Biol. Mar. Medit. (2003), 10 (2): 874-881
S. Ragonese, F. Cigala Fulgosi1, M.L. Bianchini2, G. Norrito, G. Sinacori
Ist. Risorse Marine ed Ambiente, CNR, Via L. Vaccara, 61 - 91026 Mazara del Vallo, Trapani, Italia.
1
Università di Parma, Italia.
2
CNR e Soc. Porto Romano, Roma, Italia.
ANNOTATED CHECK LIST OF THE SKATES (CHONDRICHTHYES,
RAJIDAE) IN THE STRAIT OF SICILY (CENTRAL MEDITERRANEAN)
LISTA COMMENTATA DELLE RAZZE DELLO STRETTO DI SICILIA
(MEDITERRANEO CENTRALE)
Abstract
A list of skates of the Strait of Sicily was prepared on the basis of the literature and data collected in 15 years (19852001) of scientific bottom trawl surveys. Of the 16 skate species known for the Mediterranean Sea, 14 were positively
identified in the area and their bathymetric range extended. Missing is Raja rondeleti, while the identification of a
specimen of R. naevus is doubtful. Some species (e.g., R. miraletus, R. clavata) are still very common in spite of the
high level of exploitation, whereas others were rare (R. fullonica and R. undulata) or have been strongly reduced.
Key-words: skates, Raja sp., bottom trawl, Strait of Sicily, Mediterranean Sea.
Introduction
In the Mediterranean Sea, skates (sensu Hamlett, 1999) are traditionally and frequently taken with long lines, trolling lines, bottom set net and obviously bottom
trawls; they normally represent, as a whole, a low valued by-catch of the present
demersal fisheries (Ragonese et al., 2000). Many species are edible and the most
valuable species is the thornback skate Raja clavata, which is locally very appreciated
(Minervini et al., 1985). Skates, however are generally discarded or eaten by the crew
in the Sicilian long-range fisheries. The current abundance of skates on the trawlable
bottoms may be an indicator of biocenotic and environment stress; in fact, the lower
growth rates and fecundity and the high age and length at maturity make the skates
very sensible to fishing pressure (Walker, 1996). Examples of population reduction
have been piled up in the last decade both outside and inside the Mediterranean Sea
(Stevens et al., 2000; Vacchi and Notarbartolo di Sciara, 2000). Given the difficulties
in distinguishing and correctly classifying species (Bini, 1967), the aim of this note is
to make a review of the status of knowledge about local skates starting with the few
data published (Relini et al., 2000).
Materials and methods
Historical reports and data collected during 15 years (1985-2001) of scientific
trawls, carried out by IRMA/CNR in the Strait of Sicily (Fig. 1) in the 10-800 m
depth range, representing over 1000 1-hour hauls from 23 trawl surveys, have been
examined. The principal characteristics of the GRUND and MEDITS sampling procedures are reported in Relini (1995), Relini et al. (1999) and Bertrand et al. (2000). The
skate specimens have been classified by various experts, on board and in the laboratory, using the keys of Tortonese (1956), Stehmann and Burkel (1984) and Bauchot (in
Fischer et al., 1987). The systematics of the Rajidae is under revision: the most recent
nomenclature (F. Serena, pers. comm.) is reported in Tab. 1, while shorter names are
Check list of skates in the Strait of Sicily
875
used in the text. Yields have been expressed as fishable abundance and biomass indexes
(N/km2; kg/km2) for the whole skate category (Raja sp.).
226-Fig. 1
Fig. 1 – The Strait of Sicily with evidenced the limits of both shelf (200 m) and explored (800 m) area.
Lo Stretto di Sicilia con evidenziata la piattaforma (<200 m) ed il limite inferiore dell’area esplorata
(800 m).
Tab. 1 - L
ist of the skates reported or collected by scientific trawls in the Strait of Sicily. Frequency in
% over 23 trawl surveys. Species already reported by: * Ragonese et al., 2000; ^ Cannavò et
al., 1999; “ Relini, 1995; # Pipitone et al., 1992. ° denotes endemic species; a unique specimen reported as Raja africana was not accounted for, since the species is now considered as
“not valid” (F. Serena, pers. comm.).
226-Tab. 1
Elenco delle specie di razze riportate o catturate nelle campagne scientifiche nello Stretto di Sicilia.
Frequenza in % su 23 campagne di strascico. Specie già riportate da: * Ragonese et al., 2000; ^
Cannavò et al., 1999; “ Relini, 1995; # Pipitone et al., 1992.  indica le specie endemiche; un unico
esemplare, classificato come Raja africana, non è stato considerato poiché la specie non è più ritenuta
valida (F. Serena., com. pers.).
Taxon
Rajidae
Raja (Dipturus) batis L. 1758
Raja (Dipturus) oxyrinchus L. 1758
Raja (Leucoraja) circularis Couch 1838
Raja (Leucoraja) fullonica L. 1758
Raja (Leucoraja) melitensis° Clark 1926
Raja (Leucoraja) naevus Muller & Henle 1841
literature freq. depth range (m)
size range
similarity with other skates, basic features, remarks
% overall - surveys total length, mm
"
* ^ "
^ "
*
* ^ "
Raja rondeleti° Bougis 1959
Raja (Raja) asterias Delaroche 1809
#
#
#
#
^ "
Raja (Raja) brachyura Lafont 1873
Raja (Raja) clavata L. 1758
Raja (Raja) miraletus L. 1758
Raja (Raja) montagui Fowler 1910
Raja (Raja) polystigma° Regan 1923
Raja (Raja) radula Delaroche 1809
Raja undulata Lacépède 1802
^
* ^
^
^
^
^
"
"
"
"
"
"
Raja (Rostroraja) alba Lacépède 1803
*
"
#
#
#
61
83
52
4
87
0
30-600
90-900
70-275
30-600
60-800
20-250
31-714
30-773
31-702
-39831-817
-
145-1280
105-1150
180-910
610-800
90-420
-
0
78
10-100
10-300
12-580
90-565
21
96
100
87
22
22
4
10-100
10-300
10-300
10-100
90-400
10-300
10-200
73-364
31-763
20-634
31-725
66-525
30-557
-56-
185-990
85-1100
75-625
105-615
225-500
185-500
n.a.
78
40-500
31-672
165-1550
R. oxyrinchus; black belly
R. batis - R. alba
well distinct
R. rondeleti
R. naevus
R. melitensis - R. miraletus – R. polystigma - R. radula; reported in
Pipitone et al. (1992), likely as misclassification of R. melitensis
R. fullonica; boucles of spines numerous and regular
R. brachyura- R. montagui; black and white (not on margin) points; one
specimen reported at 721 m.
R. clavata - R. montagui; white spots with black points around
R. brachyura - R. montagui - R. polystigma
R. clavata - R. naevus; generally small
R. brachyura - R. polystigma
R. montagui - R. radula
R. polystigma
Also as R. ondulata; unmistakable; very rare, and never reported before
for the area
R. oxyrinchus
S. Ragonese, F. Cigala Fulgosi, M.L. Bianchini, G. Norrito, G. Sinacori
876
Results
Of the 17 species of skates recorded for the Mediterranean Sea, R. africana (Capapé
1977) is now considered a “non-valid species” (F. Serena, pers. comm.), and 14 were
positively identified at least once in the trawl surveys catches. Only R. rondeleti, a
skate with boucles of regular spines which is a Mediterranean endemism (but might
just be a variety of R. fullonica), was never found or reported. Pipitone et al. (1992)
quoted an individual of R. naevus, but their identification is probably a misclassification
(R melitensis?). The annotated list of the valid species reported is presented in Tab 1;
the distribution of the catches inside the Strait of Sicily is reported in Tab 2; peculiar
remarks for some species follow.
Tab. 2 – Major locations of the positive hauls for skates (Raja sp.) in the Strait of Sicily.
226-Tab. 2
Principali localizzazioni delle cale positive per le razze (Raja sp.) nello Stretto di Sicilia.
Taxon
Raja (Dipturus) batis L. 1758
Raja (Dipturus) oxyrinchus L. 1758
Raja (Leucoraja) circularis Couch 1838
Raja (Leucoraja) fullonica L. 1758
Raja (Leucoraja) melitensis° Clark 1926
Raja (Leucoraja) naevus Muller & Henle 1841
Raja rondeleti° Bougis 1959
Raja (Raja) asterias Delaroche 1809
Raja (Raja) brachyura Lafont 1873
Raja (Raja) clavata L. 1758
Raja (Raja) miraletus L. 1758
Raja (Raja) montagui Fowler 1910
Raja (Raja) polystigma° Regan 1923
Raja (Raja) radula Delaroche 1809
Raja undulata Lacépède 1802
Raja (Rostroraja) alba Lacépède 1803
Major locations
sparse, mainly E of Malta, absent around Pantelleria (never caught with the MEDITS gear)
ubiquitarian
sparse, mainly SE of Malta (never caught with the MEDITS gear)
only two locations, S and far of Malta and near Linosa
ubiquitarian
absent
absent
sparse, but highly concentrated in the southern coast of Sicily
few hauls S of Egadi and one SE of Malta (never caught with the MEDITS gear)
ubiquitarian
concentrated E of Malta, S of Lampedusa and between Egadi and Pantelleria
ubiquitarian, with concentrations S and E of Malta and between Egadi and Pantelleria
sparse, mainly S of Malta
sparse, with concentration S of Lampedusa
only one location, S and close of Lampedusa
sparse S of Malta and Lampedusa, and concentrated between Egadi and Pantelleria
The most common (% of scientific trawls) Rajidae are R. miraletus (100%),
R. clavata (96%), R. oxyrinchus (83%), R. montagui (87%), R. melitensis (87%); this
last species, together with R. polystigma, are the other two Mediterranean endemisms.
Of the rarest species, only one specimen of R. undulata, and three of R. fullonica have
been collected.
Some specimens of the longnosed skate, R. oxyrinchus, caught between 500-700 m,
showed a snout lenght/interorbital length ratio shorter than the expected (2.9-4.6 vs.
5.5-7, according to Whitehead et al., 1986), but all the other characteristics did correspond to those expected.
The shagreen skate, R. fullonica, was not included in the checklists available for the
Strait of Sicily. It must be pointed out that the characterization of this species, considered as a transient species between short- and long-snout skates, (Bini, 1967) was and
still is debated; it may be confused with R. rondeleti. Three specimens were assigned
to this species; two skates were collected together in 2001, south and far of Malta at
around 400 m of depth; the third one, a small individual (650 g), with some diagnostic
Check list of skates in the Strait of Sicily
877
differences concerning the shape of the disc margins and the lacking of spines on the
shoulders (characters, however, already considered highly variable with age and size),
was caught in 1993, during a trawl survey aiming at selectivity studies (Ragonese et
al., 2000), NW of Linosa at 608 m.
The Maltese skate, R. melitensis, is a small species occurring over sandy and sandymuddy bottoms from few meters down to 800 m and more. It resembles superficially
R. naevus, but the eye spots are less distinct and the median row of spinules stops at
the hindermost portion of the tail. Endemic in the area, it is occasionally found in the
Sicilian markets (Cannavò et al., 1999).
The thornback skate, R. clavata, is frequently caught in the trawl surveys carried
on in the Strait of Sicily, but almost always catches are composed by few specimens,
as already historically reported (Arena and Li Greci, 1973). This is the only skate
for which some local demographic parameters were estimated (females: L∞ = 126 cm,
K/year = 0.098 and t0, year = –0.512; males: 116.7, 0.106 and –0.412; Cannizzaro et al.,
1995); its female sex-ratio is 44.3%. The length-frequency distribution by sex, from
data collected during the MEDITS surveys (1994-2001), is shown in Fig. 3; on average,
at least for this sample, the Sicilian thornback skates individuals are larger (40-70 cm)
than the Tyrrhenian ones (30-42 cm; page 91 of Relini et al., 1999).
226-Fig. 2
Raja spp. (10 - 200 m)
MEDITSIT spring
125
kg/km2
100
GRUND spring
GRUND autumn
75
50
25
0
1993
1994
1995
1996
1997
1998
1999
2000
2001
year
Raja spp. (201-800 m)
MEDITSIT spring
GRUND spring
GRUND autumn
125
kg/km2
100
75
50
25
0
1993
1994
1995
1996
1997
1998
1999
2000
2001
year
Fig. 2 – E
volution (1994‑2001), according the MEDITS and GRUND cruises, of the mean indexes of
fishable biomass (kg/km2) for the whole skate group (Raja sp.) in the Italian side of the Strait
of Sicily, by depth strata (shelf, 10‑200 m; slope, 201‑800 m).
Andamento degli indici medi di biomassa (kg/km2) pescabile delle razze (Raja sp.) del versante
italiano dello Stretto di Sicilia catturate nei programmi MEDITS e GRUND, divisi per piattaforma
(10‑200 m) e scarpata (201‑800 m), dal 1994 al 2001.
S. Ragonese, F. Cigala Fulgosi, M.L. Bianchini, G. Norrito, G. Sinacori
878
The spotted skate, R. montagui, and the Mediterranean endemic speckled skate,
R. polystigma, are frequently confused because of the high variability and similarity
of their characters (Quignard and Capapé, 1971); these medium-sized skates are frequently marketed.
R. undulata, of unmistakable coloration, was collected only in autumn 1985. It was
a single specimen of 600 g, caught in the southern fishing ground near Lampedusa at
56 m of depth, after a difficult and irregular tow. This is the first time this very rare
species (Bini, 1967) is reported for the Strait of Sicily.
The white skate, R. alba, is a large, “long nose” species, distinguishable for the
white ventral coloration (except on the disc margins) without black marked mucous
pores. While quite common (78% of the surveys), R. alba was not reported in the list
compiled by Bombace and Sarà (1972) and Arena and Li Greci (1973) for the Strait
of Sicily.
One of the results of these scientific cruises has been the enlargement (Tab. 1) of
the conventional bathymetric range (Fisher et al., 1987) of various skate species; in
particular, R. brachyura and R. montagui, generally considered as shallow-shelf dwellers (up to 100 m), were also captured on the upper-slope bottoms.
Referring to the whole Rajidae resources, Tab. 3 shows the fishable abundance and
biomass indexes by surveys (1994-2001), divided by depth strata (shelf, 10-200 m;
slope, 201-800 m); data indicate a relative stability on the shelf, and apparent decreasing trends on the slopes (Fig. 2). It must be noted that the MEDITS gear is different
from the trawl net used in the GRUND surveys, and is less efficient for the capture of
benthonic species, particularly on the deeper slope grounds.
Tab. 3 – M
ean indexes of fishable abundance (N/km2) and biomass (kg/km2) for the whole skate group
(Raja sp.) in the Italian side of the Strait of Sicily, by depth strata (shelf, 10‑200 m; slope,
201‑800 m); data from MEDITS (spring) and GRUND (spring and autumn), 1994‑2001.
CV% is the coefficient of variation (s.e./mean*100).
Indici medi di abbondanza in numero (N/km2) e peso (kg/km2) per la pesca riferiti all’insieme delle
razze (Raja sp.) nel versante italiano dello Stretto di Sicilia, sulla base delle campagne scientifiche
(1994‑2001) realizzate nell’ambito dei programmi MEDITS (primavera) e GRUND (primavera ed
autunno); i valori si riferiscono alla piattaforma (10‑200 m) e alla scarpata (201‑800 m). CV(%) è
il coefficiente di variazione (s.e./media*100).
226-Tab. 3
10-200 m
year
1994
1994
1994
1995
1995
1995
1996
1996
1997
1997
1998
1998
1999
2000
2000
2001
2001
survey
MEDITS
GRUND
GRUND
MEDITS
GRUND
GRUND
MEDITS
GRUND
MEDITS
GRUND
MEDITS
GRUND
MEDITS
MEDITS
GRUND
MEDITS
GRUND
season
spring
spring
autumn
spring
spring
autumn
spring
autumn
spring
autumn
spring
autumn
spring
spring
autumn
spring
autumn
201-800 m
10-200 m
201-800 m
N/km2 CV (%) N/km2 CV (%) kg/km2 CV (%) kg/km 2 CV (%)
51
38.9
3
37.7
18.5
39.7
2.6
33.2
193
25.4
87
36.8
52.2
21.6
44.0
31.9
130
26.7
56
27.8
34.6
21.4
50.0
18.0
132
40.1
7
47.9
27.8
29.0
9.5
64.7
142
20.8
247
49.8
38.9
18.4 105.1
31.5
189
27.8
120
27.0
47.7
21.5
78.3
27.7
126
35.8
2
28.0
26.0
31.8
2.8
42.9
225
29.7
40
35.4
42.4
27.3
21.1
24.8
229
41.9
8
29.0
41.3
31.0
7.9
42.5
129
25.9
50
59.1
48.9
22.6
26.6
28.5
93
45.1
13
40.6
22.8
52.9
7.6
36.3
230
41.0
41
22.7
63.3
33.6
26.6
22.0
55
39.2
11
57.1
21.3
29.0
6.4
64.7
166
67.5
13
65.3
40.8
51.4
6.2
40.3
293
38.6
12
39.3
97.9
39.1
14.0
37.4
64
37.4
11
42.5
22.7
31.5
7.2
37.2
106
27.7
12
29.2
50.6
30.8
11.6
44.0
Check list of skates in the Strait of Sicily
879
226-Fig. 3
Fig. 3 – L
ength‑frequency distribution (TL; cm) by sex of Raja clavata from data collected in the
Italian side of the Strait of Sicily during the MEDITS surveys (1994‑2001).
Distribuzioni di frequenza di lunghezza (TL; cm) di Raja clavata, divise per sesso, per il versante
italiano dello Stretto di Sicilia; dati raccolti durante le campagne MEDITS (1994‑2001).
Conclusions
Given the high individual polymorphism observed in this group, as already evidenced by many ichthyologists (Tortonese, 1956; Bini, 1967), the classification has
not been always easy. In fact, neither the phyletic relationships nor the general life
cycle of skates are well understood, and discrepancies, ambiguities and contrasts were
encountered in using the different available keys. As a matter of fact, beside the natural
variability (i.e. anomalies cannot be excluded), the distinctive features mainly used,
such as the number and distribution pattern of thorns and thornlets, the presence of
dots and eye-spots on the disc, can show differences in the same species according to
the age and sex; even the eye-spots, considered distinctive characteristics of a species,
can be absent.
In conclusion, the species occurring in the Strait of Sicily at the present state
of knowledge result to be: Raja miraletus, R. clavata, R. melitensis, R. montagui,
R. oxyrinchus, R. asterias and R. alba, very common; R. batis and R. circularis,
common; R. brachyura, R. polystigma and R. radula, seldom captured; R. fullonica
and R. undulata, rare.
Present results confirm the great adaptability of skates to depth variations and warn
of the overall decline of many species.
Referring to the still relatively high numerical consistency of some skate species on
heavily exploited grounds, one explanation of their persistence could be the increase
880
S. Ragonese, F. Cigala Fulgosi, M.L. Bianchini, G. Norrito, G. Sinacori
in food availability as a consequence of discards; a more frequent scavenger behaviour
and a reduction in size and age of maturity might partially compensate the negative
effects of the high fishing pressure. Another explanation could be the existence of
strongholds where skates cannot be fished; in fact, the presence of such natural sanctuaries may be the major reason which have precluded the full collapse of these stocks.
Given the low commercial value of skate and the full retention in the cod-end of the
currently used gears, that remain unchanged up to unproposeable (for the Mediterranean fisheries) mesh size (> 60 mm opening; Ragonese et al., 2001), the only management measure aimed at their sustainable use may be to define the suitable not-trawlable
areas and enlarge these “closed” spots, in order to protect a fraction of the population
and likely the eggs (all Rajidae are oviparous, laying down large horny rectangular
egg-cases, often found in the trawl cod-end).
References
ARENA P., LI GRECI F. (1973) - Indagine sulle condizioni faunistiche e sui rendimenti di pesca dei
fondali batiali della Sicilia occidentale e della bordura settentrionale dei banchi della soglia siculotunisina. Quad. Lab. Tecnologia Pesca, 1 (5): 157-201.
BERTRAND J., GIL DE SOLA L., PAPAKOSTANTINOU C., RELINI G., SOUPLET A. (2000) Contribution on the distribution of elasmobranchs in the Mediterranean (from the MEDIT surveys).
Biol. Mar. Medit., 7 (1): 1-15.
BINI G. (1967) - Atlante dei pesci delle coste italiane: Leptocardi, Ciclostomi, Selaci. Mondo Sommerso Ed., 1: 206 pp.
BOMBACE G., SARÀ R. (1972) - La pesca a strascico sui fondali da -500 a -700 metri nel settore a
Sud-Est di Pantelleria. Mem. Min. Mar. Merc., 33: 77 pp.
CANNAVÒ G., D’ANDREA F., GIORDANO D., HERMIDA F., ROMEO T. (1999) - Alcune osservazioni sulle razze nel Mediterraneo Centrale. Biol. Mar. Medit., 6 (1): 534-536.
CANNIZZARO L., GAROFALO G., LEVI D., RIZZO P., GANCITANO S. (1995) - Raja clavata
(Linneo, 1758) nel Canale di Sicilia: crescita, distribuzione e abbondanza. Biol. Mar. Medit., 2
(2): 257-262.
FISCHER W., BAUCHOT M.-L., SCHENEIDER M. (1987) - Fiches FAO d’identification des espèces
pour les besoins de la pêche (rev.1): Méditerranée et Mer Noire. Rome, FAO: 1530 pp.
HAMLETT W.C. (1999) - Sharks, Skates, and Rays. The Biology of the Elasmobranch Fishes. The
John Hopkins Univ. Press, Baltimore and London: 516 pp.
MINERVINI R., GIANNOTTA M., BIANCHINI M.L. (1985) - Observations on the fishery of Rajformes in Central Tyrrhenian Sea. Oebalia, 11 (2): 583-591.
PIPITONE C., BADALAMENTI F., BARBERA G., D’ANNA G., GRISTINA M. (1992) - Fish fauna
of the trawlable mesobathyal grounds in the Sicilian Channel. Oebalia, 17 (Suppl.): 151-153.
QUIGNARD J.P., CAPAPÉ C. (1971) - Liste commentée des Sélaciens de Tunisie. Bull. Inst. Océanogr. Pêche Salammbô, 2 (2): 131-141.
RAGONESE S., DI STEFANO L., BIANCHINI M.L. (2000) - Catture e selettività di pesci cartilaginei
nella pesca dei gamberi rossi nello Stretto di Sicilia. Biol. Mar. Medit., 7 (1): 400-411.
RAGONESE S., ZAGRA M., DI STEFANO L., BIANCHINI M.L. (2001) - Effect of codend mesh
size on the performance of the deep-water bottom trawl used in the red shrimp fishery of the Strait
of Sicily (Mediterranean Sea). Hydrobiologia, 449: 279-291.
RELINI G. (1995) - La fauna ittica batiale del Mediterraneo con particolare riferimento ai campionamenti dello strascico. Biol. Mar. Medit., 2 (2): 177-183.
RELINI G., BERTRAND J., ZAMBONI A. (1999) - Synthesis of the knowledge on bottom fishery
resources in Central Mediterranean (Italy and Corsica). Biol. Mar. Medit., 6 (Suppl. 1): 58-98.
RELINI G., BIAGI F., SERENA F., BELLUSCIO A., SPEDICATO M.T., RINELLI P., FOLLESA
M.C, PICCINETTI C., UNGARO N., SION L., LEVI D. (2000) - I selaci pescati con lo strascico
nei mari italiani. Biol. Mar. Medit., 7 (1): 347-384.
Check list of skates in the Strait of Sicily
881
STEHMANN M., BÜRKEL D.L. (1984) - Rajidae. In: Whitehead P.J.P., Bauchot M.L., Hureau
J.C., Nielsen J., Tortonese E. (eds), Fishes of the north-eastern Atlantic and the Mediterranean.
UNESCO, Paris, 1: 163-196.
STEVENS J.D., BONFIL R., DULVY N.K., WALKER P.A. (2000) - The effect of fishing on sharks,
rays and chimeras (chondrichthyans), and the implication for marine ecosystems. ICES Journal of
Marine Science, 57: 476-494.
TORTONESE E. (1956) - Fauna d’Italia: Leptocardia, Cyclostomata, Selachii. Ed. Calderini Bologna,
2: 334 pp.
VACCHI M., NOTARBARTOLO DI SCIARA G. (2000) - I pesci cartilaginei nei mari italiani, una
risorsa che richiede urgenti misure di tutela. Biol. Mar. Medit., 7 (1): 296-311.
WALKER P.A. (1996) - Sensitive skates or resilient rays? Annu. Rep. Neth. Inst. Sea. Res.: 60-61.
WHITEHEAD P.J.P., BAUCHOT M.L., HUREAU J.C., NIELSEN J., TORTONESE E. (1986) Fishes of the north-eastern Atlantic and the Mediterranean. UNESCO, Paris, 1-2-3: 1473 pp.
Research conducted in the framework of the GRUND and MEDITS programs with the economic support by
Ministero delle Politiche Agricole e Forestali (MiPAF; Italy) and European Union (D.G. XIV).