Comments on 1999 survey

This species mostly occurred between 100 and 500 m in western Mediterranean areas with an increasing trend from South to North of the same basin. Maximum biomass index was computed for the Sardinia Sea (sector 133; BI 12.4 kg/km², whole bathymetric range). It was less abundant In Ionian Sea with biomass indices around 1.0 kg/km². A decreasing trend was observed in the Adriatic Sea from South to North with a value of 3.2 kg/km² in the South and 1.8 kg/km² in the North.

Lengths (total length) ranged from 5 cm (Greek waters) to 38 cm (Corsica Sea); mean length per region was very variable, and it changed from 8.4 cm in the sector 223 (Greek waters) to 17.9 in the sector 133 (Sardinia Sea). Juveniles were mostly found in Greek waters.

This species shown a "patch" distribution in the Medits whole area. It was caught with low abundance in the Spanish Mediterranean waters (sectors 111, 112, 113) while biomass indices were around 10.0 kg/km² in Tyrrhenian Sea. As regard the 1994-1999 time series, it isn’t possible to detect any trends, except for sectors 134 (Strait of Sicily, decreasing trend) and 223 (Greek waters, increasing trend).

No trend analysis is possible for mean or median lengths (total length) because the species was chosen as target of the Medits project only in 1999.

Comments on 1999 survey

This species mostly occurred between 10-200 m having an irregular distribution by region. Practically absent in Alborán Sea had a value of 3,4 kg/km² in the Gulf of Lions (sector 121). Practically absent in Corsica waters (sector 131) but with noticeable values in the western part of Sardinia (2.5 kg/km²). Ligurian and Tyrrhenian seas had low biomass indices (0.2 and 0.7 kg/km² respectively). The maximum biomass index of the whole Mediterranean was computed for the North Aegean Sea (19.0 kg/km²).

Lengths ranged from 6 cm to 25 cm; mean length in the catches was around 11-13 cm TL.

Biomass index showed an increase in 1995, from 1.0 to 4.0 kg/km², respect to the other years in the Western Mediterranean.

As regard the time series 1994-1999, the minimum registered length (total length) was 6 cm and maximum 25 cm, with a mean value in Gulf of Lions of 15 cm. In Aegean Sea, where the species was more abundant, length frequency shows a bimodal distribution. The first peak was at 9-11 cm and a second less evident around 15 cm.

Comments on 1999 survey

This species occurred only in the continental shelf. The highest index was obtained from the Gulf of Lions (sector 121; 21.8 kg/km² on the shelf) and it was practically absent in the rest of the Medits areas except of low biomass indices in the Catalán and Aegean seas.

Lengths ranged from 4 cm to 34 cm on the whole Medits area; mean length was around 10 cm in the sector 121 (Gulf of Lions, highest abundance).

From a rough study of the existing data, no temporal trend was observed.

The 1994-1999 surveys minimum size (2 cm) was observed in the Ligurian Sea and in Argosaronikos Gulf. The maximum length (45 cm) was observed in the Gulf of Lions.

Comments on 1999 survey

It was present mostly in depths below 200 m in the whole Mediterranean area, showing a maximum value of about 190.0 kg/km² in the slope area of Alborán Sea and Gulf of Lions. The lower abundance was found in the Aegean Sea. It was absent in the Northern and middle Adriatic Sea.

Lengths (total length) ranged from 10 cm to 58 cm; mean length per region mostly ranged from 20 cm to 35 cm TL.

This species mostly occurred between 200 and 800 m in the whole Medits area, with an increasing trend from West to East and from South to North of the same basin, having a biomass indices around 100.0 kg/km² in the Spanish waters (sector 111) and values lesser than 10.0 kg/km² in the south-eastern zones (sectors from 221 to 225; Adriatic, Ionian and Aegean Seas). Abundance values were quite steady during 1994-1999 time period all along the Medits area.

No trend analysis is possible for mean or median lengths (total length) because the species was chosen as target of the Medits project only in 1999.

Comments on 1999 survey

It appeared mostly in depths greater than 100 m. In the western Mediterranean the highest abundance index was computed for the French area 121b (121.4 kg/km²). In the eastern Mediterranean, the highest indices were computed for the southern Adriatic (221f, 109.2 kg/km²) and the Greek Ionian seas (sector 222; 145.1 kg/km²) in depths exceeding 500 m. Lengths ranged from 2 to 30 cm and the length distributions showed several modes. Juveniles were found in almost all Medits regions.

The species shows a rather increasing trend in the overall abundance in Eastern Mediterranean areas (Aegean and Ionian seas). Changes could not be observed in the rest of the areas.

Mean length increased with depth from 4.8 cm in the shallow depth zone reaching 20 cm in the stratum 500-800 m. This pattern has remained rather stable during the studied period in most areas and an increasing trend has been observed only in the slope of the Greek Ionian Sea.

Comments on 1999 survey

The four-spotted megrim was mainly found in depths greater than 100 m. In the 200-500 depth zone the highest abundance (ranging from 9.0-13.0 kg/km²) was observed in the Gulf of Lions and in the Aegean Sea. In the 500-800 depth zone the highest index was computed for the Sardinian area 133e (15.8 kg/km²). Lengths ranged from 6 to 36 cm and the length distributions showed several modes.

The species abundance in the different areas was low (less than 10 kg/km²). Biomass indices were higher in the northern parts of the surveyed area such as the Gulf of Lions and the Northern Aegean Sea. The observed yearly abundance fluctuations did not allow the identification of any clear trend. Mean lengths fluctuated from 11 to 29 cm with the highest values observed, in general, for the continental shelf. The highest mean lengths during the whole studied period were recorded in the Gulf of Lions.

Comments on 1999 survey

It was widely distributed all over the Mediterranean Sea in all depth zones. The highest abundance index (101.5 kg/km²) was computed in the Gulf of Lions (sector 121b) in the 100-200 depth zone. Lengths ranged from 3 to 72 cm and the length distributions showed several modes. Juveniles found in almost all areas.

The species abundance showed a decreasing trend in several areas, mainly since 1997. This trend was much more pronounced along the Spanish coast and the Aegean Sea. It seems that this decrease was due to biomass reduction in the continental shelf. Mean lengths fluctuated from 10 to 50 cm. High concentrations of younger individuals were observed in some areas such as the Catalan Sea. Regarding mean lengths, a decreasing trend could be observed during the last three years along the Spanish continental shelf zone.

Comments on 1999 survey

Distributed all over the Mediterranean basin but mostly in western areas in depths from 10 down to 800 m. The highest abundance index (254.0 kg/km²) was obtained from the Gulf of Lions (sector 121b) in the 200-500 depth zone. Lengths ranged from 6 to 100 cm and juveniles were mostly found in the central and western areas.

The species has been found in smaller abundance in comparison to L. budegassa. Biomass indices, in most of the surveyed areas, did not exceed the value of 10.0 kg/km². The highest values were found out for the Gulf of Lions and the Tyrrhenian Sea while abundance was much lower in the Eastern Mediterranean areas. Bigger individuals were in general found in the depth zones of the slope where mean lengths were in most cases higher than 50 cm. The observed yearly fluctuations did not allow the identification of any clear trend neither in biomass nor in mean length.

Comments on 1999 survey

The species was widely distributed over the whole area in depths between 50 and 500 m. Higher yields were found between 50 and 200 m in the Sardinian Sea (135.0 kg/km²) and the Greek seas (142.0 kg/km²). The length frequency distributions indicated the presence of young specimens, particularly in the southern parts of Spain, Italy and Greece. Lengths ranged from 4 to 76 cm.

Biomass of M. merluccius in 1999 in comparison to the previous years was very similar except for the Sardinian waters, where an increased biomass was registered; in the Gulf of Lions the 1999 biomass index was lower with respect to other years. The six years trend shows no clear differences. However, this statement should be statistically examined.

The trend of mean length in the most surveyed areas is mostly constant.

Comments on 1999 survey

It was caught in depths greater than 50 m. The highest biomass index was obtained from the depth zone 100-200 m in the Spanish (477.0 kg/km²) and Greek waters (373.0 kg/km²). Species length frequency distributions varied between strata. The youngest individuals were found in shallower waters while in deeper areas the size range was more extended.

The biomass for all the surveyed years was characterised by a high variability. This might be related to the species characteristics (semi-pelagic, schooling behaviour).

The analysis of the length frequency distribution of M. poutassou suggested that the species mean length was almost the same for all the surveyed areas.

Comments on 1999 survey

The species was mainly caught in depth strata from 10 to 200 meters. The higher biomass indices were obtained in the northern and southwestern part of Sardinia (value = 47.7 kg/km²), in Corsica (value = 97.0), in the northern Adriatic Sea (value = 55.6), in the eastern Ionian Sea (value = 49.3), in the Argosaronikos Gulf (value = 46.9) and in the southern Aegean Sea (value = 93.3). The maximum density indices were obtained from the 10-50 m stratum, in the Southern Aegean (value = 113895 N/km²) and in the Adriatic seas (value = 18098 N/km²). Lengths ranged from 4 to 26 cm. On the shelf of the whole area a modal interval was found at 12-15 cm. A modal peak of juveniles (5-7 cm) was found in the southern Aegean and in the southern Adriatic seas. In the slope, biggest specimens (17-26 cm) were found. The higher values of biomass and density indices in the above mentioned areas corresponded to a higher number of juveniles. The latter could be attributed to an earliest recruitment period.

The biomass indices did not show evident trends in the whole area; a moderate decreasing trend was observed in the Alboran Sea and a moderate increase was verified in the Central and Northern Adriatic Sea, in the Tyrrhenian and Ligurian Sea, in Sardinia and in the Southern Aegean Sea.

Corsica, but also Southern Aegean Sea, Eastern Ionian Sea and Argosaronikos Gulf, showed a constant higher biomass indices in the period.

As far as the mean length is concerned, the values in the period did not show evident trends. The mean length constantly ranged between 12 and 15 cm, and the only relevant differences were due to the recruitment phenomenon in some areas (Eastern Ionian Sea and Southern Aegean Sea) and in some years.

Comments on 1999 survey

This species was found at depths from 10 to 500 m. The abundance was higher in the shelf of Sardinia (biomass index = 33.8), particularly in the northwestern part, and the Southern Aegean Sea (biomass index = 45.3). Length frequency distribution ranged from 3 to 37 cm with almost two modes, the first at 4-6 cm and the second from 14 to 21 cm. High concentration of juveniles were found in the central and northern Tyrrhenian Sea, central and northern Adriatic Sea and southern Aegean Sea.

In the whole area the biomass indices did not show defined trends; in some cases an increase of biomass index was observed, such as in Sardinia or in Northern Tyrrhenian Sea and in Northern Adriatic Sea, bearing in mind that these biomass indices were always very low. A moderate decrease of biomass index was observed in the Alboran Sea, as the congeneric species Mullus barbatus. In the six years of sampling, Sardinia and Argosaronikos Gulf showed constantly higher biomass indices.

As far as the mean length is concerned, the values in the period did not show evident trends; the mean length constantly ranged between 15 and 21 cm, except when the recruitment phenomenon occurred, such as in some years in the Northern Tyrrhenian Sea, Argosaronikos Gulf and Southern Aegean Sea.

Comments on 1999 survey

This species was caught in low quantities throughout the continental shelf and slope (10-500 m). The higher biomass indices were obtained in Greece over the continental shelf with a mean value of 47.0 kg/km². The length frequency distribution showed in the Gulf of Lions two modes on 19 and 25 cm. For the Tyrrhenian, Ionian and Aegean seas the observed two modes were positioned around 9 and 17 cm.

The species was caught in the whole Medits area, mainly over the shelf with biomass indices up to 406 kg/km² in Alborán Sea in 1994, but also on the slope with lower abundance (< 10.0 kg/km²).

Important changes in biomass indices were observed among years. Due to the high variability, it was quite difficult to detect any trend probably excluding the Spanish Alborán Sea that shows a negative trend from 406.0 kg/km² in 1994, to 36.0 kg/km² in 1999.

No trend was observed regarding the mean and median sizes. The modal sizes generally ranged between 16 and 22 cm; the mode was lower for the Sardinia, Southern Adriatic Sea and Greek area.

Comments on 1999 survey

The species was fished generally in small quantities except the areas of Gulf of Lions and Corsica. In those areas, the biomass indices were 29.0 and 34.0 kg/km² respectively. The length distribution showed over the shelf only one mode between 10-18 cm, while on the slope, the few individuals caught were of a larger size.

Within the genus Pagellus, this species has shown the lowest biomass indices. It was mainly caught over the slope with the higher values in Alborán Sea, Gulf of Lions and Corsica with a maximum value of 181.4 kg/km² in 1998 in Corsica. The lowest biomass index was observed in the Adriatic. The comparison of biomass values suggested positive annual trends for the Greek areas. No trend was detected regarding the mean and median sizes. Noticeable differences in modal size were observed between the western and central Medits areas and the Eastern (Greek) areas. For the first part the mode generally ranged between 24-27 cm, while for the Greek areas, this mode was around 18-19 cm.

Comments on 1999 survey

This species occurred more frequently in depths up to 100 m. Maximum biomass index was observed in the Corsican area (58,5 kg/km²). The size frequency distributions had a mode ranged from 13 to 18 cm.

The species was caught over the whole Medits area with the lower biomass indices in the Gulf of Lions and Adriatic Sea. Higher indices were found in the Eastern part of the studied area (Greece) and in Corsica where the highest values were found in 1999 (58.0 kg/km²). Despite the high-observed variability, data suggested positive trend of biomass indices for the Spanish areas (sectors 112-113) and for the Southern Adriatic and Ionian Sea (area 221).

It was not found any trend related to neither the mean nor the median size. The modal size was quite variable and ranged between 13 and 18 cm. In some cases (Alborán Sea, North Adriatic Sea and Eastern Ionian Sea) juveniles predominated with a modal size of 6-8 cm.

Comments on 1999 survey

The species was generally distributed over the slope, but it was also found in low quantities on the shelf. The biomass indices were, without exception, very low. The highest values were obtained for the Gulf of Lions (33.0 kg/km²). The modal range was from 8-13 cm on the shelf and from 10-11cm on the slope.

This species was caught over the whole area, with the higher biomass indices along the Spanish slope, while lower biomass indices were observed in Northern Adriatic Sea. Highest recorded values were in 1997 in Alborán Sea, with about 40.0 kg/km². Data suggested positive trend in biomass in the Argosaronikos Gulf and in the Southern Aegean Sea. No evident trends in mean and median sizes were observed. Juveniles predominated in almost all catches and length frequency distribution showed a mode around 10 cm. Specially for the Spanish areas (sectors 111-112) and for the Greek areas, the size distributions were polymodal, but small sized individuals still predominate.

Comments on 1999 survey

This species was caught in higher quantities in depths between 50 and 500 m around Sardinia (39.0 kg/km²), but it was occasionally found in other areas. Lengths ranged from 6 to 91cm.

Because of low occurrence and "patch" distribution of the species, no significant variations could be observed during the surveyed period; however biomass indices were low in almost all Medits regions.

Comments on 1999 survey

This species was caught in highest quantities between 50 and 500 m in the areas of Corsica and Sardinia with a maximum value of 65.0 kg/km². Lengths ranged from 10 to 56 cm.

This species occurred in the whole Medits area, having the highest biomass indices (27.0-76.0 kg/km² in the 1994-1199 period) off Corsica coast and the lowest (0.2-2.3 kg/km² in the 1994-1199 period) in the Adriatic and Ionian Seas. Abundance trend shown different pictures in the Medits regions; it seemed to decrease in northwestern sectors (111, 112, 113, 121), while it increased in southeastern areas (Aegean Sea).

No trend analysis is possible for mean or median lengths (total length) because the species was chosen as target of the Medits project only in 1999.

Comments on 1999 survey

This species was caught in low quantities and it was exclusively found in the continental shelf. In the Adriatic Sea the biomass indices ranged from 0.1 kg/km² (southern Adriatic area, western side) to 2.9 kg/km² (Albanian waters). The highest value (5.0 kg/km²) was found in the Greek area of the Ionian Sea.

Lengths ranged from 7 to 39 cm.

As a general rule the species was occasionally caught in the almost all the Medits area, but only in the continental shelf. The highest biomass indices were found in the Greek area of the Ionian Sea where they ranged from a minimum 1.8 kg/km² (1995) to a maximum of 6.3 kg/km² (1996). However, in this area the confidence interval values were high. Due to low occurrence and high variability, no trend could be detected in all the Medits regions. Few specimens were caught every year in each area. For this reason it is not possible any comment on the length structure of the stock. Moreover, considering all the six years, mean lengths mostly ranged from 20 to 30 cm TL.

Comments on 1999 survey

This species was mostly found on the continental shelf. The highest biomass indices were obtained off Corsica (sector 131) and off Sicily coasts (sector 134) with values of 79.2 kg/km² and 59.3 kg/km² respectively. The length frequency distributions ranged from 5 to 22 cm. The main modal length was of 10 –12 cm.

This species was abundantly caught over the continental shelf. All over the period the minimum biomass index (BI 0.1) was recorded in the Gulf of Lions (sector 121, year 1995), while the maximum value (BI 79.3) was recorded off the Corsican coasts (sector 121, year 1999). However high indices were mainly observed in the Tyrrhenian and coastal waters of Sardinia and Corsica Islands.

This species showed high variability and uncertain trends in all the Medits regions.

During the six years, mean lengths ranged from 7 to 19 cm TL regarding the whole Medits area; however the Northern Tyrrhenian Sea seemed to be a recruitment area for this species. Concerning length structures, no trend was observed.

Comments on 1999 survey

This species was mostly found on the continental shelf. The highest biomass indices were obtained off the Corsica coasts (sector 131) with a value of 455.7 kg/km² and CV = 34.6 %, followed by the Greek area 223 (Argosaronikos gulf) with a value of 155.3. Low biomass indices were recorded along the western part of Mediterranean, from the Alboran Sea (sector 111) to the Gulf of Lions (sector 121). The length frequency distributions ranged from 5 to 21 cm TL. The main modal length was of 12 cm.

This species was abundantly caught on the continental shelf. All over the period the minimum biomass index (BI 0.1) was recorded during the 1998 survey in Spanish waters (sector 112), while the maximum value (BI 3687.0) was recorded off the Corsican coasts during 1994. However high indices were mainly observed in the Central and Eastern Mediterranean excluding the Adriatic Sea.

Considering the whole Medits area and the six yearly surveys mean lengths ranged from 10 to 18 cm TL.

In all the Medits regions this species showed high variability and no clear trends either on abundance or on lengths.

Comments on 1999 survey

This species was mainly distributed on the shelf, with maximum biomass indices in the Gulf of Lions (62.0 kg/km²) at depths deeper than 100 m. It also reached high value in the Ligurian Sea in depths greater than 50 m (19.7 kg/km².) In the eastern Mediterranean (area GR2) the depth distribution was wider, from 10 to 500 m, with a biomass index around to 27.0 kg/km². Most of the specimens had a length between 10 to 20 cm. Mean lengths ranged from 8 to 34 cm.

Biomass fluctuated among years, but no trend was found. The semipelagic behaviour of this species could introduce a bias in the results, since it can punctually contribute to abundant catches (due to above mentioned features the same catches are not representative of the actual species distribution and abundance).

Comments on 1999 survey

It was present in all areas up to 500 m. Maximum biomass index was at the shelf of Strait of Sicily (118.0 kg/km²). The smaller individuals (mode around 7-9 cm) were mainly found on the shelf, while the individuals caught over the slope were of a larger size.

Biomass indices were quite similar during the studied years with a peak in 1995. Regarding the size, the described distributions for 1999 were very similar to the observed in the previous years; moreover the species behaviour (semi-pelagic and schooling fish) strongly affects the catches.

Comments on 1999 survey

The species was only caught between 10 and 200 m in generally low abundance. The highest biomass index was recorded in Sardinian waters (8.0 kg/km²). Lengths ranged from 4 to 32 cm. Mean lengths varied between areas ranging from 11 to 22 cm.

The analysis of biomass indices did not allow the observation of trends (both in biomass and length) during the surveyed periods also because of low occurrence of the species.

Comments on 1999 survey

This species showed an irregular distribution among the different areas and it has been mostly observed in the continental shelf zones. The highest biomass indices were computed for the continental shelf zone of the Gulf of Lions (110.1 kg/km²) and the 100-200 m depth zone of the Sardinian region (100.2 kg/km²). Lengths ranged from 3 to 24cm.

The species has been mostly found in the central and Eastern Mediterranean and the highest abundance have been observed in the Gulf of Lions. Yearly fluctuations in abundance indices did not seem to follow any specific pattern. Mean annual lengths in most of the cases were in the range of 7-10 cm and seem to decrease in some of the areas such as the Gulf of Lions and the Sardinian region.