Survey Results for Greece - area G2 - part 1: Argosaronikos area and Ionian Sea
by Chrissi-Yianna Politou and Eugenia Lefkaditou

  1. General remarks

    2. In the 40 hauls effected in the region of Argosaronikos and the Ionian Sea during Medits-GR 97, 210 animal taxa were identified. From these, the majority were fishes, 50 were crustaceans and 26 were cephalopods.

    A detailed analysis of the results concerning the target species of the project is given below.

  2. Species of the list of reference

    1. Citharus linguatula

      2. It showed low biomass indices mainly in the Ionian Sea. Present in depths between 10 and 200 m. The highest biomass was found in the region of Argosaronikos between 50 and 100 m (20.92 kg/kmē). In the Ionian Sea, its length ranged from 8 to 22 cm with most specimens being larger than 14 cm, whereas in the region of Argosaronikos its length ranged between 7 and 22 with many specimens of length less than 12 cm.

    2. Eutrigla gurnardus

      3. Fished in very low abundance in depths from 50 to 200 only in the region of Argosaronikos. The highest biomass index (2.54 kg/kmē) was obtained for the zone 50 - 100 m.

    3. Helicolenus dactylopterus

      4. Found in depths greater than 200 m. Its abundance was generally low for both regions. The highest value was obtained for the zone 200 - 500 m of the Ionian Sea (22.08 kg/kmē), where its length ranged from 3 to 19 cm. In the region of Argosaronikos its length ranged between 2 and 29 cm.

    4. Lepidorhombus boscii

      5. Found in the slope of both regions presenting the highest biomass index in the zone 200-500 m (7.87 kg/kmē for the region of Argosaronikos and 15.64 kg/kmē for the Ionian Sea). The lengths ranged between 5 and 32 cm for both regions.

    5. Lophius budegassa

      6. Generally abundant in depths between 10 and 500 m, but also present in the zone 500 - 800 m in both regions. Its biomass indices were higher in the zone 200 - 500 m of the Ionian Sea (40.63 kg/kmē) and in the zone 100 - 200 m of the region of Argosaronikos (53.32 kg/kmē). A dominance of immature (less than 30 cm) was observed in both regions, although larger individuals up to 95 cm were also fished.

    6. Lophius piscatorius

      7. Few mainly large specimens were caught in both regions. Although its biomass index reaches 29.09 kg/kmē in the zone 200 -500 of the Ionian Sea and 52.67 in the zone 100 - 200 m of the region of Argosaronikos its presence could be generally characterised as accidental.

    7. Merluccius merluccius

      8. More abundant in the region of Argosaronikos. The highest biomass indices were obtained for depths between 50 and 200 m in the region of Argosaronikos (max. 141.52 kg/kmē for the zone 100 - 200 m). In the Ionian Sea the highest value was 52.39 kg/kmē for the zone 200 - 500 m. A strong presence of young specimens was observed in Argosaronikos.

    8. Micromesistius poutassou

      9. Present in depths greater than 100 m in both regions with maxima biomass indices 43.46 kg/kmē in the zone 200 - 500 m of the region of Argosaronikos and 23.91 kg/kmē in the zone 100 - 200 m of the Ionian Sea. The specimens fished in the zone 100 - 200 m of both regions were of length between 10 and 18 cm, whereas they were larger (20 to 32 cm) in the deeper zones.

    9. Mullus barbatus

      10. Abundant in depths shallower than 100 m, although fished down to depths of 200 m in the region of Argosaronikos. The highest biomass index (288.24 kg/kmē) was observed in the zone 10 - 50 m of the region of Argosaronikos. In this region most specimens caught were of length between 10 and 20 cm, whereas in the Ionian Sea smaller specimens (0-group) were dominant.

    10. Mullus surmuletus

      11. Scarce in the Ionian Sea. Found in depths less than 500 m of the region of Argosaronikos with the highest abundance obtained in the shallowest zone (121.02 kg/kmē). The specimens caught had lengths from 10 to 21 cm.

    11. Pagellus acarne

      12. Found only in the region of Argosaronikos in depths between 50 and 100 m with the maximum biomass index obtained in the shallowest zone (32.31 kg/kmē). The length range was between 9 and 20 cm.

    12. Pagellus bogaraveo

      13. Generally scarce with the highest biomass index observed in the shallowest zone of the region of Argosaronikos (7.53 kg/kmē). The length of the specimens caught ranged between 14 and 32 cm.

    13. Pagellus erythrinus

      14. Found mainly in depths less than 100 m in the Ionian Sea and less than 200 m in the region of Argosaronikos. Generally abundant especially in the shallowest zone (163.45 kg/kmē in Argosaronikos and 30.11 kg/kmē in the Ionian Sea). Its length ranged from 8 to 32 cm with a high presence of specimens smaller than 12 cm observed only in Argosaronikos.

    14. Phycis blennoides

      15. Found in depths greater than 200 m. The highest biomass index (42.66 kg/kmē) was calculated for the zone 500 - 800 m of the Ionian Sea, whereas in the region of Argosaronikos the maximum biomass index was 11.99 kg/kmē in both the zone 200 - 500 m. Its length ranged from 6 to 40 cm in Argosaronikos and from 9 to 44 cm in the Ionian Sea.

    15. Raja clavata

      16. More abundant in Argosaronikos with the highest biomass index calculated for the zone 100 - 200 m (51.81 kg/kmē). In the Ionian Sea the highest biomass index was observed in the same zone (21 kg/kmē). The length of the specimens fished ranged between 14 and 66 cm.

    16. Solea vulgaris

      17. Scarce in Argosaronikos, fished mainly in the Ionian Sea, where it was absent in depths greater than 200 m. Generally of low abundance with maximal value for the zone 10 -50 m (7.53 kg/kmē). Its length ranged between 23 and 40 cm.

    17. Spicara flexuosa

      18. Found only in the Ionian Sea in depths less than 100 m with maximal biomass index in the zone 50 - 100 m (25.34 kg/kmē). The specimens caught had lengths ranging from 8 to 16 cm.

    18. Trachurus mediterraneus

      19. Found in depths less than 200 m with generally low abundance indices. A high biomass index was obtained for the shallowest zone of Argosaronikos (62.96 kg/kmē). Almost all specimens caught in the Ionian Sea were larger than 10 cm, whereas in Argosaronikos there was a dominance of small individuals (<10 cm) in the zone 100 - 200 m.

    19. Trachurus trachurus

      20. Not abundant in the Ionian Sea with a maximum of 6.24 kg/kmē in the zone 100 - 200 m. More abundant in the region of Argosaronikos with the highest biomass indices calculated for the depth zones 10 - 50 m (29.42 kg/kmē) and 100 - 200 m (28.78 kg/kmē). Most specimens caught were juveniles.

    20. Trisopterus minutus capelanus

      21. Fished in depths from 50 to 500 m, but abundant in depths from 100 to 200 m. The highest biomass index (79 kg/kmē) was obtained for the zone 100 - 200 m of the Ionian Sea, whereas in Argosaronikos it reached 42.84 kg/kmē in the same zone. In Argosaronikos, almost all the specimens caught were immature (less than 11 cm length), whereas in the Ionian Sea specimens of length up to 19 cm were fished.

    21. Zeus faber

      22. 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 (30.15 kg/kmē). A high presence of small individuals (<20 cm) was observed.

    22. Aristeus antennatus

      23. It was not fished at all.

    23. Aristaeomorpha foliacea

      24. This species was found in very low abundance (max. 0.43 kg/kmē) in depths from 200 to 800 m in Argosaronikos. It was not fished at all in the Ionian Sea.

    24. Nephrops norvegicus

      25. It was fished in depths between 100 and 500 m. Its abundance was higher in the zone 200 - 500 m (13.35 kg/kmē for the Ionian Sea and 8.05 kg/kmē for Argosaronikos). Most of the specimens caught had carapace lengths from 22 to 50 mm.

    25. Parapenaeus longirostris

      26. This species was fished in depths 50 - 100 m and 200 - 800 m in the Ionian Sea (max. 21.37 kg/kmē in 200 - 500 m) an in higher abundance (max. 39.96 kg/kmē in 100 - 200 m) in depths between 50 and 800 m in Argosaronikos. The carapace lengths ranged from 7 to 37 mm.

    26. Eledone moschata

      27. During the 1997 survey, it was caught only in the region of Argosaronikos in depths up to 121 m, but in greater quantities (>75 kg/kmē) in the stratums 10 - 100 m. Its abundance appeared increased in comparison with the previous years (1994: 5.34 kg/kmē, 1995: 3.35 kg/kmē, 1996: 6.38 kg/kmē, 1997: 10.19 kg/kmē). The mantle lengths ranged from 4 to 14 cm. The length distribution showed two modal peaks. The group of smaller individuals (ML: 4 - 7 cm) was more abundant in the first stratum, whereas that of the larger ones was more abundant in the stratum 50-100 m.

    27. Eledone cirrhosa

      28. Generally present in depths between 50-505 m. In the region of Argosaronikos its abundance is notably higher (100.02 kg/kmē) in the stratum 50-100 m so that its mean abundance in this area appears increased in comparison with that of 1996. In the Ionian Sea the catches of the species are very limited and consist of recruits (ML less than 4 cm). In Argosaronikos the recruits were present at depths between 50-500 m but more abundant in the stratum 100-200 m, while a second mode of larger individuals (ML: 4 - 11 cm) appears in the length frequency in all strata between 50 and 505m of depth.

    28. Illex coindetii

      29. This species was fished in depths between 50 and 500 m in both investigated areas, where the highest abundance indices were observed in the stratum 100-200 m (Ionian Sea: 1.04 kg/kmē, Argosaronikos: 79.75 kg/kmē). In the Ionian Sea, the catches were much lower and consisted mostly of recruits (ML less than 10 cm), whereas in the region of Argosaronikos, several modes within a mantle length range from 2 to 25 cm appeared. Illex coindetii was the most abundant cephalopod species in the continental shelf of Argosaronikos.

    29. Loligo vulgaris

      30. The presence of the species was very scarce in the region of Argosaronikos, where a juvenile was caught in the stratum 100-200 m and two mature individuals in the stratum 10-50 m. In the Ionian Sea, where the catches consisted mostly of recruits (ML less than 10 cm), the greater number of individuals was caught in depths between 50 and 100 m, whereas the catch of greater individuals in depths 10-50 m resulted in a higher biomass index (3.01 kg/kmē) in this stratum.

    30. Octopus vulgaris

      31. It was fished in depths between 10 and 200 m in both investigated areas and the mantle length of the individuals caught ranged from 3 to 16 cm. Octopus vulgaris, as it was also observed in 1996, was the most abundant cephalopod species in terms of weight on the continental shelf of the Ionian Sea , whereas its abundance in the region of Argosaronikos appeared lower this year.

    31. Sepia officinalis

    It was very scarcely caught in depths between 10 and 100 m in the Ionian Sea and only in the first stratum in the region of Argosaronikos. The dorsal mantle length of the individuals caught ranged from 4 to 12 cm.

  3. Comments per stratum

    1. Stratum 10 - 200 m

      2. All the target species, with the exception of Lepidorhombus boscii, and the red shrimp Aristaeomorpha foliacea, were found in this depth zone. Helicolenus dactylopterus was fished in very low quantities in this zone and only in Argosaronikos, whereas Phycis blennoides was scarce in both regions. It must be reminded that Aristeus antennatus was not fished at all in the study areas independently of depth.

      In the Ionian Sea, the highest biomass indices were obtained for the following species by order of importance: Lophius budegassa (24.53 kg/kmē), Mullus barbatus (23.33 kg/kmē), Trisopterus minutus capelanus (22.28 kg/kmē), Pagellus erythrinus (20.81 kg/kmē), Octopus vulgaris (19.28 kg/kmē), Merluccius merluccius (17.70 kg/kmē), and Spicara flexuosa (12.61 kg/kmē). In this area, apart from the earlier mentioned species, Eutrigla gurnardus and Pagellus acarne were not found.

      In the region of Argosaronikos, high biomass indices were obtained for Merluccius merluccius (111.69 kg/kmē) and Mullus barbatus (73.52 kg/kmē), which were followed by Illex coindetii (56.38 kg/kmē), Lophius budegassa (49.23 kg/kmē), Pagellus erythrinus (43.34 kg/kmē), Lophius piscatorius (38.72 kg/kmē), Raja clavata (36.86 kg/kmē), Mullus surmuletus (31.71 kg/kmē) and Trisopterus minutus capelanus (30.49 kg/kmē). Spicara flexuosa was not fished at all in the area independently of depth.

    2. Stratum 200 - 800 m

      3. Only 19 of the target species were found in this stratum, and among these 6 were caught in quantities lower than 1 kg/kmē in both regions.

      In the Ionian Sea, the most abundant by weight species were Merluccius merluccius (32.69 kg/kmē) and Phycis blennoides (30.98 kg/kmē) followed by Lophius budegassa (20.58 kg/kmē), Lophius piscatorius (13.11 kg/kmē), Micromesistius poutassou (12.62 kg/kmē) and Nephrops norvegicus (11.23 kg/kmē).

      The highest biomass index in the region of Argosaronikos was obtained for Merluccius merluccius (48.50 kg/kmē). Other abundant species were Micromesistius poutassou (23.65 kg/kmē), Lophius budegassa (17.80 kg/kmē), Parapenaeus longirostris (11.08 kg/kmē), Illex coindetii (10.30 kg/kmē) and Helicolenus dactylopterus (10.13 kg/kmē).

    3. Discussion

A global analysis of the data of the Ionian Sea, irrespective of depth zones, showed that from the target fish species the most important in weight were Merluccius merluccius (23.94 kg/kmē) and Lophius budegassa (22.89 kg/kmē). Mullus barbatus (13.61 kg/kmē), Trisopterus minutus capelanus (13.00 kg/kmē), Phycis blennoides (12.91 kg/kmē) and Pagellus erythrinus (12.15 kg/kmē) followed. From the cephalopods, Octopus vulgaris (11.25 kg/kmē) was the most abundant, whereas the others were found in very low quantities. Finally, concerning the crustaceans, only Nephrops norvegicus (4.68 kg/kmē) and Parapenaeus longirostris (4.08 kg/kmē) were found. Nevertheless, it must be noted that the two red shrimps that were not fished at all in this area in the framework of this project, were caught in quite high quantities during the surveys of a deep water fisheries project.

In the region of Argosaronikos, the most abundant target fish species were Merluccius merluccius (74.36 kg/kmē), Lophius budegassa (30.66 kg/kmē) and Mullus barbatus (30.09 kg/kmē). Raja clavata (19.53 kg/kmē), Pagellus erythrinus (17.74 kg/kmē), Micromesistius poutassou (17.53 kg/kmē) and Lophius piscatorius (15.85 kg/kmē) followed. Regarding the target species of cephalopods, Illex coindetii (29.16 kg/kmē) was the most abundant with Eledone cirrhosa (6.99 kg/kmē) and Octopus vulgaris (4.36 kg/kmē) following. From the crustaceans, the most abundant species was Parapenaeus longirostris (18.07 kg/kmē), whereas the others were found in very low quantities or were not fished at all (Aristeus antennatus).

These results show the importance of Merluccius merluccius and Lophius budegassa in the Greek waters (similar results were found in other Greek areas, too). Argosaronikos remains an important nursery ground for Merluccius merluccius. This region also remains a rich area showing relatively high abundance indices for many target species.