML >7 cm) were more
abundant in the first stratum resulting to a higher biomass index (75,87
kg/kmē).
Illex coindetii
In both
areas it was found in all five strata, but it was more abundant in the stratum
200-500 m (Argosaronikos: 75,7 kg/kmē, Ionian Sea: 20,80 kg/kmē). In
Argosaronikos, it presented the highest overall abundance indices (32.2 kg/kmē,
895 N/kmē) among the cephalopod target species. The larger individuals (DML:
11-21 cm) were widely distributed in both regions, whereas the smaller
ones (DML: 3-10 cm) were caught down to 500 m of depth in the Ionian
Sea and were mainly distributed between 100 and 200 m in Argosaronikos.
Loligo vulgaris
The
juveniles (DML< 8 cm) composed the bulk of the individuals caught. In
the region of Argosaronikos, only three individuals were caught in the first
stratum. In the Ionian Sea, it showed the highest density index (1252 N/kmē),
among the cephalopod target species in the zone 10-200 m, due mainly to
the high recruitment observed in the narrow continental shelf of the
Korinthiakos Gulf.
Octopus vulgaris
In the
Ionian Sea, the species biomass was equally distributed in the first three
depth strata, the mean biomass index of the zone 10-200 reaching the 11, 6
kg/kmē. In Argosaronikos, it was fished in depths shallower than 200 m
showing a higher biomass index in the first stratum (90,2 kg/kmē) where it was
the most abundant cephalopod species in terms of biomass. Its ventral mantle
length ranged between 4 and 16 cm.
Sepia officinalis
It was
fished very scarcely in the shallows (<100 m) of the studied regions.
The specimens caught had dorsal mantle lengths ranging from 3 to 9 cm in
the Ionian Sea and from 11 to 13 cm in the region of Argosaronikos.
In the shallowest
stratum, 40 fish species were caught in the Ionian Sea and 44 in Argosaronikos.
The most abundant fishes of the Ionian Sea in kg/kmē were Pagellus acarne (81.66), Mullus
barbatus (50.93), Diplodus annularis
(45.13), Pagellus erythrinus (40.98),
Lophius budegassa (35.98), Raja asterias (33.08) and Serranus hepatus (25.14). In
Argosaronikos, the highest biomass indices were obtained for the following
fishes: Spicara smaris (307.03), Diplodus annularis (258.18), Pagellus acarne (193.81), Mullus barbatus (150.37), Epinephelus aeneus (84.18), Lophius budegassa (71.57), Pagellus erythrinus (70.97), Spicara maena (59.02), and Trigloporus lastoviza (55.70).
From the
crustaceans, 15 species were found in the Ionian Sea, from which the most
abundant was Dorippe lanata with
biomass index 2.32. In Argosaronikos, 5 species were found in negligible
quantities.
Concerning
cephalopods, 9 species were caught in the Ionian Sea, from which the most
abundant were Alloteuthis media
(15.29) and Octopus vulgaris (13.29).
In Argosaronikos, 6 cephalopod species were caught in this stratum, from which Octopus vulgaris (90.23 kg/kmē) and Eledone moschata (75.87 kg/kmē) were
particularly abundant.
In this
stratum, 55 fish species were caught in the Ionian Sea and 51 in Argosaronikos.
The species with the highest biomass indices in the Ionian Sea were Spicara smaris (67.13), Trachurus mediterraneus (51.29), Mullus barbatus (50.00), Mustelus mustelus (26.11), Lophius budegassa (25.84), Spicara flexuosa (25.50), Merluccius merluccius (22.86), and Lepidotrigla cavillone (22.00). In
Argosaronikos, the following fishes were the most abundant in kg/kmē: Merluccius merluccius (236.42), Mullus barbatus (83.56), Pagellus erythrinus (82.50), Serranus hepatus (55.94), Sardina pilchardus (32.92), Lophius budegassa (28.26) and Citharus linguatula (27.91).
Concerning
crustaceans, 13 species were identified in the Ionian Sea and 11 in
Argosaronikos. Low biomass indices were obtained for the Ionian Sea with
highest values 3.26 for Liocarcinus
depurator and 1.67 for Parapenaeus
longirostris, whereas in Argosaronikos, a biomass index of 38.63 was
calculated for Liocarcinus depurator.
10
cephalopod species were found in the Ionian Sea and 10 in Argosaronikos. In the
Ionian Sea, the most abundant cephalopods were Alloteuthis media (10.78 kg/kmē) and Octopus vulgaris (10.40 kg/kmē) with Loligo vulgaris (7.18 kg/kmē) and Eledone cirrhosa (7.00 kg/kmē) following. In Argosaronikos, the
highest biomass index was calculated for Eledone
cirrhosa (104.28) with Octopus
vulgaris (62.24), Illex coindetii
(43.99) and Eledone moschata (26.56)
following.
In the
Ionian Sea, 48 fish species were caught in this depth stratum, whereas 69 were
identified in Argosaronikos. In the Ionian Sea, the highest biomass indices
were obtained for Mullus barbatus
(45.88), Macrorhamphosus scolopax
(24.94), Lophius budegassa (23.82), Argentina sphyraena (19.16), Lepidotrigla dieuzeidei (15.84), Spicara smaris (10.83) and Trachurus trachurus (10.69). In Argosaronikos,
a very high biomass index was obtained for Micromesistius
poutassou (533.39) and it was followed by Merluccius merluccius (182.54), Trachurus
trachurus (129.94), Spicara smaris
(115.63), Boops boops (90.73), Raja clavata (57.10), Lophius budegassa (55.84), Dentex maroccanus (36.59), Scyliorhinus canicula (29.26), Lepidopus caudatus (26.93), Serranus hepatus (25.13), Aspitrigla cuculus (24.17), Mullus surmuletus (23.20), Pagellus erythrinus (18.53), Serranus cabrilla (17.19), Argentina sphyraena (16.14) and Zeus faber (13.91).
From the
crustaceans identified in that stratum (10 species in the Ionian Sea and 17 in
Argosaronikos) Parapenaeus longirostris
was the most abundant species in both regions (6.25 kg/kmē in the Ionian Sea
and 18.28 kg/kmē in Argosaronikos). Second in abundance was Liocarcinus depurator (2.35 kg/kmē) in
the Ionian Sea and Munida iris (6.16 kg/kmē) in Argosaronikos.
Concerning
cephalopods, 9 species were caught in the Ionian Sea with the highest biomass
indices obtained for Octopus vulgaris
(11.67) and Alloteuthis media (9.65).
In Argosaronikos, 11 species were found, from which Illex coindetii (36.03) and Eledone
cirrhosa (11.49) showed the highest biomass indices.
From the
49 fish species caught in this stratum in the Ionian Sea, Squalus blainvillei (47.23) showed the highest biomass index,
whereas Capros aper (22.73), Argentina sphyraena (17.96) and Lophius budegassa (15.76) followed. In
Argosaronikos, 53 fish species were identified, from which Capros aper showed the highest biomass index (291.73). Other
species with high biomass indices were: Argentina
sphyraena (197.84) and Trigla lyra
(173.44) followed by Scyliorhinus
canicula (62.28), Squalus blainvillei
(55.08), Peristedion cataphractum
(44.38), Raja clavata (42.77), Mullus surmuletus (20.17), Raja oxyrinchus (20.13), Scorpaena elongata (19.97), Chlorophthalmus agassizii (19.79) and Nezumia sclerorhynchus (17.44).
18 and
28 species of crustaceans were identified in this stratum in the Ionian Sea and
in Argosaronikos respectively. In the Ionian Sea, only Parapenaeus longirostris showed a worth mentioning biomass index
(10.46). In Argosaronikos, the most abundant species were Munida intermedia (17.11 kg/kmē), Plesionika edwardsii (4.04 kg/kmē) and Nephrops norvegicus (3.29 kg/kmē).
From the
15 species of cephalopods caught in the Ionian Sea, Illex coindetii (20.76) and Loligo
forbesi (14.34 kg/kmē) were the most important. In Argosaronikos, also 15
species were found, however Illex
coindetii was dominating (75.74 kg/kmē).
40 fish
species were caught in the Ionian Sea, from which very abundant were Chlorophthalmus agassizii (222.23
kg/kmē) and Helicolenus dactylopterus
(145.12 kg/kmē). High biomass indices were also obtained for Hoplostethus mediterraneus (86.02), Galeus melastomus (84.19), Squalus blainvillei (43.59), Phycis blennoides (39.79), Lophius piscatorius (38.73), Peristedion cataphractum (35.16), Pagellus bogaraveo (28.53), Conger conger (28.12), coelorhynchus coelorhynchus (21.05) and Merluccius merluccius (20.29 kg/kmē). In
Argosaronikos, 40 fish species were caught, from which the most important in
kg/kmē were Helicolenus dactylopterus
(39.14), Heptranchias perlo (37.97), Lophius budegassa (35.88), Merluccius merluccius (34.89), Trachyrhynchus trachyrhynchus (34.35), Chimaera monstrosa (28.99), Coelorhynchus coelorhynchus (26.76), Galeus melastomus (21.74), and Scyliorhinus canicula (18.39).
21
species of crustaceans were identified in the Ionian Sea, and the most abundant
were Aristaeomorpha foliacea (26.23
kg/kmē), Plesionika martia (12.47
kg/kmē) and Aristeus antennatus (5.98
kg/kmē). In Argosaronikos, the crustacean species were 17 and the most abundant
were Nephrops norvegicus (20.89
kg/kmē), Plesionika martia (17.97
kg/kmē), Parapenaeus longirostris
(7.79 kg/kmē), and Aristaeomorpha
foliacea (6.11 kg/kmē).
7
species of cephalopods were caught in the Ionian Sea; the most abundant of
which was Todarodes sagittatus (12.58
kg/kmē) with Loligo forbesi (2.33
kg/kmē) being second. In Argosaronikos, 12 species of cephalopods were caught
and Illex coindetii (5.22 kg/kmē) was the most important.
A global
analysis of the data showed that concerning fish, the species number was lower
in the deepest and shallowest zones for both regions. Argosaronikos was an area
with generally higher species number and abundance of many target species
compared to the Ionian Sea. However, it must be underlined that this year, the
deepest stratum of the Ionian Sea was richer in fish comparing to the shallower
strata of this region and to the deepest stratum of Argosaronikos, and it
showed high abundance indices for some target species.
Referring
to crustaceans, they generally showed low abundance, whereas the quantities
caught were negligible in the shallowest stratum of both areas. The richest
stratum for crustaceans was the deepest one for both regions, where the highest
biomass indices were obtained for most target species. It must be also noted
that for the first time this year Aristeus
antennatus was caught in Argosaronikos.
Concerning
cephalopods, their abundance was generally higher in Argosaronikos, where high
biomass indices for some target species were obtained in depths shallower than
100 m. The deepest stratum of both regions was the poorest in cephalopods,
however the relatively high presence of Todarodes sagittatus in this stratum of
the Ionian Sea must be underlined.
According
to the above results, Argosaronikos remains an area showing generally higher
species number and abundance for many target species compared to the Ionian
Sea. However, this year, the deepest stratum of the Ionian Sea was found to be
richer in fishery resources than that of Argosaronikos.