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Chapter 2 Ecological aspects

Italian and the subdivision of the Mediterranean in GSA Considerations on data collection for the evaluation of living resources and the monitoring of fisheries on the fleets that operate in the determined the subdivision of the latter in a series of reference areas for both management activities and scientific surveys. Such areas represent a compromise among legislative, geographic and environmental aspects. The Mediterranean Sea was subdivided in 30 sub-areas, named GSA (Geographic Sub Areas). The term “sub” refers to the fact that the Mediterranean Sea is one of the 60 Large Marine on the planet. Geographical Sub-Areas in the GFCM area were established amending the Resolution GFCM/31/2007/2, on the advise of the GFCM Scientific Advisory Committee (SAC). The 30 areas largely differ in size and characteristics. The geographic division of fisheries areas in the Mediterranean Sea is still evolving and is subject to periodical improvement by SAC.

1 Northern 11.2 (east) 22 2 Alboran Island 12 Northern 23 Island 3 Southern Alboran Sea 13 Gulf of Hammamet 24 North Levant 4 14 Gulf of Gabes 25 Island 5 Balearic Island 15 Island 26 South Levant 6 Northern 16 South of 27 Levant 7 Gulf of Lions 17 Northern Adriatic 28 Marmara Sea 8 Corsica Island 18 Southern 29 9 Ligurian and North 19 Western 30 Azov Sea 10 South Tyrrhenian Sea 20 Eastern Ionian Sea 11.1 Sardinia (west) 21 Southern Ionian Sea

17 2.1 Environmental characterisation of fishing areas 2.1.1 GSA 9 - Ligurian and Northern Tyrrhenian Seas Relini G., Sartor P., Reale B., Orsi Relini L., Mannini A., De Ranieri S., Ardizzone G.D., Belluscio A., Serena F.

Ecological context and geographical and environmental aspects GSA 9 (figure 2.1) covers an area of 42,410 km2 that includes the Ligurian and Northern and Central Tyrrhenian Seas and belongs to the FAO division 37.1.3 (Sardinia); the total area involves 1,245 km of coastline and includes , Tuscany and and 10 maritime departments, plus a part of the district of .

Figure 2.1 - Geographic boundaries of GSA 9. The 200 and 800 m bathymetric contours are shown, together with the port authority headquarters of the various maritime departments.

18 First section - Chapter 2 - Ecological aspects It is a heterogeneous area in terms of morphological and ecological features, containing a variety of , environmental conditions and biological communities. The coastline of Liguria extends for approximately 330 km; the in the Western Riviera, from Cape Mortola to Cape Arenzano, is very narrow, although it becomes wider towards the east, near Punta Bianca. One of the most relevant feature of the seabeds, which also has an effect on resources, is the number of canyons that furrow the continental slope and the high depths close to the western and central shores. The coast of Tuscany stretches for over 600 km, including around 400 km of mainland and 200 km of insular coastline in the . There are present areas with low, sandy coasts and with high rocky coasts, particularly along the isles of the archipelago. The continental shelf between the Gulf of and the Island of Elba is wide and slightly sloping, particularly between Livorno and Elba, and extends 35-40 km from the coast, reaching a depth of about 150 m. Between the islands of Capraia and Gorgona the continental shelf is interrupted by the Elba canyon, which descends in depth towards north-west. The seabed between Elba and the Argentario Peninsula comprises a single basin, bounded to the west by the Elba Ridge, to the east by the Tuscany coast and to the north by the Piombino channel and the Elba Island. The continental shelf in Lazio, with a longitudinal extension of 290 km, has a narrower central section, between Cape Linaro and Cape Circeo (with an extension of 20 km), and is wider (30-40 km) towards the north (between the Argentario Peninsula and Cape Linaro) and south (between Cape Circeo and Gaeta). It has an average decreasing slope of about 0.5°; the shelf break ranges from 120 to 150 m. The central area of the Lazio shelf is characterised by the submerged alluvial of the Tiber . The river supplies condition the physical, chemical and trophic characteristics of much of the coastal area of the central Lazio. The Pontine Archipelago is off the southern coast of Lazio and includes the islands of , and to the west and and Santo Stefano to the east, which are mainly composed of volcanic deposits. The are characterised by steeply sloping seabeds and the presence of numerous canyons. The water circulation features a series of vortexes caused by the wind. These contain cold water and undergo significant changes from season to season. The current flow increases in the frontal of the vortexes in winter and the associated upwelling moves towards the west and increases in intensity. This is the season in which the flow between Tyrrhenian Sea and , through the Corsica Channel, reaches its peak. Upwelling causes the mixing of waters originating from the Atlantic (AW) with the Levantine Intermediate Water (LIW), changing the physical and chemical properties of the water mass. To the North of Capraia Island, the Eastern Corsica current merges with the colder Western Corsica current forming the Ligurian current (figure 2.2). This supports a cyclonic circulation in the whole Ligurian Sea, involving waters of Atlantic origin (AW) on the surface and Levantine waters (LIW) at a greater depth. It is one of the most important upwelling areas in the Mediterranean Sea. The flow of the Ligurian current is huge: it can reach around 1.6 million m3/sec, a value similar to the Atlantic current that flows into the Strait of . It is a river of water approximately 20 km wide, with a depth of around 150 m, which flows continuously throughout the year, although with variations in intensity. The Ligurian Sea is one of the most important places for the transformation of waters in winter, due to the action of cold and dry continental winds. The cooling and evaporation of the masses of superficial water in the Ligurian Sea and the adjacent Gulf of Lyons are responsible to the formation of the deep-water, which is one of the great oceanographic processes of the Mediterranean Sea.

19 Figure 2.2 - Circulation of surface and intermediate currents. AW: waters of Atlantic origin (blue arrows); LIW: waters of Levantine origin (red); LC: Ligurian current (violet); WCC: Western Corsican Current, a branch of waters of Atlantic origin; ECC: Eastern Corsica Current, of Atlantic origin.

The seasonal phytoplankton dynamics in GSA 9 are typical of subtropical areas, with a maximum in the cold season, from October to April, and a minimum in the summer. A positive correlation has been confirmed between the concentration of chlorophyll in spring and the remixing of the waters in the previous months (autumn-winter), under the effect of the wind. The narrow extension of the Ligurian continental shelf influences all the biotic communities of sands and detritic bottoms, as well as those of the coastal terrigenous muds. The hard bottoms often are distributed following a vertical direction (Portofino cliffs, Mesco cliffs, etc.). Some of the most interesting Gorgonian coral (Paramuricaea clavata) and red coral (Corallium rubrum) facies of the Italian coast are also in Liguria. meadows can be found more or less

20 First section - Chapter 2 - Ecological aspects everywhere along the coast, although their extension is limited due to the steepness of the seabeds. The benthic communities of the islands of the Tuscan Archipelago also display a high level of heterogeneity. The offshore mobile bottoms host biocoenoses mainly originating from the series of detritic bottoms, which are replaced by muddy communities at greater depths. The between 80 and 150 m depth in the western and southern sectors of the island of Elba host biocoenoses of detritic bottoms, characterised by the dominance of the crinoid Leptometra phalangium. These feature a highly diversified and productive community and host nurseries of commercial species, such as the European . The hard coastal bottoms display the typical biotic communities of vertical walls. Marine phanerogam meadows thrive particularly along the island coasts of the Tuscan Archipelago, particularly in Pianosa. As concerns Lazio, the soft bottoms closer to shore display communities typical of fine sand and well-calibrated fine sediments. Due mainly to the Tiber supplies, these communities are replaced offshore by mixed sandy-muddy bottoms, which form an area of transition to the coastal terrigenous muds (VTC) distributed along the deep portion of the continental shelf. Detritic seabeds (DC) are found at the edges of rocky shallows, around the Pontine islands and beyond the lower limit of the Posidonia meadows. The edge of the continental shelf is characterised by the presence of detritic bottoms (DL), with high concentrations of the crinoid L. phalangium. To the South of the Tiber estuary, the mobile seabeds are interrupted by the Tor Paterno bank. P. oceanica is found along practically all of the Lazio coastal areas, with the exception of the Tiber area. All the GSA 9 is characterised by a wide biodiversity, taking into account that only 14 of the 162 benthic communities (habitats) listed in the Barcelona Convention are not found here. Fish, and species assemblages exploited by fisheries have also been described for the various habitats (cf. Relini et al., 1986). As far as offshore waters are concerned, GSA 9 includes the western portion of the Pelagos sanctuary for Mediterranean marine mammals, in which the water column, with an average depth of 2,500 m, has often been described by oceanographers as a “miniature ocean” in view of the great oceanographic processes and biotic complexity of this area (Relini, 2007). The offshore water of the Western Ligurian Sea, with large cetaceans, including baleen whales and toothed whales, large perciformes (, swordfish and other billfish) and pelagic sharks (Isuridae, Alopidae and Carcharhinidae), has a great natural value and forms the heart of the Pelagos sanctuary. The abundance in this area, not only of cetaceans, is mainly due to oceanographic factors in which the wind plays an important role. During winter, the wind extends the upwelling process constantly found in the frontal zone of the Ligurian current, causing the surface water to evaporate and lowering the temperature, thereby increasing the water density. As a result, the heavier surface waters sink and are replaced by deeper waters, which surface once more. The arrival of fresh nutrients to the surface helps to increase primary productivity and the productivity of all the links in the food chain leading to the large pelagic species. These organisms are concentrated in this sea for at least a certain period of the year due to the presence of abundant food, particularly the krill (as the euphausiid shrimps of the species Meganyctiphanes norvegica), which are the exclusive food of fin whales when present in the Ligurian Sea. M. norvegica is the key species in the food web in the pelagic zone of the Ligurian Sea and it also has a certain importance for demersal resources. The close interactions between the benthic and pelagic zones emerge clearly from several studies of the food webs to which the target species belong. Concerning the human impacts, all GSA 9 is heavily anthropised, with large towns, industrial

21 development and important ports. Maritime traffic creates significant disturbance to the ecosystem and to fishing activities, particularly along the main routes. Linked to this traffic is the issue of hydrocarbon pollution and the possibility of disasters, such as that of the Haven in April 1991 (Relini, 1994): still today large stretches of seabed cannot be trawled due to the presence of crude oil deposits. Furthermore, various contaminants can reach the sea through watercourses. Even certain fishing activities can contribute to the alteration of seabeds.

Fisheries characteristics According to recent estimates (Irepa, 2010), the fishing fleet in GSA 9 consists of 1,778 boats, approximately 13% of the total number of Italian fishing vessels. Also in recent years, following the guidelines for the protection of living resources, the process of reduction of the fishing capacity has continued. Between 1996 and 2009 the fishing fleet in GSA 9 was reduced by about 35%, with the loss of over 600 boats, whereas total tonnage and engine power decreased by 30% and 25% respectively. The fishing fleet operating in GSA 9 is characterised by a high proportion of small-scale artisanal vessels, which accounts for about three quarters of the boats. Nevertheless, fishing vessels equipped with trawl nets provide the highest landing and sales levels. The annual landing (2009) for GSA 9, for all fishing activities, amounts to around 20,000 , slightly less than 10% of the national total.

Trawling The trawl fleet in GSA 9 (2009) consists of 339 boats, with an overall tonnage of approximately 13,000 GT, representing about 70% of the fishing capacity employed in the area. In 2009, the landing volume produced by trawlers was about 8,000 tonnes. This production features a high proportion of fish (58%), followed by molluscs (27%) and crustaceans (15%). The most landed species are European hake, red and horned , but Norway and deep-water rose shrimp and giant red and blue and red shrimps also play an important role. The fishing effort exerted by trawlers is not uniformly distributed throughout GSA 9. In the Western Liguria the fishing activity on the shelf is reduced, due to its limited extension, and most vessels, particularly of Sanremo and Imperia, concentrate their activity on bathyal bottoms, targeting blue and red shrimp (Aristeus antennatus). In Eastern Liguria the circalittoral muddy bottoms are wider and the fisheries also target species of the continental shelf, such as the horned octopus and red mullet. The main fleet of Liguria, based in the port of Santa Margherita Ligure, operates in this area. The northern coast of Tuscany (south-eastern Ligurian Sea) is influenced by the input of freshwater from the rivers Magra, Serchio and Arno, which increases the nutrients in the coastal area. The shelf is very wide and is characterised by soft bottoms suitable to trawling. These conditions have led to the development of the fleet of Viareggio, which is the largest one in the Ligurian Sea. South of the Island of Elba (Southern Tuscany) the shelf is slightly narrower and fishing activity is concentrated on the continental slope. Important trawling fleets operate in this area (Porto Santo Stefano, Porto Ercole and Castiglione della Pescaia), working intensively both on the shelf and the slope and targeting European hake, red mullet, horned octopus, deep-water rose shrimp, Norway lobster and giant red shrimp (Aristaeomorpha foliacea). In Lazio, the fishing effort by trawlers is uniformly distributed, both on the continental shelf and on the slope. Smaller vessels normally operate on the shelf, targeting European hake, red mullet, spottail , common octopus and horned octopus, while larger vessels operate mainly on the slope, targeting European hake, deep-water rose shrimp, red shrimps and Norway lobster. The fleet in Lazio is uniformly

22 First section - Chapter 2 - Ecological aspects distributed among the main ports of Civitavecchia, Fiumicino, , and Gaeta-. Almost all the trawlers in GSA 9 usually carry out one day fishing trips, with the exception of certain fleets, as that of Porto Santo Stefano, where it is common to make trips of two and, occasionally, three days, particularly in summer.

Small-scale coastal fisheries The group known as “small-scale coastal fisheries” comprises 1,296 boats with a total tonnage of 2,630 GT; the average GT is around 2.0, with an average crew of 1.2 fishermen per boat. The vessels have a typical overall length of less than 12 metres, employing passive gears, such as driftnets, long lines, pots and other traditional techniques, and often have a family-based technical and administrative operation.

Other fisheries In GSA 9, particularly in Liguria and Tuscany, there are 51 boats (approximately 2,000 GT) targeting small pelagics ( and ) mainly using purse seine. The production of and in 2009 was 2,500 and 5,700 tonnes respectively, representing 5% and 30% of total national production. In addition to these fisheries, there are some vessels using hydraulic dredges, present in the Lazio maritime departments of , Gaeta and Civitavecchia (22 boats in total) to exploit clams (379 tonnes in 2009) and razor shells. The official statistics also mention the presence of polyvalent passive gears (50 boats in total).

References - Irepa Onlus (2010) - Osservatorio economico sulle strutture produttive della pesca marittima in Italia. 2009. Edizioni Scientifiche Italiane, Napoli: 184 p. - Relini G. (1994) - Gli ecosistemi e le risorse biologiche del Mar Ligure dopo il disastro della Haven. Biol. Mar. Mediterr., 1 (1): 3-42. - Relini G. (ed) (2007) - Dominio Pelagico. Il Santuario dei Cetacei “Pelagos”. Quaderni 16. Ministero dell’Ambiente e delle tutela del Territorio e del Mare. Museo Friulano di Storia Naturale. di : 156 p. - Relini G., Peirano A., Tunesi L. (1986) - Osservazioni sulle comunità dei strascicabili del Mar Ligure centro- orientale. Boll. Mus. . Biol. Univ. Genova, 52 (Suppl.): 139-161.

2.1.2 GSA 10 - South and Central Tyrrhenian Sea Spedicato M.T., Lembo G.

Ecological context and geographical and environmental aspects GSA 10 (South and Central Tyrrhenian Sea- figure 2.3) has an extension of 20,255 km2 (from about 10 to 800 m in depth) and comes under FAO statistical division 37.1.3. The total area includes 12 maritime departments and the coastlines of 5 : Lazio (only a few kilometres), , , (Tyrrhenian side) and Sicily (northern coast), with a coastal extension of 1,129 km. According to the GFCM-FAO classification, GSA 10 is encompassed within a section of the Tyrrhenian Sea bounded by the coast and a line joining two points on ideal perpendiculars extending offshore from the coast: one in the South, 70 miles offshore from Trapani, and one in the North, 90 miles offshore from the Circeo Promontory.

23 Figure 2.3 - Geographic boundaries of GSA 10. The 200 and 800 m bathymetric contours are shown, together with the port authority headquarters of the various maritime departments.

The South and Central Tyrrhenian Sea features one of the most complex structures in the seas around the , due to its morphological and geophysical characteristics and water mass dynamics. The coastlines are generally very rugged and the island system is the most numerous in the Italian seas. The geodynamic evolution of the South and Central Tyrrhenian can be seen from two main abyssal plains, which reach maximum depths between 2,900 and 3,600 m and contain two large basaltic volcanic edifices, the Vavilov and Marsili seamounts (the first of which is around 85 miles south-east of the Gulf of and the second 54 miles from the Cilentan coast). The area near the Vavilov seamount also contains a smaller volcano, the Magnaghi seamount, which is probably not active. A mountainous chain of volcanic origin runs through the areas around the Marsili seamount (height 3,500 m, length around 60 km), which rises from the seabed to a depth of around 500 m. This topography influences the circulation of the water masses; the Vavilov

24 First section - Chapter 2 - Ecological aspects seamount in particular has been found to be partially responsible for the persistence, in various seasons, of anticyclonic vortices fed by water masses produced during the winter in the North- western Mediterranean Sea (Western Intermediate Waters, WIW) (Budillon et al., 2009a). The continental shelf (up to 200 m) of the South and Central Tyrrhenian Sea has a limited extension on the northern edge of Sicily and along the coasts of Calabria and Basilicata, although it extends further from the shores of Campania and Lazio, where, in the northernmost stretch, it forms a continuation of the alluvial plain of the rivers Garigliano and Volturno towards the sea and, further south, that of the river Sele in the . The extension of the continental shelf tends to decrease from NW to SE in the , narrowing from around 20 km near the mouth of the Garigliano to less than 10 km south of the river Volturno, where the platform is furrowed by the Cuma canyon. In the the shelf is interrupted at a certain distance offshore, between the islands of and , by two large canyons: the Magnaghi and the Dohrn. In the section between Punta Campanella and Amalfi, the continental shelf tends to disappear and the seabed rapidly reaches depths of over 300 m, whereas from Amalfi to Capo d’Orso the shelf has a width of only 2-4 km, reaching 10-12 km from the coastline near Salerno and extending as far as 15-25 km from the coast near the mouth of the Sele river. The Gulf of Policastro features some sections with a narrow continental shelf (less than 3 km) and others where it reaches an extension of around 8 km, with a slope at 130 and 140 m. Where the shelf is less-developed, the upper part of the slope is narrow, uneven and furrowed by terraces and canyons. The Strait of Messina separates the continental area of GSA 10 from that of Northern Sicily and marks the physiographic boundary between the South and Central Tyrrhenian and the Ionian Seas. The Strait provides a morphological barrier for the exchange flow between the two basins. Fluctuations in the Atlantic-Ionian Stream (AIS) cause a very particular internal dynamic in the Strait; moreover, although the tidal excursions in the Mediterranean Sea are relatively small, they become quite significant in the Strait of Messina, as the semi-diurnal tides in the Tyrrhenian and the Ionian seas are approximately in phase opposition. This gives rise to large vertical and horizontal gradients, causing the Ionian waters to enter the Tyrrhenian Sea on the surface during the northward tidal flow and the Tyrrhenian waters, on the contrary, to enter the Ionian at a depth of around 100 m during the southward tidal flow (Brandt et al., 1999). Upwelling phenomena, which bring deep-waters to the surface, cause the presence of noticeably colder surface waters in the Strait than at a similar depth in other areas of the Ionian Sea. Nitrogen and phosphorus salts, brought to the surface levels by the deep Ionian waters, allow the production of a large quantity of organic substance, which supplies the food cycle of both the coastal benthic populations and the pelagic communities. The Strait of Messina is a fundamental transit point for numerous Mediterranean migratory species (tuna, swordfish and cetaceans). The particular circulation of the water masses in the Strait determines the presence of bathypelagic fauna (for example, Chauliodus sloani and Argyropelecus hemigymnus) in the shallower levels, a phenomenon that attracted considerable research on the abyssal fauna in this area, particularly between the late 19th and early 20th century. Like a large part of the continental coastline, the northern coast of Sicily features a steep slope, with the seabed reaching an average depth of 500 m at distances of between 4 and 15 km from the coast (figure 2.3). The Tyrrhenian Sea exchanges water with the rest of the Mediterranean Sea through the Sardinian and Corsican channels and the , which form morphological thresholds that prevent the recirculation of the deep

25 levels (Sparnocchia et al., 1999). The Tyrrhenian Sea is an active area in terms of water mass movements, characterised by significant mesoscale dynamics (Vetrano et al., 2010) (figure 2.4). The waters can be classified into three main levels: • the surface level, to a depth of 200 m, occupied by Modified Atlantic Water (MAW - AW in figure 2.4), which flows with the Atlantic current from the Strait of Gibraltar and is modified en route, increasing in ; • the intermediate level, from a depth of around 200 to 700 m, is occupied by a mixture of intermediate waters (LIW, Levantine Intermediate Water) (Gasparini et al., 2005) that flow from the Strait of Sicily; • the deep level, occupied by Tyrrhenian Deep-water (TDW), which flows out from the Sardinian Channel along the Sea of Sardinia. Recent evidence from the work by Millot and collaborators (2006) suggests that the dense Tyrrhenian Deep-water (TDW) plays a crucial role in the deep circulation of the western basin, as well as being one of the main tributaries to the flow of water from the Mediterranean Sea into the . A consistent input of water from the eastern basin of the Mediterranean Sea (LIW and underlying levels) flows through the Strait of Sicily and enters the Tyrrhenian basin, where it sinks and mixes with the waters of the western basin of the Mediterranean Sea (Sparnocchia et al., 1999). The most recent measurements of temperature and salinity, taken near the Strait of Gibraltar, indicate that the denser Mediterranean waters, which flow into the Atlantic Ocean, have undergone continuous transformations, becoming increasingly warmer and more saline. Hence, the denser waters that currently flow out from the Mediterranean Sea are TDW, mainly composed of EOW (Eastern Overflow Water). The denser part of the flow has thus increasingly assumed the characteristics of the eastern , coming under the influence of the Eastern Mediterranean Transient (EMT), an anomaly due to a significant input of dense water from the Aegean caused by particular climatic events, which has brought changes to the composition and circulation of the water masses in the Mediterranean Sea. Available observations show that the transient reached the Tyrrhenian Sea between April and May in 1992 and its impact in the western basin was greatest in the two-year period from 1992-1994, when a substantial portion of the flow from the Strait of Sicily sunk in the Tyrrhenian Sea, reaching the greatest depths (Budillon et al., 2009b). The velocity of the surface currents in the central Mediterranean Sea is quite low, generally less than one knot, except in the Strait of Sicily. A branch of the surface current that comes from the western basin and flows towards the Strait of Sicily separates from the main trunk, flowing along the northern coast of Sicily and joining the cyclonic circulation of the Tyrrhenian Sea, which flows from south to north along the continental coastline (Istituto Idrografico della Marina, 1982). In winter, a further branch of this current flows up as far as Elba and returns along Sardinia, while another branch feeds a cyclonic vortex in the central-southern basin. This vortex extends almost to the coast of Sardinia in springtime and breaks into two main circuits in the summer. The seasonal variations in the general circulation accentuate the strength and structure of the cyclonic currents. On a sub-basin scale, cyclonic and anti-cyclonic structures, interconnected with meanders and featuring occasional seasonal dynamics, play a key role in the development of the water masses and the general thermohaline circulation.

26 First section - Chapter 2 - Ecological aspects Figure 2.4 - Circulation of surface (AW) and intermediate (LIW) currents; AW: waters of Atlantic origin (blue); LIW: waters of Levantine origin (red).

The surface temperature (at -5 m) can vary from around 13 °C in February to around 28 °C in August, while the salinity ranges from 38.1-38.6 psu. The offshore waters are considered oligotrophic. At the coastal level, however, the areas in front of the river Volturno have eutrophic/mesotrophic features, whereas the strip in front of Naples and the mouth of the Sarno river shows phenomena of localised eutrophication. The Gulf of Salerno, less affected by anthropic pressure, has mesotrophic characteristics, whereas oligotrophic conditions can be seen along the Cilentan coast. The South and Central Tyrrhenian Sea features a high bionomic variation (in the sense of Pérès &

27 Picard, 1964) with Posidonia oceanica meadows within a depth of 50 m, particularly in the channel between Ischia and , between Acciaroli and Capo Palinuro, in the and in the stretch of coast between Termini Imerese and Cefalù. The same bathymetric zone also features meadows, particularly in the stretch of sea between Punta Diamante and Capo Suvero and between Cefalù and the Gulf of Patti. Biotic communities of coastal terrigenous mud (VTC) and coastal detritic bottom (DC) are frequently found at bathymetric levels up to a depth of 100 m. From depths between 100 and 200 m, communities of shelf-edge detritic bottom (DL) are frequently found, inhabiting a coarse organogenic detritus matrix and featuring the presence of the crinoid Leptometra phalangium, the most abundant of the macro- epibenthic filter-feeding organisms in this biotic community. The areas with the greatest presence of the Leptometra phalangium community are the offshore seabeds between Punta Licosa and Capo Palinuro, and between Scalea and Capo Bonifati, where intrusions of this community have even been observed at depths over 200 m, and offshore from Santo Stefano di Camastra and Palermo. Facies with Leptometra phalangium is considered a hot spot with high levels of biodiversity and concentration of the juvenile stages of various species (for example, , Parapenaeus longirostris, Trisopterus minutus capelanus, Trachurus trachurus, Spicara flexuosa, Illex coindetii, etc.). Seabeds beyond a depth of 200 m generally feature communities of bathyal muds. In the upper horizon, up to a depth of 450 m, the characteristic species include Parapenaeus longirostris, , Cidaris cidaris, and Funiculina quadrangularis, while those of the lower horizon include Aristeus antennatus, Aristaeomorpha foliacea, Geryon longipes, Polycheles typhlops, Isidella elongate and Gryphus vitreus (Spedicato et al., 1998). Lastly, as an indication of the variety of environments and species that characterise the South and Central Tyrrhenian, mention should be made of the cetaceans found in the area of the , in the vicinity of the Cuma canyon, where the presence of seven species has regularly been noted: Stenella coeruleoalba, Tursiops truncatus, Delphinus delphis, Grampus griseus, Globicephala melas, Physeter catodon and Balaenoptera physalus (Mussi et al., 1998). Some signs of intrusion by species from the eastern basin are given by Lessepsian migrants, such as Fistularia commersonii and Syganus luridus (Golani et al., 2007).

Fisheries characteristics The South and Central Tyrrhenian seas fleet is composed of around 2,800 boats and contributes to approximately 12% of national production (Irepa data, 2010). The relatively narrow continental shelf has clearly favoured artisanal fishing systems (trammel nets, gillnets, combined nets, long lines, hand lines, pots, harpoons and “menaide” nets), which are used by 84% of the boats, while 9% use trawl nets and 4% seine nets. In regard to catches (Irepa data, 2010), pelagic species are the most abundant: anchovy account for around 24.5% of production, sardine 9.3% and swordfish 6.3%. European hake (Merluccius merluccius), which ranks fifth among the most captured species after the group category “other fish”, accounts for 5%, while deep-water rose shrimp, another demersal species with significant catch numbers, accounts for 1.5%. These, together with red shrimps, red mullet and octopus, are the most highly valued species in economic terms. The main fishing ports in GSA 10 are: Portici, del Greco, Salerno, Acciaroli, Cetraro, Vibo Valentia Marina, Tropea and Palmi along the continental shore and Milazzo, Porticello and Castellammare del Golfo on the north Sicily shore.

28 First section - Chapter 2 - Ecological aspects Certain fisheries with particular characteristics are carried out in GSA 10. For example, techniques using fish aggregating devices (FADs) are practised along the coast of Northern Sicily. Another typical fisheries in GSA is the capture of swordfish with harpoons, practised in Strait of Messina using characteristic boats known as “felucche”. Red coral fisheries was common in the Gulf of Naples until the 1980s, but is no longer practised due to the depletion of the colonies. The fishing effort exerted by trawlers fluctuates between 54 and 68% of the total effort in the last seven years, followed by activities that can be classified as artisanal fisheries (22-12%) and by small and large pelagic fisheries (on average 11% and 7% respectively). Fishing habits vary among marine communities, although in most cases fishing trips have a duration of one day.

References - Brandt P., Rubino A., Quadfasel D., Alpers W. (1999) - Evidence for the influence of Atlantic-Ionian stream fluctuations on the tidally induced internal dynamics in the Strait of Messina. Journal of Physical Oceanography, 29: 1071-1080. - Budillon G., Gasparini G.P., Schroeder K. (2009a) - Persistence of an Eddy Signature in the Central Tyrrhenian Basin. Deep-Sea Res. Part II, 56: 713-724. - Budillon G., Cotroneo Y., Fusco G., Rivaro P. (2009b) - Variability of the Mediterranean deep and bottom waters: some recent evidences in the western basin. In: Briand F. (ed), Dynamics of Mediterranean deep-waters. CIESM Workshop Monographs, 38, : 57-65. - Gasparini G.P., A., Budillon G., Astrali M., Sansone E. (2005) - The effect of the Eastern Mediterranean Transient on the hydrographic characteristics in the Strait of Sicily and the Tyrrhenian Sea. Deep-Sea Res. Part. I, 52: 915-935. - Golani D., Azzurro E., Corsini-Foka M., Falautano M., Andaloro F., Bernardi G. (2007) - Genetic bottlenecks and successful biological invasions: the case of a recent Lessepsian migrant. Biol. Lett., 3: 541-545. - Istituto Idrografico della Marina (1982) - Atlante delle correnti superficiali dei mari italiani. Genova: 45 p. - Millot C., Candela J., Fuda J.L., Tber Y. (2006) - Large warming and salinification of the Mediterranean outflow due to changes in its composition. Deep-Sea Res. Part I, 53: 655-666. - Mussi B., Gabriele R., Miragliuolo A., Battaglia M. (1998) - Cetacean sightings and interaction with fisheries in the Archipelago Pontino-Campano, South Tyrrhenian sea, 1991-1995. In: Evans P.G.H. (ed), European Research on Cetaceans 12. European Cetacean Society, Cambridge, UK: 63-65. - Pérès J.M. & Picard J. (1964) - Nouveau manuel de bionomie benthique de la Mer Méditerranée. Rec. Trav. Mar. Endoume, 31 (47): 137 p. - Sparnocchia S., Gasparini G.P., Astraldi M., Borghini M., Pistek P. (1999) - Dynamics and mixing of the Eastern Mediterranean Outflow in the Tyrrhenian basin. Journal of Marine Systems, 20 (1-4): 301-317 - Spedicato M.T., Lembo G., Carbonara P., Silecchia T. (1998) - Valutazione delle risorse demersali dal Fiume Garigliano a Capo Suvero. Biol. Mar. Mediterr., 5 : 64-73. - Vetrano A., Napolitano E., Iacono R., Schroeder K., Gasparini G.P. (2010) - Tyrrhenian Sea circulation and water mass fluxes in spring 2004: Observations and model results. J. Geophys. Res., 115, C06023.

29 2.1.3 GSA 11 - Sardinia Sea Follesa M.C., Locci I., Pesci P., Floris E., Cau A.

Ecological context GSA 11 (figure 2.5) extends for 23.700 km2 and includes all the seas around Sardinia.

Figure 2.5 - Geographical position of GSA11 its five marine districts.

It is part of the FAO statistical sub-area 37.1.3 (Sardinia); it has 1,846 km of non omogeneous coasts, both for extension and oceanographic, geomorphological and bionomical features (Cau et al., 1994; Addis et al., 1998). From an oceanographical point of view, this area belongs to two different basins: the Algerian- Provençal and the Thyrrenian ones, connected each other by the Sardinian Channel.

30 First section - Chapter 2 - Ecological aspects From a baty-morphological point of view, Sardinian bottoms can be divided in four main zones: • The Western Coast (Sardinian Sea) is characterized by a wide extension of the continental shelf and slope. In fact, continental shelf ends between 150 and 200 m, with a not much marked decline and it is followed by the continental slope. Mud bottoms are scarce and gross sand bottoms are very common. Both this feature and the great water trasparency allow a good growth of the vegetation: wide Posidonia oceanica meadows are found between 0 and 40 m. Algal Coastal Detritic and Coralligenous can be found. Typical biocenosis are the Gorgoniacea (Paramuricaea clavata) and red coral (Corallium rubrum) facies. Leptometra phalangium reaches wide concentration on the detritic bottoms of the continental shelf edge. • The Northern Coast is characterized by the Gulf and Bonifacio Straits. The continental Shelf has a moderate extension while the Slope is narrow and steep. • The Eastern Coast is characterized by little and steep fishing grounds and the 1000 m bathymetric line run very close to the coast. Continental shelf is irregular and very narrow, and some submarine canyons, mountains and valley can be found (Palomba & Ulzega, 1980). The Southern Coast is characterized by the Cagliari Gulf. The shelf is wider in its western part (40 km) than in the eastern one (11 km). 500 m isobaths run less than 3 km from the coastline. The batymetric division of the GSA11 bottoms points out that the great part of them (about 67%) are found over 100 m deep. Water masses involved in fishing activities are mainly the superficial and intermediate ones (figure 2.6). Surface circulation in the southern Sardinia is mainly related to the Atlantic Water (AW) flow that feeds the Algerian current (Ribotti et al., 2004). This current flows easterly along the African continental Slope, between 10 and 100 m depth. Anticyclonic Eddies are generated from the Algerian Current by its baroclinic instabilities. Some of them can last for long time and, once separated from the Algerian coasts, can accomplish several cyclonic path in the Algerian basin and amass between the Balearic Island and Sardinia. Part of the AW flows in the Sicily Strait through the Sardinian Channel. Another part goes in the Southern Tyrrhenian Sea and flows cyclonically along the Northern Sicilian Slope. Southern Tyrrhenian Sea, mainly the Sardinian-Sicilian part, constitutes a key area in the hydrologic dynamics between West and East Mediterranean Sea.

31 Figure 2.6 - Surface (AW, blue) and Intermediate (LIW) water mass circulation in GSA 11. Mesoscale structures (light blue) have high spatial and temporal variability. Va: anticyclonic eddies of Atlantic origin. Vv: wind induced eddies. Sc: Eastern Sardinia cyclonic Gyre, AW-CA: Algerian Current carrying on Atlantic Waters (Source: IAMC- CNR Oristano; Elaboration A. Olita).

The Intermediate Levantine Water (LIW) and a branch of the Eastern Mediterranean Deep-water (EMDW) enter in the Tyrrhenian Sea through the Sicilian Channel. Some this waters flow along the Corsica and Sardinia, mixing with the deep Tyrrhenian water (TDW) (Millot, 1999). Along the South-Western coasts of Sardinia, LIW and TDW flow northward, showing a change in path due to the interaction with the Algerian eddies and with topography.

32 First section - Chapter 2 - Ecological aspects Fisheries characteristics Trawling The trawling sector in Sardinia is characterised by prominent small-scale coastal fishing as well as by a marked polyvalence. Small-scale coastal fisheries is the most relevant segment, nevertheless trawling plays a role that is certainly not secondary in the regional context. In 2009, production from trawling amounted to slightly over 3 thousand tonnes, with a value of 20.3 million euros. The composition of landings features a high presence of fish (61%), followed by molluscs (28%) and crustaceans (11%) (Irepa, 2010). The trawling fleet operating in Sardinia comprises 137 boats and the sector provides employment for 433 fishermen. In 2009, the average activity for trawling boats in the area was 147 days per boat, compared to a national figure of 159 days. The larger dimensions of Sardinian trawlers is a direct consequence of the need to sail further from the coast to reach areas with a greater abundance of fish and geomorphological characteristics that are better suited to the use of trawl nets. Nevertheless, despite the significant presence of deep-sea fishing vessels with a GT>50 (about 1/3 of the trawlers), mention should be made of the presence of numerous small- sized boats (GT < 15) within the island’s trawling system that are regularly engaged in coastal fishing. In terms of geographical distribution, the regional trawling fleet is concentrated in the Cagliari district; about 60% of the trawling vessels (80 units), with greater respective tonnage, are registered in this area; this is followed by the departments of Olbia and Porto Torres.

Other systems The grouping classified as “other systems” includes boats that use passive fishing gears. Artisan fisheries is widely practiced throughout the territory, providing work for a relevant number of fishermen (approximately 1,823 employed individuals). The characteristic polyvalence of this system also allows the targeting of resources to be adapted to a seasonal regimen, with the use of different equipment according to the abundance of species in any given period. In 2009, the Sardinian fleet fishing with passive equipment (driftnets, handlines and pots) had a structure comprising 1,109 boats, with a total of 3,641 GT and 51,003 kW. In geographical terms, this fleet is mainly concentrated in the district of Cagliari (434 boats), followed by that of Oristano (303 boats). In regard to the targeted species, strong competition is noted between “other” systems and trawlers for capture of the same species. The catch composition is mainly fish (73.4%), molluscs (21.7%) and crustaceans (5%). The productive mix is characterised by a wide range of species, with red mullet (5.8% of total catches) and common octopus (10.4% of production) being most common; the average production price (summer 2011) is approximately 9.00 €/kg.

References - Addis P., Campisi S., Cuccu D., Follesa M.C., Murenu M., Sabatini A., Secci E. Cau A. (1998) - Mari di Sardegna: sintesi delle ricerche pesca a strascico negli anni 1985-1997. Biol. Mar. Mediterr. 5(3): 85-95. - Cau A., Sabatini A., Murenu M., Follesa M.C., Cuccu D (1994) - Considerazioni sullo stato di sfruttamento delle risorse demersali (Mari di Sardegna). Biol. Mar. Mediterr. 1(2): 67-76. - Irepa Onlus (2010) - Osservatorio economico sulle strutture produttive della pesca marittima in Italia. 2009. Edizioni Scientifiche Italiane, Napoli: 184 p. - Millot C. (1999) - Circulation in the Western Mediterranean sea. J. Mar. Syst. 20: 423-442. - Palomba M. & Ulzega A. (1984) - Geomorfologia dei depositi quaternari del Rio Quirra e della piattaforma continentale antistante (Sardegna Orientale). Rendiconti del Seminario della Facoltà di Scienze, 54: 109-121. - Ribotti A., Puillat I., Sorgente R., Natale S. (2004) - Mesoscale circulation in the surface layer off the southern and western Sardinia island in 2000-2002. Chem. Ecol., 20(5): 345-363.

33 2.1.4 GSA 16 - Southern coast of Sicily Fiorentino F., Bono G., Gancitano V., Garofalo G., Gristina M., Ragonese S., Vitale S.

Ecological context and geographical and environmental aspects In the statistical division FAO 37.2.2 (Ionian Division) the GSA 16 represents the northern part of the Strait of Sicily (figure 2.7).This area is featured by a complex bottom topography and hydrographic circulation pattern linked to water exchange between the western and eastern Mediterranean basins.

Figure 2.7 - Geography delimitation of the GSA 16. The bathymetric of 200 and 800 m and the main Harbor Master’s Offices are reported In the map.

It is considered an area with a high productivity of fish resources, although waters productivity it is not affected by the outflow of large rivers.

34 First section - Chapter 2 - Ecological aspects Among the main factors contributing to the observed high fisheries yield the following can be mentioned: • A large extension of the continental shelf both on the Sicilian and African side and the occurrence of offshore fishing banks; • Occurrence of stable upwelling and frontal systems enhancing primary and secondary production; • High biodiversity due to the ecotonal characteristics of the area between the eastern and western basins. The continental shelf along the Southern coasts of Sicily is wide and characterized by the Adventure and Malta banks, respectively on the western and eastern side, separated by a narrow shelf strip in the middle. The African shelf is wide along the Tunisian coasts and, with the exception of the Sirte Gulf, it becomes narrower along the Libyan coasts. The continental slope is generally steeper and more irregular between Sicily and Tunisia and along the eastern side of the Maltese bank than in the area between Malta Island and the Libyan coasts. The general circulation pattern (figure 2.8) is dominated by the inflow of the Modified Atlantic Water (MAW), flowing eastward and by the outflow of the Intermediate Levantine Waters (LIW), which moves westward along the Sicilian slope (200-500 m). The MAW current splits in two main streams, the Atlantic Ionic Stream (AIS) and the Atlantic Tunisian Current (ATC, Béranger et al., 2004). Flowing along the Adventure Bank margin, the AIS approaches the coast in the central area and moves offshore in the Ionian Sea when it meets the Malta Bank. Almost stable cyclonic geostrophic gyres and upwelling, enhanced by S-SW and N-NW winds, are linked to AIS along the Adventure Bank and eastward to Malta Island. Here the MAW meets the more salty and warm Ionian waters producing a permanent thermohaline front extending along the Maltese continental shelf margin (Sorgente et al., 2003). The main branch of ATC flows along the Tunisian continental shelf margin forming a strong coastal current along the Lybian coasts (Millot & Taupier-Letage, 2005).

35 Figure 2.8 - Streams circulation in the Strait of Sicily. Are reported the stable mesa-scale structure in the reported area. ABV: vortex of the Adventure Bank; ATC: Tunisian stream; AIS: Atlantic stream; ISV: Ionian vortex; LIW: Intermediate Levantine Waters (red); AW: Atlantic water (blue).

The Strait of Sicily is recognized as a high biodiversity hot spot also associated with complex and diversified benthic biocoenosis (Garofalo et al., 2007a). Recent studies showed a high diversity and biomass of demersal communities over the offshore detritic bottoms of the Adventure bank (Gristina et al., 2004, Garofalo et al., 2007a).

Fisheries characteristics Bottom trawling is the most important fishing activity along the Italian sector of the Strait of Sicily. The development of the Sicilian trawl fleet, occurred mainly during the 1970s, can be explained

36 First section - Chapter 2 - Ecological aspects with the co-occurrence of different factors, namely: i) availability of economic incentives during the ‘1970s for the construction of new trawlers; ii) good fishing opportunities due to both abundant fisheries resources and large trawable fishing grounds. Artisanal fishery, mainly carried out with with trammel nets, bottom and floating longlines for large pelagics, is still important, with several boats and fishermen involved, in some ports such as Marsala, Porto Empedocle, Licata, Gela, Scoglitti and Pozzallo. Two main trawl fishing activities can be identified: • inshore trawling, mainly based on the exploitation of the continental shelf, carried out by the fleets of Sciacca, Porto Empedocle, Licata, Gela, Scoglitti, Pozzallo, Porto Palo di Capo Passero and a small portion (about 15%) of trawlers from Mazara del Vallo. Trawlers accomplish usually 2 hauls 4-5 hours long per day, going out for fishing in early morning and coming back in port to sell fish in the afternoon. Their main target species and fishing grounds are listed in table 2.1. • II) an offshore trawling, conducted by trawlers generally over 24 m LFT and belonging to the Mazara del Vallo port. This fleet exploits fishery resources in international waters working both on the continental shelf and slope up to 700-800 m depth. Trawlers generally undertake long fishing trips (15-30 days) also exploiting areas in other GSAs inside the Strait of Sicily (i.e GSA 12, 13, 14, 15, 16 and 21).

Table 2.1 - Main target species of the trawl fisheries in the Strait of Sicily by different fishing type.

Fishing type Main target species Incidental Species Coastal fishing Red and striped red mullet, European hake, Pandora spp., common star gazer, greater weever, horned octopus, common , greater forkbeard, white and black anglerfish, deep-water rose shrimp, broadtail shortfin , Norway lobster, , Ray spp. (mixed fisheries) Off-shore fishing Red and striped red mullet European hake, pandora, common star gazer, (main striped red mullet) Ray spp., greater weever, horned octopus, common cuttlefish, greater forkbeard, white and black anglerfish Deep-water rose shrimp Norway lobster, European hake, greater forkbeard, lesser flying squid, white and black anglerfish, red and striped red mullet, Pandora spp., john dory, Ray spp. Red giant shrimp Norway lobster, European hake, lesser flying squid, white and black anglerfish, blackbelly rosefish, forkbeard, Ray spp.

In 2004 due to the decreasing catches of red shrimp in the Strait of Sicily, some trawlers begun to exploit fishing grounds in the Eastern basin (Garofalo et al., 2007b). From 2007 the number of vessels based in the Eastern Mediterranean Sea increased as also consequence of the extension of the Libyan economic exclusive zone to 74 miles from the coastline in 2005. Currently about 15 trawlers are involved in bathyal trawling for the giant red shrimp (Aristaemorpha foliacea) in the international waters offshore , , Cyprus, , , , . The fishing trips can last 2-3 months and every 20-30 days the frozen on-board catch is shipped to .

37 References - Béranger K., Mortier L., Gasparini G. P., Gervasio L., Astraldi M., Crepon M. (2004) - The dynamics of the Sicily Strait: a comprehensive study from observations and models. Deep-Sea Research Part II, 51: 411-440. - Garofalo G., Fiorentino F., Gristina M., Cusumano S., Sinacori G. (2007a) - Stability of spatial pattern of fish species diversity in the Strait of Sicily (central Mediterranean). Hydrobiologia, 580: 117-124. - Garofalo G., Giusto G.B., Cusumano S., Ingrande G., Sinacori G., Gristina M., Fiorentino F. (2007b) - Sulla cattura per unità di sforzo della pesca a gamberi rossi sui fondi batiali del Mediterraneo orientale. Biol. Mar. Mediterr., 14 (2): 250-251. - Garofalo G., Gristina M., Toccaceli M., Giusto G.B., Rizzo P., Sinacori G. (2004) - Geostatistical modelling of biocenosis distribution in the Strait of Sicily. In: Nishida T., Kailola P.J., Hollingworth C.E. (eds), Proceeding of the Second International Symposium on GIS/Spatial Analyses in Fishery and Aquatic Sciences, (Vol. 2). University of Sussex, Brighton: 241-250. - Gristina M., Garofalo G., Bianchini M.L., Camilleri M., Fiorentino F. (2004) - Evaluating the performance of an index of trawling impact in the Strait of Sicily. Biol. Mar. Mediterr., 11 (2): 230-241. - Millot C. & Taupier-Letage I. (2005) - Circulation in the Mediterranean Sea. In: Saliot A. (ed), Handbook of Environmental Chemistry, vol. 5, part K. Springer, New York: 29-66. - Sorgente R., Drago A.F., Ribotti A. (2003) - Seasonal variability in the central Mediterranean Sea circulation. Ann. Geophys., 21: 299-322.

2.1.5 GSA 17 - Northern Adriatic Sea Manfredi C., Piccinetti C.

Ecological context and geographical and environmental aspects GSA 17 (figure 2.9), which covers an area of 92,660 km², includes the Northern and Central Adriatic Seas, from the Gulf of to the line from the Promontory to the border between and and comes under the FAO statistical division 37.2.1 (Adriatic Sea). The overall area includes the coastlines of the Venezia Giulia, , Emilia , , and regions on the Italian side, and the coasts of , Croatia and Bosnia on the eastern side. The Italian side includes twelve maritime departments. Great morphological differences are found between the Italian side and the eastern side. The eastern coast is high, rocky and indented, with many small and large islands, defining channels, large internal marine areas and bays. The western coast is mainly low, flat and sandy, with the exception of and the Gargano Promontory. Large are found in the northern part, in the area of the Delta and to the north of the Gargano Promontory. The Northern and Central Adriatic Sea is characterised by a wide continental shelf that extends along most of the area. The northern part has shallow waters that gradually increase in depth towards the south, reaching a maximum of 70 metres. The Central Adriatic Sea reaches its maximum depth in the Pomo Depression (273 m); this is the only area of the basin with a depth of over 200 metres, together with the southern boundary between GSA 17 and GSA 18, where the depth increases at the slope of the South Adriatic depression. The temperature of the surface waters in the Adriatic Sea shows a clear seasonal cycle, with temperature fluctuations of over 10 °C due to atmospheric heat transfer (Artegiani et al., 1997b). In the summer, when a thermocline at a depth of 30 m in the Northern Adriatic Sea and of 50 m in the Central Adriatic Sea (Artegiani et al., 1997a) clearly separates the upper layer from the water below it, the surface temperature is fairly uniform throughout the entire basin and is 23-24 °C in the open sea. In winter, the rapid cooling of the sea surface in the northern basin, particularly with the north-easterly winds, affects the entire depth of the sea. In this season the temperature field shows a clear frontal area in the northernmost area and along the western coast (Artegiani et al., 1997b).

38 First section - Chapter 2 - Ecological aspects An increasing temperature gradient can normally be observed directly from the western to the eastern coast, with temperatures of below 11 °C along the Italian coast and of around 14 °C in the centre of the basin (Artegiani et al., 1997a). At depth (Pomo Depression) the temperature remains constant at around 11.5 °C.

Figure 2.9 - Geographical boundaries of GSA 17. The 200 and 800 m bathymetric contours are shown, together with the port authority headquarters of the various maritime departments.

In coastal and areas, high variations in temperature condition the movements of various organisms and certain biological cycles. In the winter many exploitable demersal species migrate from the coast to the open sea, where less extreme temperature conditions are found. The Adriatic Sea has relatively high salinity, with an average value of 38.3 psu (Vrgoč et al., 2004). As a general rule, the salinity of the Adriatic Sea decreases from the south to the north and from the open sea to the coast. The saline balance of the surface levels is clearly influenced by the input from rivers, which are numerous in the northern and western part of the Adriatic Sea and limited to a just few on

39 the eastern shore. The fresher coastal waters are always separate and distinguishable from the offshore waters and a marked saline frontal system is particularly evident along the western coast (Artegiani et al., 1997a). Seasonal variations in the salinity of the coastal waters, due to the changing capacity regime of the fresh water courses during the year, influence the movements of certain organisms, particularly from brackish environments to the open sea and vice versa. The high input of nutrients from river waters causes an increase in primary production, which is reflected in the food chain, leading to high fish productivity and making the Adriatic Sea one of the most productive areas in the Mediterranean Sea for fishing purposes. The input of fresh river waters conditions the productivity of certain areas in particular, such as the mouth of the river in Croatia and the area around the mouth of the Po in Italy. In the summer, when warm marine weather conditions, long periods of calm seas, large inputs of freshwater, etc., cause a marked stratification, with separation of the deeper waters from the warmer and less salty surface waters – where the nutrients remain confined – exceptional algal blooms of Dinoflagellates can develop. These blooms are often associated with hypoxia and anoxia phenomena, which cause considerable damage to demersal resources and benthic species. The general circulation is cyclonic in nature, with masses of water formed in the Eastern Mediterranean Sea entering through the Channel and flowing northwards along the eastern coast. The return flow is provided by the cold waters of the Northern Adriatic Sea (NAdDW), which are formed in winter and flow southwards at depth along the Italian coastline. Part of these go to replenish the deep-waters (MAdDW) in the Pomo area of the Central Adriatic Sea. The general circulation is composed of currents and vortexes, which appear, become stronger and change on a spatial scale in the various seasons (figure 2.10). The circulation of the Northern Adriatic Sea is dominated by the Northern Adriatic current (NAd-C), which flows southwards and shows a clear seasonal variation, and by the Northern Adriatic vortex (NAd- G), which can be seen in summer and is more intense in the autumn. In winter, the Northern Adriatic current is limited to the northernmost area of the basin, whereas in spring and summer it extends towards the central and southern basin, with phenomena of local intensification. The branch of this current in the Central Adriatic Sea is known as the Central- western Adriatic current (W-MAd-C), as it is separate from the Northern Adriatic current in the summer and both currents extend out to the open sea. In autumn the Northern and Central- western Adriatic currents combine to form a single current that flows towards the Southern Adriatic basin. A cyclonic structure (MAd-G) is present in the Central Adriatic Sea in all seasons except for winter (Artegiani et al., 1997b). Most of the seabed is covered by recent sediments of various mineral and granulometric composition, the movement of which is linked to the sea currents, which favour a longitudinal dispersion of the sediments. Stretching away from the Italian coast, towards the open sea, there is a narrow strip of coastal sand up to a depth of 5-7 metres, followed by a large strip of sand mixed with mud and then mud alone, up to 30-40 km from the coast, which extends from the mouth of the Po southwards until it joins the deep deposits in the southern zone. The situation is therefore different between the seabeds south of , covered with fine material and little sand, and the area further north. In the northern part, further offshore, after an area of mixed sediments (muddy sands and sandy muds) sands are once more found, considered to be “relict” deposits left during the Flandrian Transgression period (6,000 BC). These would have been deposited when the sea, which had withdrawn to the south as far as Pescara due to the

40 First section - Chapter 2 - Ecological aspects effect of the last glacial period (which occurred 15-18,000 years ago), began to return, spreading beach deposits over the exposed plain (Colantoni et al., 1979).

Figure 2.10 - Surface circulation and vortexes in GSA 17. NAd-C: Northern Adriatic current; NAd-G: Northern Adriatic vortex (autumn); W-Mad-C: Central-western Adriatic current (spring, summer, autumn); MAd-G: Central Adriatic vortex (spring, summer, autumn); W-Sad-C: South-western Adriatic current (spring, summer, autumn); E-SAd-C: South-eastern Adriatic current (spring, summer, autumn).

There are two other types of seabeds of notable interest in the Northern Adriatic Sea; the first consists of small sandy mounds, varying in diameter from a few hundred metres to a few kilometres, which emerge from the muddy seabeds and host a particular biological community; smooth clams are fished in this area. The same area also features a large number of so-called “tegnue”, solid substrate structures of biological origin which house solid substrate fauna and prevent fishing with towed nets.

41 Various works have been written on the distribution of benthic communities in the Adriatic Sea; the publication by Gamulin-Brida (1974), who adopted the classification proposed by Pérès and Picard (1964) to provide a new description of the faunal communities previously described by Vatova in 1949, is of fundamental importance. On the western side, the slight incline of the seabeds determines the distribution of the biotic communities along strips running parallel to the coast; on the eastern side, however, the seabeds and their respective communities form a mosaic structure. Within the Croatian channels the large variety of coastal sediments, mixed with those typical of deep offshore waters, forms a composition of benthic communities that is extremely complex and heterogeneous. Communities of fine sands in very shallow waters (SBS) are found from the western coast towards the open sea, at a depth of around 2.5 metres, characterised by bivalves of the genera Donax, Tellina tenuis and Lentidium mediterraneum. These are then replaced by communities of well- sorted fine sands (WCFS), characterised by the dominance of , other bivalves including Ensis spp. and the gastropod mollusc Nassarius mutabilis. Further offshore, between 15 and 20 metres in depth, with an increase in the muddy component, there is a transitional community between that of well-calibrated find sands and coastal terrigenous muds, with Corbula gibba representing the dominant species. Further offshore, up to around 50-60 metres in depth, there is a large strip of coastal terrigenous mud communities (VTC), dominated by the gastropod mollusc Turritella communis, and the bivalves Corbula gibba and Nucula nucleus. Alongside this, in the eastern part, are shelf-edge detritic bottom (DL) communities, featuring compact sandy sediments and characterised by the presence of Tellina distorta and abundant epifauna (sea sponges, ascidians, anthozoans, etc.). Coastal detritic bottom (DC) communities are found in the Central-eastern area of the Gulf of , between the coastal terrigenous mud communities and those of the shelf-edge detritic bottom, whereas south of Pescara, beyond the coastal terrigenous muds, are found offshore mud (VL) communities, with Nephrops norvegicus and Nucula profonda facies. Following widespread blight due to phenomena of anoxia, particularly in 1977, many changes were observed in the composition of certain biotic communities in the Northern Adriatic Sea and still today, within certain areas, large fluctuations in the abundance of certain species can still be noted. It should be borne in mind that the benthos is also greatly affected by fishing activities; for example, areas where fishing with bottom trawl was difficult in the past, due to a great abundance of sponges of the geodia genus, have gradually been cleared of large specimens and can now be trawled. Certain environments of considerable interest can be found In the Northern and Central Adriatic Seas, even if sometimes of limited size. The large lagoons of Grado, Marano and Venice, and the valleys of Comacchio and the Po Delta are particular environments, with fundamental roles for the biological cycle of euryhaline species. The sandy mounds and Tegnue of the Northern Adriatic, as well as the numerous rocky shallows that emerge from sea beds at a depth of over 100 metres in the Central Adriatic Sea, are all particular environments that contribute in a fundamental way to the biological diversity of the Adriatic.

Fisheries characteristics Age-old traditions can be found in the marine fishing communities, each with their own particular features due to the fact that the various fishing activities developed in relation to the natural

42 First section - Chapter 2 - Ecological aspects environment, the available species and the equipment and fishing methods that could be used. This process of change in fishing methods on the basis of available technologies is still in progress today. There has been a shift from trawling, particularly that involving fishing trips of over 24 hours, towards less strenuous activities, such as clam fishing with hydraulic dredges and fishing with set gillnets and traps, which can be carried out close to the coast on boats with a crew of one or two fishermen. In GSA 17 that age-old process that has led to the development and decline of marine communities in relation to fisheries, their legislation and market trends still continues: if in the past there were few rules, of a general nature, it should be borne in mind that present regulations, particularly those of the European Community, have outlawed many forms of traditional fishing in the Adriatic Sea (due to mesh types, catch sizes, fishing zones or use of gear that is no longer permitted).

Trawling 747 Italian trawlers were operating in GSA 17 in 2009, with a tonnage of 32,475 GT, 155,972 kW of power and a total production of 27,564 tonnes (Source: Irepa). The Croatian trawling fleet, consisting of 503 vessels with a tonnage of 11,960 GT, 71,508 kW of power and a production of 5,000 tonnes (Source: MPRRR), and the small Slovenian trawling fleet, composed of 21 vessels totalling 281 GT, 2,998 kW and a production of 134 tonnes, operated on the same resources. It is interesting to note that, according to official data, the Italian vessels caught a quantity of fish per kW 2.5 times greater than Croatia and 4 times greater than Slovenia; this difference can be partly attributed to limits in the official statistics on catch quantities and different fishing times.

Small-scale coastal fisheries The most widespread form of fishing throughout GSA 17 is that carried out with fixed gear, particularly set gillnets, traps and hooks. This type of fishing is a source of transmitted knowledge on the presence and behaviour of many organisms. The number of vessels involved in this kind of fishing is very high, even if it is difficult to determine, since, particularly on the eastern shore, there are tens of thousands of boats fishing with fixed gear, making production difficult to assess due to the extreme dispersion of the territory and the variability of the gear and species caught.

Other fishing activities Small-scale pelagic fisheries on the Italian shore is mainly carried out using pelagic trawl; a small number of vessels operate using purse seine exclusively in the southern part of the Central Adriatic Sea. Small-scale pelagic fishing is carried on the Croatian shore out using purse seine together with lamps, and only a few units in the Northern Adriatic operate using pelagic trawl. Bivalve fishing using hydraulic dredges has considerable importance on the Italian shore, where it is carried out by more than 600 vessels; this type of fishing is not practised in Croatia and Slovenia.

References - Artegiani A., Bregant D., Paschini E., Pinardi N., Raicich F., Russo A. (1997a) - The Adriatic Sea general circulation. Part I: air-sea interactions and water mass structure. Journal of Physical Oceanography, 27: 1492-1514. - Artegiani A., Bregant D., Paschini E., Pinardi N., Raicich F., Russo A. (1997b) - The Adriatic Sea general circulation. Part II: Baroclinic circulation structure. Journal of Physical Oceanography, 27: 1515-1532. - Colantoni P., Gallignani P., Lenaz R. (1979) - Late and evolution of the North Adriatic continental shelf (Italy). Marine geology, 33: 41-50.

43 - Gamulin-Brida H. (1974) - Biocoenoses benthiques de la Mer Adriatique. Acta Adriatica, 15 (9): 102 p. - Pérès J.M. & Picard J. (1964) - Nouveau manuel de bionomie benthique de la Mer Méditerranée. Rec. Trav. Stat. Mar. Endoume, 31 (47): 137 p. - Vatova A. (1949) - La fauna bentonica dell’Alto e Medio . Nova Thalassia, 1 (3): 110 p. - Vrgoč N., Arneri E., Jukić-Peladić S., Krstulović-Šifner S., Mannini P., Marčeta B., Osmani K., Piccinetti C., Ungaro N. (2004) - Review of current knowledge on shared demersal stocks of the Adriatic Sea. FAO-MiPAAF Scientific Cooperation to Support Responsible Fisheries in the Adriatic Sea. AdriaMed Technical Documents, 12: 91 p.

2.1.6 GSA 18 - Southern Adriatic Sea Lembo G., Spedicato M.T.

Ecological context and geographical and environmental aspects Geographical sub-area 18 (GSA 18 - Southern Adriatic Sea, figure 2.11) has an extension of 29,008 km2 (from around 10 to 800 m in depth) and comes under FAO statistical division 37.2.1 (Adriatic Sea). The total area includes the Italian coasts of the Puglia region, on the western side, and those of Montenegro and on the eastern side. The western shore of GSA 18, which covers approximately 520 km of coastline, includes four maritime departments. The Southern Adriatic Sea extends from the line between Gargano and to the boundary with the Ionian Sea at the of Otranto (Artegiani et al., 1997). This southern section of the entire Adriatic Sea is characterised by the presence of a deep central depression known as the “South Adriatic Pit” (or Pit). The seabed reaches a depth of 1,233 m in this area. These boundaries for the Southern Adriatic Sea correspond to a large degree to the GFCM-FAO classification of geographical sub-area 18. The northern and southern portions of the Southern Adriatic Sea feature substantial differences; the first contains a wide continental shelf (the distance between the coastline and a depth of 200 m is around 45 nautical miles) and a very gradual slope; in the second, the isobathic contours are very close, with a depth of 200 m already found at around 8 miles from the Cape of Otranto. The continental shelf break is at a depth of around 160-200 m and is furrowed by the heads of canyons running perpendicular to the line of the shelf. These incisions in the seabed provide preferential routes for the transfer of sediments towards the abyssal plain, particularly when they are nearer to the coastline. In regard to water masses, the Adriatic Sea can be divided into three main levels: the surface, intermediate and deep levels, with differences in the salinity and thermal characteristics of the water masses according to the latitude. These levels, although exerting a reciprocal influence, have an independent system of currents and the circulation is characterised by cyclonic movements (Artegiani et al., 1997). The characteristics of the main water masses affecting the Southern Adriatic circulation can be summarised as follows: • Surface Water (SAdSW), which reaches a depth of 50 m, with seasonal and annual variations. This mass of water reaches the thermocline (even as far as 70 m) during summer, while in winter it descends in depth and occupies the intermediate level, either entirely or in part; • Levantine Intermediate Water (LIW), from 150 to 400 m; • Deep-water (SAdDW), over 800 m in depth. The Southern Adriatic Sea is linked to the Northern Ionian Sea through the Otranto Channel. The water masses that enter from the Eastern Mediterranean Sea flow along the eastern shore, while the cold water of the North Adriatic (NAdDW, North Adriatic Deep-water) flows from north to south

44 First section - Chapter 2 - Ecological aspects along the western shore (Vilibic and Orlic, 2002). The sinking of these denser waters is compensated by the flow of Ionian waters (Ionian Surface Water, ISW) and Levantine Intermediate Water (LIW), which contributes to maintaining the salinity of the basin and, together with the ISW, compensates for its heat loss. In the intermediate level (LIW), the incoming flow of the water masses continues throughout the year, particularly during summer, when prevailing southern winds facilitate the entrance of waters through the Otranto Channel. The intermediate level is therefore characterised by Eastern Mediterranean waters, which are warmer and more saline. The exiting flow prevails, however, particularly in winter, to compensate for the inflowing water.

Figure 2.11 - Geographical boundaries of GSA 18. The 200 and 800 m bathymetric contours are shown, together with the port authority headquarters of the various maritime departments.

45 Figure 2.12 - Circulation of surface (AW) and intermediate (LIW) currents in GSA 18. AW: modified waters of Atlantic origin (blue); LIW: Intermediate waters of Levantine origin (red); SAd-G: Southern Adriatic vortex; E-SAd-C: South-eastern Adriatic current; W-SAd-C: South-western Adriatic current.

The deep thermoaline circulation is joined by a surface thermoaline circulation, with an anticlockwise movement and a cyclonic structure, to form the Southern Adriatic vortex (SAd-G): this structure produces an upwelling of water from its centre. The two main coastal currents (figure 2.12) are the South-eastern Adriatic current (E-SAd-C) and the South-western Adriatic current (W-SAd-C). The first carries warm, saline waters to the Adriatic, while the second is mainly composed of cold waters with low salinity, coming mainly from the input of the Po river, which pushes the waters of the Adriatic towards the Ionian Sea (Zore-Armanda, 1969). This current only departs from the

46 First section - Chapter 2 - Ecological aspects coastline near the Gulf of ; the presence of the Gargano promontory forces it to flow in a wide curve, creating a local anti-clockwise circuit in the gulf, before returning to flow along the shore near Bari. The surface circulation structures show significant seasonal variations. The Southern Adriatic basin contributes to the entire Mediterranean water mass circulation with its flow of deep-waters, which are formed in the Southern Adriatic pit by the mixing of highly saline waters from the Levant basin with dense waters from the Northern Adriatic and by local convection from surface cooling (Vilibic & Orlic, 2002). The Adriatic Sea, together with the Levant basin, is one of three areas in the Mediterranean where down-welling processes produced by surface cooling lead to the formation of so-called “dense waters”, rich in oxygen, which supply the lower levels. The spatial and temporal variability of the currents influences vitally important life-history traits of fish populations, as the reproductive events and the success of recruitment. An important change in water mass circulation, known as the Eastern Mediterranean Transient (EMT), has affected Mediterranean circulation since the late 1980s, following particular climatic events. The flow of the deep-waters of the Southern Adriatic Sea was replaced by warmer and more saline waters from the Aegean, causing a rise in salinity and temperature, with probable consequences on the productivity of the basin (CIESM, 2000). The input of saline waters from the Levant basin through the Otranto Channel gives this area the highest level of salinity in the entire Mediterranean Sea, with peaks of 39.1 psu. In fact, the seabed in the eastern part of the southern basin have higher salinity and temperature regimes than the western part (Artegiani et al., 1997). The average salinity of the basin is 38.5 psu. The LIW waters in the south-eastern area have an average salinity of 38.75 psu (and a temperature of 13.7 °C), while the deep-waters have an average figure of 38.65 psu (and a temperature of 13.3 °C). Salinity measurements taken repeatedly over the years, both in coastal areas and the open sea, suggest a slight but constant increase in the average salinity of the Adriatic Sea (Zore-Armanda, 1991). The surface water temperature varies from 28-29 °C in summer to 9-11 °C in winter. Nitrogen and phosphorus concentrations, with an average respective variation of 25-35 µg/l and 7-12 µg/l (Casavola et al., 1995), cause a condition of oligotrophy and the concentration of chlorophyll a is 0.5-1.5 µg/l. The seabed on the continental shelf has a slight slope and is almost exclusively sedimentary. As the distance from the coastline and the gradient in the seabed gradually increase, together with the lower hydrodynamism, mud gradually becomes prevalent, favouring the establishment of biotic communities of muddy sands. The area of the , protected by the direct effect of the W-SAd-C current by the presence of the Gargano Promontory, is subject to hydrodynamic conditions that facilitate and enrich the waters with nutrients, creating favourable conditions to bivalve mollusc populations of commercial significance. In particular, in the areas closest to the coast, communities of fine sand (SFBC) prevail, characterised by the bivalves Chamelea gallina and Acanthocardia tuberculata, while offshore, sediments of organogenic origin (maerl and pre-coralligenous seabeds) are populated by Venus verrucosa and Laevicardium oblungum (Vaccarella et al., 1996). Offshore from Bari, communities of coastal detritic bottom (DC) and shelf-edge detritic bottom (DL) are established on relict sediments, to which fine detritic-organogenic materials have been added. In the coastal zone between Bari and , from the shoreline towards the open sea,

47 there is a succession of rocky seabeds, mainly colonised by photophilic algae (AP) communities, short sandy stretches at depths of up to 5-6 m, Posidonia oceanica meadows, coralligenous formations (already at 12 m and up to 22 m) and finally, terrigenous coastal muds (VTC). In the stretch of coast between Brindisi and Otranto, the infralittoral zone is characterised by a limited strip with fine sands (SFBC), followed by an extensive strip of sea grass, established both on “mattes” and on sand and, in some stretches, even on the rocky substrate. The largest expanse of , just over 3 km in extension, has been found in this zone (CRISMA, 2006a). Biotic communities equivalent to a “pre-coralligenous” environment can be found in the “inter- matte” zones. A coralligenous environment is found up to 40-50 m, where it is then replaced by seabeds with terrigenous coastal muds (VTC), characterised by the gastropod Turritella communis. In the Southern Adriatic Sea, the lower limit of the seagrass never exceeds 25 m in depth, whereas the upper limit is often at around 6-7 m and in rare cases even seems to extend to shallower waters, as in an area to the south of San Cataldo () (CRISMA, 2006a).

Fisheries characteristics The Southern Adriatic sea makes a substantial contribution to national fishery production, with an input comparable to that of the Strait of Sicily, accounting for about 13% of production (Irepa data, 2010). The Italian fleet in the Southern Adriatic Sea is composed of around 1,100 boats: 44% of the boats are equipped with artisanal fishing gear, 43% are trawlers and 7% are dredges for bivalve mollusc fishing (Irepa, 2009). The main fishing ports are Manfredonia, , , and . Edible bivalve mollusc stocks, abundant in the 1980s, have undergone a gradual decline, both due to environmental causes and excessive fishing. Two producer associations (Co.Ge.Mo.), in and Manfredonia, now manage the harvesting of Chamelea gallina by a series of shared rules, observing fishing ban periods and harvesting the product in response to a specific market request. The production of C. gallina, the third of the 10 most important species for commercial landings, currently accounts for around 6% of the local production (Irepa, 2010). Anchovy (Engraulis encrasicolus), which occupies the first place in terms of commercial yields in the Southern Adriatic, represented around 29% of catches in 2010 (Irepa, 2010). The Gulf of Manfredonia is an area with a high concentration of juvenile forms of small . Anchovy and sardine in the adult stage are fished throughout the year in circalittoral areas parallel to the coast, mainly with the use of seine, “ciancioli” or “lampare” nets, as well as with “volante”-type pelagic trawl nets. Bianchetto (juvenile sardine, Sardina pilchardus) fisheries, which are highly developed in Manfredonia, are now subject to thorough revision and specific management plans following the enforcement of the Regulation (EC) 1967/2006. Fishing for common octopus, which is found abundantly in the first 50 m of depth, is still quite common along the Bari coastline, as is that for the sea urchin Paracentrotus lividus, which since the mid-1990s has been subject to specific regulations limiting quantities, size and fishing periods (Ministerial Decree 12/01/95, Sea urchin fisheries regulation). In the fishing communities of Mola di Bari, Monopoli and Savelletri, the large Scombroidei Xiphias gladius (swordfish) and Thunnus alalunga (albacore) are fished seasonally, from May to November, using long-lines. Fishing for large hake (Merluccius merluccius) with bottom long lines is also very common in these fishing communities, particularly in Monopoli. This type of fishing involves less than 5% of the entire South-western Adriatic fleet, but accounts for a significant share of hake production (around 10-12%, according to Irepa, 2010).

48 First section - Chapter 2 - Ecological aspects Trawling is the most significant fishing activity in the whole area, with a fishing effort representing around 70% of the total effort (Irepa, 2010). Trawling is also prevalent on the eastern shore (Mannini et al., 2004). The area potentially exploited by this type of fishery is around 15,000-17,000 km2 (70% on the western side and 30% on the eastern side). The size of the trawlable area increases along a latitudinal gradient from the south towards the north of the basin. The slope is difficult to trawl due to the presence of “dirty” seabeds and war remnants. A recently created geo-referenced information system provides the spatial location and description of around 300 obstacles, obtained through images from side scan sonar systems and ROVs (CRISMA, 2006b). Fishing habits change from one fishing community to another and depend to a large extent on fleet capacity. For example, the largest fleet is concentrated in Molfetta and makes trips of 2 to 3 days, whereas the largest number of trawling vessels is located in Manfredonia, where one-day trips are made (Lembo & Donnaloia, 2007).

References - Artegiani A., Bregant D., Paschini E., Pinardi N., Raicich F., Russo A. (1997) - The Adriatic Sea general circulation. Part I: air-sea interactions and water mass structure. Journal of Physical Oceanography, 27: 1492-1514. - Casavola N., Martino G., Hajderi E. (1995) - Caratteristiche trofiche delle acque del Basso Adriatico. Biol. Mar. Mediterr., 2 : 573-574. - CIESM (2000) - The Eastern Mediterranean climatic transient: its origin, evolution and impact on the ecosystem. CIESM Workshop Series, 10, Trieste: 86 p. - CRISMA (2006a) - Inventario e cartografia delle praterie di Posidonia nei Compartimenti marittimi della Puglia. POR Puglia 2000/2006. Consorzio per la Ricerca applicata e l’Innovazione tecnologica nelle Scienze del Mare, Bari: 204 p. - CRISMA (2006b) - Inventario e cartografia degli ostacoli alla pesca nei Compartimenti marittimi della Puglia. POR Puglia 2000/2006. Consorzio per la Ricerca applicata e l’Innovazione tecnologica nelle Scienze del Mare, Bari: 72 p. - Lembo G. & Donnaloia L. (2007) - Osservatorio Regionale Pesca e Acquacoltura. Puglia 2007. COISPA, Bari: 89 p. - Mannini P., Massa F., Milone N. (2004) - Adriatic Sea fisheries: outline of some main facts. In: AdriaMed Seminar on Fishing Capacity: Definition, Measurement and Assessment. FAO-MiPAAF Scientific Cooperation to Support Responsible Fisheries in the Adriatic Sea. AdriaMed Technical Documents,13: 13-33. - Vaccarella R., Pastorelli A.M., De Zio V., Rositani L., Paparella P. (1996) - Valutazione della biomassa di molluschi bivalvi commerciabili presenti nel Golfo di Manfredonia. Biol. Mar. Mediterr., 3: 237-241. - Vilibic I. & Orlic M. (2002) - Adriatic water masses, their rates of formation and transport through the Otranto Strait. Deep Sea Res., 49: 1321-1340. - Zore-Armanda M. (1969) - Water exchange between the Adriatic and Eastern Mediterranean. Deep Sea Res., 16: 171-178. - Zore-Armanda M. (1991) - Natural characteristics and climatic changes of the Adriatic sea. Acta Adriatica, 32: 567-586.

49 2.1.7 GSA 19 - North-Western Ionian Sea Tursi A., D’Onghia G., Sion L., Carlucci R., Capezzuto F., Maiorano P.

Ecological context and geographical and environmental aspects The GSA 19 (FAO statistical division 37.2.2-Ionian Sea) (figure 2.13) is located between Cape Otranto (Lecce) and Cape Passero (Siracusa). This area covers a surface of about 16,500 km2, is 10- 800 m deep and has a coast line of about 1,000 km along the , Lucania, Calabria and Sicily regions, where eight maritime compartments are located.

Figure 2.13 - Geographical Sub Area (GSA) 19 with indication of the contour lines of 200 and 800 m in depth and the harbour offices of their maritime compartments.

50 First section - Chapter 2 - Ecological aspects The North-Western Ionian Sea is geo-morphologically divided in two sectors by the Taranto Valley (NW-SE canyon exceeding 2200 m in depth): an Eastern sector and a South-Western one. The former is located between the Taranto Valley and the Apulia and is represented by a broad continental shelf with abrasion terraces and bioclastic calcareous deposits with several coral rocks (Senatore et al., 1980). The South-Western sector constitutes the southern continuation of the Apennine thrust sheets. Along the Calabria and Sicily, the shelf is generally very limited with the shelf break located at a depth varying between 30 and 100 m. Many submarine canyons are located along these coasts (Rossi & Gabbianelli, 1978), playing an important role in the transport of terrigenous debris from coastal waters to deeper grounds. The canyons are sites of vertical displacement for , some species of which have a commercial interest, such as the deep-water shrimps Aristeus antennatus and Aristaeomorpha foliacea (Matarrese et al., 1995; Relini et al., 2000). These habitats are unsuitable for trawling and represent a sheltered site for species during sensitive phases of their life cycle. The canyons can act as “ecological refuge” for many bathyal and endemic species constituting “hot-spots” of biodiversity in the Mediterranean Sea where conservation measures are needed (Gili et al., 1998). From a hydrographic point of view, the Ionian Sea receives surface Atlantic Water (AW) from the Western Mediterranean through the Sicilian Channel, with salinity increasing from 37.5 psu in Sicilian Channel to 38.6 psu near the Cretan Passage (Theocaris et al., 1993) (figure 2.14). AW extends down to 60-150 m and its temperature can range from about 13 °C in winter to 28 °C in summer, with seasonal changes. Levantine Intermediate Water (LIW) lies under the surface layer and extends down to 800-900 m. LIW is characterized by variable salinity and temperature values between the Southern and Northern Ionian. The Adriatic Sea is considered the main source of cold and less saline Eastern Mediterranean Deep-water (EMDW) (Canals et al., 2009) which underlies LIW and extends down to the bottom. The general cyclonic circulation in the Ionian Sea is markedly influenced by the cold dense deep-water masses of the Adriatic Sea inflowing through the Otranto Channel. Hydrographic observations and current measurements performed in the 1990s revealed strong modifications in the dynamics of the entire water column termed Eastern Mediterranean Transient (EMT) which at the present seems to be concluded (Klein et al., 1999; Manca et al., 2002). The Ionian Sea, like most of the Mediterranean Sea, shows oligotrophic conditions (Rabitti et al., 1994). Nitrogen and phosphate concentrations are about 90% and 129%, respectively, lower than the western basin. Although the Ionian Sea shows a general low productivity, the total vertical flux of particulate matter recorded on the slope in the Otranto Channel was found to be similar to that observed in coastal areas of the Western Mediterranean and Northern Adriatic seas. Different biocoenoses are distributed along the very long Ionian arc from the coastal to the bathyal grounds. Along the Apulia coast, rocky bottoms dominate on the shelf, rich in marine caves of high ecological importance. In addition, Posidonia oceanica meadows and biocoenosis of coralligenous are widespread in this geographic sector, making it a priority habitat for conservation purposes. The former extends, mostly from Gallipoli and Torre Ovo, from a few metres to about 30 m deep. This seagrass, together with Cymodocea nodosa, is spread on sandy bottoms in the Porto Cesareo MPA. The coralligenous bottoms occur mainly from 40 to 80 m deep. In shallower waters, portions of coast are characterized by the biocoenoses of coarse sands and fine gravels under bottom currents (SGCF) and superficial muddy sands in sheltered areas (SVMC). Along the Lucania and Calabria coasts, the presence of several streams and rivers (the Bradano, Basento, Cavone, Agri, Sinni, Crati etc.) resulted in broad alluvial sandy beaches characterized

51 by stretches of dunes covered by evergreen maquis. In many coastal areas, fine and coarse sand bottoms alternate with coastal detritic communities and seagrass meadows (P. oceanica and C. nodosa). In the circalittoral zone, both along the Apulia and Calabria coasts, the biocoenosis of the terrigenous mud is widespread from a depth of 70-80 m. In Calabria, at South-West of Cape Spulico, the Amendolara seamount extends covering an area of about 31 km2 with a high diversity of fish, crustaceans and cephalopods seek by local fishermen.

Figure 2.14 - Circulation of surface Atlantic Waters (AW), Levantine Intermediate Waters (LIW) and Eastern Mediterranean Deep-waters (EMDW) in the North-Western Ionian Sea. AW-a (blue): annual surface circulation of modified Atlantic Waters; AW-s (sky blue): seasonal surface circulation of modified Atlantic Waters; LIW (red): circulation of Levantine Intermediate Waters; EMDW (black): Eastern Mediterranean Deep-waters.

52 First section - Chapter 2 - Ecological aspects On the shelf edge, in both sectors of the North-Western Ionian Sea, there are some areas with the biocoenosis of the shelf-edge detritic often characterised by the dominance of the sea-lily Leptometra phalangium, while over the continental slope the biocoenosis of the bathyal mud extends in the whole Ionian Sea. In the context of this biocoenosis, the facies characterised by the species Funiculina quadrangularis and Isidella elongata have almost completely disappeared due to trawl fishing. These two facies were often associated to the presence of commercial species such as P. longirostris and Nephrops norvegicus for the former and A. antennatus and A. foliacea for the latter. In the bathyal ground, the (SML) coral province, characterized by living Madrepora-Lophelia-bearing coral mounds, extends within an area of about 900 km2 between 350 and 1100 m deep. More than 220 species were identified in this area. The SML coral province represents a Mediterranean deep-water biodiversity “hot-spot” which could also play an important role as nursery and spawning area for demersal species (D’Onghia et al., 2010). In order to protect this site, in January 2006 the GFCM created the new legal category of “Deep-sea fisheries restricted area”. The most important resources in the North-Western Ionian Sea are represented by the red mullet () on the continental shelf, hake (Merluccius merluccius), deep-water rose shrimp (Parapenaeus longirostris) and Norway lobster (Nephrops norvegicus) on a wide bathymetric range and by the deep-water shrimps (Aristeus antennatus and Aristaeomorpha foliacea) on the slope. Other important commercial species in the GSA 19 are the octopus (Octopus vulgaris), the cuttlefish (Sepia officinalis) and common pandora (Pagellus erythrinus) on the shelf, the horned octopus (Eledone cirrhosa), the (Illex coindetii and Todaropsis eblanae), the blue whiting (Micromesistius poutassau), the anglers ( and Lophius budegassa) on a wide bathymetric range, the greater forkbeard (Phycis blennoides), the rockfish (Helicolenus dactylopterus) and the shrimps Plesionika heterocarpus and Plesionika martia on the slope. In addition, many other species are generally caught and totally discarded due to their lack of economic value such as the chondrichthyes Galeus melastomus and Etmopterus spinax and the osteichthyes Hoplostethus mediterraneus, Coelorinchus caelorhincus, Nezumia sclerorhynchus and Hymenocephalus italicus.

Fisheries characteristics In the North-Western Ionian Sea fishing occurs from coastal waters to about 800 m. Gallipoli, Taranto, Crotone and Reggio Calabria represent the most important fisheries although with a different distribution of the fishing effort. In the whole GSA19 different fishing techniques are used. The number of vessels and mean gross tonnage (GT) for different gears recorded in the main fisheries (Gallipoli, Taranto, Crotone and Reggio Calabria) of the GSA19 are reported in table 2.2 (Mipaaf_Irepa Font). The national official statistics (Mipaaf_Irepa Font) report the highest percentage of big gross tonnage vessels (≥ 10 GRT) in Crotone (42%) followed by Gallipoli (33%), while Taranto and Reggio Calabria fisheries are mainly made up by small vessels. Small scale fishing, which utilizes mostly trammel nets, longlines and traps, is widespread in the North- Western Ionian Sea. Trawlers represent about 21% in number, 64% in gross tonnage and 56% in engine power in the whole GSA19. However, in all Ionian fisheries fishing boats registered as polyvalent fishing vessels often change type of fishing according to the season and sea-weather conditions as well as to the changing availability of resources and market demand.

53 Trawling is carried out during daily trips, from Monday to Friday, at different depths, generally from 200 to about 800 m; fishing is not allowed at night or weekends. The mean annual catch of trawling is due to the three main fisheries of the North-West Ionian Sea (Crotone, Taranto and Gallipoli) representing about 3% of the whole Italian production (Maiorano et al., 2010).

Table 2.2 - Number of vessels and mean gross tonnage (GT) for different gears recorded in the main fisheries (Gallipoli, Taranto, Crotone and Reggio Calabria) of the GSA19.

Trawling Longline Gillnet Purse seine Fisheries N. vessels Mean GT N. vessels Mean GT N. vessels Mean GT N. vessels Mean GT Gallipoli 75 11.61 16 8.22 313 3.58 - - Taranto 53 9.27 2 9.43 118 2.65 6 8.92 Crotone 95 18.55 16 9.31 262 2.71 - - Reggio Calabria 1 19.55 4 15.40 121 2.15 - -

References - Canals M., Danovaro R., Heussner S., Lykousis V., Puig P., Trincardi F., Calafat A.M., Durrieu De Madron X., Palanques A., Sànchez-Vidal A. (2009) - Cascades in Mediterranean submarine grand canyons. Oceanography, 22(1): 26-43. - D’Onghia G., Maiorano P., Sion L., Giove A., Capezzuto F., Carlucci R., Tursi A. (2010) - Effects of deep-water coral banks on the abundance and size structure of the megafauna in the Mediterranean Sea. Deep-Sea Research, II, 57: 397-411. - Gili J.M., Bouillon J., Pages F., Palanques A., Puig P., Heussner S. (1998) - Origin and of deep-water Mediterranean Hydromedusae including the description of two new species collected in submarine canyons of Northwestern Mediterranean. Sci. Mar., 62(1-2): 113-134. - Klein B., Roether W., Manca B., Bregant D., Beitzel V., Kovacevic V., Luchetta A. (1999) - The large deep transient in the Eastern Mediterranean. Deep-Sea Res. Part I 46: 371-414. - Maiorano P., Sion L., Carlucci R., Capezzuto F., Giove A., Costantino G., Panza M., D’onghia G., Tursi A. (2010) - The demersal faunal assemblage of the North-Western Ionian Sea (Central Mediterranean): present knowledge and perspectives. Chemistry and , Volume 26(1): 219-240. - Manca B.B., Ursella L., Scarazzato P. (2002) - New development of Eastern Mediterranean circulation based on hydrological observations and current measurements, P.S.Z.N. Marine Ecology 23, Suppl. 1: 237-257. - Matarrese A., D’onghia G., De Florio M., Panza M., Costantino G. (1995) - Recenti acquisizioni sulla distribuzione batimetrica di Aristaeomorpha foliacea ed Aristeus antennatus (Crustacea, Decapoda) nel Mar Jonio. Biol. Mar. Medit. 2 (2): 299-300. - Rabitti S., Bianchi F., Bolfrin A., Da Ros L., Socal G., Totti C. (1994) - Particulate matter and phytoplankton in Ionian Sea. Oceanologica Acta 17 (3): 297-307. - Relini M., Maiorano P., D’Onghia G., Relini L.O., Tursi A., Panza M. (2000) - A pilot experiment of tagging the deep shrimp Aristeus antennatus (Risso, 1816). Scientia Marina 64(3), 357-361. - Rossi S. & Gabbianelli G. (1978) - Geomorfologia del Golfo di Taranto. Boll. Soc. Geol. It., 97: 423-437. - Senatore M.R., Mirabile L., Pescatore T., Tramutoli M. (1980) - La piattaforma continentale del settore nord-orientale del Golfo di Taranto (piattaforma pugliese). Geol. Appl. Idrogeol.: 33-50. - Theocharis A., Georgopoulos D., Lacsaratos A., Nittis K. (1993) - Water masses and circulation in the central region of the Eastern Mediterranean: Eastern Ionian, South Aegean and Northwest Levantine, 1986-1987. In Tropical studies in Oceanography II, Robinson A.R. and Malanotte-Rizzoli eds. Deep-Sea Res. 40 (6): 1121-1142.

54 First section - Chapter 2 - Ecological aspects 2.2 Coastal lagoons in Italy Ciccotti E., Tancioni L., Cataudella S.

Historical and geographical background Italy has an extensive coastline, extremely varied in morphology and design. Its profile has been shaped over time by geological processes involving marine and continental dynamics, through the transport of materials, erosion and sedimentation, that resulted in a extraordinary richness of lagoons, and coastal lagoons. The current ​​lagoon area is approximately 160,000 hectares. This is the remnant of a much larger area: in pre-Roman times wetlands area of in Italy amounted to more than 3 million hectares. The first drainage works date back in Italy to the Romans, who claimed land in the Pontine Plain (LT), in Val di Chiana, in Ansedonia. In the following centuries, in different moments, there were other important interventions: between the twelfth and thirteenth centuries, many Benedictine monasteries were built in areas that were made suitable to building and agriculture by the implementation of hydraulic drainage, sewerage and irrigation interventions. Around the middle of 1500, the Venetian Republic reclaimed over 40,000 acres. In 1865, the Italian wetlands were reduced to 1.3 million hectares, representing however still 4.6% of the area of ​​Italy. In the late nineteenth and early twentieth centuries, Italian wetlands suffered the most radical contraction, with the loss of over 1.1 million hectares. The increase in population, the need for large areas for agriculture, but also the urgent need to address malaria that affected rural populations in many areas, led to massive land reclamation, most of which was implemented in the Fascist period. With the reclamation of the lagoon areas between Modena and Ferrara, the landscape of the lower radically changed, and in the Maremma and the Pontine Plain many wetlands, that had survived for thousands of years, disappeared. Also on the coasts of and its islands, primarily Sardinia, large areas of wetlands and coastal ponds were removed. Even in the Republican period, however, and in some cases up to 50 years ago, reclamation continued through various forms of intervention on the territory, also due to the construction of infrastructures. Italian coastal lagoons are concentrated in four regions of the country (figure 2.15). North Adriatic includes the largest extension, over 120,000 hectares, with the large micro-tidal lagoons (tidal range > 0.5 m) of Venice, , Grado and Marano, and more than 45,000 hectares of wetlands and valli of the Po Delta. In the southern Adriatic, Lesina and Varano lagoons are the most important, while in the central Tyrrhenian there are several coastal lakes in Latium and the Orbetello lagoon, the largest in . The two Italian major islands, Sicily and Sardinia, totalled over 15,000 hectares of lagoons, most of them located in Sardinia. All these lagoon environments are classified as “non-tidal”, with tide excursion less than 0.5 m. Overall, Italian coastal lagoons amount in number to more than 190, including, in addition to lagoons and coastal lakes and ponds, also sacche, deltaic areas and valli.

55

120,000

s) 100,000

80,000

60,000 ace (hecta re 40,000 Surf 20,000

0 North South Central Islands Adriatic Sea Adriatic Sea Tyrrhenian Sea

Figure 2.15 - Italian coastal lagoons: distribution and surface.

Lagoon typologies in Italy The lagoon typologies to which Italian lagoons can be ascribed are many, and the distinction between them is essentially based on their geological origin and the presence, more or less marked, of tides. There is indeed a certain impropriety in the use of terms lagoon, coastal and pond, in Italy as in the rest of the Mediterranean sea. This confusion stems in part from the use of terms of local use: Orbetello, in Tuscany, is called lagoon, although more properly it should be named coastal lake, while in Sardinia lagoons are always calledm ponds. Moreover, the term lagoon can have a different meanings for a biologist or a geologist, on the basis of geo-morphological characteristics. According to the classification proposed by Brambati (1988), the key parameter to distinguish between lagoons and coastal ponds is the presence of tidal range, present in lagoons and not present in coastal ponds. Recently, the problem of classifying Mediterranean lagoons has become particularly topical in relation to some criteria introduced by the WFD, 60/2000/CE, which provides for the protection and sustainable management of inland water ecosystems, including those of transitional waters, coastal waters and groundwater. The Directive has introduced a new terminology for aquatic

56 First section - Chapter 2 - Ecological aspects systems. In particular, transitional waters are defined as “surface water bodies in the vicinity of the mouth of a river, saline because of their proximity to coastal waters but essentially influenced by freshwater flows.” According to the definition, and the interpretation given to it (De Wit et al., 2007), most of the Mediterranean lagoons, and hence all the Italian lagoons, fall within the definition of coastal lagoons, in contrast to many Atlantic lagoons which are considered coastal waters in relation to the fact that they are affected in a determinant way by the tide. Within the lentic transitional waters, Italian lagoons are classified according to the influence of the tide (micro-tidal lagoons, with a range of more than 50 cm, and non-tidal lagoons, with a range of less than 50 cm), while a second level of subdivision concerns size, discriminating between lagoons with a surface area greater or less than 3 km2 (Basset et al., 2004). With specific reference to the classification of Italian coastal water bodies, a characterization based on geological features (Cataudella & Tancioni, 2007), also used for the “geographic information system of Italian coastal ponds”, is the following: • Pond - marine-marginal water body without natural channels of communication with the sea (most are defined coastal lakes); • Pond system - pond integrated with “backshore” aquatic environments and marshes; • Lagoon - coastal marine water body separated from the sea by a or stable barrier, with one or more mouths; • Lagoon system - lagoon integrated with “backshore” aquatic environments and marshes; • Barrier-lagoon system - marine-coastal water body, separated from the sea by a thin and mobile barrier, engraved by some mouths, eventually integrated with surrounding wetlands; • Bay - marine water body with one large marine mouth opening (includes deltaic areas called Sacca).

In table 2.3, Italian coastal lagoons are grouped by geographical area, for each area lagoons are grouped also by main typologies, with the relative surfaces.

Photo by G. Lariccia.

57 Table 2.3 - Coastal lagoons in Italy grouped by geographic area and by “Regione”: number and surface (hectares).

Area Region Site Tipology sensu WFD Typology N Surface North Adriatic Friuli VG Grado Marano Microtidal Large + Modified Lagoon and valli 3 12,700 Modified Small Valli 43 1,660 Veneto Venezia Microtidal Large Lagoon 1 50,000 Modified Large Valle 13 7,620 Modified Small Valle 13 1,284 Modified Large Complex of valli 2 600 Caorle Modified Large Valle 3 1,312 Modified Small Valle 1 176 Total North Adriatic without Po delta 79 75,352 North Adriatic/ Veneto Po delta Modified Large Sacca (bay) 7 8,150 Po Delta Modified Large Valle 17 7,155 Modified Small Valle 2 449 Wetland 2 1,250 Delta branches 6 4,000 Emilia Po delta Modified Large Valli 6 21,313 Romagna Microtidal Large Sacca (bay) 1 2,150 Wetland (oasi) 3 1,670 Coastal lake (art) 1 90 Modified Small Valle 2 118 Total Po Delta 48 46,345 Total North Adriatic & Po Delta 127 121,697 South Adriatic Puglia Non tidal Large Lagoon 2 11,186 - Saltworks 1 4,500 - Enclosed coastal area 2 5,670 (bay) Non tidal Large (Limit S-L) Coastal lake 1 256 Non tidal Small Coastal lake 2 91 Total South Adriatic 8 21,703 Central ThyrrenianToscana Non tidal large Lagoon 1 2,700 Non tidal large Wetland 1 1,100 Non tidal large Coastal lake 2 1,110 Lazio Non tidal large Coastal lake 4 1,401 - Saltmarsh 1 170 Non tidal small Coastal lake 2 142 Campania Non tidal Small Coastal lake 5 487 Total Central Thyrrhenian 16 7,110 Islands Sardegna Non tidal Large Pond 14 13,915 Non tidal Small Pond 36 2,127 Total Sardegna 50 16,042 Sicilia - Saltworks 1 480 Non tidal Large (Limit S-L) Coastal bay 1 265 Non tidal Small Pond 2 223 Non tidal Small Coastal lakes 1 55 Total Sicilia 5 1,023 All All Total, all typologies 198 167,575

58 First section - Chapter 2 - Ecological aspects Ecological aspects Despite the wide variability in geological and morphological features, and the structural and functional differences that result from this variability, lagoons and coastal lakes share many ecological characteristics. This is because they are transitional ecosystems, and, because of the intermediate position between and sea, they are affected by both. Most Italian lagoons are characterized by shallow waters; therefore the entire system is exposed to the effects of weather and climate forcing, due to air temperature and winds. The factors that affect lagoon ecology are mainly the hydrodynamic and the edaphic characteristics. Water quality depends on the lagoon water exchanges taking place through the tidal channels, that regulate marine inflows and lagoon outflows, on any contribution by waters of continental origin and by ground water, and on winds, that strongly influence hydrodynamics. Of great relevance is the role of tidal channels, through which lagoon environments are connected hydrologically and biologically with the marine environment. Brackish coastal ponds and lagoons are very productive ecosystems, characterized by a productivity higher than that of marine environments within the same coastal system, in relation to the high energy flows and the ability to trap energy from various sources (Cataudella et al., 2001). Most of the ecological properties of a lagoon therefore originate from its and its configuration. The average depth is seldom over than 2 m, and therefore the bottoms are usually well irradiated. Currents and hydrodynamics, closely influenced by bathimetry and bottom morphology, are always reduced. The wind regime involves the entire water column, resulting in the suspension of materials and nutrients in the water column. The abiotic factors always show a great variability, and the rate of sedimentation is always high. In general, in Italian lagoons, the severity of the environmental conditions may prove to be restrictive as regards the number of species that make up the resident communities, both planktonic and benthonic. This also applies to the fish community. The species that find favourable conditions, on the other hand, can reach high densities. However, the overall species richness can be significantly high in those lagoons, usually larger ones, in which there is a mosaic of environments. The salinity gradient as a function of water circulation and of the exchange rate with the sea, or the different features of the sediments, may lead to a different vegetation cover: this can result in the presence of different micro-environments, positively influencing the number of species of both plant and communities. Notwithstanding common features, each coastal lagoon has its own peculiar ecology that results from the interaction between geology and hydrology, climate and morphology, abiotic factors and living organisms. As a consequence, a northern Adriatic lagoon is very different in ecological terms from a Sardinian pond, but also from a coastal lake in the Southern Adriatic Sea. This is because geological origin and climate, as well the anthropogenic pressures that on each of them insist, are different. The morphological characteristics of coastal lakes, also near in space, can be different, in terms of volume, oxygen or salinity, and this means that the biological communities that live in them are also different. Compared to Atlantic lagoons, Mediterranean lagoons are scarcely affected by tidal regime, and consequently the connections with the sea tend to become clogged, and coastal lagoons tend to disappear in the long run (Brambati, 1988). Therefore, the conservation of these ecosystems is closely related to management by man, in particular the maintenance of links with the sea (Pérez-Ruzafa et al., 2010) and, where present, the management of continental fresh water inputs. These, in fact, play a primary role in various fundamental processes of the lagoon, such as, for example, its function as a nursery, allowing the

59 recruitment of fish species to the lagoon. Coastal lagoons, like all transitional environments, are important sites for fish, as growing areas, wintering sites, migration routes and, more generally areas that support large densities of individuals (Koutrakis et al., 2005, Franco et al., 2006). The basic structure of the fish communities of Italian lagoons does not differ from that of other Mediterranean lagoon environments, and shows a substantial stability. This is because despite fluctuations, the abiotic and biotic factors that determine this structure can be attributed in all cases to the dominance of tolerant taxa and to the structure of food webs that are established in these systems. Some fish that can be found in Italian lagoons are resident species. The big-scale sand smelt, for example, Atherina boyeri, or the Mediterranean killifish, phasciatus, both gregarious species, are adapted to erratic conditions such as those of coastal lagoons, and therefore very abundant, as in the coastal lakes of Circeo or Lesina. Pipefish are present in many lagoons, with lower abundances in relation to their reproductive biology: they produce a very limited number of eggs, which are incubated by males in a pocket on the belly. Many gobies are part of the ichthyofauna of Italian lagoons. The goby (Potamoschistus marmoratus) and the sand goby (P. minutus) are euryhaline species, tolerant to salinity variations. Other euryhaline gobids are P. canestrini, present only in the lagoons of th Adriatic coast, and Knipowitschia panizzae, the lagoon goby, reported also in the Tyrrhenian coast lagoons. The mosquito fish, Gambusia affinis holbrooki, on the other hand is present only in low salinity lagoons. This species was introduced in Italy by the U.S. in the twenties in the Pontine Marshesas an attempt to biologically control malaria. From an ecological point of view, these species are important links in the food web. Most of the fish biomass of the lagoons, however, is due to the group of migratory species. Among these, the , Anguilla anguilla, has always been one of the most typical inhabitants of the Italian lagoons. In the , the lagoon of Orbetello and Sardinian ponds, local traditions are inextricably linked to eel. Today this species is facing a diffuse decline, in Italian and Mediterranean lagoons as well as in the rest of the inland and coastal waters of and North . The eel is a catadromous species that suffers from a number of problems related to the complex biology of the species and to impacts of anthropogenic nature, including fishing, pollution, . At present, a plan for the recovery of the stock is being implemented, which involves all European countries, on the basis of a specific regulation (Reg. 1100/2007). Very important in lagoon ecosystems are grey mullets, which reproduce at sea and colonize estuarine waters and lagoons as juveniles. Each species migrates to estuaries and lagoons tidal channels in a specific season, typically after reproduction at sea, to colonize lagoon waters for trophic reasons. Juveniles up to about 30 mm in size feed on zooplankton, but at the adult stage grey mullets feed essentially on detritus, while also being able to ingest invertebrates or algae. They are equipped with an apparatus, the pharyngo-branchial organ, that sifts the silt in the bottom, retaining organic particles, such as diatoms. All Mugilid species are euryhaline, but some to a greater extent than others: Liza ramada and Mugil cephalus withstand low . The latter is the best known and more appreciated species, as it reaches larger sizes, up to 70 cm, and females produce large ripe ovaries, which are salted and dried and sold as a delicacy. Sea bass, Dicentrarchus labrax, and gilthead, Sparus aurata, are present in all Italian lagoons: juveniles of both species move in lagoons where they spend the first growth period, in late winter or early spring. Both are however less tolerant to low temperatures, and to reduced salinities, if compared to the grey mullets or eel.

60 First section - Chapter 2 - Ecological aspects In many Italian lagoons a high number of marine adventitious species are sporadically present. These species are coastal marine that occasionally enter the lagoon when they find favourable conditions, and remain there for a longer or shorter period. Sardines, croaker, sea bream, red mullet, flounder, sole, grouper, can be episodically found in a lagoon, but sometimes they become part of the lagoon fish assemblage in a more stable way. The Caprolace coastal lake, for example, but also some ponds in Sardinia, due to reduced amounts of freshwater, take on marine characteristics, and become therefore particularly suitable for these species. In the Comacchio valli, since several years anchovy, Engraulis encrasicolus, and sprat have been present in the last few years, and even sustain a fishery. In some lagoons, occasional dwellers are some freshwater species, such as carp and tench, which enter the lagoon from neighbouring channels and remain in low salinity areas.

Figure 2.16 - Fishes from a coastal lagoon.

Within the lagoon fauna, the most obvious component is represented by water birds. The number of species that can be observed in Italian coastal lagoons amounts to several hundreds, given that Italy is affected by migration of birds arriving on the peninsula for the winter from northern . Many species nest in reed beds or Salicornia meadows, while the bottoms provide great abundance of food. Avian species richness and numerical abundance of populations mean that the bird fauna of a lagoon is one of the most important components in ecological terms and for conservation.

61 Production Fisheries and extensive have always been practiced in the coastal lagoons of the Mediterranean region, taking advantage of the migration of euryhaline marine species between sea and lagoon. In most Italian lagoons, fish productions are supported by natural recruitment, artisanal fisheries are present and no hydraulic management occurs. This management scheme is quite simple, characteristic of most Italian lagoons of the Tyrrhenian coast. Here, despite local traditions and specific models of management, fisheries, and environmental protection of these ecosystems, have received in the past only marginal attention (Ardizzone et al., 1988). The exploitation of lagoons for fishing purposes is closely intertwined with the origin of aquaculture, because the management patterns have evolved over time towards increased forms of management. The presence of more or less complex management patterns allows to distinguish extensive aquaculture practiced in many Italian lagoons by capture fisheries typical of other lagoons, but it is clear that the interactions between fisheries and farming activities are inextricably linked, and often difficult to distinguish. In all cases, both the productions from capture fisheries and from extensive aquaculture in coastal lagoon environments are based on the use of natural trophic resources. However, extensive farming can foresee the hydraulic control of water for the management of fish, and restocking with juveniles of various species to enhance production. The classical case of extensive aquaculture, typical of the northern Adriatic, is the vallicoltura. Capture in lagoons can be exclusively based on small-scale fisheries, as in many ponds of Sardinia or some of the Tyrrhenian coastal lakes, or include the use of fixed capture systems, the lavorieri (fish barriers). Catch composition, and more generally the productivity of a lagoon, can be extremely variable. The most productive lagoons in Italy are the Sardinian ponds, which in the past have achieved productions up to 600 kg / hectare, a value observed for example in the pond of Tortolì in the 80’s. However, today productions are much more reduced, mainly due to a series of environmental problems that concern all Italian coastal lagoons, except for a few cases. The Orbetello lagoon, which exceeded in the 80’s 180 kg per hectare, of which almost 50% were , today shows much lower productions, catches concerning now other species such as grey mullet and sea bream. The same can be observed in the lagoon of Lesina. In the forties the average production ranged between 120 and 140 kg per hectare, to drop below 60 kg in the sixties. Today annual production average, which largely consists of grey mullet, never exceeds 20 kg/ha. Lagoon catches can be an important indicator of the ecological status of the lagoons, to be considered also in environmental monitoring. For example, the reconstruction of historical trends in catches can provide information about the state of a lagoon ecosystem. The limitations lie in the fact that fluctuations in catches, as well as the species composition of the catch, can result from several factors, environmental as well as socio-economic. Therefore, accurate indicators such as fishing effort or catch per unit of effort are needed, to correctly interpret observations. Despite these limitations, in many cases this approach has proved informative. An interesting example is that of the lagoon of Venice, illustrated by Libralato et al., 1994: the success of the introduction of the Manila clam, together with the environmental effects resulting from its mechanical harvesting, could be a main cause of the striking decline in catches from lagoon fisheries. According to these authors, to the environmental consequences of dredging are also due the changes in the trophic level of the species that make up the catches.

62 First section - Chapter 2 - Ecological aspects Environmental aspects and management Declines in lagoon catches, as well as the change in the composition of the catch, result from a series of changes in the lagoon ecological conditions. These are in turn due to various causes, but undoubtedly a crucial role is played by water quality. Eutrophication is a common phenomenon in the lagoons. This phenomenon of nutrient enrichment, when it reaches unsustainable levels, triggers anoxia and widespread die-offs of organisms, with serious consequences on the lagoon, and major impacts on economic activities linked to the lagoon (Magni et al., 2009). This entails the need for environmental measures, such as those implemented for the Orbetello lagoon in the 90’s to limit eutrophication and the dystrophic crises that resulted from it. Human pressure on Italian lagoons certainly did not end with the completion of reclamation, but it continued and evolved. Precisely because of their location in lowlands and coastal areas, often representing the final section of river basins, lagoon environments are affected by the effects of agriculture and industrial activities, and of urbanization, that take place in upstream areas in most of them. In the North-Adriatic, there is an obvious impact on the resulting from the economic choices that led to the creation of the industrial area of Porto​​ Marghera during the early twentieth century. Development of and seaside resorts, and industrialization in the vicinity of most Italian lagoons overlaps also with some effects of changes on a global scale. Climate change and consequences that will follow will have a more disruptive impact on transition areas, first of all on coastal lagoons. The lifetime of a coastal lagoon is always closely linked to the nature of management interventions that are made in it. Because of the dynamics by which they originate, and their geographical location, lagoons are “ephemeral” systems which tend to disappear over time. In this context, the use of lagoons for capture fisheries and aquaculture has always allowed not only the conservation of major portions of lagoons from reclamation, but also their protection from a qualitative point of view. Throughout history, precisely because the tendency was to enhance the productive potential of the lagoons, the evolution of the early models of exploitation of lagoon living resources has gone towards developing increasingly complex management systems. The interventions of “manipulation” of the abiotic and biotic components have been progressively addressed to stabilize lagoon morphology, partly contrasting the natural course of the interaction between terrestrial inputs and transport along the coast. Complex management systems, such as the northern Adriatic vallicoltura have received, for a variety of historical reasons and also in relation to the regime of exclusive property, greater attention than lagoon management in other Italian regions. For this reason extensive fish productions in the northern Adriatic can be considered as having historically contributed to the conservation of these natural environments. Many Italian lagoons, and especially the valli da pesca, can be considered environments heavily manipulated by man, and therefore “modified water bodies”. On the other hand, these coastal wetlands are characterized by a high degree of “naturalization.” This leads to consider them areas of high conservation concern (especially for birds), and the development of environmentally friendly activities may lead to consider these semi-natural areas, if well managed, as “reference models “ to produce and at the same time preserve.

63 The protection of coastal wetlands, including lagoons, has become a priority objective in the policy of resource conservation in the Mediterranean. The multifunctional nature of lagoon ecosystems, which has among its possible uses also environmental protection and conservation, has been the objective of Conventions and international and EU guidelines Among these, the first in chronological order is the (1975). This convention makes explicit reference to the fact that «the landscapes and wildlife of wetlands are the result of complex interactions between people and nature over the centuries.» More recently, the Birds Directive (EC), the Habitats Directive (1992) and its implementation at the national level through the Natura 2000 network, led to the identification of a number of Sites of Community Interest (SCI) and Special Protection Areas for birds (SPAs) in many Italian lagoon environments.

Conclusions The links between ecosystem functioning and exploitation are very strong, have a long tradition and are often affected by man-made environmental management. Fishing is an element of pressure on lagoon ecosystems, but, depending on the quality of the environment, the natural trophic availability to support production and good physical and chemical characteristics of the water, it can be considered a good indicator of ecosystem functions and efficiency. In other words, lagoon fisheries depends on the availability of natural resources, whose state depends in turn on the levels of harvest and on the quality of the environment. However, new management models must be conceived to achieve sustainability, both for fisheries and for extensive productions, based on an ecosystem approach to fisheries (EAF). It is now accepted at all levels that there is the need to revise the current fisheries management, and this applies to small-scale fishing practiced in coastal and inland waters. There is also the need to take into account interactions between fishing systems and ecosystems, and the fact that both are affected by natural variability in the long term, and influenced also by other uses not related to harvest. EAF is an innovative approach to fisheries management, that calls into question both human well-being and that of the ecosystems (Garcia et al., 2003). Thus, two related models merge, potentially converging. On the one hand there is the ecosystem management that aims at the protection and preservation of the structure and functions of ecosystems and on the other hand there is the fisheries management, which tends to provide food, income and livelihood for humans (ICES, 2010). The current approach when identify management strategies for coastal lagoons cannot be regardless of their framing in integrated coastal zone management (ICZM), also taking into account the principles of sustainability and responsibility contained in the Code of Conduct for Responsible Fisheries (FAO, 1995) and in the specific technical guidelines (FAO, 1999). In this context, one of the key concepts is the importance of an approach that enhances the multifunctional nature of lagoon ecosystems. In general, lagoon fisheries and extensive aquaculture are activities that can be well integrated with other uses, such as the use of the environment oriented to tourism, research and environmental education. These activities may also involve fishers, leading to the identification of new professional profiles or otherwise to diversify their activities towards uses less consumptive of living resources. Within this framework, fisheries and extensive aquaculture in coastal lagoons can be a unique opportunity to safeguard the environment, especially if planned with the utmost responsibility and focused on quality.

64 First section - Chapter 2 - Ecological aspects References - Ardizzone G.D., Cataudella S., Rossi R. (1988) - Management of coastal lagoon fisheries and aquaculture in Italy. Vol. 293. FAO, Fisheries Technical Paper, Roma: 103 p. - Basset A., Sabetta L., Fonnesu A., Mouillot D., Do Chi T., Viaroli P., Giordani G., Reizopoulou S., Abbiati M. and Carrada G. C. (2006) - Typology in Mediterranean transitional waters: new challenges and perspectives. Aquatic Conservation: Marine and Freshwater Ecosystems, 16: 441–455. - Bianchi C.N. (1988) - Tipologia ecologica delle lagune costiere italiane. In: Carrada G.C., Cicogna F., Fresi E. (Eds.), Le lagune costiere: ricerca e gestione. CLEM, Massa Lubrense (Napoli), Italy: 57-66. - Brambati A. (1988) - Lagune e stagni costieri: due ambienti a confronto. In: Carrada G.C., Cicogna F., Fresi E. (Eds.), Le lagune costiere: ricerca e gestione. CLEM, Massa Lubrense (Napoli), Italy: 9-33. - Carrada G.C. & Fresi E. (1988) - Le lagune salmastre costiere. Alcune riflessioni sui problemi e sui metodi. In: Carrada G.C., Cicogna F., Fresi E. (eds.) - Le lagune costiere: ricerca e gestione. CLEM, Massa Lubrense (Napoli), Italy: 35-56. - Cataudella S. (1988) - Contributi dell’acquacoltura alla gestione produttiva degli ambienti lagunari. In: Carrada, G.C., Cicogna F., Fresi E. (eds.) - Le lagune costiere: ricerca e gestione. CLEM, Massa Lubrense (Napoli), Italy: 147-156. - Cataudella S., Tancioni L., Cannas A. (2001) - L’acquacoltura estensiva. In: Cataudella S. & P. Bronzi (eds), Acquacoltura responsabile. Unimar-Uniprom: 283-306. - Cataudella S. & Tancioni L. (2007) - Direttiva per le acque e impatto sul settore della pesca. In: Zucaro R. (ed), Direttiva Quadro per le acque 2000/60 – Analisi dell’impatto sul settore irriguo e della pesca. Istituto Nazionale di Economia Agraria: 151-160. - Commissione Europea (2000) - Direttiva 2000/60/CE del Parlamento Europeo e del Consiglio, del 23/10/2000, che istituisce un quadro per l’azione comunitaria in materia di acque. - Commissione Europea (2007) - Regolamento (CE) N. 1100/2007 del Consiglio del 18 settembre 2007 che istituisce misure per la ricostituzione dello stock di anguilla europea, G.U. dell’Unione Europea, 22.09.2007, L 248: 17-23. - Crivelli A.J. & Ximenes M.C. (1992) - Alterations to the functioning of Mediterranean lagoons and their effects on fisheries and aquaculture. In: Finlayson M., Hollis M., Davis T. (Eds.). Managing Mediterranean Wetlands and their Birds, vol. 20. IWRB Special Publication, Grado, Italy: 134-140. - De Wit R., Mostajir B., Trousselier M. & T. Do Chi (2007) - Environmental management and sustainable use of coastal lagoons ecosystems. In: Froiedman A.G. (ed), Lagoons: Biology, Management and Environmental Impact. Nova Science Publishers: 333-350 - Franco A., Franzoi P., Malavasi S., Riccato F. & P. Torricelli (2006) - Use of shallow water habitats by fish assemblages ina Mediterranean coastal lagoon. Estuarine coastal and Shelf Science, 66: 67-83. - Franco A., Franzoi P., Torricelli P. (2008) - Structure and functioning of Mediterranean lagoon fish assemblages: a key for the identification of water body types. Estuarine Coastal and Shelf Science, 79: 549-558. - Koutrakis E.T., Tsikliras A.C., Sinis A.I. (2005) - Temporal variability of the ichthyofauna in a Northern Aegean coastal lagoon (Greece). Influence of environmental factors. Hydrobiologia, 543: 245-257. - Lagune d’Italia (1999) - Visita alle zone umide lungo le coste dei nostri mari a piedi, in barca, in bicicletta. Guide d’Italia – Touring Club Italiano: 144 p. - Libralato S., Pranovi F., Torricelli P., Raicevich S., Da Ponte F., Pastres R. & D. Mainardi (2004) - Ecological stages of the Venice Lagoon alaysed using landing time series data. Journal of Marine systems, 51: 331-334. - Magni P., Tagliapietra D., Lardicci C., Balthis L., Castelli A., Como S., Frangipane G., Giordani G., Hyland J., Maltagliati F., Pessa G., Rispondo A., Tataranni M., Tomassetti P. & P. Viaroli (2009) - Animal- relationships: Evaluating the “Pearson-Rosenberg paradigm” in Mediterranean coastal. Marine Pollution Bulletin, 58: 478-496. - Marino G., Boglione C., Livi S. & S. Cataudella (2009) - National Report of estensive and semi-intensive production practices in Italy. Seacase, EU project n. 044483, Deliverable 20: 88 p. - Pérez-Ruzafa A., Marcos C. & J.M. Pérez-Ruzafa (2010) - Mediterranean coastal lagoons in a ecosystem and aquatic resources management context. Physics and Chemistry of the , 36 (5-6): 160-166. - Rossi Doria M. & P. Bevilacqua (1984) - Le bonifiche in Italia dal ‘700 ad oggi. Ed. Laterza, Bari. - Torricelli P., Boatto V., Franzoi P., Pellizzato M., Silvestri S. (2009) - Piano per la gestione delle risorse alieutiche delle lagune della Provincia di Venezia. Provincia di Venezia, Assessorato caccia, Pesca e Polizia provinciale: 203 p.

65 2.3 The state of demersal resources in Italian seas Living resources in the GSAs This paragraph provides some considerations on the state of demersal resources in each GSA, based on data from the Medits (Bertrand et al., 2002) and GRUND (Relini, 2000) surveys as well as from CAMPBIOL (biological sampling of landings). More specifically, the main descriptive parameters (abundance and demography, biology and spatial distribution, recruitment and nursery areas) and the state of exploitation are given for each species. More detailed information on the Italian resources can be found in Mannini & Relini (2010) and in Relini et al. (1999). The base maps used for the various GSA were prepared by M. Murenu of the University of Cagliari. The maps of nursery areas proceeded from Lembo (2010) (Nurseries project coordinator).

References - Bertrand J., Gil De Sola L., Papacostantinou C., Relini G., Souplet A. (2002) - The general specifications of the MEDITS surveys. Sci. Mar., 66 (Suppl. 2): 9-17. - Lembo G. (ed) (2010) - Identificazione spazio-temporale delle aree di concentrazione dei giovanili delle principali specie

demersali e localizzazione geografica di aree di nursery nei mari italiani - Nursery. Progetto di ricerca SIBM-MiPAAF n.

6A92. Relazione finale, Società Italiana di Biologia Marina, Genoa: 120 pp + cartography.

- Mannini A. & Relini G. (eds) (2010) - Rapporto Annuale sullo Stato delle Risorse Biologiche dei Mari Italiani. Anno 2008.

Biol. Mar. Mediterr., 17 (Suppl. 3): 210 p.

- Relini G. (2000) - Demersal Trawl Surveys in Italian Seas: a short review. In: Bertrand J., Relini G. (eds), Demersal

resources in the Mediterranean. Proceedings of the Symposium on Assessment of demersal resources by direct

methods in the Mediterranean and adjacent seas. IFREMER Ed., Plouzane, , 26: 46-75.

- Relini G., Bertrand J., Zamboni A. (eds) (1999) - Sintesi delle conoscenze sulle risorse da pesca dei fondi del Mediterraneo centrale (Italia e Corsica). Anno 2008. Biol. Mar. Mediterr., 6 (Suppl. 1): 869 p.

2.3.1 GSA 9 - Ligurian and Northern Tyrrhenian Seas Mannini A., Relini G., Sartor P., Ligas A., Abella A., Silvestri R., De Ranieri S., Lanteri L., Colloca F.

Abundance and demography Biomass index of the community The time series of biomass indices for the four main faunal categories captured during the MEDITS trawl survey are shown in figure 2.17. The highest values are those for bony fish, which nevertheless show a tendency towards a decrease over time. No particular temporal variations, however, are noted for cartilaginous fish, one of the faunal categories that is most sensitive to fisheries pressure. Biomass indices for cephalopods and crustaceans show wide variations which are inserted in a negative trend for the former and a positive trend for the latter. In this last case “driven” by deep-water rose shrimp, which appear to be undergoing a biomass increase during these years (figure 2.17).

66 First section - Chapter 2 - Ecological aspects Teleosteans biomass indices Selachians biomass indices Teleosteans biomass indices Selachians biomass indices 450 70 404500 70 40 60 400 35400 60 50 303500 50 2 2 2 253000 2 40 2 2 2 250 2 40 202500 30 kg/km kg/km kg/km kg/km 152000 30 kg/km kg/km kg/km kg/km 20 101500 20 10500 10 10 500 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 Years Years

Cephalopods biomass indices Crustaceans biomass indices Cephalopods biomass indices Crustaceans biomass indices 60 40 60 40 50 35 35 50 30 40 30 2 2 2 40 2 25 30 2 2 2 2 25 30 20 kg/km kg/km kg/km kg/km 20 20 kg/km kg/km

kg/km kg/km 15 20 10 15 10 10 10 0 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 Years Years

Figure 2.17 - GSA 9. Biomass indices (kg/km2) and respective confidence limits (broken lines) for the main faunal categories: Teleosteans, Selachians, Cephalopods, Crustaceans (Source: MEDITS 1994-2010).

Biomass and density indices for the main fishery target species The biomass and density indices for the European hake (Merluccius merluccius), one of the most exploited species in Italian seas and the entire Mediterranean Sea, do not show significant temporal differences in spite of wide fluctuations. The indications from stock assessment nevertheless recommend the need for a more prudent management of this important resource, safeguarding in particular the areas of high concentration of juveniles (figure 2.18), which are mainly captured by trawling, but also reducing the fishing pressure on the parental stock, which is mainly caught by other fishing gear (e.g. gill nets). Red mullet show wide variations in density indices since 2002, but do not display a corresponding variation in biomass indices. This result is the consequence of the abundant catches of juveniles recorded in 2002, 2005 and 2007, years in which the trawl surveys were carried out in mid and late summer, when the species shows its massive recruitment in shallow waters. The noticeable temporal reduction in both biomass and density indices for horned octopus seems to indicate a state of distress for this species. It is known that cephalopods have relatively short life cycles (1-2 years) and their abundance is strongly influenced by the successful recruitment, which in turn is affected by environmental parameters. Recent studies (Orsi Relini et al., 2006) show, at least for the northern part of the GSA9, a correlation between the success of recruitment and the meteorological stability during winter months in the , which is linked in turn to variations in the NAO index (North Atlantic Oscillation Index).

67 The biomass indices for Norway lobster do not show significant variations for this period, whereas density indices seem to indicate an increase, reflecting a possible reduction in the average size of the specimens caught (cf. table 2.4). These variations, observed in a relatively short time period, may be more linked to variations in the success of recruitment, rather than to changes in fishing pressure. The deep-water rose shrimp is an important resource, particularly in the southern part of GSA9, where it is particularly abundant. In recent years the species is showing a considerable increase in both density and biomass, very probably linked to the variation of certain environmental conditions, such as the increase in water temperature.

EurEuropeope hak hakee biomass biomass indices indices (10-800 (10-800 m) m) EurEuropeanopean hak hakee density density index index (10-800 (10-800 m) m) Europe hake biomass indices (10-800 m) European hake density index (10-800 m) Europe hake biomass indices (10-800 m) European hake density index (10-800 m) 8080 90009000 80 9000 70807080 8000900080009000 8000 70 80007000 60706070 70008000 7000 60 6000700060007000 50605060 2 2

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n/km 4000 40 n/km 40005000

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RedRed mullet mullet biomass biomass indices indices (10-200 (10-200 m) m) RedRed mullet mullet density density indices indices (10-200 (10-200 m) m) Red mullet biomass indices (10-200 m) Red mullet density indices (10-200 m) Red mullet biomass indices (10-200 m) Red mullet density indices (10-200 m) 161600 70007000 161600 70007000 141416000 600060007000 140 6000 12141214000 6000 500050006000 120 10121012000 5000 2 5000 2 5000 2 2 100 40004000 2 2

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15 2 2 15 100

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NorwayNorway lobster lobster biomass biomass indices indices (200-800 (200-800 m) m) NorwayNorway lobster lobster density density indices indices (200-800 (200-800 m) m) Norway lobster biomass indices (200-800 m) Norway lobster density indices (200-800 m) 3030 Norway lobster biomass indices (200-800 m) 707000 Norway lobster density indices (200-800 m) 30 700 3030 707000 2525 606000 25 606000 2525 505060000 2020 First section - Chapter 2 - Ecological aspects 500

68 2 500 2 2 2 20 500 2020 404000 2 2 2 2 2 2 400 15 2

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15 n/km n/km 300

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Deep-waterDeep-water r roseose shrimp shrimp biomass biomass indices indices (10-800 (10-800 m) m) Deep-waterDeep-water r roseose shrimp shrimp density density indices indices (10-800 (10-800 m) m) Deep-water rose shrimp biomass indices (10-800 m) Deep-water rose shrimp density indices (10-800 m) Deep-water1414 rose shrimp biomass indices (10-800 m) 14001400Deep-water rose shrimp density indices (10-800 m) 1414 14001400 121214 120012001400 1212 12001200 101012 100010001200 10 1000

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HornedHornedHorned octopus octopusoctopus biomass biomassbiomass indices indicesindices (10-800 (10-800(10-800 m) m)m) HornedHornedHorned octopus octopusoctopus density densitydensity indices indicesindices (10-800 (10-800(10-800 m) m)m)

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Deep-waterDeep-waterDeep-water r roseroseose shrimp shrimpshrimp biomass biomassbiomass indices indicesindices (10-800 (10-800(10-800 m) m)m) Deep-waterDeep-waterDeep-water r roseroseose shrimp shrimpshrimp density densitydensity indices indicesindices (10-800 (10-800(10-800 m) m)m)

141414 140014001400

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222 202020000

000 000 199419941994 199619961996 199819981998 200020002000 200220022002 200420042004 200620062006 200820082008 201020102010 199419941994 199619961996 199819981998 200020002000 200220022002 200420042004 200620062006 200820082008 201020102010 YYYearsearsears YYYearsearsears

Figure 2.18 - GSA 9. Biomass (kg/km2) and density (n/km2) indices and respective confidence limits (broken lines) for the main target species estimated for their area of distribution (Source: MEDITS 1994-2010).

95th percentile sizes for the main target species The table 2.5 shows the 95th percentile sizes proceeding from an analysis of annual length/ frequency distributions irrespective of sex, for the MEDITS 1994-2010 surveys; the Spearman’s rho value, a coefficient that provides an interpretation of the variations in this indicator (95th percentile size), is shown for the entire time period under examination. For red mullet, horned octopus and deep-water rose shrimp no significant variations in sizes emerged, while European hake and Norway lobster show a significant reduction in size, which could be caused both by the fishing pressure and by phenomena related to variations in recruitment processes.

69 Table 2.4 - GSA 9. Size: 95% percentile length per species (TL = Total Length, DML = Dorsal Mantle Length, CL = Carapace Length). The significant Spearman rho values are shown in bold.

European Deep-water hake Red mullet Horned octopus Norway lobster rose shrimp Year TL (cm) TL (cm) DML (cm) LC (mm) CL (mm) 1994 20.0 19.3 10.8 48.0 37.5 1995 17.0 18.8 10.5 47.5 36.5 1996 17.3 18.3 10.0 47.5 36.0 1997 16.0 17.8 9.5 48.5 32.0 1998 15.5 18.8 10.5 47.5 29.5 1999 17.3 19.3 10.5 48.0 32.5 2000 17.0 18.5 11.3 46.5 34.5 2001 17.3 17.8 9.5 45.5 35.5 2002 11.8 15.5 10.8 46.5 35.0 2003 15.0 16.8 11.3 47.5 33.5 2004 13.8 17.8 11.0 47.5 31.5 2005 17.0 14.8 11.0 45.5 33.0 2006 19.3 18.3 11.0 46.5 35.5 2007 16.0 16.8 6.8 44.5 35.5 2008 15.0 19.3 10.0 45.5 31.0 2009 13.8 19.8 11.0 45.0 32.5 2010 15.0 19.8 10.5 47.0 29.5 Spearman’s rho -0.515 0.036 0.151 -0.715 -0.462

Biology and spatial distribution The reproduction period The reproduction periods of the five species (table 2.5) were identified by combining data on sexual maturity, obtained from experimental trawl surveys (GRUND and MEDITS) and commercial catches through biological sampling (CAMPBIOL). For European hake, specimens with mature gonads were rarely found, either during the experimental surveys or in the commercial catch sampling. Nevertheless, an analysis of the available data shows that although the reproductive period of the species extends throughout the entire year, a peak in sexual activity is present from January to March. The reproductive periods of red mullet and horned octopus are concentrated from May to July for the former species and from June to August for the latter. Specimens of Norway lobster with mature gonads are mainly found in summer, while winter seems to be the preferred reproductive season for deep-water rose shrimp.

Table 2.5 - GSA 9, Peak reproductive periods for each species. Months Species J F M A M J J A S O N D European hake X X X X X Red mullet X X X Horned octopus X X X Norway lobster X X X Deep-water rose shrimp X X X

70 First section - Chapter 2 - Ecological aspects Recruitment areas and intensity Many studies have shown that GSA 9 is among the areas with the greatest concentrations of European hake recruits in the entire Mediterranean region. Recruits are mainly found from 100 to 250 m depth, especially between the Isles of Elba and Giglio and to the north-east of the Island of Capraia, both between spring and summer and in autumn. The presence of recruits is characterised by high temporal and spatial persistency (figure 2.19).

Figure 2.19 - GSA 9. European hake nursery areas.

71 Red mullet recruits (figure 2.20) are more abundant along the coastal strip of the Southern Ligurian Sea (to the south of La Spezia) and to the north of the Argentario promontory in the Northern Tyrrhenian sea, whereas in the southern part of GSA 9 (the Lazio coast) they show a lower density. The nursery areas of these species also show a high level of stability over time.

Figure 2.20 - GSA 9. Red mullet nursery areas.

72 First section - Chapter 2 - Ecological aspects Juveniles of horned octopus are distributed in several areas near the deep shelf (80-200 m). The most stable nurseries over time are located between the Island of Elba and the Island of Giglio, offshore Viareggio and along the Eastern Riviera in Liguria. The areas with the greatest concentration of deep-water rose shrimp recruits are found to the south of the Island of Elba as far as the Argentario promontory, at a depth of between 80 and 200 m.

Evaluation using stock assessment models Summaries of the stock assessment performed for certain species are given below. More detailed information about the results and the methodology employed are available in the STECF-SGMED and GFCM-SCSAC reports.

Merluccius merluccius - European hake (from: SGMED report 03-10) Stock assessments of European hake in GSA 9 carried out during these years, using various methods and data, agree to indicate a state of overexploitation of this species, characterised by excessive fishing pressure on recruits. The most recent assessments were carried out during SGMED 03-10. An Extended Survivor Analysis (XSA) was carried out on DCF data from 2005 to 2009, which produced fish mortality estimates (average valued for the age groups 1-3) ranging from 1.3 to 1.6. The F1-3 values estimated on the basis of the 1994-2008 trawl survey data were similar, ranging between 0.8 and 1.74.

The F estimates are greater than those of the reference point, F0,1, which is 0.22. The current F values therefore situate the GSA 9 hake stock in a state of overexploitation, which would require a reduction of the current F. However, the predictive model employed indicates a rapid recovery potential for the hake stock in GSA 9, if F is reduced to values closer to the reference value (F0,1).

Parapenaeus longirostris - deep-water rose shrimp (from: SGMED report 03-10)

The fishing mortality estimated for pink shrimp specimens between 1 and 3 years old (F1-3), using SURBA software and MEDITS data, was between 0.64 and 1.6.

Using the LCA method, however, the following F1-3 values were estimated for the period 2006- 09: 0.24 in 2006, 0.55 in 2007, 0.23 in 2008 and 0.59 in 2009. These values are lower than the estimated F0,1 reference point value, corresponding to 0.7. These results seems to indicate that rose shrimp stock in GSA 9 is at present in a situation of sustainable exploitation.

Small-scale coastal fisheries Small-scale coastal fishery is very common and widespread along the Ligurian and Tuscan coasts, as far as along the coastline of Lazio, and in the numerous isles of the Tuscan and Pontine Archipelago. It consists of a plurality of fishing systems, with characteristics closely related to the morphological and ecological aspects of the exploited areas. Small-scale coastal fisheries play a decisive role for many local communities, due to its social, economic and environmental implications, and also provides an example of sustainable exploitation of resources. The ecosystems on which the small-scale coastal fishery depends are showing signs of distress, due to the degradation of habitats, as well as excessive exploitation by semi-industrial fisheries. This has also led to conflicts over the course of time between “large” and “small-scale” fisheries. Unlike other fishing activities, the knowledge on small-scale coastal fishery is scarce, because of the relative difficulties in monitoring due to the numerous landing points, the often irregular and seasonal activity and the marketing methods, which are often oriented towards direct sales and

73 local markets. There is also a lack of data for a proper assessment of the fishing effort and the impact of this activity on the biological resources, especially in sensitive habitats. Small-scale coastal fishery is often the only professional fishing activity allowed in the marine protected areas. Initiatives related to fishing tourism have been consolidated in the area in recent years, in order to revitalise the small-scale coastal fisheries and also improve its sustainability. The gears used by the small-scale fishing fleet in the GSA 9 are extremely diversified: various types of trammel nets and gillnets for red mullets and white fish, longlines (islands), combined nets, trammel nets for cuttlefish (sandy bottoms), gillnets for hake (Tuscan and Pontine Archipelago); drifting longlines for swordfish and tuna; pots and traps for cuttlefish (sandy bottoms), octopus and crustaceans (islands and rocky bottoms); dredges for bivalves (sandy bottoms); boat seines for transparent goby (Ligurian and Tuscan coasts); scuba fishing, mainly to exploit red coral, bivalve molluscs and echinoderms. Small-scale fishery in GSA 9 is going through a period of crisis (Irepa, 2010), as in the rest of Italy, due not only to the reduction of catches, but also to the increase of costs and the scarce organisation in the production chain.

References - Irepa Onlus (2010) - Osservatorio economico sulle strutture produttive della pesca marittima in Italia. 2009. Edizioni Scientifiche Italiane, Napoli: 184 pp. - Orsi Relini L., Mannini A., Fiorentino F., Palandri G., Relini G. (2006) - Biology and fishery of Eledone cirrhosa in the Ligurian Sea. Fish. Res., 78 (1): 72-88.

2.3.2 GSA 10 - South and Central Tyrrhenian Seas Spedicato M.T. , Lembo G.

In the GSA 10, the main demersal resources on the continental shelf, which occupies around 36% of the fishing area (7,370 km2), are European hake (Merluccius merluccius), red mullet (Mullus barbatus), pandora (particularly Pagellus erythrinus) and, among cephalopods, squids (e.g. Todarodes sagittatus, IIlex coindetii), cuttlefish (particularly Sepia officinalis) and octopus (in particular Octopus vulgaris). Deep-water rose shrimp (Parapenaeus longirostris), Norway lobster (Nephrops norvegicus) and red shrimps (Aristaeomorpha foliacea and Aristeus antennatus) are the most important resources on the slope and bathyal beds, which occupy about 64% of the fishing area (13,000 km2). The demersal resources in GSA 10 are not classed as shared with other Mediterranean countries but can be assessed as a pool, assuming negligible phenomena of immigration and emigration. The temporal series of abundance indices (density n/km2 and biomass kg/km2), obtained for individual species and fish communities by the MEDITS experimental surveys, provide a useful contribution to the assessment process, which is based, in a complementary and integrated manner, on these results and those obtained by the application of conventional stock assessment methods. The Yearbook on the state of fishery resources by Italian Marine Biology Society (SIBM, 2010) provides a summary of this approach.

Abundance and demography Community biomass index From 1994 to 2010, the overall biomass for the species varied with no specific trend. Significant biomass increases are only seen for Selachii. Over the past year the biomass indices for teleosteans, selachians and crustaceans reached the highest figures in the historical series, whereas the abundance of cephalopods is similar to that of the previous years (figure 2.21).

74 First section - Chapter 2 - Ecological aspects Teleosteans biomass indices

500 450 400 350 2 300 250 kg/km 200 150 Biomass and density indices for the main fishery target100 species 50 At the population level, biomass and density indices for0 hake (figure 2.22) vary with significant 1994 1996 1998 2000 2002 2004 2006 2008 2010 positive trends and the largest density is seen in 2005, similar to whatY earswas noted in GSA 18. Relatively high density levels, although lower than that of 2005, are maintained over the next 4 years, while in 2010 abundance returns to the level of the historicalTeleosteans series prior biomass to 2005. indices For deep- Teleosteans biomass indices 500 Selachians biomass indices water rose shrimp and Norway lobster two positive peaks450 in density are observed in 1999 and 500 2005, with subsequent decreases, showing a minimum250400 for Norway lobster in 2009 and for deep- 450 350 water400 rose shrimp in 2007. Nevertheless, 2010 shows2 200 signs of recovery for the latter species, 300 350 with2 significant increases in density indices. It is interesting250 to note, however, that the minimum 2 300 kg/km 150 200 densities250 for deep-water rose shrimp in this GSA, as in the Southern Adriatic, are seen in the first kg/km

kg/km 150 200 100 years of the MEDITS historical series. This fact could confirm100 the hypothesis, for this species, of a 150 dynamic mainly driven by environmental changes, such50 as those observed in the Mediterranean 100 50 0 Sea following50 the establishment of the Eastern Mediterranean1994 1996 Transient, 1998 2000 2002which 2004 have2006 2008favoured 2010 thermophilic0 and alophilic species such as deep-water 0rose shrimp (AbellóYears et al., 2002). 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Teleosteans biomass indices CephalopodsSelachians biomass biomass indice indicess 500 Selachians biomass indices 250 450 40 400 35 250 200 350

2 30

200300 2 2 25150 250 kg/km 2 150200 kg/km 20

kg/km 100 150 15 kg/km 100 100 1050 50 5 500 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 Years 1994 1996 1998 2000 Years2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Cephalopods biomass indices Selachians biomass indices Cephalopods biomass indices 40 Crustaceans biomass indices 250 35 40 45 30 20035 40

2 25 30 35 2 150 3020 2 25 2 kg/km 25

kg/km 15 10020 kg/km

kg/km 20 10 15 15 50 5 10 10 0 50 5 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 Years 1994 1996 1998 2000Y ears2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Cephalopods biomass indices Crustaceans biomass indices Figure40 2.21 - GSA 10. Biomass indices (kg/km2) and respective confidence limits (broken lines) for the main taxa: Crustaceans biomass indices 45 teleosteans,35 selachians, cephalopods, crustaceans (Source: MEDITS40 1994-2010). 45 30 35 40

2 25 30 35 2 25 2030 kg/km 2

kg/km 20 1525 15

kg/km 1020 10 155 5 10 0 0 5 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years 0 Years 1994 1996 1998 2000 2002 2004 2006 2008 2010 75 Years

Crustaceans biomass indices 45 40 35 30 2 25

kg/km 20 15 10 5 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years EurEuropeanopean hake ha biomasske biomass indices indices (10-800 (10-800 m) m) EurEuropeanopean hak hake densitye density indices indices (10-800 (10-800 m) m) 60 60 35003500 EurEuropeanopean ha keha kebiomass biomass indices indices (10-800 (10-800 m) m) EurEuropeanopean hak hake densitye density indices indices (10-800 (10-800 m) m) 30003000 5060 Eur6050 Europeanopean ha keha biomasske biomass indices indices (10-800 (10-800 m) m) 35003500 Eur Europeanopean hak hake densitye density indices indices (10-800 (10-800 m) m) 25003500 60 60 3000300025003500 2 402 40

50 50 2 EurEuropeanopean ha hakeke biomass biomass indices indices (10-800 (10-800 m) m) 2 EurEuropeanopean hak hake densitye density indices indices (10-800 (10-800 m) m) 20003000 50 250020003000 60 6050 350025003500 2 302 kg/km 40 4030 n/km kg/km n/km 2 150025002 2000200015002500 2 402 40 30003000 2 50 50 2 2030 3020 kg/km n/km kg/km 10002000n/km 10002000 1500250015002500 30 2 kg/km 30 n/km 2 40kg/km 40 n/km 2 1020 2010 15005002 1500 500 1000200010002000 2030 20 100001000 0 kg/km 30 n/km 0kg/km 500n/km 500 10 100 15001500 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 10 1994 1996 1998 2000 2002 2004 2006 2008 2010 500 500 20 2010 Years 0 0 YearsY ears 0 0 Years 10001000 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 0 0 0 0 10 10 YearsYears 500500 1994 1994 1996 1996 1998 1998 2000 2000Y ears2002Y ears 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 YearsYears YearsYears 0 0 0 0 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 Red19941994Red mullet 1996 mullet1996 1998biomass 1998 biomass 2000 2000 indices2002 indices2002 2004 (10-2002004 (10-2002006 2006 m)2008 m)2008 2010 2010 RedRed mullet mullet density density indices indices (10-200 (10-200 m) m) YearsYears YearsYears 60 60 35003500 RedRed mullet mullet biomass biomass indices indices (10-200 (10-200 m) m) RedRed mullet mullet density density indices indices (10-200 (10-200 m) m) 3000 5060 6050Red Red mullet mullet biomass biomass indices indices (10-200 (10-200 m) m) 350035003000 RedRed mullet mullet density density indices indices (10-200 (10-200 m) m) 60 60 2500350025003500 4050 5040 RedRed mullet mullet biomass biomass indices indices (10-200 (10-200 m) m) 30003000 RedRed mullet mullet density density indices indices (10-200 (10-200 m) m) 2 2 20003000 2 20003000 50 2 60 6050 250035002500 3040 4030 3500 15002500

2 2500 2 1500 kg/km n/km

kg/km 2000n/km 2000 2 40 40 30002 3000 2050 50 2 20 302 30 10002000 2 10002000 150025002 15002500 kg/km n/km 30kg/km n/km 40 4030 1020 2010 15005001500 500 2 kg/km n/km 2 kg/km 10002000n/km 1000 2 2000 20 2 30 3020 10000 100 100 5001000500 0 15001500 1994 1996 1998 2000 2002 2004 2006 2008 2010 kg/km n/km 1994 1996 1998 2000 2002 2004 2006 2008 2010 kg/km 1994 1996 1998 2000 2002 2004 2006 2008 2010 n/km 10 1994 1996 1998 2000 2002 2004 2006 2008 2010 20 2010 Years 500 500 Years 0 0 Years 100001000 0 Years 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 0 0 0 0 10 10 YearsYears 500500 YearsYears 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 Years YearsYears Years 0 0 0 0Red shrimp biomass indices (200-800 m) RedRed shrimp shrimp density density indices indices (200-800 (200-800 m) m) 19941994Red 1996 shrimp1996 1998 1998 biomass2000 2000 2002 2002indices 2004 2004 (200-8002006 2006 2008 2008 m)2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 YearsYears 3000 YearsYears 25 25Red Red shrimp shrimp biomass biomass indices indices (200-800 (200-800 m) m) 3000Red Red shrimp shrimp density density indices indices (200-800 (200-800 m) m) RedRed shrimp shrimp biomass biomass indices indices (200-800 (200-800 m) m) 2500300030002500 Red Red shrimp shrimp density density indices indices (200-800 (200-800 m) m) 2025 2520 25 25 30003000 RedRed shrimp shrimp biomass biomass indices indices (200-800 (200-800 m) m) 2000250025002000 RedRed shrimp shrimp density density indices indices (200-800 (200-800 m) m)

2 20 20 152

15 2 250030002 2500 2025 2520 15002000200015003000 /km /km 2 2 kg/km n

15kg/km 15 n 2 10 10 20002 2000 100025002500 2 15001000 15202 20 1500

15 2 2 /km /km kg/km n kg/km 1500n 1500 105 10 20002000

5 /km 500 1000/km 1000 500 2 kg/km n 2 15kg/km n

10 15 2

10 2 100015001000 5 5 50001500 500 0

0 /km

0 /km

kg/km n 1994 1996 1998 2000 2002 2004 2006 2008 2010 kg/km n 1994 1996 1998 2000 2002 2004 2006 2008 2010 105 1019945 1994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 500 500 Years 10001000 YearsY ears 0 0 Years 0 0 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 0 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 05 50 500500 0 YearsYears 1994 1996 1998 2000Years 2002Years 2004 2006 2008 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years YearsYears 0 Years 0 0 0 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 Norway19941994Norway 1996 1996lobster 1998 lobster 1998 biomass2000 2000 biomass 2002 2002 indices 2004 indices2004 2006(10-800 2006 (10-800 2008 2008 m) 2010 m)2010 NorwayNorway lobster lobster density density indices indices (10-800 (10-800 m) m) YearsYears YearsYears 90 90 4 4Norway Norway lobster lobster biomass biomass indices indices (10-800 (10-800 m) m) NorwayNorway lobster lobster density density indices indices (10-800 (10-800 m) m) 80 80 3 3Norway Norway lobster lobster biomass biomass indices indices (10-800 (10-800 m) m) 90 90 NorwayNorway lobster lobster density density indices indices (10-800 (10-800 m) m) 4 4 70 70 90 34 34 80 8090 3 3 NorwayNorway lobster lobster biomass biomass indices indices (10-800 (10-800 m) m) 60 60 NorwayNorway lobster lobster density density indices indices (10-800 (10-800 m) m) 2 2 7080 7080 2 502 23 23 90 50 34 34 6070 609070 40 2 2 40 kg/km n/km

kg/km 80n/km 2 23 23 602 80 23 23 50 5060

2 30 2 30

2 70 2 70 12 2 4050 4050 kg/km n/km kg/km 1 20n/km 23 23 60 20 3040 306040 2 kg/km n/km 2 2kg/km 10 n/km

1 2 2 10 1 502 12 12 2030 205030 0 0 01 01 40 40

kg/km n/km 20 1 kg/km 1 10n/km 10201994 1994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 2 19942 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 30 30 1 1 Years 100 100 YearsY ears 0 0 Years 1 1 20 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 0 200 0 0 YearsYears 10 19941994 1996 1996 1998 1998 2000 Y2000ears 2002Years 2002 2004 2004 2006 2006 2008 2008 2010 2010 1 11994 1994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 10 YearsYears YearsYears 0 0 0 0 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 Years YearsYears Years Deep-watrer rose shrimp density indices (200-800 m) Deep-watrDeep-watrer rerose rose shrimp shrimp biomass biomass indices indices (200-800 (200-800 m) m) Deep-watrer rose shrimp density indices (200-800 m) 14001400 10 10 Deep-watrer rose shrimp density indices (200-800 m) Deep-watrDeep-watrer rerose rose shrimp shrimp biomass biomass indices indices (200-800 (200-800 m) m) Deep-watrer rose shrimp density indices (200-800 m) 76 9 First9 section - Chapter 2 - Ecological aspects 12001200 Deep-watrer rose shrimp biomass indices (200-800 m) Deep-watr1400Deep-watr1400 er rerose rose shrimp shrimp density density indices indices (200-800 (200-800 m) m) 108Deep-watr 108 er rose shrimp biomass indices (200-800 m) 1000140010001400 9 12001200 107 1097 Deep-watrDeep-watrer errose rose shrimp shrimp density density indices indices (200-800 (200-800 m) m) 2 2

Deep-watrer rose shrimp biomass indices (200-800 m) 2 1200 Deep-watr89 89 er rose shrimp biomass indices (200-800 m) 8002 1200 800 6 6 1000140010001400 51078 1078

2 5 2 10006001000 600 kg/km n/km kg/km n/km 2 9 12008002 1200800 467 6497 2 2 2 4008002 400 800 356 8 586 600600

kg/km n/km 1000 kg/km 3 n/km 1000 457 475 200600

2 2 600 kg/km n/km 200

2 2 kg/km 400n/km 400 2 6 8002 800 134 3164 4000 4000 235 253 200600200 600 kg/km 0 n/km kg/km 0 n/km 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 124 1994142 1994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 200 200 0 0 YearsY ears YearsY ears 400400 013 031 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 0 0 02 20 200200 1994 1996 1998 2000Years 2002Years 2004 2006 2008 2010 YearsYears 1994 1996 1998 2000 2002 2004 2006 2008 2010 1 11994 1994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 YearsYears YearsYears 0 0 0 0 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 YearsYears YearsYears

HornesHornes octopus octopus biomass biomass indices indices (10-800 (10-800 m) m) HornedHorned octopus octopus density density indices indices (10-800 (10-800 m) m) 7 7 70 70 HornesHornes octopus octopus biomass biomass indices indices (10-800 (10-800 m) m) HornedHorned octopus octopus density density indices indices (10-800 (10-800 m) m) 6 60 60 7 76Hornes Hornes octopus octopus biomass biomass indices indices (10-800 (10-800 m) m) 70 70 HornedHorned octopus octopus density density indices indices (10-800 (10-800 m) m) 5070 70 57 57 60 6050 6 6 Horned octopus density indices (10-800 m) 2 Horned octopus density indices (10-800 m) 2 HornesHornes octopus octopus biomass biomass indices indices (10-800 (10-800 m) m) 2 402 60 60 46 46 50 5040 57 57 70 70 2 2 50

kg/km n/km 30 50

5kg/km n/km 30 2 3 35 402 40 46 46 60 60 2 2 2 402 24 24 20 2040 kg/km n/km kg/km 30n/km 30 35 35 50 50 2

kg/km n/km 30 2 13 kg/km 3 10n/km 1030 1 2 202 20 24 24 40 40 200 20 02 02 10 100

kg/km n/km 30 13kg/km 1 n/km 30 19943 1994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 10 10 Years 1 1 YearsY ears 0 0 Years 02 02 20 20 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 0 0 0 0 YearsYears 10 10 YearsYears 1 11994 1994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 YearsYears YearsYears 0 0 0 0 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 YearsYears YearsYears EuropeanEuropean hake ha biomasske biomass indices indices (10-800 (10-800 m) m) EuropeanEuropean hake hak densitye density indices indices (10-800 (10-800 m) m) 60 60 3500 3500 European hake biomass indices (10-800 m) European hake density indices (10-800 m) European hake biomass indices (10-800 m) 3000 3000 European hake density indices (10-800 m) 50 50 3500 60 3500 60 2500 2500 2 2 40 40 3000 2 50 2 3000 50 2000 2000 30 30 2500 kg/km n/km kg/km n/km

2 2500 40 1500 2 1500 2 40 20002 20 20 2000 30 1000 1000 kg/km 30 n/km

kg/km 1500n/km 1500 10 10 500 500 20 1000 20 1000 0 0 0 0 10 500 1994 19941996 19961998 19982000 20002002 20022004 20042006 20062008 20082010 2010 199410 19941996 19961998 19982000 20002002 20022004 20042006 20062008 20082010 2010 500 Years Years Years Years 0 0 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Years Years

Red Redmullet mullet biomass biomass indices indices (10-200 (10-200 m) m) Red Redmullet mullet density density indices indices (10-200 (10-200 m) m) 60 60 3500 3500 Red mullet biomass indices (10-200 m) Red mullet density indices (10-200 m) 50 50 Red mullet biomass indices (10-200 m) 3000 3000 Red mullet density indices (10-200 m) 60 3500 60 3500 2500 2500 40 40 3000 50 3000 2 2 50 2000 2000 2 2 30 30 2500 40 2500 40 1500 1500 kg/km n/km kg/km n/km 2 2000 2 202 20 2000 30 10002 1000 30 1500

kg/km n/km 1500

10 kg/km 10 n/km 20 500 500 20 1000 1000 0 0 0 0 10 500 1994 19941996 19961998 19982000 20002002 20022004 20042006 20062008 20082010 2010 199410 19941996 19961998 19982000 20002002 20022004 20042006 20062008 20082010 2010 500 Years Years Years Years 0 0 0 19940 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Years Years Red Redshrimp shrimp biomass biomass indices indices (200-800 (200-800 m) m) Red Redshrimp shrimp density density indices indices (200-800 (200-800 m) m) 25 25 3000 3000 Red shrimp density indices (200-800 m) Red Redshrimp shrimp biomass biomass indices indices (200-800 (200-800 m) m) Red shrimp density indices (200-800 m) 2500 2500 2025 20 3000 25 3000 2000 2000 2500 2 2 1520 15 2500 2 20 2 1500 1500 2000 /km /km 2000 kg/km n kg/km n 2 1015 10 2 2 15 1000 1000 15002 1500 /km kg/km n 105 5 500/km 500 kg/km 10 1000n 1000 0 0 05 0 500 19945 19941996 19961998 19982000 20002002 20022004 20042006 20062008 20082010 2010 5001994 19941996 19961998 19982000 20002002 20022004 20042006 20062008 20082010 2010 Years Years Years Years 0 0 0 19940 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Years Years

NorwayNorway lobster lobster biomass biomass indices indices (10-800 (10-800 m) m) NorwayNorway lobster lobster density density indices indices (10-800 (10-800 m) m) 4 4 90 90 Norway lobster biomass indices (10-800 m) 80 80 Norway lobster density indices (10-800 m) 3 3 Norway lobster biomass indices (10-800 m) Norway lobster density indices (10-800 m) 4 7090 70 4 90 3 3 6080 60 3 80 2 2 2 3 2 70 2 2 50 7050 3 3 4060 40 kg/km n/km kg/km n/km 60 2 2 2 2 2 50

2 30 2 30 2 50 1 1 2040 20 kg/km 2 n/km 40 kg/km 2 30 n/km 1 1 10 3010 1 20 1 0 200 0 0 1994 19941996 19961998 19982000 20002002 20022004 20042006 20062008 20082010 2010 1 1994 19941996 19961998 19982000 20002002 20022004 20042006 20062008 20082010 2010 10 1 10 Years Years Years Years 0 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 19940 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Years Years

Deep-watrer rose shrimp density indices (200-800 m) Deep-watrDeep-watrer roseer rshrimpose shrimp biomass biomass indices indices (200-800 (200-800 m) m)Deep-watrer rose shrimp density indices (200-800 m) 1400 1400 10 10 Deep-watrer rose shrimp density indices (200-800 m) Deep-watr9 9 er rose shrimp biomass indices (200-800 m) 1200Deep-watr 1200 er rose shrimp density indices (200-800 m) Deep-watrer rose shrimp biomass indices (200-800 m) 1400 108 8 1400 10 1000 1000 79 7 1200 2 2 9 1200 2 68 6 2 800 800 8 1000 1000 57 5 600 600 kg/km n/km kg/km n/km

2 7 2 46 2 4 800 2 800 6 400 400 35 3 600 kg/km 5 n/km 600 24 kg/km 2 200n/km 200 4 400 13 1 400 3 0 0 02 0 200 1994 19941996 19961998 19982000 20002002 20022004 20042006 20062008 20082010 2010 19942 19941996 19961998 19982000 20002002 20022004 20042006 20062008 20082010 2010 200 1 Years Years 1 Years Years 0 0 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Years Years

HornesHornes octopus octopus biomass biomass indices indices (10-800 (10-800 m) m) HornedHorned octopus octopus density density indices indices (10-800 (10-800 m) m) 7 7 70 70 Hornes octopus biomass indices (10-800 m) Horned octopus density indices (10-800 m) 6 6 Hornes octopus biomass indices (10-800 m) 60 60 Horned octopus density indices (10-800 m) 7 70 7 70 5 5 50 50 6 60 2 2 6 60 2 4 4 2 40 40 5 50 5 50 kg/km n/km kg/km n/km 30 30

2 3 3 2 2 40

4 2 4 40 2 2 20 20

kg/km 3 n/km 30 kg/km 3 n/km 30 1 1 10 10 2 20 2 20 0 0 0 0 1 10 1994 19941996 19961998 19982000 20002002 20022004 20042006 20062008 20082010 2010 19941 19941996 19961998 19982000 20002002 20022004 20042006 20062008 20082010 2010 10 Years Years Years Years 0 0 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Figure 2.22 - GSA 10. BiomassYears (kg/km 2) and density (n/km2) indices and respectiveYears confidence limits (broken lines) for the main target species estimated for their distribution area (Source: MEDITS 1994-2010).

The trend of density index for giant red shrimp shows some similarities to what has been seen for deep-water rose shrimp. Two positive peaks in density and biomass are seen in 2005 and 2010, which nevertheless do not match the exceptional density figures of 1997. The abundance of red mullet shows points of greater density, coinciding with the years in which the recruitment was intercepted by the survey. However, the lowest density figures in the historical series are seen in the period 2003-2006, and then in 2008 and 2010, with significantly lower biomass indices. This pattern is also reflected in commercial catches of this species, which have fallen dramatically over time. Density and biomass for horned octopus vary, but with no trend. Abundance trends for hake, deep-water rose shrimp and giant red shrimp reflect the success of recruitment to a large extent, and 2005 appears to be an exceptional year, particularly for hake and deep-water rose shrimp. These effects, if preserved over time, could lead to the establishment of strong age classes, particularly in the case of long-living species such as hake, which can give the population greater capacities of resilience, allowing it to sustain greater fishing pressure for short periods. Nevertheless, exceptional recruitments and concentrations of recruits are not signs that can be interpreted univocally as a condition of well-being among the populations. They could be due to other causes, such as the removal of larger individuals from the population, with a consequent reduction in the effect of cannibalism (in the case of hake, for example), or the influence of environmental factors, which temporarily enhance stock renewal processes, but

77 could be compromised by fishing carried out in unsustainable manner. Thus fisheries may even consume the benefits derived from factors mainly beyond human control too rapidly and therefore experience, but fail to manage, relatively positive phases, at least in terms of the availability of fish resources, followed by relatively acute moments of crisis. In order for the positive variations in abundance indices to be interpreted as the effects of a reduction in fishing pressure, and therefore of conditions that facilitate the stocks’ capacity for replenishment, other indicators used to estimate their exploitation levels should also provide similar signs.

95th percentile size of the main target species Signs of stress due to excessive exploitation can also be gained through indicators that measure the presence of larger individuals in the demographic structure of the population, such as the indicator L0.95. In the historical series of the MEDITS experimental surveys, this indicator reflects significant size reduction trends for hake (table 2.6). This could be the symptom of a noticeable decrease in larger individuals, i.e. spawners, within the population.

Table 2.6 - GSA 10. Size: 95% percentile length per species (TL = Total Length, DML = Dorsal Mantle Length, CL = Carapace Length). The significant Spearman rho values are shown in bold.

European Horned Norway Deep-water Red hake Red mullet octopus lobster rose shrimp shrimp Year TL (cm) TL (cm) DML (cm) CL (mm) CL (mm) CL (mm) 1994 21.5 20.5 10.5 52.0 34.0 58.5 1995 21.3 19.0 11.3 49.5 31.5 45.0 1996 21.8 18.8 11.5 59.0 31.5 54.0 1997 19.0 18.8 12.3 51.5 29.0 41.5 1998 24.0 18.3 11.3 55.5 31.0 47.0 1999 22.0 19.3 11.0 49.5 29.5 45.5 2000 20.8 19.8 13.0 49.5 29.5 54.0 2001 25.0 18.8 11.0 53.0 31.5 51.0 2002 20.0 16.0 10.5 49.0 27.5 52.0 2003 19.8 15.8 11.3 52.5 28.5 41.5 2004 20.5 19.5 11.0 54.0 29.0 48.5 2005 17.5 21.0 13.5 47.0 28.5 46.5 2006 20.3 19.0 11.8 50.5 29.0 49.0 2007 15.5 15.8 10.3 54.0 32.5 58.5 2008 19.3 18.5 12.0 56.0 29.0 46.5 2009 18.0 15.3 11.8 56.0 31.5 47.0 2010 21.3 20.8 11.0 59.5 31.5 46.5 Spearman’s rho -0.545 -0.163 0.001 0.320 -0.206 -0.099

The abundance and demography indicators are complementary assessment elements that need to be corroborated by estimates based on population dynamics models, capable of evaluating the current stock condition in relation to both limit and target reference points (LRPs and TFRs).

78 First section - Chapter 2 - Ecological aspects Biology and spatial distribution Reproduction period The reproduction period of the various species, estimated by combining the data obtained from the experimental campaigns with that from commercial landings, shows a continuous pattern for hake, which reproduce throughout the year (table 2.7), with a peak in the late autumn and winter months (December-March), and deep water rose shrimp, whereas the reproductive season for red mullet and giant red shrimp is limited to a few months in late spring and summer. An intermediate situation is observed for horned octopus and Norway lobster.

Table 2.7 - GSA 10. Reproductive period for the various species.

Months Species J F M A M J J A S O N D European hake X X X X X X X X X X X X Red mullet X X X X Horned octopus X X X X X Norway lobster X X X X X X X X Deep-water rose shrimp X X X X X X X X X X Red shrimp X X X

Area and intensity of recruitment Large concentrations of recruits have been located on the northern side of GSA 10 (Gulf of Naples and Gaeta) through the use of geostatistical methods (Lembo et al., 1998; 2000a). Analyses conducted more recently in the Nursery Project (supported by MiPAAF) confirmed the presence of significant recruit concentration zones in the northernmost region of GSA10 (figure 2.23), as well as indicating probable nursery sites in the Gulf of Salerno and Northern Sicily (Gulf of Castellammare). Some of these areas (the Gulfs of Gaeta and Salerno) coincide in terms of space with zones with the highest probability of containing deep-water rose shrimp nurseries (figure 2.24). Core areas with particular concentrations of juvenile rose shrimp are also found in the vicinity of Cape Bonifati (Tyrrhenian Calabria) (Lembo et al., 2000b). The most probable core areas are generally located near the shelf-break, at a depth of between 100 and 200 m, with intrusions between 50 and 100 m also in certain zones (Gulf of Salerno and Cape Bonifati). The areas with a greater concentration of hake and deep-water rose shrimp are generally associated with biotic communities of detritic bottom with Leptometra phalangium as a characteristic species. The red mullet nursery areas (figure 2.25) are mainly concentrated along the mouth of the Garigliano river, in the northernmost part of the surveyed area, along the Calabrian coast, particularly in the area in front of Amantea, and along the northern coast of Sicily, in the area of the Gulf of Palermo, generally within 50 m depth. Nursery areas that show levels of spatial persistence over time are more conducive to protective actions and establishing their location is a useful tool for the preparation of targeted management measures.

79 Figure 2.23 - Hake nursery areas with indication of persistence.

80 First section - Chapter 2 - Ecological aspects Figure 2.24 - GSA 10. Deep-water rose shrimp nursery areas.

81 Figure 2.25 - GSA 10. Red mullet nursery areas.

82 First section - Chapter 2 - Ecological aspects Evaluation using stock assessment models Assessments of the state of demersal resources, using approaches based on population dynamics models, have indicated a condition of stress for certain commercial resources (Spedicato & Lembo, 1994). The need to reduce fishing pressure has emerged from analyses conducted, since 1995, for sensitive species such as Aristeus antennatus, suggesting F0.1 as a reference point (Spedicato et al., 1995). Similar conclusions have been reached in regard to giant red shrimp (Spedicato et al., 1998a). Assessments for both hake and red mullet have shown converging results, even with the use of different methods. The stocks of the two species were evaluated in a condition of overexploitation, both through the use of analytical models with reference points, such as Fmax, F0.1, SPR (Spawning Potential Ratio) (Spedicato et al., 1998b; 2006; STECF, 2011), as well as through the use of production models (Abella et al., 1999), which provided estimates of total mortality higher than the reference point ZMBP (total mortality at maximum biological production ). The hake, together with the deep-water rose shrimp and red mullet, is a key species of the fishing assemblage in the South and Central Tyrrhenian Sea and is fished together with other important commercial species: Illex coindetii, Eledone spp., Todaropsis eblanae, Lophius spp., Pagellus spp., Phycis blennoides and Nephrops norvegicus. Hake production grew from 1,338 to 1,544 tonnes between 2004 and 2006, but decreased in 2009 (1,091 tonnes). There was an increase in 2010, which brought production to around 1,330 tonnes. Most landed hake come from trawlers and small-scale coastal fisheries, but there are also substantial catches using longlines. The fishing areas for red mullet are located within the continental shelf along the coastlines of the entire area. Production data are in clear decline and fell from 524 tonnes in 2004 to 278 tonnes in 2009 and 177 tonnes in 2010, which is the lowest recorded figure. Production of deep-water rose shrimp increased constantly in the southern basin until 2006, when it reached around 10% of demersal species landings. Between 2006 and 2009, however, a significant fall in production is noted, from 1,089 tonnes in 2006 to 370 in 2010. The estimates obtained using the ALADYM model (Lembo et al., 2009; Spedicato et al., 2010) and the SURBA and VIT models (Needle, 2003; Lleonart & Salat, 1997) for the years from 2008 to 2010 (STECF, 2011) have revealed a condition of overexploitation of hake, red mullet and deep- water rose shrimp stocks, indicating the need to considerably reduce fishing pressure. However, the significant productivity of the hake stock, due to high rates of fertility and a reproduction period extended throughout the year, and the high growth rates of red mullet and rose shrimp, species maturing respectively in the second and first years of life, make these stocks capable of quickly recovering their productive potential if fishing mortality is reduced. The simulation of short-term scenarios (2010-2012) one in which the status quo is maintained and the other one in which a reduction of fishing pressure is applied has shown that a 30% reduction of Fstq (F = 0.43) for hake would produce a decrease in catches of around 13% compared to 2009, but a 36% growth in the spawning stock biomass (SSB indicator) over the following three years. The same reduction applied to red mullet (F=0.4) would produce a decrease in catches of around 13% compared to 2009, but a 24% growth in the spawning stock over the three following years. In the case of rose shrimp, a 30% reduction in mortality (F=0.84) would lead to a 6% reduction in catches compared to 2009, but a 17% growth in the spawning stock over the following three years. A long-term projection of hake stock and catches is shown by way of example (2009-2030),

83 obtained by simulating various scenarios with stochastic variations. A gradual reduction (14% per year) of F status quo was applied until F0.1 is reached in 2020 (figure 2.26).

Recruitment and F vector

70,000 0,7 60,000 0,6 50,000 0,5 40,000 0,4 F 30,000 0,3 R (thousand) 20,000 0,2 10,000 0,1 0 0 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029

SSB 25,000

20,000

15,000 tonnes 10,000

5,000

0

Catches 3,000 2,500 2,000

tonnes 1,500 1,000 500 0 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029

5% 25% 50% 75% 95% F vector 50%

Figure 2.26 - Long-term projection calculated for hake in GSA 10 with attainment of F0.1 in 2020 and maintenance of the same fishing pressure until 2030. Recruitment is of the same initial magnitude but with random variations. The bootstrap confidence intervals are shown with broken lines.

The results show a clear growth of the spawning stock biomass (SSB) and a significant increase in catches over the long term. Simulations carried out using the ALADYM model also showed that various management strategies, implemented in a complementary form (permanent withdrawal, temporary fishing ban and increase in mesh size), could allow a better use of the productive potential of the three stocks in the medium and long-term period (MiPAAF Management Plan).

References - Abella A., Belluscio A., Bertrand J., Carbonara P.L., Giordano D., Sbrana M., Zamboni A. (1999) - Use of MEDITS trawl survey data and commercial fleet information for the assessment of some Mediterranean demersal resources. Aquat. Living Resour., 12 (3): 155-166. - Abelló P., Abella A., Adamidou A., Jukić-Peladić S., Spedicato M.T., Tursi A. (2002) - Global population characteristics of two decapod crustaceans of commercial interest (Nephrops norvegicus and Parapenaeus longirostris) along the European Mediterranean coasts. Scientia Marina, 66 (Suppl. 2): 125-141. - Lembo G., Abella A., Fiorentino F., Martino S., Spedicato M.T. (2009) - ALADYM: an age and length-based single species simulator for exploring alternative management strategies. Aquat. Living Resour., 22: 233-241.

84 First section - Chapter 2 - Ecological aspects - Lembo G., Silecchia T., Carbonara P., Spedicato M.T. (2000a) - Nursery areas of Merluccius merluccius in the Italian Seas and in the East Side of the Adriatic Sea. Biol. Mar. Mediterr., 7 : 98-116. - Lembo G., Silecchia T., Carbonara P., Contegiacomo M., Spedicato M.T. (2000b) - Localization of nursery areas of Parapenaeus longirostris (Lucas, 1846) in the Central-Southern Tyrrhenian Sea by Geostatistics. Crustaceana, 73: 39-51. - Lembo G., Spedicato M.T., Silecchia T., D’agostino V. (1998) - Distribution of nursery areas of Merluccius merluccius obtained by geostatistical techniques. Cah. Options Méditerr., 35: 147-154. - Lleonart J. & Salat J. (1997) - VIT: Software for fishery analysis. User’s manual. FAO Computerised Information Series (Fisheries), 11, Rome: 105 p. - Needle C.L. (2003) - Survey-based assessments with SURBA. Working Document to the ICES Working Group on Methods of Fish Stock Assessment, Copenhagen. - SIBM (2010) - Rapporto annuale sullo stato delle risorse biologiche dei mari circostanti l’Italia. Relazione finale della Società Italiana di Biologia Marina al Ministero per le Politiche Agricole Alimentari e Forestali: 271 p. - Spedicato M.T., Carbonara P., Rinelli P., Silecchia T., Lembo G. (2006) - Biological reference points based on spawning stock biomass levels: the case of red mullet (Mullus barbatus L., 1758). Biol. Mar. Mediterr., 13: 112-123. - Spedicato M.T., Greco S., Lembo G., Perdichizzi F., Carbonara P. (1995) - Prime valutazioni sulla struttura dello stock di Aristeus antennatus (Risso, 1816) nel Tirreno Centro-Meridionale. Biol. Mar. Mediterr., 2: 239-244. - Spedicato M.T. & Lembo G. (1994) - Considerazioni sullo stato di sfruttamento delle risorse demersali (Fiume Garigliano - Capo Suvero). Biol. Mar. Mediterr., 1 : 47-59. - Spedicato M.T., Lembo G., Silecchia T., Carbonara P. (1998a) - Contributo alla valutazione dello stato di sfruttamento del gambero rosso (Aristaeomorpha foliacea, Risso, 1827) nel Tirreno Centro-Meridionale. Biol. Mar. Mediterr., 5: 252-261. - Spedicato M.T., Lembo G., Carbonara P., Silecchia T. (1998b) - Valutazione delle risorse demersali dal Fiume Garigliano a Capo Suvero. Biol. Mar. Mediterr., 5: 64-73. - Spedicato M.T., Poulard J.C., Politou C.Y., Radtke K., Lembo G., Petitgas P. (2010) - Using the ALADYM simulation model for exploring the effects of management scenarios on fish population metrics. Aquat. Living Resour., 23: 153-165. - STECF (2011) - Report of the SGMED-10-03 Working Group on the Mediterranean Part II: 648 pp. (https://stecf.jrc. ec.europa.eu/home). 2.3.3 GSA 11 - Sardinian Seas Follesa M.C., Locci I., Pesci P., Floris E., Cau A.

Assessments of the state of demersal resources in GSA 11 show a better condition of resource exploitation than those seen in other areas of Italy. The current conditions are due to both the application of management regulations and a recent development of the fleet in Sardinian seas. In the late 1980s, there was a general situation of of neritic resources in the seas around the island, in contrast to a lower exploitation of epi-mesobathyal resources (Cau, 2008). In the coastal strip the normal activity of artisanal fisheries was supplanted by that of small trawling boats, which were obsolete and poorly suited to offshore fisheries. This situation was causing a reduction in the availability of coastal resources and conflicts between trawling and small-scale coastal fisheries. The increase in total recorded mortality rates Z for red shrimp over the last few years and the reduction in the mortality rates for red mullet underlines how fishing bans and fleet modernisation (with the consequent transfer of fishing pressure towards deep areas and a better division of the fishing effort) has led to a general improvement in the exploitation of neritic resources. A detailed analysis of the results from the data for the systematic categories and main demersal species is provided below.

85 Abundance and demography Community biomass index Teleostei are the most prevalent category in terms of weight in trawl catches in Sardinia; these are followed by Selachii, cephalopods and crustaceans (figure 2.27). The biomass indices for teleostei show a decrease from 1994 until 2002, followed by a gradual recovery until they reach the maximum value in 2010 (893.7 kg/km2). Cephalopods show a weight increase in catches between 1996 and 2001, followed by a decrease, reaching a minimum in 2007 (21.7 kg/km2). Biomass indices for Selachii remained close to an average value of 86.0 ± 29.8 kg/km2 between 1994 and 2008. A significant increase in catches has been recorded over the last two years (2009: 126.3 kg/km2; 2010: 227.5 kg/km2). This increase has also been recorded for crustaceans (2009: 18.3 kg/km2; 2010: 34.5 kg/km2).

TTeleosteansTeleosteanseleosteans biomass biomass biomass indices indices indices CephalopodsCephalopodsCephalopods biomass biomass biomass indices indices indices 1,201,201,20000 141414000 121200 1,001,001,00000 12120 0 101010000 808080000 2 2 2 2 80 2 2 2 2 808080 606060000 6060

kg/km kg/km 6060 kg/km kg/km kg/km kg/km 404040000 kg/km kg/km 404040 202020000 202020 0 000 000 199419941994199619961996199819981998200020002000200220022002200420042004200620062006200820082008201020102010 199419941994199619961996199819981998200020002000200220022002200420042004200620062006200820082008201020102010 YYearsYearsears YYearsYearsears

SelachiansSelachiansSelachians biomass biomass biomass indice indice indicesss CrustaceansCrustaceansCrustaceans biomass biomass biomass indices indices indices 303030000 454545 404040 252525000 353535 200 202020000 303030 2 2 2 2 2 2 2 2 252525 151515000 202020 kg/km kg/km kg/km kg/km

kg/km 10kg/km 0 kg/km kg/km 101010000 151515 101010 505050 555 00 0 0 000 199419941994199619961996199819981998200020002000200220022002200420042004200620062006200820082008201020102010 199419941994199619961996199819981998200020002000200220022002200420042004200620062006200820082008201020102010 YYearsYearsears YYearsYearsears

Figure 2.27 - Biomass indices (kg/km2) and respective confidence limits (broken lines) for the main faunal categories: teleostei, selachii, cephalopods and crustaceans (Data: MEDITS 1994-2010).

Biomass and density indices for the main fishery target species European hake is the most represented species of those under examination: average abundance indices were 1,998 individuals/km2 and 61.9 kg/km2 (figure 2.28). The biomass indices show a statistically significant increasing trend (Spearman test). Red mullet, which is the second most important target species after European hake in terms of numbers and weight, shows no relevant temporal trends for either of the indices, though the last survey year shows an increase in value (figure 2.28). The abundance indices for Norway lobster have not shown any statistically significant trends (figure 2.28). There is a gradual increase in values from 2001, with the exception

86 First section - Chapter 2 - Ecological aspects of 2009, when there was a sharp decline in both indices. Red shrimp shows a variable trend, with maximum values in the period 2000-2002. A slight recovery in the values is seen between 2008 and 2010 (figure 2.28). Also for curled octopus no statistically significant trends have been observed.

European hake biomass indices European hake density indices 200 EurEuropeanopean hak hakee biomass biomass indices indices 9,000 EurEuropeanopean hak hakee density density indices indices 200 9,000 20201800 9,009,008,0000 18160 8,000 181800 8,008,007,0000 16140 7,000 160 7,007,006,0000 140

120 2 2 2 141400 6,000 6,006,005,0000

120 2 2 2 12100 2

120 2 /km 2

2 120 2 5,000

n 4,000 10800 5,005,0000 kg/km kg/km /km 101000 /km /km n /km 4,000 n 4,003,000

80 n 4,000

n 4,000 kg/km 8060 kg/km 80

kg/km 80 kg/km 60 3,002,000 606040 3,003,0000 40 2,000 404020 2,002,001,0000 20 1,000 20200 1,001,0000 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 00 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 19941994 19961996 19981998 20002000 20022002Years 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002Years 20042004 20062006 20082008 20102010 Years Years YYearsears YYearsears

Red mullet biomass indices Red mullet density indices 120 RedRed mullet mullet biomass biomass indices indices 3,000 RedRed mullet mullet density density indices indices 120 3,000 121200 3,003,0000 100 2,500 100 2,500 101000 2,502,5000 80 2,000 2

2 80 2,000 8080 2,002,0000 2 60 2 2 1,500 2 2 2 2 2 60 n/km 1,500 kg/km 6060 1,501,5000 n/km 40 n/km 1,000 n/km n/km kg/km kg/km kg/km kg/km 40 1,000 4040 1,001,0000 20 500 20 500 2020 505000 0 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 00 00 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 19941994 19961996 19981998 20002000 20022002Years 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002Years 20042004 20062006 20082008 20102010 Years Years YYearsears YYearsears

Norway lobster biomass indices Norway lobster density indices 18 NorwayNorway lobster lobster biomass biomass indices indices 400 NorwayNorway lobster lobster density density indices indices 18 400 181816 40403500 16 350 161614 35353000 1412 300 14 30302500 2 2 12 121210 250 2 2 2 2 25252000 2 2 2 2 10 10108 n/km 200 kg/km 20201500

8 n/km 86 n/km

8 n/km n/km kg/km 8 kg/km 150 kg/km 150 kg/km 6 15151000 664 100 4 10500 442 100 2 50 220 50500 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 00 00 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 19941994 19961996 19981998 20002000 20022002Years 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002Years 20042004 20062006 20082008 20102010 Years Years YYearsears YYearsears

Red shrimp biomass indices Red shrimp density indices 18 RedRed shrimp shrimp biomass biomass indices indices 1,600 RedRed shrimp shrimp density density indices indices 18 1,600 181816 1,601,601,4000 16 1,400 161614 1,401,401,2000 1412 1,200 14 1,201,201,0000 2 2 12 121210 1,000 2 2 2 2 1,001,008000 2 2 2 2 10 10108 n/km 800 kg/km 80806000

8 n/km 86 n/km

8 n/km n/km kg/km 8 kg/km 600 kg/km 600 kg/km 6 60604000 664 400 4 40200 442 400 2 200 220 202000 87 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 00 00 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 19941994 19961996 19981998 20002000 20022002Years 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002Years 20042004 20062006 20082008 20102010 Years Years YYearsears YYearsears

Horned octopus biomass indices Horned octopus density indices 30 HornedHorned octopus octopus biomass biomass indices indices 250 HornedHorned octopus octopus density density indices indices 30 250 3030 252500 25 200 25 200 2525 202000 2 2 20 150 2 2 20 2 150 2 20 150 2 2 20 2 150 2 20 150 n/km

kg/km 15 100 n/km n/km n/km n/km kg/km 15 100 kg/km 15 100

kg/km 15 100 kg/km 15 100 10 50 10 50 1010 5050 0 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 00 00 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 19941994 19961996 19981998 20002000 20022002Years 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002Years 20042004 20062006 20082008 20102010 Years Years YYearsears YYearsears EurEuropeanopean hak hakee biomass biomass indices indices EurEuropeanopean hak hakee density density indices indices 202020000 9,009,009,00000 181818000 8,008,008,00000 161600 161600 7,007,007,00000 141414000 6,006,006,00000

120 2

120 2 2 2

121200 2 2 2 2 5,005,005,00000 101010000 /km /km /km /km

n 4,000

n 4,000 8080 n n 4,004,0000 kg/km

kg/km 8080 kg/km kg/km 3,003,0000 606060 3,003,0000 404040 2,002,002,00000 202020 1,001,001,00000 000 000 199419941994 199619961996 199819981998 200020002000 200220022002 200420042004 200620062006 200820082008 201020102010 199419941994 199619961996 199819981998 200020002000 200220022002 200420042004 200620062006 200820082008 201020102010 YYearsearsears YYearsearsears

RedRed mullet mullet biomass biomass indices indices RedRed mullet mullet density density indices indices 121212000 3,003,003,00000

101010000 2,502,502,50000

808080 2,002,002,00000 2 2 2 2 2 2 2 2 606060 1,501,501,50000 n/km n/km n/km n/km kg/km kg/km kg/km kg/km 404040 1,001,001,00000

202020 505050000

000 000 199419941994 199619961996 199819981998 200020002000 200220022002 200420042004 200620062006 200820082008 201020102010 199419941994 199619961996 199819981998 200020002000 200220022002 200420042004 200620062006 200820082008 201020102010 YYearsearsears YYearsearsears

NorwayNorway lobster lobster biomass biomass indices indices NorwayNorway lobster lobster density density indices indices 181818 404040000 161616 353535000 1414 1414 303030000 1212 1212 252500

2 252500 2 2 2 2 2 2 2 101010 202020000

8 n/km 8 n/km

88 n/km n/km kg/km kg/km kg/km kg/km 151515000 666 101000 444 101000 50 222 505050 000 000 199419941994 199619961996 199819981998 200020002000 200220022002 200420042004 200620062006 200820082008 201020102010 199419941994 199619961996 199819981998 200020002000 200220022002 200420042004 200620062006 200820082008 201020102010 YYearsearsears YYearsearsears

RedRed shrimp shrimp biomass biomass indices indices RedRed shrimp shrimp density density indices indices 181818 1,601,601,60000 161616 1,401,401,40000 1414 1414 1,201,201,20000 1212 1212 1,001,0000

2 1,001,0000 2 2 2 2 2 2 2 101010 808080000

8 n/km 8 n/km

88 n/km n/km kg/km kg/km kg/km kg/km 606060000 666 404000 444 404000 200 222 202020000 000 000 199419941994 199619961996 199819981998 200020002000 200220022002 200420042004 200620062006 200820082008 201020102010 199419941994 199619961996 199819981998 200020002000 200220022002 200420042004 200620062006 200820082008 201020102010 YYearsearsears YYearsearsears

HornedHorned octopus octopus biomass biomass indices indices HornedHorned octopus octopus density density indices indices 303030 252525000

252525 202020000 2 2 2

2 20 150

20 2 2 150 2 2 2020 151500 n/km n/km n/km n/km kg/km kg/km 1515 101000 kg/km kg/km 1515 101000

101010 505050

000 000 199419941994 199619961996 199819981998 200020002000 200220022002 200420042004 200620062006 200820082008 201020102010 199419941994 199619961996 199819981998 200020002000 200220022002 200420042004 200620062006 200820082008 201020102010 YYearsearsears YYearsearsears

Figure 2.28 - Biomass indices (kg/km2) and respective confidence limits for the main target species estimated for their area of distribution (Source: MEDITS 1994-2010).

95th percentile size of the main target species The 95th percentile sizes were considerably constant over time, possibly indicating a relative stability of the stocks (table 2.8). Red shrimp is an exception, showing a statistically significant decreasing trend. Until 2001, the 95th percentile size was above 53.5 mm for SL and showed no signs of decrease; since 2002, however, the values have gradually decreased, reaching the minimum value (46.0 mm SL) in 2005 and 2009.

88 First section - Chapter 2 - Ecological aspects Table 2.8 - Size: 95th percentile length of the main fishery target species (the significant Spearman rho values are shown in bold)

European Norway Horned hake Red mullet lobster Red shrimp octopus Year TL (cm) TL (cm) CL (mm) LC (mm) DML (cm) 1994 31.3 18.8 52.5 56.0 11.8 1995 31.8 18.5 50.5 55.5 11.5 1996 28.5 19.8 50.5 54.0 10.3 1997 29.5 19.8 50.5 53.5 10.8 1998 30.0 20.3 51.0 56.5 11.3 1999 29.0 19.8 50.5 54.0 11.5 2000 33.0 19.8 52.5 53.5 12.0 2001 29.0 19.8 53.0 57.0 11.5 2002 32.3 18.3 55.5 51.5 10.3 2003 29.0 18.8 50.5 51.5 10.8 2004 26.5 19.0 52.5 47.0 10.5 2005 29.0 19.0 49.0 46.0 10.5 2006 29.8 19.3 51.5 48.5 11.8 2007 34.0 20.3 50.0 50.5 8.5 2008 27.0 19.3 50.0 54.0 11.0 2009 26.8 19.3 50.5 46.0 11.0 Spearman’s rho -0.283 0.073 -0.103 -0.724 -0.332

Biology and spatial distribution Reproduction period The reproduction period was estimated by combining the data obtained from the experimental campaigns (Grund & Medits) with that from commercial catches (Campbiol) (tab. 2.9). Merluccius merluccius was found to have a reproductive period extending throughout the entire year, with a peak between January and March. The reproductive period of Mullus barbatus is concentrated in the time between late spring and summer, whereas that of Eledone cirrhosa is centred on summer. Mature exemplars of Aristaeomorpha foliacea reproduce prevalently during summer months (with a peak in July).

Table 2.9 - Peak reproductive periods for target species in GSA 11. Integrated information from the Medits and Grund campaigns and from commercial catches from all fleet segments combined.

Months Species J F M A M J J A S O N D M. merluccius X X X X X X X X X X M. barbatus X X X N. norvegicus X X X E. cirrhosa X X X X X A. foliacea X X X

Recruitment areas and intensity The geographical distribution of hake nursery areas confirmed the presence of important recruit concentration zones in western Sardinia (SIBM, MiPAAF Nursery project). Hake recruits in particular are present in the entire area, mainly at a depth of between 100 and 300 m, with

89 greater persistence in South-western Sardinia (figure 2.29). Red mullet recruits have always been abundant along the island’s western coastal strip, with greater concentrations in the south. Curled octopus juveniles were found to be particularly abundant in the western and southern coasts, and a nursery area was identified on the south-west coast. Recruitment has not shown any statistically significant annual fluctuation.

Figure 2.29 - Hake nursery areas, with indication of persistence.

Evaluation using stock assessment models The assessments were made using Yield software (Branch et al., 2000) and the LCA routine implemented in the VIT software (Lleonart & Salat, 1997) with MEDITS data from 1994 to 2009. The VIT analysis was conducted using a vectorial fish mortality obtained through the ProdBiom routine (Abella et al., 1997).

90 First section - Chapter 2 - Ecological aspects Aristaeomorpha foliacea, red shrimp

Fishing mortality was between 0.6 (F1999) and 1.2 (F2009). These values are all higher than the estimated Reference Point value Fmax=0.5. The exploitation rate was found to be between 0.6

(E2007) and 0.7 (E2009). These results indicate that the red shrimp stock in GSA11 is overexploited and that this condition seems to have intensified in recent years. The estimated F values, considerably higher than F0.1, are indicators of excessive exploitation, which could be due to the observed increase in the fishing effort since 1991 (Sabatini et al., 2002). Situations of local overfishing were recorded in certain areas of Sardinia (eastern coast). The progressive increase in fishing mortality rates in

South-eastern Sardinia, which exceeded Fmax in 2001, should also be considered as an important sign of overfishing (Sabatini et al., 2006).

Mullus barbatus, red mullet

Fishing mortality was between 0.4 (F1996) and 0.7 (F1994). The estimated Reference Point value

Fmax is 0.6. The rate of exploitation was between 0.6 (E2007) and 0.8 (E1994). A reduction in E values is seen from 2001 onwards, remaining at around 0.6. These results indicate a progressive improvement in the exploitation of the resource. This condition seems to underline the beneficial effects caused by the modification of the fleet and the consequent change in the fishing habits of the Sardinian fleet.

Merluccius merluccius, European hake

The target reference point F0.1 was 0.15, in line with the SGMED 10-03 proposal. The exploitation analyses showed fishing mortality ranging between 0.6 (F07) and 0.942 (F04) and an average exploitation rate of 0.7. These results indicate a situation of overfishing, which has remained stable over the years. This situation could be due to the fact that the catches come mainly from trawl fisheries, which has a greater impact on the “young” portion of the population, without undermining the stock of large reproducers, which ensure constant recruitment over the years.

Conclusions It would appear that the policy for a more rational management of demersal resources, adopted at both a regional and a national level, is beginning to produce results. Greater control of fishing pressure in the bathyal strip should however be exercised. It is hoped that additional legislation, such as the regulation of more selective gear and periodic closure of the nursery areas, may be adopted in order to maintain or further improve the stock conditions currently achieved.

Small-scale coastal fisheries Artisanal fisheries is practised throughout the region of Sardinia. The most widely used gear mainly consists of driftnets, pots and hand lines. This gear is used according to a seasonal system: the operators normally place the gear in the sea depending on the abundance of the species in a given period. The turnover from lobster Palinurus elephas fishing in the period from March to August is seen to be substantial (see box). The production mix of small-scale fisheries is generally characterised by a wide range of species in which striped red mullet Mullus surmuletus, and common octopus Octopus vulgaris are predominant (table 2.10). Fishing for striped red mullet is mainly practised during the autumn and, in recent years, also in spring. Octopus pots, however, are used exclusively in the period from spring to summer.

91 Table 2.10 - Landing data for Mullus surmuletus and Octopus vulgaris in GSA 11 for the period 2004-2010 (Source: Irepa).

Mullus surmuletus Octopus vulgaris Gill nets Gill nets Pots 2004 377 362 7.52 2005 723 678 38.31 2006 823 519 319 2007 364 97 600 2008 216 122 254 2009 295 268 350 2010 257 295 336

References - Abella A., Caddy J.F., Serena F. (1997) - Do natural mortality and availability decline with age? An alternative yield paradigm for juvenile fisheries, illustrated by the hake Merluccius merluccius fishery in the Mediterranean. IFREMER Aquat. Living Resour., 10: 257-269. - Branch T.A., Kirkwood G.P., Nicholson S.A., Zara S.J. (2000) - YIELD version 1.0. MRAG Ltd, London. - Cau A. (2008) - Relazione finale: Valutazione Risorse Demersali – Gruppo Nazionali Demersali - G.R.U.N.D. – GSA 11 - Mari circostanti la Sardegna. Ministero delle Politiche Agricole Alimentari e Forestali. - Lleonart J. & Salat J. (1997) - VIT: Software for fishery analysis. User’s manual. FAO Computerized Information Series (Fisheries), 11, Rome, FAO: 105 p. - Sabatini A., Cuccu D., Follesa M.C., Murenu M., Cau A. (2002) - Status of red shrimp (Aristaeomorpha foliacea) population in the Sardinian Seas. GFCM-SAC. Working paper, 20-22/3/2002, Roma, Italy: 12 p. - Sabatini A., Cabiddu S., Cuddu D., Murenu M., Pendugiu A.A., Pesci P., Follesa M.C., Cau A. (2006) - Searching adequate BPR for Aristaeomorpha foliacea stock off southern coats of Sardinia . Biol. Mar. Mediterr., 13 (3): 87-97.

2.3.4 GSA 16 - Southern coast of Sicily Fiorentino F., Bono G., Gancitano V., Garofalo G., Gristina M., Ragonese S., Vitale S.

The population structure of the main species occurring in the Strait of Sicily is still unclear. Based on the available information (i.e. species biology, morpho-bathymetry, water circulation) two different groups of species can be distinguished (Fiorentino et al., 2004) for the identification of stock units. The first includes coastal species whose life cycles are accomplished entirely on the continental shelf area. For these species like red mullet, striped red mullet, common pandora, common octopus, it is reasonable to assume the occurrence of separate stocks on the African and Sicilian shelves. To the second group belong those species with a wider depth distribution, from the shelf to the slope, exploited also in International waters, which are considered to form shared stocks in the Strait of Sicily. Biomass indices of all the species from 1994 to 2010 range between 313 (2001) and 696 kg/ km2 (2009) with a statistically significant trend. Teleosts are the most abundant taxa with a growth phase (2007-2009) in the last years. Elasmobranchs indices show a significant increasing trend, while Cephalopods fluctuate without clear trends. Crustaceans, finally, show a significant statistically upward trend throughout the period examined. The time series of the abundance indices by weight for the main target species are reported below. Taking into account the hake (M. merluccius), it is possible to observe a first phase of growth with a peak in 2005 and then a constant high levels. For red mullet (M. barbatus) a significant trend of the increased biomass throughout the whole period can be highlighted. This

92 First section - Chapter 2 - Ecological aspects increased biomass was also recorded for Norway lobster (N. norvegicus). The deep-water rose shrimp (P. longirostris) shows a cyclical pattern with a peak in the whole time series recorded in 2009. The biomass indices of red shrimp (A. foliacea) shows large fluctuations with no apparent long-term trends. Considering the time series by the numerical abundance of the hake (M. merluccius) is notable, an initial reduction followed by an increasing of abundances, culminating in a peak in 2005, followed by a new phase of decrease in number. The red mullet (M. barbatus) time series shows growth phase with a high index of abundance in 2003 and 2005 due to recruitment peaks. For Norway lobster (N. norvegicus) there is a growing trend, since 2005 with a peak in 2009 and a subsequent decrease in 2010. P. longirostris shows a cyclical pattern, with the last maximum detected in 2009. Finally, the red shrimp (A. foliacea) shows an increased abundance indices during the period 2007-2009 followed by a decrease in abundance in 2010. In table 2.11 are reported the length at 95th percentile obtained with the analysis of the annual length frequency distribution by combined sex collected in the MEDITS surveys 1994-2010.

Table 2.11 - GSA 16. Length structure: length at 95th percentile by specie (TL = Total Length, DML = Dorsal Mantle Length, CL = Carapace Length).

European Deep-water Giant hake Red mullet Norway lobster rose shrimp red shrimp Years TL (cm) TL (cm) CL (mm) CL (mm) CL (mm) 1994 23 19 49 30.5 58.5 1995 27 19 46.5 31 59 1996 26 17.5 45.5 27.5 60 1997 21 17 43.5 26 56.5 1998 27 18 44.5 26 59 1999 25 19 49.5 26.5 59.5 2000 26 16.5 45.5 28.5 57.5 2001 29 19 41 27 58 2002 27 17 45 27.5 59 2003 21 14 48 27 58 2004 25 17 48 25.5 57.5 2005 22 17.5 48.5 28 55 2006 22 17.5 46.5 28 57.5 2007 20 17 46.5 30 59 2008 24 18 46.5 26 59.5 2009 23 17 46.5 27.5 58.5 2010 29 17.5 49 27.5 59.5 Spearman’s rho -0.177 -0.357 0.239 -0.121 -0.013

A recent synthesis on the distribution of the nursery area of the main demersal species and the relation with the streams and the oceanographic process in the GSA 16 are reported in Garofalo et al. (2011) and in the literature there reported (figure 2.30).

93 Assessments carried out in the last years indicated an overexploitation state of the main stocks. This general state of fisheries resources was recognized since the end of 1980s using global production models (Levi & Andreoli, 1989). Results of these models showed that the production was below the maximum sustainable yield (MSY). In more recent years the application of analytical models has allowed to identify an overexploitation status, also due to a too low size-at first capture, of all the main commercial species. A summary of the assessments carried out since early ‘90s is showed in table 2.12.

Figure 2.30 - The main nursery area in GSA 16 of Red mullet, European hake, Horned octopus, Deep-water rose shrimp, Greater forkbeard, Norway lobster and Giant red shrimp. Main hydrological features and morfo- batimetric in the northern sector of the Strait of Sicily (AIS, Atlantic Ionian Stream; ABV, Adventure Bank Vortex; ISV, Ionian Shelf-break Vortex) (modified from Garofalo et al., 2011).

94 First section - Chapter 2 - Ecological aspects Table 2.12 - Summary of assessments conducted on the state of demersal resources in the Strait of Sicily.

Current exploitation index Species GSA Exploitation status, Current exploitation management indications and Author Time Method optimal notes

Red mullet 15 and 16 yield per recruit (BHM & Ec=0.70-0.75 Overfishing. TBM) using survey data The reduction of the fishing mortality of 40% and the increase

Levi et al., Emax=0.44; of the mesh size from 32 to 40

1993 1985-1987 E0.1=0.59 mm duplicate the economic value of the catch

Deep rose pink 12, 13, 14, Yield per recruit (BHM & Ec=0.80 Overfishing. shrimp 15 e 16 TBM) using commercial More sustainable exploitation

landings Emax=0.67; reducing the fishing mortality of

E0.1=0.66 20% or increase mesh size from Levi et al., 1995 32 to 40 mm 1989-1990

Giant red 15 e 16 Yield and Biomass per Fc=0.6 Exploitation forthcoming to max shrimp recruit (BHM) using survey

data Fmax=0.6 Ragonese & 1985-1987 Bianchini, 1996

European hake 15 e 16 LCA and Yield and Fc=0.54 Overfishing. Biomass per recruit using Reduce fishing mortality about

commercial landings F0.1=0.27 70% Gancitano et al., 2005-2006 2007

European hake 15 e 16 Surba and global model Fc=0.47 Overfishing. using survey data Reduce of fishing mortality about

SGMED, 2008 1994-2006 FMBP=0.395 20%

Red shrimp 15 e 16 LCA and Yield and Fc=0,44 Overfishing. Biomass per recruit using Reduce of fishing mortality about

Gancitano et al., commercial landings Fmax=0,47; 35%

2010 F0.1=0,28 2006

Common 16 LCA and Yield and Fc (trawler)= 0.23; Overfishing.

Pandora Biomass per recruit using Fc (artisanal fishery)=0.04 Reduce of fishing mortality by commercial landings trawler of 50% pesca dello Gancitano et al., 2007-2009

2010 Fmax=0.28;

F0.1=0.16

Deep-water 12, 13, 14, Yield and Biomass Fc=1.16-1.25 Overfishing. pink shrimp 15 e 16 per recruit (VIT) using Reduce of fishing mortality of

commercial landings F0.1=1.00 20% Ben Mariem et 2007-2008 al., 2010

The case of the deep-water rose shrimp, considered as the most important commercial stock in the area and exploited in a large area (figure 2.31) is rather interesting. Its production rose from 4,000-6,500 tonnes during the 1980s to the current 6,000-10,000 tonnes.

95 Figure 2.31 - The main fishing areas of P. longirostris for distant (coloured) and coastal (black) Sicilian trawlers in the Strait of Sicily (modified from Levi et al., 1995).

A recent assessment carried out joining data from Italy, Malta and Tunisia in the frame of the regional project FAO MedSudMed showed a high fishing mortality on juveniles mostly due to the inshore Sicilian trawlers (Ben Meriem et al., 2010). The average fishing mortality (F) was between 1.16 and 1.25 a 20% above the assumed reference points (F01) for the stock (figure 2.32).

7 3

6 2,5 5 2 4 1,5 Y/R (g)

SSB/R (g) 3 1 2

1 0,5

0 0 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1 1,1 1,2 1,3 1,4 1,5 1,6 1,7 1,8 1,9 2

Multiplier Fc

SSB Y/R ITA 12_24 ITA >24 TUN

Figure 2.32 - Curves of yield (Y/R) and spawning stock biomass (SSB/R) per recruit of deep-water pink shrimp (sexes combined) in the Strait of Sicily obtained through the cohort analysis by length according to the current fishing mortality value equal to 1.21 corresponding to the continuous line x = 1. The dotted line corresponding to value of F0.1 (x = 0.77 of Fc, corresponding to new fishing mortality of 0.93). The curves of yield per recruit are also reported maintaining separate smaller Italian boats (ITA 12_24), the largest (ITA > 24) and the Tunisian boats (TUN). The contribution of the yield of Maltese trawlers is not shown as lower to 1% of the total (modified from Ben Meriem et al., 2010).

96 First section - Chapter 2 - Ecological aspects However, according to trawl survey data (e.g. standardized abundance indices) several fish stocks on the continental shelf of GSA 16, such as red mullet, showed some signals of recovery in the period 1994-2010 (Gancitano et al., 2010). It is also important to consider that stocks can undergo temporal fluctuations as observed for the deep-water rose shrimp which shows a cyclic stock increase every 4-5 years. Significant signal of recovery of fisheries resources are highlighted by the temporal trend of some community metrics calculated using the MEDITS survey time series. The proportion of fish over 30 cm long is increasing as well as fish maximum size. In addition, there is a clear growing pattern in the abundance indices of selaceans which are considered as a taxon very sensible to the fishing pressure (Gancitano et al., 2010). The observed recovering trend observed in the GSA 16 exploited demersal communities is probably due to the additive effect of different co-occurring main factors, namely: • reduction of the fishing pressure on the shelf as effect of a decreasing of the fleets partially compensated by an increased efficiency of the vessels; • significant changes in the target species of the trawl fleet with an increasing pressure on bathyal crustaceans (red shrimps) inside and outside the GSA 16 have induced a reduction of the fishing activity on the continental shelf (Garofalo et al., 2007); • modification of the hydrological pattern associated with the ongoing climate change has enhanced the recruitment habitat of some coastal species. The positive effect of higher sea surface temperature on the recruitment success of red mullet was demonstrated for red mullet (Levi et al., 2003). A similar dynamic was also observed for the common octopus (Garofalo et al., 2010). It is however important to note that such improvement of the condition of the exploited communities needs to be considered within the general pattern of overexploitation of the main commercial species highlighted by population dynamics models (table 2.12). Given the shared characteristics of the stocks in the Strait of Sicily to improve the knowledge on the state of fisheries resources it will important in the next future to extend the monitoring of fleets and resources also to the other GSAs of the area. This because the observed reduction of the fleet in the GSA 16 could be compensated by increasing in other marine sectors. The Tunisian fleet for instance has recently expanded its fishing capacity and spatial range and in several fishing grounds an increasing of conflicts with the Italian trawlers exploiting the deep-water rose shrimp was observed. A similar situation occurs on fishing grounds located South to Lampedusa island (GSA 14) as also Egyptian and Cypriot trawlers have begun to exploits shared resources in international waters. In addition fast modifications in the fleet behavior can be induced by political changes in the countries bordering the area. During the recent Libyan civil war some Italian trawlers started exploiting again red shrimp in the exclusive fishing zone claimed by Libya taking advantage by the temporary lack of patrolling. All these aspects of fisheries in the area make clear the urgent need for a Mediterranean fisheries management plan for offshore fisheries, as a tool for the sustainable exploitation of shared resources in the Strait of Sicily.

References - Ben Meriem S., Fiorentino F., Dimeck M., Gancitano V., Knittweis L., Jarboui O., Ceriola L., Arneri E. (2010) - Assessment of the shared stock of deep-water pink shrimp (Parapenaeus longirostris Lucas, 1841) in the MedSudMed area. Working Group on stock assessment of demersal species. SAC GFCM Stock Assessment Forms.

97 - Fiorentino F. (2010) - Alcuni spunti per migliorare la sostenibilità bio-economica della pesca del gambero rosa dello Stretto di Sicilia. In: Osservatorio della Pesca del Mediterraneo (ed). Rapporto Annuale 2010 sulla Pesca e sull’Acquacoltura in Sicilia: 138-153. - Gancitano V., Cusumano S., Badalucco C., Rizzo P., Comparetto G., Sabatella E., Fiorentino F. (2007) - Analisi di coorte in lunghezza del nasello (Merluccius merluccius, L., 1758) (Pisces-Merluccidae) nello Stretto di Sicilia. Biol. Mar. Mediterr., 14 (2): 354-355. - Gancitano V., Basilone G., Bonanno A., Cuttitta A., Garofalo G., Giusto G.B., Gristina M., Mazzola S., Patti B., Sinacori G., Fiorentino F. (2010) - GSA 16 Lo Stretto di Sicilia. In: Mannini A., Relini G. (eds), Rapporto annuale sullo stato delle risorse biologiche dei mari italiani. Anno 2008. Biol. Mar. Mediterr. 17 ( Suppl. 3): 93-116. - Garofalo G., Ceriola L., Gristina M., Fiorentino F., Pace R. (2010) - Nurseries, spawning grounds, and recruitment of Octopus vulgaris in the Strait of Sicily, central Mediterranean Sea. ICES J. Mar. Sci., 67 (7): 1363-1371. - Garofalo G., Fortibuoni T., Gristina M., Sinopoli M., Fiorentino F. (2011) - Persistence and co-occurrence of demersal nurseries in the Strait of Sicily (central Mediterranean): Implications for fishery management. J. Sea Res. 66 (2): 29-38. - Garofalo G., Giusto G.B., Cusumano S., Ingrande G., Sinacori G., Gristina M., Fiorentino F. (2007) - Sulla cattura per unità di sforzo della pesca a gamberi rossi sui fondi batiali del Mediterraneo orientale. Biol. Mar. Mediterr., 14 (2): 250-251. - Levi D. & Andreoli M.G. (1989) - Valutazione approssimata delle risorse demersali nei mari italiani. Oebalia, 15 (2): 653-674. - Levi D., Andreoli G., Giusto G.B. (1993) - An analysis based on trawl-survey data of the state of the “Italian” stock of Mullus barbatus in the Sicilian Channel, including management advice. Fish. Res. 17: 333-341. - Levi D., Andreoli M.G., Giusto R.M. (1995) - First assessment of the rose shrimp, Parapenaeus longirostris (Lucas 1846), in the central Mediterranean. Fish. Res., 21: 375-393. - Levi D., Andreoli M. G., Bonanno A., Fiorentino F., Garofalo G., Mazzola S., Norrito G., Patti B., Pernice G., Ragonese S., Giusto G.B., Rizzo P. (2003) - Embedding sea surface temperature anomalies in the stock recruitment relationship of red mullet (Mullus barbatus L.) in the Strait of Sicily. Sci. Mar., 67 (Suppl. 1): 259-268. - Ragonese S. & Bianchini M.L. (1996) - Growth, mortality and yield-per-recruit of the deep-water shrimp Aristeus antennatus (Crustacea-Aristeidae) of the Strait of Sicily (Mediterranean Sea). Fish. Res., 26: 125-137.

2.3.5 GSA 17 - Northern Adriatic Sea Manfredi C., Piccinetti C.

The information about the main resources in GSA 17 comes from multiple publications produced by research scientists operating in the Adriatic Sea, using fishing survey data from the Pipeta, GRUND and MEDITS series and from co-ordinated sampling conducted by research institutes in Italy, Slovenia and Croatia. The work has often been carried out in collaboration with these institutes and presented, discussed and published by AdriaMed, the FAO international collaboration programme for the Adriatic Sea (Jukić et al., 1999; Vrgoč et al., 2004). GSA 17 forms a unique environment in which the fishing vessels of the three coastal countries, Slovenia, Croatia and Italy, operate on the same resources, with spatial restrictions. The living resources are in common, both because they are fished in the same areas by vessels of various nationalities, and also due to the biological cycles which occur in an integrated manner in the of the various countries. For example, sole reproduce in the coastal waters of and Slovenia and juveniles grow in the coastal lagoons and along the coast of Italy; the juvenile stages of squid and red mullet are concentrated along the Italian coasts and then migrate, as they grow, towards Croatian waters. The surveys for sampling demersal resources at sea, known as MEDITS, have been carried out jointly since 1996 by three research institutes: the Laboratory of Marine Biology and Fishing of the University of Bologna in , for the Italian part, the Institute of Oceanography and Fisheries in Split, for the former Yugoslavian and then Croatian part, and the Fisheries Research Institute in for Slovenia. The total information gathered forms a common database, which is updated annually and overcomes the inherent division in all previous research, in which only a part of the area was examined, since no institute had access to the territorial waters of the other countries.

98 First section - Chapter 2 - Ecological aspects This common database is indispensable for knowledge of the state of living resources in GSA 17, but when speaking of Italian fisheries in GSA 17, it must be borne in mind that Italian vessels do not have access to the territorial waters of the other countries and vice versa, and therefore in order to link the fleet with catches and available resources, the situation must be analysed for the area where the Italian vessels operate, i.e. only Italian and international waters. In regard to demersal resources, there is no distinction in the Adriatic Sea between species fished with trawl nets and with the gear used by small-scale coastal fisheries. There is in fact an area where both fishing systems catch the same resources and there are small fishing vessels that operated using trawl nets at a depth of 10-15 metres, at a distance of 3 miles from the coast. Until 2010, trawling was allowed up to 1,000 metres from the coast in the Northern Adriatic Sea for certain special cases. This situation strongly limited the development of fishing for demersal resources with fixed gear, which is practiced along a limited section of the coast. The various forms of small-scale coastal fisheries include squid fishing with pots, which has been practiced for over a century along the coastal strip in April and May, and fishing for mantis shrimp () using small shrimp pots, which has developed recently in . Mention should also be made of fishing for the gastropod Nassarius mutabilis, known as mutable nassa, in which a few hundred fishermen in GSA 17 are employed. Fishing with set gillnets is mainly carried out by small, fast fishing boats, which each set 3,000-4,000 m of nets in the coastal strip where trawling is prohibited, or up to 4-6 miles offshore in periods when there is no trawling activity (weekends or periods of temporary closure of fishing). These catch mantis shrimp, squid, sole and tub gurnard, particularly during summer months. In the southernmost part of GSA 17 fishing with trammel nets is carried out in the rocky shallows, also distant from the coast. The situation of small-scale coastal fisheries is considerably different on the eastern coast of GSA 17, where thousands of small boats fish using fixed gear within a mile from the coasts of the numerous islands and catch very diverse species, including scorpionfish, triglidae, John Dory, common pandora, and octopus, operating at times on rocky seabeds were trawling is not practised. Fishing for bivalve molluscs using vessels fitted with hydraulic dredges is highly developed and targets only the species Chamelea gallina, Ensis minor and Callista chione. There are around 600 Italian vessels involved in this type of fishing, which vessels often exceed 10 TSL and have more than one fishing licence. These vessels operate on resources that are managed by regulating fishing intensity in terms of time and space and by closing off various areas in rotation; restocking actions with juveniles are also carried out. In the following description of abundance indices and biological parameters, certain species captured almost exclusively with trawl nets will be examined (hake, Norway lobster, musky octopus, red mullet and whiting), as well as species caught using both trawl and fixed gear (common pandora, squid and mantis shrimp).

99 Teleosteans biomass indices 600

500

Distribution and abundance indices 400 2 There are few species whose distribution extends over 300more than 50% of the GSA 17 area. Most of the species live in a modest portion of the entire expansekg/km 200 of GSA and these areas, which differ according to the species, are associated with particular types of sediment and various biotic 100 communities and depths. The exploitable fish in one zone are different from those available in 0 other zones or in other seasons and this should be taken into1994 1996account1998 2000 in fisheries2002 2004 2006management.2008 2010 Years Abundance and demography Teleosteans biomass indices Selachians biomass indices Biomass index of the community Teleosteans biomass indices 600 600 The historical series of biomass indices for the main faunal600 categories captured during the MEDITS 500 500 surveys in the area of Italian and international territorial waters500 in GSA 17 are shown in figure 2.33. 400 400 Bony fish biomass varies but without any significant temporal400 trend; nevertheless a continuous 2 2

300 2 300 reduction in this faunal category can be seen since 2005.300 The abundance of Selachii remains kg/km kg/km

200 kg/km 200 fairly constant at low levels, with the exception of 1998,200 when an exceptional catch of spiny dogfish100 in one haul led to a peak in biomass records. 100Cephalopods, characterised by short life 100 cycles 0of 1-2 years, display wide fluctuations without showing0 any significant trend over time. 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Crustaceans show an overall reduction in abundance. 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Years

Selachians biomass indices Teleosteans biomass indices CephalopodsSelachians biomass biomass indice indicess 600 600 60080 500 70 500 500 60 400 400 40050 2 2 2 2 300 40 300 300 kg/km

kg/km 30

200 kg/km kg/km 200 200 20 100 100 10010 0 0 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 Years Years Yearsears

CephalopodsSelachians biomass biomass indice indicess Crustaceans biomass indices Cephalopods biomass indices 80 12 600 80 70 10 500 70 60 60 8 40050 2 2 50 2 40 2 6 300 40 kg/km 30 kg/km kg/km 4 200 kg/km 30 20 20 2 10010 10 0 0 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Years Years

Figure 2.33 - GSA 17. Biomass indices (kg/km2) and respective confidence limits (broken lines) for the main faunal Crustaceans biomass indices categories: Teleostei,Cephalopods Selachii, biomassCephalopods indices and Crustaceans estimated forCrustaceans the area of biomass Italian indicesand international 12 waters 80(Source: MEDITS 1994-2010). 12 10 70 10 608 8

2 50 2 2 6 40 6

kg/km 4 kg/km kg/km 30 4 202 2 10 100 0First section - Chapter 2 - Ecological aspects 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Years

Crustaceans biomass indices 12

10

8 2 6

kg/km 4

2

0 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Biomass and density indices for the main fishery target species For the management of fishing activities it is necessary to bear in mind that the available resources vary according to the area and season. are distributed unevenly in the Central-Northern Adriatic Sea, since they are almost absent in the area north of the Po and more numerous in the Central Adriatic depression, where juveniles are concentrated. A temporal reduction of hake is shown in terms of biomass. Density indices, after a peak in abundance in 2005, also show a continuous reduction over the following years, touching the historical minimum for the series in 2010 and indicating a clear situation of distress for this species. Red mullet show density and biomass indices that are fairly constant over time. The high biomass and density value recorded for red mullet in 1999 is due to the fact that the sampling was conducted in late summer, due to the on-going conflict in the , which led to a substantial capture of recruits. Common pandora show a noticeable temporal increase in abundance overall, although with fluctuations over the years, mainly connected with the capture of recruits. The adults of this species are prevalently distributed along the eastern coast, where they are mainly caught using fixed gear; along the Italian coast, during summer months, there is a concentration of juveniles, which are partly caught using trawl nets. Whiting distribution is restricted to the Northern Adriatic Sea, where it is an important species and a substitute for hake in trawl fishing catches. This species shows wide fluctuations in abundance. It is interesting to note how the maximum values (1998, 2005 and 2009) were recorded two years after the minimum values (1996, 2003 and 2007), highlighting the species’ capacity for recovery, even from very low densities. Both the biomass and density indices for Norway lobster show a significant reduction over time. The greatest abundance of this species is found in the Central Adriatic Sea, in the Pomo area. Mantis shrimp, due to its coastal distribution, is fished using fixed gear and trawl nets. Because this species lives in deep tunnels, from which it emerges during night hours, the biomass and density indices obtained by the MEDITS surveys, which operates only during the day, are largely underestimated and show wide fluctuations. The biomass values for horned octopus oscillate between a maximum in 1994 and a minimum in 1999, while the density indices oscillate between a maximum in 1994 and a minimum in 2009. This species is not found in the Northern Adriatic Sea. The biomass and density of the three cephalopods examined, horned octopus, musky octopus and squid, vary without showing any temporal trend (figure 2.33).

EurEuropeanopean hak hake biomasse biomass indices indices EurEuropeanopean hak hake densitye density indices indices 70 70 3,0003,000

60 60 2,5002,500 50 50 2,0002,000 2 2 2 402 40 1,5001,500 n/km 30 30 n/km kg/km kg/km 1,0001,000 20 20

10 10 500 500

0 0 0 0 199419941996199619981998200020002002200220042004200620062008200820102010 199419941996199619981998200020002002200220042004200620062008200820102010 YearsYears YearsYears

RedRed mullet mullet biomass biomass indices indices RedRed mullet mullet density density indices indices 70 70 4,0004,000

60 60 3,5003,500 3,0003,000 50 50 2,5002,500 2 2 2 402 40 2,0002,000 /km /km n 30 30 n kg/km kg/km 1,5001,500 101 20 20 1,0001,000 10 10 500 500

0 0 0 0 199419941996199619981998200020002002200220042004200620062008200820102010 199419941996199619981998200020002002200220042004200620062008200820102010 YearsYears YearsYears

HornedHorned octopus octopus biomass biomass indices indices HornedHorned octopus octopus density density indices indices 30 30 140 140

25 25 120 120 100 100 20 20 2 2 2 2 80 80 15 15 /km /km n n 60 60 kg/km 10kg/km 10 40 40

5 5 20 20

0 0 0 0 199419941996199619981998200020002002200220042004200620062008200820102010 199419941996199619981998200020002002200220042004200620062008200820102010 YearsYears YearsYears

NorwayNorway lobster lobster biomass biomass indices indices NorwayNorway lobster lobster density density indices indices 7 7 350 350

6 6 300 300

5 5 250 250 2 2 2 2 4 4 200 200 n/km 3 3 150n/km 150 kg/km kg/km 2 2 100 100

1 1 50 50

0 0 0 0 199419941996199619981998200020002002200220042004200620062008200820102010 199419941996199619981998200020002002200220042004200620062008200820102010 YearsYears YearsYears

SpottailSpottail mantis mantis shrimp shrimp biomass biomass indices indices SpottailSpottail mantis mantis shrimp shrimp density density indices indices 6 6 200 200 180 180 5 5 160 160 4 4 140 140 2 1202 120 2 2 3 3 100 100 /km /km n n 80 80 kg/km kg/km 2 2 60 60 1 1 40 40 20 20 0 0 0 0 199419941996199619981998200020002002200220042004200620062008200820102010 199419941996199619981998200020002002200220042004200620062008200820102010 YearsYears YearsYears

MuskMusky octopusy octopus biomass biomass indices indices MuskMusky octopusy octopus density density indices indices 30 30 300 300

25 25 250 250

20 20 200 200 2 2 2 2 15 15 150 150 n/km n/km kg/km 10kg/km 10 100 100

5 5 50 50

0 0 0 0 199419941996199619981998200020002002200220042004200620062008200820102010 199419941996199619981998200020002002200220042004200620062008200820102010 YearsYears YearsYears

CommonCommon cuttlefish cuttlefish biomass biomass indices indices CommonCommon cuttlefish cuttlefish density density indices indices 9 9 120 120 8 8 100 100 7 7 6 6 80 80 2 2 2 2 5 5 60 60 4 4 n/km n/km kg/km kg/km 3 3 40 40 2 2 20 20 1 1 0 0 0 0 199419941996199619981998200020002002200220042004200620062008200820102010 199419941996199619981998200020002002200220042004200620062008200820102010 YearsYears YearsYears

CommonCommon pandor pandora biomassa biomass indices indices CommonCommon pandor pandora densitya density indices indices 6 6 200 200 180 180 5 5 160 160 4 4 140 140 2 1202 120 2 2 3 3 100 100 n/km n/km 80 80 kg/km kg/km 2 2 60 60 1 1 40 40 20 20 0 0 0 0 199419941996199619981998200020002002200220042004200620062008200820102010 199419941996199619981998200020002002200220042004200620062008200820102010 YearsYears YearsYears

WhitingWhiting biomass biomass indices indices WhitingWhiting density density indices indices 50 50 3,0003,000 45 45 40 40 2,5002,500 35 35 2,0002,000 30 30 2 2 2 2 25 25 1,5001,500 n/km 20 20 n/km kg/km kg/km 15 15 1,0001,000 10 10 500 500 5 5 0 0 0 0 199419941996199619981998200020002002200220042004200620062008200820102010 199419941996199619981998200020002002200220042004200620062008200820102010 YearsYears YearsYears European hake biomass indices European hake density indices European hake biomass indices EurEuropeanopean hakhakee densitydensity indicesindices 70 European hake biomass indices 3,000 7070 3,0003,000 60 60 2,500 6060 2,5002,500 50 50 2,000 5050 2,000

2 2,0002,000 2 40 2 2 40 2 2 2 40 1,500 2 40 1,500

30 n/km 1,5001,500 30 n/km kg/km kg/km

30 n/km 30 n/km 1,000 kg/km

kg/km 20 20 1,0001,000 20 20 500 10 500 500 1010 500 0 0 0 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 Years YYearsears YYearsears

Red mullet biomass indices Red mullet density indices RedRed mulletmullet biomassbiomass indicesindices RedRed mulletmullet densitydensity indicesindices 70 4,000 7070 4,0004,000 3,500 60 3,500 3,5003,500 6060 3,000 50 3,000 50 3,0003,000 5050 2,500 2 2 2 2 40 2,5002,500 2 2 2 2,000 2 4040 2,000 /km /km

30 n 2,000 30 n 2,000 /km /km kg/km 1,500

kg/km 1,500 n 3030 n

kg/km 1,500

kg/km 1,500 20 1,000 2020 1,0001,000 10 500 10 500500 10 0 0 0 00 00 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 YYearsears YYearsears

Horned octopus biomass indices Horned octopus density indices HornedHorned octopusoctopus biomassbiomass indicesindices HornedHorned octopusoctopus densitydensity indicesindices 30 140 3030 140140 25 120 25 120 2525 120 100 20 20 100100

20 2 2 20 2 80 2 80 2 2 2 15 2 15 8080 /km /km

15 n 60

15 n 60 /km /km kg/km kg/km

n 60 10 n 60 kg/km kg/km 40 1010 40 4040 5 20 5 20 5 2020 0 0 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 00 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 Years YYearsears YYearsears

Norway lobster biomass indices Norway lobster density indices 7 NNorwayorway lobsterlobster biomassbiomass indicesindices NorwayNorway lobsterlobster densitydensity indicesindices 7 350 77 350 6 350 6 300 66 300 5 300 5 250 5 5 250250 2 2 4 2 2 4 200 2 2 2 4 2 4 200200

3 n/km 3 n/km 150 kg/km kg/km

3 n/km 3 n/km 150150 kg/km kg/km 2 100 22 100100 1 50 11 5050 0 0 00 1994 1996 1998 2000 2002 2004 2006 2008 2010 00 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 YYearsears YYearsears

Spottail mantis shrimp biomass indices Spottail mantis shrimp density indices 6 SpottailSpottail mantismantis shrimpshrimp biomassbiomass indicesindices SSpottailpottail mantismantis shrimpshrimp densitydensity indicesindices 6 200 66 200180200 5 180 5 180180 55 160 160160 4 140 4 140140 4 2 120 2 2 120 2

2 120 2 2 3 120 2 3 100 /km 3 /km 3 n n 100100

/km 80 /km kg/km 80 kg/km n 2 n 80

kg/km 80

kg/km 60 22 60 604060 1 40 40 11 2040 20 0 200 0 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 YYearsears YYearsears

Musky octopus biomass indices Musky octopus density indices MuskMuskyy octopusoctopus biomassbiomass indicesindices MuskMuskyy octopusoctopus densitydensity indicesindices 30 European hake biomass indices 300 European hake density indices 3030 300300 70 3,000 25 250 2560 250 2560 2,500250 20 200 50 2050 2 2 200 20 2 200 2 2,000 2 2 2

2 15 150 15 2 150 2 40 2 2 40 15 n/km 15 n/km 1,500150150 kg/km 1,500 kg/km n/km 10 n/km 100 1030 n/km

kg/km 100

30 n/km kg/km kg/km

kg/km 10 100 10 1,000100 205 50 55 5005050 10 500 0 0 00 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 00 1994 1996 1998 2000 2002 2004 2006 2008 2010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 YYearsears YYearsears Years Years

Common cuttlefish biomass indices Common cuttlefish density indices CommonCommon cuttlefishcuttlefish biomassbiomass indicesindices CommonCommon cuttlefishcuttlefish densitydensity indicesindices 9 Red mullet biomass indices 120 Red mullet density indices 99 120120 708 4,000 8 100 78 607 3,500100100 6077 6 80 3,000

506 2 8080 2 506 2 2 5 2 2 2 2,50060 2 5 2,50060 5 2 2 2

2 404 404 n/km 6060 n/km

kg/km 4 2,000

kg/km 2,000

4 n/km /km n/km 40 3 /km 40 n kg/km 30 kg/km 30 n

kg/km 3 1,5004040 kg/km 3 1,500 2 20 2022 1,00020 1 2020 11 100 5000 0 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 0 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 2002Y2002ears 20042004 20062006 20082008 20102010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 YYearsears YYearsears Years Years European hake biomass indices European hake density indices Common pandora biomass indices Common pandora density indices 70706 CommonCommon pandorpandoraa biomassbiomass indicesindices 3,0003,000 CommonCommon pandorpandoraa densitydensity indicesindices 6 Horned octopus biomass indices 200 Horned octopus density indices 66 200 6060 2,5002,500180200 305 140 180160180 505055 160 2,0002,000160160120 254 140 2 2 2 2 40404 140140 4 2 120 2 2 120 2 1,5001,500100

20 2 120 2 2 203 120 2 3 100

3030 n/km n/km 2 2

3 2 3 n/km 10080 2 n/km kg/km kg/km 1008080

kg/km 80

kg/km 1,0001,000

15 n/km 152 n/km 80 2020 /km 80 kg/km /km 60 kg/km 60 n 60 22 n 60

kg/km 60 kg/km 5005004060 1010101 40 1 4040 11 204040 005 202000 05 200 0 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 1994 1996 1998 2000 Y2002earsears 2004 2006 2008 2010 0 1994 1996 1998 2000 Y2002earsears 2004 20062006 20082008 20102010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 1994 1996 1998 2000 Y2002ears 2004 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 YY2002earsears 2004 2006 2008 2010 1994 1996 1998 2000 YY2002earsears 2004 2006 2008 2010 Years Years Red mullet biomass indices Red mullet density indices Whiting biomass indices Whiting density indices 7070 WhitingWhiting biomassbiomass indicesindices 4,0004,000 WhitingWhiting densitydensity indicesindices 50 3,000 Norway lobster density indices 50 Norway lobster biomass indices 3,000 Norway lobster density indices 4550 3,5003,0003,5003,000 6060457 4545 2,500350 40 3,0003,0002,500 5040506 2,5002,500 35406 300 35 2,5002,5002,000 35 2 2 2 2 30 4040 2 2 305 2 2,000 2 5 2,000250 30 2,0002,000250 30 2 2 2 2 25 /km /km 1,500 2 n n 2 30304 2 2 254 n/km 200 25 n/km 1,500 kg/km kg/km 20 1,5001,5001,500200

kg/km 20 kg/km n/km 20 n/km 1,000

kg/km 20 1,000 kg/km 2020153 n/km 153 n/km 1,0001,000150 kg/km 1,0001,000 kg/km 151015 10102 500500 102 500100 105 500500 0501 00 051 500 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 0 1994 1996 1998 2000 Y2002earsears 2004 2006 2008 2010 0 1994 1996 1998 2000 Y2002earsears 2004 2006 2008 2010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 1994 1996 1998 2000 Y2002ears 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 YYearsears YYearsears Years Years Horned octopus biomass indices Horned octopus density indices 3030 140140 Spottail mantis shrimp biomass indices Spottail mantis shrimp density indices 6 120120 25256 200 100100180 20205 160 2 2 2 2 1408080 15154 140 /km /km

2 120 2 2 n n 1206060 2

kg/km kg/km 3 10103 100 /km /km

n 4040 n 80 kg/km 80 kg/km 2 55 202060 1 40 001 00 20 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 0 0 Yearsears Yearsears 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Norway lobster biomass indices Norway lobster density indices 77 Musky octopus biomass indices 350350 Musky octopus density indices 66 30 300300300 55 250250 10225 First section - Chapter 2 - Ecological aspects 250 2 2 2 2 44 200200 20 200 2

33 n/km n/km 2 2 150150 2 kg/km kg/km 15 150 22 100100 n/km n/km kg/km kg/km 10 1011 1005050

005 5000 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 0 Yearsears 0 Yearsears 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Spottail mantis shrimp biomass indices Spottail mantis shrimp density indices 66 200200 Common cuttlefish biomass indices Common cuttlefish density indices 180180 559 120 9 160160120 8 140140 44 100 7 7 2 2 120120 2 2 336 10010080 /km /km n n 2 2 2

2 8080 kg/km kg/km 5 22 60 4 6060

4 n/km n/km

kg/km 4040 kg/km 113 40 2020 2 00 2000 1 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 0 Yearsears 0 Yearsears 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Musky octopus biomass indices Musky octopus density indices 3030 Common pandora biomass indices 300300 Common pandora density indices 6 25256 250250200 180 5 180 20205 200200160 2 2 2 2 4 140 15154 150150

2 120 2 2

n/km n/km 120 2

kg/km kg/km 3 10103 100100100 n/km n/km 80

kg/km 80 kg/km 2 55 505060 1 40 001 00 20 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 0 0 Yearsears Yearsears 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Common cuttlefish biomass indices Common cuttlefish density indices 120120 99 Whiting biomass indices Whiting density indices 5088 50 3,000100100 4577 4066 2,5008080 2 2 2 2 3555 2,0006060 30 44 2 2 30 2 n/km n/km 2 kg/km kg/km 2533 1,5004040 n/km 20 n/km

kg/km 20

kg/km 22 15 1,0002020 1511 10 1000 50000 5 5 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 0 0 0 Yearsears Yearsears 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years Years Common pandora biomass indices Common pandora density indices 66 200200 180180 55 160160 44 140140

2 2 120120 2 2 33 100100

n/km n/km 8080 kg/km kg/km 22 6060 11 4040 2020 00 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 Yearsears Yearsears

Whiting biomass indices Whiting density indices 5050 3,0003,000 4545 4040 2,5002,500 3535 2,0002,000 3030 2 2 2 2 2525 1,5001,500

2020 n/km n/km kg/km kg/km 1515 1,0001,000 1010 500500 55 00 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 Yearsears Yearsears EurEuropeanopean hakhakee biomassbiomass indicesindices EurEuropeanopean hakhakee densitydensity indicesindices EurEuropeanopean hakhakee biomassbiomass indicesindices EurEuropeanopean hakhakee densitydensity indicesindices 7070 3,0003,000 7070 3,0003,000 6060 2,5002,500 6060 2,5002,500 5050 5050 2,0002,000 2,0002,000 2 2 2 2 4040 2 2 2 40 2 40 1,5001,500 1,5001,500

30 n/km

30 n/km n/km

kg/km 30 kg/km 30 n/km 1,000 kg/km 1,000 kg/km 2020 1,0001,000 2020 500500 1010 500 1010 500 00 00 00 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 YYearsears YYearsears YYearsears YYearsears

RedRed mulletmullet biomassbiomass indicesindices RedRed mulletmullet densitydensity indicesindices RedRed mulletmullet biomassbiomass indicesindices RedRed mulletmullet densitydensity indicesindices 7070 4,0004,000 7070 4,0004,000 6060 3,5003,500 6060 3,5003,500 3,0003,000 5050 3,000 50 3,000 50 2,5002,500 2 2 2 2 4040 2,5002,500 2 2 2 2 4040 2,0002,000 /km /km 2,0002,000 n n 30 /km

30 /km kg/km n 1,500 kg/km 1,500 3030 n

kg/km 1,500

kg/km 1,500 2020 1,0001,000 2020 1,0001,000 1010 500500 1010 500500 0 00 0 0 00 0 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 YYearsears YYearsears YYearsears YYearsears

HornedHorned octopusoctopus biomassbiomass indicesindices HornedHorned octopusoctopus densitydensity indicesindices HornedHorned octopusoctopus biomassbiomass indicesindices HornedHorned octopusoctopus densitydensity indicesindices 3030 140140 3030 140140 120120 2525 120 2525 120 100100 2020 100100 2020 2 2 2 2 8080 2 2 2 2 1515 8080 /km 1515 /km n 60 n /km 60 /km n kg/km 60 kg/km n 60

kg/km 1010 kg/km 1010 4040 4040 55 5 2020 5 2020 00 00 00 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 YYearsears YYearsears YYearsears YYearsears

NNorwayorway lobsterlobster biomassbiomass indicesindices NorwayNorway lobsterlobster densitydensity indicesindices NNorwayorway lobsterlobster biomassbiomass indicesindices NorwayNorway lobsterlobster densitydensity indicesindices 77 7 350350 7 350350 66 6 300300 6 300300 55 5 250250 5 250250 2 2 2 2 44 200

2 200 2 2 4 2 4 200200

3 n/km 3 n/km 150150 kg/km 3 n/km kg/km 3 n/km 150150 kg/km kg/km 22 100100 22 100100 11 5050 11 5050 00 00 00 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 YYearsears YYearsears YYearsears YYearsears European hake density indices EurEuropeanopean hakhakee biomassbiomass indicesindices European hake density indices 70 SpottailSpottail mantismantis shrimpshrimp biomassbiomass indicesindices 3,0003,000 SSpottailpottail mantismantis shrimpshrimp densitydensity indicesindices 7070 SpottailSpottail mantismantis shrimpshrimp biomassbiomass indicesindices 3,0003,000 SSpottailpottail mantismantis shrimpshrimp densitydensity indicesindices 66 6066 200200 6060 2,5002,500200200 2,5002,500180180 5055 180180 505055 2,000160160 2,0002,000160160

2 140 2 2 404 140 2 404 2 2

2 2 140 404044 1,500140 2 1,500 2 120 2 120 2 1,5001,500

2 120 2 2

30 n/km 120 2 3033 n/km 100 3030 n/km n/km 100 kg/km /km kg/km 33 /km 100 kg/km kg/km 1,000 n 100 n /km 1,000 /km 1,0001,00080

kg/km 20 80 n

kg/km 20 20202 n 80 kg/km 2 80 kg/km 22 6060 10 50050060 1010 50050060 11 4040 1 4040 100 202000 00 202000 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 2002Y2002earsears 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 2002Y2002earsears 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 Y20022002earsears 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 Y20022002earsears 20042004 20062006 20082008 20102010 YYearsears YYearsears YYearsears YYearsears

RedRed mulletmullet biomassbiomass indicesindices RedRed mulletmullet densitydensity indicesindices Musky octopus biomass indices Musky octopus density indices 70 Musky octopus biomass indices 4,000 Musky octopus density indices 7070 MuskMuskyy octopusoctopus biomassbiomass indicesindices 4,0004,000 MuskMuskyy octopusoctopus densitydensity indicesindices 3030 300300 306030 3,5003,500300 6060 3,5003,500300 3,000 255025 3,0003,000250250 50255025 250250 2,5002,500 2 2 2 2,5002,500 2 204020 200200 40 2 2 2 2 40204020 200200 2 2,000 2 2 2,000 2

/km 2,0002,000 /km 2 2 2 2 /km /km n 15303015 n 150150 n n kg/km 3030 1,500 kg/km 1515 1,500150 kg/km kg/km n/km 1,5001,500150 n/km kg/km n/km kg/km 2020 n/km 1,000

kg/km 10 1,000 kg/km 202010 1,0001,000100100 1010 100100 500 1010 500500 101055 5050 5 50 50 5000 00 00 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 2002Y2002earsears 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 2002Y2002earsears 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 Y20022002earsears 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 Y20022002earsears 20042004 20062006 20082008 20102010 YYearsears YYearsears YYearsears YYearsears Horned octopus density indices HornedHorned octopusoctopus biomassbiomass indicesindices Horned octopus density indices 30 CommonCommon cuttlefishcuttlefish biomassbiomass indicesindices 140140 CommonCommon cuttlefishcuttlefish densitydensity indicesindices 3030 CommonCommon cuttlefishcuttlefish biomassbiomass indicesindices 140140 CommonCommon cuttlefishcuttlefish densitydensity indicesindices 99 120120 2599 120120 252588 120120 8 100100 8 100100 2077 100100100 202077 2 2 2 6 8080 2 6 8080 2 2 2 2 66 808080

15 2 2

2 15 2

5 /km 1515 /km 5 2 2 2 /km /km n 2 60 55 n 6060

n n 6060 kg/km kg/km 44 6060 kg/km kg/km n/km 10104 n/km

10104 n/km kg/km

kg/km 40 n/km 40 kg/km 33 404040 kg/km 353 4040 5252 2020 22 202020 20 1001 200 0101 00 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 2002Y2002earsears 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 2002Y2002earsears 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 Y20022002earsears 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 Y20022002earsears 20042004 20062006 20082008 20102010 YYearsears YYearsears YYearsears YYearsears

NNorwayorway lobsterlobster biomassbiomass indicesindices NorwayNorway lobsterlobster densitydensity indicesindices 7 CommonCommon pandorpandoraa biomassbiomass indicesindices CommonCommon pandorpandoraa densitydensity indicesindices 77 CommonCommon pandorpandoraa biomassbiomass indicesindices 350350 CommonCommon pandorpandoraa densitydensity indicesindices 66 350350 66 200200 66 200300200 66 300180300180 55 180 5 180 55 160250250160 55 250160250160 4 140140 4 2 2 2 4 2 4 140 4 2 2 140200 2 2 44 200

2 200120200 2

2 120 2

2 120 2 2 120 2

33 n/km 3 n/km 100150150100

33 n/km n/km kg/km 3 150150 kg/km 3 100100 n/km n/km kg/km kg/km 8080 kg/km n/km kg/km 22 n/km 1001008080 kg/km 2

kg/km 22 22 1001006060 6060 11 40505040 111 50405040 11 2020 00 200 00 2000 00 1994 1996 1998 2000 2002 2004 2006 2008 2010 00 1994 1996 1998 2000 2002 2004 2006 2008 2010 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 2002Y2002ears 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 2002Y2002ears 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 Y20022002earsears 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 Y20022002earsears 20042004 20062006 20082008 20102010 YYearsears YYearsears Years Years Years Years SpottailSpottail mantismantis shrimpshrimp biomassbiomass indicesindices SSpottailpottail mantismantis shrimpshrimp densitydensity indicesindices 6 WhitingWhiting biomassbiomass indicesindices WhitingWhiting densitydensity indicesindices 66 WhitingWhiting biomassbiomass indicesindices 200200 WhitingWhiting densitydensity indicesindices 50 200200 50 3,0003,000180 50505 3,000180180 454555 3,000 45 160160 45 2,500160160 4040 2,500140 404044 2,5002,500140140 353544 2 120 2 2 120 2 35 2,000 35 2 2 2,000120120 2 2 30 2,000 303 2 2,000 3 2 2 100 2 100 3033 /km /km 30 2 100100 2 2 2 /km /km n 2525 n 1,500

n n 1,50080

kg/km 80 kg/km 2525 1,5008080 kg/km kg/km 2 n/km 1,500 202022 n/km kg/km

n/km 60 kg/km 20 n/km 6060

kg/km 20 kg/km 1,0001,000 15151 1,0001,0004040 151511 4040 1010 2020 1010 5005002020 5005 50050000 0505 00 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 2002Y2002earsears 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 2002Y2002earsears 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 Y20022002earsears 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 Y20022002earsears 20042004 20062006 20082008 20102010 YYearsears YYearsears YYearsears YYearsears Figure 2.34 - GSA 17. Biomass (kg/km2) and density (n/km2) indices and respective confidence limits (broken lines) Musky octopus biomass indices Musky octopus density indices for the main targetMusk speciesy octopus estimated biomass in indicesthe area of Italian and international Muskwatersy octopus(Source: density MEDITS indices 1994-2010). 30 300 3030 300300 25 250 2525 250250 20 200 103 2020 200200 2 2 2 2 2 2 2 2 15 150 1515 150150 n/km n/km n/km n/km kg/km kg/km

kg/km kg/km 10 100 1010 100100 5 50 55 5050 0 0 00 00 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 Years Years Yearsears Yearsears

Common cuttlefish density indices CommonCommon cuttlefishcuttlefish biomassbiomass indicesindices Common cuttlefish density indices 9 120120 99 120120 88 88 100100 7 100100 77 6 8080 66 8080 2 2 2 2

5 2 2

2 2 5 55 6060 4 6060

4 n/km 44 n/km n/km n/km kg/km kg/km

kg/km kg/km 3 4040 33 4040 22 22 2020 1 2020 11 0 00 00 00 1994 1996 1998 2000 2002 2004 2006 2008 2010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 Years Yearsears Yearsears Yearsears

CommonCommon pandorpandoraa biomassbiomass indicesindices CommonCommon pandorpandoraa densitydensity indicesindices 66 200 66 200200 180180 55 180180 55 160 160160 4 140140 44 140140

2 120 2 2 120 2

2 2 120120 2 2 33 100 33 100100 n/km n/km 80

n/km n/km 80 kg/km kg/km 8080

kg/km kg/km 2 22 60 6060 40 11 4040 11 20 2020 0 0 00 00 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 Years Years Yearsears Yearsears

WhitingWhiting biomassbiomass indicesindices WhitingWhiting densitydensity indicesindices 5050 3,000 5050 3,0003,000 45 4545 40 2,5002,500 4040 2,5002,500 3535 3535 2,0002,000 30 2,0002,000 30 2 2 2 2 3030 2 2 2 2 2525 1,500 2525 1,5001,500 n/km 20 n/km n/km n/km

kg/km 20 kg/km 2020 kg/km kg/km 15 1,0001,000 1515 1,0001,000 10 1010 500500 5 500500 55 0 00 00 00 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 Years Years Yearsears Yearsears 95th percentile size of the main target species The lengths obtained by the sampling conducted in the MEDITS surveys were affected by the net used, which had a cod-end with very fine mesh (20 mm). This mesh was used to have an estimate of the significance of the juvenile classes, which cannot be obtained with the biological sampling of commercial fisheries. The 95th percentile sizes of the examined species captured in the MEDITS surveys did not show significant variations over time, as is indicated statistically by the Spearman test. Hake show slight fluctuations in capture size over the years until 2008; the higher 95th percentile size values for the years 2009 and 2010 are due to the marked reduction in juvenile fish of less than 16 cm. This worrying reduction in recruitment is also observed in Croatian territorial waters. The capture size of red mullet, as well as of common pandora, shows a variability over the years, related to the period during the survey in which the stations closest to the coastal area of juveniles concentration were conducted, and the slight variations over the years in the reproduction period or the period in which the survey was carried out. The quantity of recruits greatly influences the capture size of the species. The three species of cephalopods examined showed fluctuations in 95th percentile size, which can be linked to their short life-cycle (less than 2 years) and the presence of just two age groups; the significance of the individual groups, which can vary over the years, modifies the size. Squid in particular show wide fluctuations due to their brief life cycle and the area of coastal recruitment, which was only partially covered by the sampling.

Table 2.13 - GSA 17. Size: 95th percentile length per species (TL = Total Length, DML = Dorsal Mantle Length, CL = Carapace Length). The significant Spearman rho values are shown in bold.

European Red Common Horned Musky Common Norway hake mullet pandora octopus octopus cuttlefish lobster Year TL (cm) TL (cm) TL (cm) DML (cm) DML (cm) DML (cm) CL (mm) 1994 29.3 18.0 15.5 10.3 8.5 12.0 43 1995 26.3 17.3 20.5 12.5 9.3 9.5 46 1996 26.5 17.5 31.5 10.8 9.8 14.0 43.5 1997 29.5 17.8 20.0 11.0 8.3 15.5 48.5 1998 26.0 17.8 17.3 12.5 9.8 8.8 42 1999 28.8 14.0 15.5 6.0 10.0 8.8 51 2000 23.5 17.0 17.5 12.0 8.3 17.5 57 2001 24.5 17.5 16.5 10.0 8.5 17.3 42.5 2002 23.5 15.8 17.8 9.5 8.5 8.8 57 2003 26.3 17.3 18.8 10.0 8.8 12.0 42 2004 24.0 15.5 15.5 10.8 8.8 15.5 44 2005 19.0 16.8 15.5 11.0 9.8 11.5 43 2006 24.0 14.8 15.0 10.5 9.5 8.3 38 2007 25.8 16.3 16.8 11.3 9.5 13.5 41.5 2008 26.0 17.0 17.0 11.8 9.0 13.5 46 2009 41.0 17.3 17.0 11.8 7.5 14.3 59 2010 31.8 16.5 17.3 11.0 8.0 13.0 51.5 Spearman’s rho -0.106 -0.541 -0.332 0.086 -0.223 0.065 0.065

104 First section - Chapter 2 - Ecological aspects Biology and spatial distribution The spawning period The length of spawning period of the individual species cannot be determined merely by surveys, repeated each year during the same season, and therefore the information was obtained from the entire research carried out in GSA 17. Hake have a very extensive spawning period, and adults with mature gonads can be found all year round; despite variations due to differences between areas and sizes, the spawning peak can be considered to occur during the winter months. In regard to red mullet, a different spawning period is noted for medium-sized mullet and those much larger in size. Most red mullet reproduce in the Central Adriatic Sea in the period from May to June, whereas very large-sized red mullet have a later reproductive period, from September to October, and so two recruitments are observed, a more substantial one from July to September and a more modest one in late winter. For Norway shrimp, females with eggs are found in almost all months. The horned octopus is captured as a recruit during the MEDITS surveys in June and July, and so the main spawning occurs from April to May, although with differences according to areas and years. Squid approach the western coast to reproduce between late March and June; the movement begins with larger squid, followed by smaller specimens. The eggs, deposited on substrates, require more than a month to hatch; the baby squid remain in the coastal areas after hatching, and gradually move away as they grow. Depending on the area, squid fishing begins in the summer months from August to September, when the have reached a weight of 10-50 grams.

Area and intensity of recruitment Juvenile hakes in GSA 17 are concentrated on muddy seabeds at a depth of more than 100 metres in the Central Adriatic Sea, where there is an abundance of small crustaceans (krill, mysidacea and amphipoda) which comprise the main food of the recruits. There is a second hake nursery area in the Croatian channels to the south of , where there is a depression of just over 100 metres in depth. The young hake remain in deep-waters until they reach a size of 12-15 cm, when, with a change in their diet, they move towards shallower seabeds and gradually cover their entire area of distribution. The amount of recruitment is not identical over the years. Recruitment for hake in 2009 and 2010 was very low. The juvenile stages of red mullet are concentrated in a long, narrow coastal strip. The species reproduces in a vast area in the central zone of the Adriatic Sea, where the adults live; the currents transport the eggs, larvae and early juvenile stages (up to 3-4 cm) towards the coastal waters, which are a few metres in depth, where the red mullet metamorphosis takes place, with the change from a planctophagous to a benthophagous diet. The young red mullet grow rapidly in the warmer and more productive waters and then gradually move away from the coast, becoming distributed over an increasingly wide area. At the end of October, when they have normally reached a length of 12 cm, at the first noticeable drop in water temperature, they quickly move from the Italian territorial waters towards the central area of the basin and the Croatian waters. The recruitment quantity for red mullet is highly variable. The nursery area for hake is occupied throughout the year. For red mullet, the nursery area is limited seasonally to the period between July and October.

105 For common pandora, there is a concentration of juvenile stages in coastal areas with shallow waters in the period from summer to autumn, and the small fish gradually move offshore as they grow. Whiting have a concentration of juvenile forms in the coastal strip of the Northern Adriatic Sea during the spring. Squid have an area of concentration for juvenile stages connected with reproductive migration, which brings the adults towards the coasts to deposit their eggs on certain substrates between March and May. The small squid, which hatch after an incubation period of more than one month, move away from the coast when the waters begin to grow colder, in a similar way to red mullet. The other species considered in this study, Norway lobster, mantis shrimps, horned octopus and musky octopus, have no particular nursery zone, as their juveniles are found together with the adults and there are no known processes of concentration.

Assessment using models Research scientists that have historically concentrated on commercial species of the Adriatic Sea have been operating for decades using various models, which have gradually been developed, obtaining indications that have not always proven correct in subsequent years. These poor results are due to the lack of information referring to the entire area of distribution for each species, or at least to the whole of GSA 17. For certain species the apparent fluctuations in recorded abundance are much larger than the variations in fishing intensity for the same period and there is a widespread conviction that these fluctuations in the indices are related more to ecological factors than to fishing activity. The density and biomass indices obtained with the MEDITS surveys show that after years of very low values, some species recover quickly and reach high figures once more, without any management intervention in regard to fishing mortality. On the other hand, certain indicators of high abundance can suddenly fall, without overall changes in the fishing effort. This could indicate that natural mortality figures vary greatly over time and, as a result, the relationship between fishing mortality and natural mortality, a key aspect for many models, fluctuates to such an extent that its use becomes limited.

References - Jukić S., Vrgoč N., Dadiì V., Krstulović-Šifner S., Piccinetti C., Marčeta B. (1999) - Spatial and temporal distributions of some demersal fish populations in the Adriatic Sea described by GIS technique. Acta Adriatica, 40 (Suppl.): 55-66. - Vrgoč N., Arneri E., Jukić-Peladić S., Krstulović-Šifner S., Mannini P., Marčeta B., Osmani K., Piccinetti C., Ungaro N. (2004) - Review of current knowledge on shared demersal stocks of the Adriatic Sea. FAO-MiPAAF Scientific Cooperation to Support Responsible Fisheries in the Adriatic Sea. AdriaMed Technical Documents, 12: 91 p.

106 First section - Chapter 2 - Ecological aspects 2.3.6 GSA 18 - Southern Adriatic Sea Lembo G. , Spedicato M.T.

The main demersal resources of the Southern Adriatic fisheries are: European hake (Merluccius merluccius), cuttlefish (Sepia officinalis), Norway lobster (Nephrops norvegicus), squids (Illex sp.), deep-water rose shrimp (Parapenaeus longirostris), horned and musky octopus (Eledone spp.) and red mullet (Mullus barbatus). Hake alone represented around 13.6% of catches on the Western shore of the basin in 2010 (Irepa data), whereas the other mentioned species accounted in total for around 21%. This is therefore a pool that provides around 34% of the production of the western shore of the Southern Adriatic Sea. Most of the fishery resources in the Southern Adriatic Sea are shared between Italy, Albania and Montenegro (Vrgoč et al., 2004). Their assessment must therefore take data from both shores into account. Similarly, the achievement of more sustainable exploitation levels, for example, the Maximum Sustainable Yield (MSY) target in 2015, should assume complementary and shared management policies. Regional projects such as AdriaMed (GFCM-FAO) have the objective of harmonising the development of knowledge, encouraging the integration of scientific approaches through the application of common stock assessment methods, and promoting an ecosystem approach. A scientific method which combines: • data from various sources (from experimental surveys, such as MEDITS, which explores the population at sea, and from commercial fisheries); • the structure of the system (fish community and population); • the various dimensions of the phenomena (space and time); • the approaches (models of varying complexity and indicators); in an attempt to overcome estimate uncertainty is obviously desirable, although extremely complex. In this attempt, the temporal series of abundance indices (density n/km2 and biomass kg/km2) for individual species and fish communities, obtained by the MEDITS experimental surveys, provide a useful contribution to the assessment process. This exercise is conducted annually at a national level by the Italian Society of Marine Biology for the preparation of the yearbook on the state of fishery resources, to which the reader should refer for more detailed information (SIBM Yearbook, 2010).

Abundance and demography Community biomass index From 1994 to 2010, the biomass of most taxa estimated on the western shore of the Southern Adriatic Sea varies, but without specific trends, with the exception of cephalopods, which shows a significant increase (figure 2.35). An increase in the biomass of selachians and crustaceans is also seen, particularly for the last year.

107 Teleosteans biomass indices 450 400 350 2 300 250 kg/km 200 150 100 50 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 Years

Teleosteans biomass indices TSelachianseleosteans biomass biomass indice indicess 450 45040 400 40035 350 35030 2 2

300 2 300 25 250 250 kg/km kg/km 20 200 kg/km 200 15 150 150 100 10010 50 50 5 0 0 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 20062006 20082008 20102010 Years YYearsears

Cephalopods biomass indices SelachiansTeleosteans biomass biomass indice indicess 90 Selachians biomass indices 80 45040 40 70 40035 35 2 60 35030 30 2

2 50 300 2 25 kg/km 4025 250

kg/km 20 20 kg/km

kg/km 30 200 15 15 150 20 10010 1010 505 05 1994 1996 1998 2000 2002 2004 2006 2008 2010 00 0 19941994 19961996 19981998 2000 2002 2004 2006 20082008 20102010 1994 1996 1998 2000Years 2002 2004 2006 2008 2010 YearsYears Years

Cephalopods biomass indices CephalopodsCrustaceans biomass indices 90 50 Selachians biomass indices 90 80 4580 40 40 70 70 2

2 35

2 35 60 60 30 30 50 50 2 kg/km

kg/km 25 25 kg/km 40 2040 3020 kg/km 1530 2015 1020 1010 510 0 0 5 0 1994 1996 1998 2000 2002 2004 2006 2008 2010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 0 Years 1994 1996 1998 2000Years 2002 2004 2006 2008 2010 Years Years Figure 2.35 - GSA 18. Biomass indices (kg/km2) and respective confidence limits (broken lines) for the main taxa: teleosteans, selachians, cephalopods and crustaceans (Source: MEDITS 1994-2010). CephalopodsCrustaceans biomass biomass indices indices Crustaceans biomass indices 50 90 50 45 Density80 indices for the main fishery target species 45 40 40 70 2

35 2

At the2 population level, the abundance indices of some35 of the most important species in the area 60 30 30 vary, without50 any specific trends, such as the density index for hake and Norway lobster, whereas

kg/km 25 kg/km 25 kg/km a significant20 40 growth is observed for deep-water rose shrimp,20 due to the increase in abundance since15 2000 30 (figure 2.36), probably as a response to the15 establishment of environmental changes 10 20 10 at the5 mesoscale10 level in the Southern Adriatic Sea (Abelló5 et al., 2002). 0 0 0 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 HakHake ebiomass biomass indicesY earsindicesYears (10-800 (10-800 m) m) HakHake edensity densityY indicesears indices (10-800 (10-800 m) m)

6060 2,5002,500

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2 35 500500 1010 30

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1414 2 2 2 2 2,0002,000

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NorwayNorway lobster lobster biomass biomass indices indices (200-800 (200-800 m) m) NorwayNorway lobster lobster density density indices indices (200-800 (200-800 m) m)

1414 700700

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Deep-waterDeep-water ro rosese shrimp shrimp biomass biomass indices indices (10-800 (10-800 m) m) Deep-waterDeep-water ro rosese shrimp shrimp density density indices indices (10-800 (10-800 m) m)

1212 1,6001,600 1,4001,400 1010 1,2001,200

8 8 2 2

2 2 1,0001,000 6 6 800800 n/km n/km

kg/km kg/km 600600 4 4 400400 2 2 200200 0 0 0 0 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 YearsYears YearsYears HornedHorned octopus octopus biomass biomass indices indices (10-800 (10-800 m) m) HornedHorned octopus octopus density density indices indices (10-800 (10-800 m) m)

4040 160160 3535 140140

2 2 3030 120120 2525 2 2 100100 kg/km kg/km n/km n/km

20 20 8080 1515 6060 1010 4040 5 5 2020 0 0 0 0 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 YearsYears YearsYears

RedRed shrimp shrimp biomass biomass indices indices (200-800 (200-800 m) m) RedRed shrimp shrimp density density indices indices (200-800 (200-800 m) m)

1414 700700 1212 600600

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2 50 2 2 2 2 2 2,000 2 2 2 2 4040 4040 50 2 2 2 4040 2 2,0001,5001,5001,500

1,500/km 40 /km /km /km

2 1,5001,500 n n kg/km kg/km /km /km n 2 n kg/km kg/km 303030 1,500

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n/km n/km 400 kg/km 8

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6 n/km 800 66 n/km 800800 n/km n/km kg/km kg/km kg/km

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6 n/km 800 n/km 600 kg/km kg/km 600 44 600600 kg/km

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20 80 20 80 kg/km n/km n/km kg/km 20 20 8080 n/km

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20 80 1515 1515 606060 1515 60 6060 15 6060 1010 1010 404040 1010 40 4040 10 4040 5 555 202020 55 20 2020 5 2020 000 00 0 00 0 0 01994 199419941994 1996 199619961996 1998 199819981998 2000 200020002000 2002 200220022002 2004 200420042004 2006 200620062006 2008 200820082008 2010 201020102010 00 0 199419941994 199619961996 199819981998 200020002000 200220022002 200420042004 200620062006 200820082008 201020102010 0 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 01994 19941994 1996 19961996 1998 19981998 2000 20002000 2002 20022002 2004 20042004 2006 20062006 2008 20082008 2010 20102010 1994 1996 1998 2000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 YearsYYearsearsears YYearsearsears YYearsears YearsYYearsears YYearsears YearsYears

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2 500500 2 1010 1010 500500 2 2 2 101010 500500500 2 2 2 2

10 2 500 2 2 8 888 2 400400400400 109 2

kg/km 400400 kg/km 888 400 kg/km kg/km 8 400 kg/km kg/km n/km kg/km n/km n/km 66 n/km 300300 kg/km 6 300

6 n/km n/km 666 n/km 300300300300 6 n/km 300 4 444 200200200 444 200200200200 4 200 2 222 100100100 222 100100100100 2 100 0 000 00 000 0 00 01994 199419941994 1996 199619961996 1998 199819981998 2000 200020002000 2002 200220022002 2004 200420042004 2006 200620062006 2008 200820082008 2010 201020102010 00 199419941994 199619961996 199819981998 200020002000 200220022002 200420042004 200620062006 200820082008 201020102010 199419941994 199619961996 19981998 20002000 20022002 20042004 20062006 200820082008 201020102010 01994 199419941994 1996 1996 19961996 1998 1998 19981998 2000 2000 20002000 2002 2002 20022002 2004 2004 20042004 2006 2006 20062006 2008 2008 20082008 20102010 20102010 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 YearsYYearsearsears YYearsearsears YYearsears YearsYearsYYearsears Years Years HakHake biomasse biomass indices indices (10-800 (10-800 m) m) HakHake densitye density indices indices (10-800 (10-800 m) m)

60 60 2,5002,500

50 50 2,0002,000 2 2 2 40 40 2 1,5001,500 /km /km n kg/km n kg/km 30 30 1,0001,000 20 20 500 10 10 500

0 0 0 0 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 YearsYears YearsYears

RedRed mullet mullet biomass biomass indices indices (10-200 (10-200 m) m) RedRed mullet mullet density density indices indices (10-200 (10-200 m) m)

20 20 3,0003,000 18 18 2,500 16 16 2,500 2 14 2

2 14 2 2,0002,000

12 /km 12 /km n n 10 10 1,5001,500 kg/km kg/km 8 8 1,000 6 6 1,000 4 4 500500 2 2 0 0 0 0 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 YearsYears YearsYears

NorwayNorway lobster lobster biomass biomass indices indices (200-800 (200-800 m) m) NorwayNorway lobster lobster density density indices indices (200-800 (200-800 m) m)

14 14 700700

12 12 600600 10 500 2 10 2 500 2 2 8 8 400400 n/km n/km kg/km kg/km 6 6 300300

4 4 200200

2 2 100100

0 0 0 0 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 YearsYears YearsYears

Deep-waterDeep-water ro sero seshrimp shrimp biomass biomass indices indices (10-800 (10-800 m) m) Deep-waterDeep-water ro sero seshrimp shrimp density density indices indices (10-800 (10-800 m) m)

12 12 1,6001,600 1,4001,400 10 10 1,2001,200

8 2

8 2 2 1,000 2 1,000 6 800 6 800n/km n/km kg/km kg/km 600600 4 4 400400 2 2 200200 0 0 0 0 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 YearsYears YearsYears HornedHorned octopus octopus biomass biomass indices indices (10-800 (10-800 m) m) HornedHorned octopus octopus density density indices indices (10-800 (10-800 m) m)

40 40 160160 35 35 140140

2 30 120 2 30 120 2 25 25 2 100100 kg/km kg/km n/km

20

n/km 80

20 80 15 15 60 60 10 10 40 40 5 5 20 20 0 0 0 0 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 YearsYears YearsYears

RedRed shrimp shrimp biomass biomass indices indices (200-800 (200-800 m) m) RedRed shrimp shrimp density density indices indices (200-800 (200-800 m) m)

14 14 700700 12 12 600600 2 2 10 10 500500 2 8 8 2 400400 kg/km kg/km n/km 6 6 n/km 300300

4 4 200200

2 2 100100

0 0 0 0 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 19941994 1996 1996 1998 1998 2000 2000 2002 2002 2004 2004 2006 2006 2008 2008 2010 2010 YearsYears YearsYears

Figure 2.36 - GSA 18. Biomass (kg/km2) and density (n/km2) indices and respective confidence limits (broken lines) for the main target species estimated for their area of distribution (Source: MEDITS 1994-2010).

The abundance indices for red mullet and giant red shrimp have shown significant positive variations. In particular, for resources such as giant red shrimp (Aristeomorpha foliacea), in the past viewed as sporadic in the Southern Adriatic Sea, the density indices, although modest compared to those of other species, show considerable peaks in recruitment for certain years. Probably also in this case, environmental changes may have influenced the population dynamics of the stock, favouring recruitment. Nevertheless, 2007 is seen to be a year marked by significant reduction in biomass and density indices, both for giant red shrimp and deep-water rose shrimp. Abundance indices for horned octopus vary without trends over the course of the historical series, which shows a high initial figure for abundance that is no longer matched in the following years. Trends for abundance of hake and deep-water rose shrimp reflect the success of recruitment to a large extent and 2005 is seen to have been an exceptional year for both stocks. If maintained over time, these effects could lead to the establishment of strong age groups, particularly for long-living species such as hake, which can give the population greater capacities of resilience and allow it to sustain greater fishing pressure for short periods. Nevertheless, recruitments and exceptional concentrations of recruits are not signs that can be interpreted univocally as a condition of well-being among the populations. The biomass of Selachii, a resource sensitive to exploitation due to its low resilience, appears to have slightly increased in recent years, but this observation is still too limited in time to conclude that a counter-trend phenomenon is occurring in regard to the continuous decline of this resource in the Adriatic Sea (Jukić-Peladić et al., 2001). A similar increase can be seen for crustaceans as a whole, probably favoured by the climatic changes that have taken place in the Southern Adriatic Sea. Nevertheless, for these indices to be interpreted as a recovery from intense fishing pressure, other indicators used to estimate stock exploitation levels should also provide consistent signs.

95th percentile size of the main target species Signs of stress due to excessive exploitation can also be gained through indicators that measure the presence of larger individuals in the demographic structure of the population, such as the indicator L0.95. In the historical series of the MEDITS experimental surveys for two species, the horned octopus E. cirrhosa and the deep-water rose shrimp P. longirostris, this indicator reflects significant decreasing trends (table 2.14). The use of the indicators should, however, be preferably

110 First section - Chapter 2 - Ecological aspects accompanied by assessments based on population dynamics models, capable of estimating the actual condition of the stock compared to both limit and target reference points (LRPs and TRPs).

Table 2.14 - GSA 18. Size: 95% percentile length per species (TL = Total Length, DML = Dorsal Mantle Length, CL = Carapace Length). The significant Spearman rho values are shown in bold.

European Red Horned Norway Deep-water Broadtail hake mullet octopus lobster rose shrimp shortfin squid Year TL (cm) TL (cm) DML (cm) CL (mm) CL (mm) DML (cm) 1994 30.0 23.0 14.0 52.5 37.0 17.5 1995 25.0 23.0 15.0 48.5 37.0 19.0 1996 25.3 6.5 14.5 47.0 36.0 17.8 1997 30.5 22.3 15.0 52.0 35.5 17.8 1998 24.3 21.3 13.3 47.0 36.0 16.8 1999 28.5 12.8 13.3 48.0 32.0 15.8 2000 25.5 22.5 12.0 45.5 32.0 17.3 2001 25.3 22.5 12.3 44.5 28.5 11.5 2002 25.5 24.0 13.0 48.0 29.5 15.5 2003 29.8 21.3 13.0 51.0 29.5 16.3 2004 27.5 20.0 12.5 49.0 30.0 9.8 2005 22.5 16.5 10.5 46.0 30.0 10.3 2006 29.3 21.0 11.3 49.0 32.5 17.5 2007 24.8 17.0 8.5 41.0 29.5 10.0 2008 24.3 21.5 11.5 50.0 34.5 17.8 2009 33.0 22.0 12.5 42.5 33.0 15.5 2010 28.0 18.8 13.3 45.5 30.5 14.8 Spearman’s rho -0.045 -0.254 -0.650 -0.400 -0.523 -0.482

Biology and spatial distribution Reproduction period The reproduction period of the various species, estimated by combining the data obtained from the experimental campaigns with data from commercial landings, shows a continuous pattern for hake, which reproduce throughout the year (table 2.15) with a peak in the late autumn and winter months (December-March), deep-water rose shrimp and broadtail squid, whereas the reproductive season for red mullet is concentrated into a few months, in late spring and summer. An intermediate situation is observed for horned octopus and Norway lobster.

Table 2.15 - GSA 18. Reproductive period for the various species.

Months Species J F M A M J J A S O N D European hake X X X X X X X X X X X X Red mullet X X X X Horned octopus X X X X X Norway lobster X X X X X X X X Deep-water rose shrimp X X X X X X X X X X Broadtail shortfin squid X X X X X X X X X X X X

111 Area and intensity of recruitment The geographical distribution of the nursery areas for certain key species, such as hake, shows fairly stable features over time, as seen from the results of the studies conducted in GSA 18 over the last 12 years using geostatistical methods (Lembo et al., 2000; Carlucci et al., 2009; Lembo, 2010). On the western shore, high concentrations of recruits have been located in the north of GSA 18, particularly off the Gargano Promontory and extending to the Gulf of Manfredonia (figure 2.37). In the continental shelf of this area there is also persistence over time in the aggregation of recruits. Other locations with high concentrations of hake recruits are also found further south in the GSA, in an area near the Egnatia canyon. The northern area of GSA 18, near the Gargano Promontory, is also a preferential location for nurseries of M. barbatus (figure 2.38). Another highly probable red mullet nursery location is the coastal strip to the south of Molfetta.

Photo by G. Lembo.

112 First section - Chapter 2 - Ecological aspects Figure 2.37 - GSA 18. European hake nursery areas.

113 Figure 2.38 - GSA 18. Red mullet nursery areas.

114 First section - Chapter 2 - Ecological aspects Assessments of the state of exploitation through the use of stock assessment models A joint assessment of hake exploitation conducted by research scientists from Italy, Montenegro and Albania is a representative case for GSA 18. The hake is a sequential spawner, reproducing throughout the year, with a peak in the late autumn and winter months (December-March). It has a high reproduction rate and the size at which females reach initial sexual maturity in the Southern Adriatic is approximately 33 cm total length. Recruitment also shows two seasonal peaks, one in spring and another in autumn. The fishing zones are located on the continental shelf and the upper portion of the slope. Trawl catches are made at depths of between 50 and 500 m; hake is fished together with other commercially important species: Illex coindetii, Mullus barbatus, Parapenaeus longirostris, Eledone spp., Todaropsis eblanae, Lophius spp., Pagellus spp., Phycis blennoides and Nephrops norvegicus. Assessments of the state of exploitation (GFCM, 2011; STECF-SGMED, 2011) were made using data from experimental surveys (MEDITS 1994-2009 and GRUND 1994-2006) together with that from commercial fisheries (2007-2009 data collection programme). Various models were applied, two of which based on experimental survey data (SURBA model; Needle, 2003) and on commercial fisheries data (VIT model; Lleonart and Salat, 1997) respectively, with a third model (ALADYM Age Length Based Dynamic Model; Lembo et al., 2009; Spedicato et al., 2010) being based on simulation techniques. This model allows the assessment of various scenarios, on the basis of population parameters and information on the exploitation pattern by the fleet. To allow for elements of uncertainty in the assessment, two different hake growth hypotheses, a slower and a faster one, were also tested. The experimental data shows an increase in recruitment, with the highest figure reached in 2005. This figure was followed by a sudden decline and a subsequent levelling out at around the average figure for the historical series. In particular, recruitment in 2008-2009 was slightly higher than the average level for the historical series.

If F0.1 is adopted as the limit reference point to ensure long-term sustainable yields, then the target fishing mortality would have to be around 0.2. Therefore, according to the analyses of 2007- 2009, the stock appears to be overfished, with mortality rates at around 0.95. Despite the growth pattern considered, a significant reduction is necessary in order to reach the reference point F0.1. Nevertheless, considering the high productivity in terms of the number of individuals entering the population each year, this stock is potentially capable of rapid recovery if fishing mortality were to be reduced. Simulation of two short-term scenarios (2010-2012), in one maintaining the status quo and in the other reducing the fishing pressure, showed that a 30% reduction of Fstq (F = 0.67) would produce a decrease in catches of around 18% compared to 2009, but a 43% of growth of spawning stock biomass (SSB indicator) over the following three years. A long-term projection of stock and catches (2010-2030) was made by simulating various scenarios with stochastic variations. In particular, a gradual reduction (14% per year) of F status quo was applied until F0.1 was reached in 2020 (figure 2.39). The results show a clear growth in the spawning stock biomass (SSB) and a significant increase in catches over the long term.

115 Recruitment and F vector 300,000 1 0.9 250,000 0.8 200,000 0.7 eclute 0.6 r F

R: 150,000 0.5 0.4 100,000 0.3 (number in thousand) 50,000 0.2 0.1 0 0 2009 2012 2015 2018 2021 2024 2027 2030

SSB 100,000 90,000 80,000 70,000 60,000

tonnes 50,000 40,000 30,000 20,000 10, 000 0 2009 2012 2015 2018 2021 2024 2027 2030

Catches 9,000 8,000 5% 25% 50% 75% 95% 7,000 6,000 5,000

tonnes 4,000 3,000 2,000 1,000 0 2009 2012 2015 2018 2021 2024 2027 2030

5% 25% 50% 75% 95% F vector 50%

Figure 2.39 - Long-term projection calculated for hake in GSA 18 with attainment of F0.1 in 2020 and maintenance of the same fishing pressure until 2030. Recruitment is of the same initial magnitude but with casual variations. The bootstrap confidence intervals are shown with broken lines. 5% 25% 50% 75% 95%

A forecast of the potential effects of the change in selectivity over the long term was made using the ALADYM simulation model, comparing the status quo scenario (40 mm mesh) and the scenario with the new cod-end mesh (50 mm), while maintaining the other factors that contribute to the definition of fishing pressure constant (figure 2.40). This forecast shows a minimal loss in catches over the short term and a stable situation in the future, when catches should be at a figure of about 10% higher than the current one. Furthermore, stock sustainability would progressively improve to the point that SSB would increase by about 30% and the average length of individuals caught would grow by around 20%, with the product probably obtaining better profits. However, these estimates assume as a necessary condition a fully compliance with the application of the mesh size regulation and the survival of fish that escape from the 50 mm cod-end mesh.

116 First section - Chapter 2 - Ecological aspects 16,000 14,000 12,000 10,000 SBB (ton) 6,000 4,000 2,000 0 1996 1999 2002 2005 2008 2011 2014 2017 2020 Years SSB mesh 50 mm SSB status quo

8,000 7,000 6,000 5,000 4,000 eld (tonnes)

Y 3,000 2,000 1,000 0 1996 1999 2002 2005 2008 2011 2014 2017 2020 Years Landing on the west Yeld status quo Yeld mash 50 mm 5% 25% 50% 75% 95%

300 250 age 200 150

length (mm) 100 Catches aver 50 0 1996 1999 2002 2005 2008 2011 2014 2017 2020 Years Average length status quo Average length mesh 50 mm

Figure 2.40 - Forecasts of the following indicators using the ALADYM simulation model: SSB, yield and average 5% 25% 50% 75% 95% catch length.

The adoption, over the long term, of a multi-year management plan along the lines of that adopted in 2008 could enable the stock to recover greater sustainability levels compared to those with current exploitation levels.

References - Abelló P., Abella A., Adamidou A., Jukić-Peladić S., Spedicato M.T., Tursi A. (2002) - Global population characteristics of two decapod crustaceans of commercial interest (Nephrops norvegicus and Parapenaeus longirostris) along the European Mediterranean coasts. Scientia Marina, 66 (Suppl. 2): 125-141. - Carlucci R., Lembo G., Maiorano P., Capezzuto F., Marano C.A., Sion L., Spedicato M.T., Ungaro N., Tursi A., D’Onghia G. (2009) - Nursery areas of red mullet (Mullus barbatus), hake (Merluccius merluccius) and deep-water rose shrimp (Parapenaeus longirostris) in the Eastern-Central Mediterranean Sea. Estuarine, Coastal and Shelf Science, 83: 529-538. - GFCM (2011) - Report of the 12th session of the SAC Sub-Committee on stock assessment (SCSA). Saint George’s Bay Malta, 28 November-3 December 2010: 74 p. - Jukić-Peladić S., Vrgoč N., Krstulović-Šifner S., Piccinetti C., Piccinetti-Manfrin G., Marano G., Ungaro N. (2001) - Long term changes in demersal resources of the Adriatic Sea: comparison between trawl surveys carried out in 1948 and 1998. Fish. Res., 53: 95-104.

117 - Lembo G., Silecchia T., Carbonara P., Spedicato M.T. (2000) - Nursery areas of Merluccius merluccius in the Italian Seas and in the East Side of the Adriatic Sea. Biol. Mar. Mediterr., 7 (3): 98-116. - Lembo G., Abella A., Fiorentino F., Martino S., Spedicato M.T. (2009) - ALADYM: an age and length-based single species simulator for exploring alternative management strategies. Aquat. Living Resour., 22: 233-241. - Lembo G. (ed) (2010) - Identificazione spazio-temporale delle aree di concentrazione dei giovanili delle principali specie demersali e localizzazione geografica di aree di nursery nei mari italiani - Nursery. Progetto di ricerca SIBM-MiPAAF n° 6A92. Relazione finale, Società Italiana di Biologia Marina, Genoa: 120 pp. + maps. - Lleonart J. & Salat J. (1997) - VIT: Software for fishery analysis. User’s manual. FAO Computerised Information Series (Fisheries), 11, Rome: 105 pp. - Needle C.L. (2003) - Survey-based assessments with SURBA. Working Document to the ICES Working Group on Methods of Fish Stock Assessment, Copenhagen. - SIBM (2010) - Rapporto annuale sullo stato delle risorse biologiche dei mari circostanti l’Italia. Relazione finale della Società Italiana di Biologia Marina al Ministero per le Politiche Agricole Alimentari e Forestali: 271 p. - Spedicato M.T., Poulard J.C., Politou C.Y., Radtke K., Lembo G., Petitgas P. (2010) - Using the ALADYM simulation model for exploring the effects of management scenarios on fish population metrics. Aquat. Living Resour., 23: 153-165. - STECF (2011) - Report of the SGMED-10-03 Working Group on the Mediterranean, Part II: 648 p. (https://stecf.jrc. ec.europa.eu/home). - Vrgo č N., Arneri E., Jukić-Peladić S., Krstulović-Šifner S., Mannini P., Marčeta B., Osmani K., Piccinetti C., Ungaro N. (2004) - Review of current knowledge on shared demersal stocks of the Adriatic Sea. FAO-MiPAAF Scientific Cooperation to Support Responsible Fisheries in the Adriatic Sea. GCP/RER/010/ITA/TD-12. AdriaMed Technical Documents, 12: 91 p.

2.3.7 GSA19 - North-Western Ionian Sea Sion L., Tursi A., D’Onghia G., Maiorano P., Capezzuto F., Carlucci R.

Information on the time series of the main descriptive parameters of demersal resources on the basis of MEDITS, CAMPBIOL and GRUND data projects are reported in this chapter.

Abundance and demography Biomass index of the community The osteichthyes biomass index decreased from 1997 to 2003. The maximum values of 348 and 368 kg/km2 were shown in 1997 and 2005 respectively. Despite of large fluctuations, both chondrichthyes and cephalopods showed a highly significant increase in abundance from 1994 to 2010. On the contrary crustaceans did not show any significant trend over time (figure 2.41).

OsteichthyesOsteichthyes biomass biomass indices indices ChondrichthyesChondrichthyes biomass biomass indices indices 500500 5050 450450 4545 400400 4040 350350 3535 2 2 2 2 300300 3030 250250 2525 kg/km kg/km kg/km kg/km 200200 2020 150150 1515 100100 1010 5050 55 00 00 199419941996199619981998200020002002200220042004200620062008200820102010 199419941996199619981998200020002002200220042004200620062008200820102010 YearsYears YearsYears

CephalopodsCephalopods biomass biomass indices indices CrustaceansCrustaceans biomass biomass indices indices 7070 8080 6060 7070

5050 6060 2 2 2 2 5050 4040 4040

3030 kg/km kg/km kg/km kg/km 3030 2020 118 First section - Chapter 2 - Ecological aspects 2020 1010 1010 00 00 199419941996199619981998200020002002200220042004200620062008200820102010 199419941996199619981998200020002002200220042004200620062008200820102010 YearsYears YearsYears OsteichthyesOsteichthyes biomass biomass indices indices ChondrichthyesChondrichthyes biomass biomass indices indices 500500 5050 450450 4545 400400 4040 350350 3535 2 2 2 2 300300 3030 250250 2525 kg/km kg/km kg/km kg/km 200200 2020 150150 1515 100100 1010 5050 55 00 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 YYearsears YYearsears

CephalopodsCephalopods biomass biomass indices indices CrustaceansCrustaceans biomass biomass indices indices 70 70 8080 6060 7070

5050 6060 2 2 2 2 5050 4040 4040 kg/km

30 kg/km kg/km 30 kg/km 3030 2020 2020 1010 1010 00 00 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 19941994 19961996 19981998 20002000 20022002 20042004 20062006 20082008 20102010 YYearsears YYearsears

Figure 2.41 - GSA 19. Biomass index (kg/km2) with confidence limits (dashed lines) of the main faunistic categories: osteichthyes, chondrichthyes, cephalopods, crustaceans (Source: MEDITS 1994-2010).

Biomass and density index for the main target species Biomass and density index of the European hake, the red mullet, the blue and red shrimp, the deep-water rose shrimp and the Norway lobster are reported in figure 2.42. The European hake did not show any significant trend over time. A significant increase of both indexes was shown for red mullet. The highest values of biomass and density were observed during 2007 due to a relevant catch of juveniles. The blue and red shrimp and the Norway lobster did not show any significant trend over time, while the deep-water rose shrimp showed a significant increase only in the density index.

EurEurEuropeanopeanopean hak hakhakeee biomass biomassbiomass indices indicesindices EurEurEuropeanopeanopean hak hakhakeee density densitydensity indices indicesindices 80808080 2,502,502,502,500000 45454545 2,002,002,00000 40404040 2,000 35353535 1,501,501,50000 2 2

2 1,500 2 2 2 2 2 30303030 252525

25 n/km n/km n/km n/km 1,001,001,001,000000 kg/km kg/km kg/km kg/km 20202020 15151515 500500500500 10101010 0000 0000 1994199419941994 1996199619961996 1998199819981998 2000200020002000 2002200220022002 2004200420042004 2006200620062006 2008200820082008 2010201020102010 1994199419941994 1996199619961996 1998199819981998 2000200020002000 2002200220022002 2004200420042004 2006200620062006 2008200820082008 2010201020102010 YYYearsearsearsears YYYearsearsearsears

RedRedRed mullet mulletmullet biomass biomassbiomass indices indicesindices RedRedRed mullet mulletmullet density densitydensity indices indicesindices 400400400400 18,00018,00018,00018,000 350350350350 16,00016,00016,00016,000 300300300300 14,00014,00014,00014,000 12,00012,00012,000 250250250250 12,000 2 2 2 2 2 2 2 2 10,00010,00010,00010,000 200200200200 8,008,0000

n/km 8,000 n/km n/km 8,000 n/km

kg/km 150 kg/km 150 kg/km 150

kg/km 150 6,006,006,006,000000 100100100100 4,004,004,004,000000 50505050 2,002,002,002,000000 000 0 0000 1994199419941994 1996199619961996 1998199819981998 2000200020002000 2002200220022002 2004200420042004 2006200620062006 2008200820082008 2010201020102010 1994199419941994 1996199619961996 1998199819981998 2000200020002000 2002200220022002 2004200420042004 2006200620062006 2008200820082008 2010201020102010 YYYearsearsearsears YYYearsearsearsears

BlueBlueBlue and andand re rerereddd shrimp shrimpshrimp biomass biomassbiomass indices indicesindices BlueBlueBlue and andand re rerereddd shrimp shrimpshrimp density densitydensity indices indicesindices 16161616 900900900900 14141414 800800800800 119 700700700 12121212 700 600600600600 10101010 2 2 2 2 2 2 2 2 500500500500 8888 400400400400 n/km n/km n/km 666 n/km kg/km kg/km kg/km 6 kg/km 300300300300 4444 200200200200 222 2 100100100100 0000 0000 1994199419941994 1996199619961996 1998199819981998 2000200020002000 2002200220022002 2004200420042004 2006200620062006 2008200820082008 2010201020102010 1994199419941994 1996199619961996 1998199819981998 2000200020002000 2002200220022002 2004200420042004 2006200620062006 2008200820082008 2010201020102010 YYYearsearsearsears YYYearsearsearsears

Deep-waterDeep-waterDeep-water r rroseoseose shrimp shrimpshrimp biomass biomassbiomass indices indicesindices Deep-waterDeep-waterDeep-water shrimp shrimpshrimp density densitydensity indices indicesindices 161616 16 3,003,003,003,000000 14141414 2,502,502,502,500000 12121212 10101010 2,002,002,002,000000 2 2 2 2 2 2 2 2 8888 1,501,501,501,500000 n/km n/km n/km 666 n/km

kg/km 6 kg/km kg/km kg/km 1,001,001,001,000000 4444 2222 500500500500 0000 0000 1994199419941994 1996199619961996 1998199819981998 2000200020002000 2002200220022002 2004200420042004 2006200620062006 2008200820082008 2010201020102010 1994199419941994 1996199619961996 1998199819981998 2000200020002000 2002200220022002 2004200420042004 2006200620062006 2008200820082008 2010201020102010 YYYearsearsearsears YYYearsearsearsears

NNNorwayorwayorway lobster lobsterlobster biomass biomassbiomass indices indicesindices NorwayNorwayNorway lobster lobsterlobster density densitydensity indices indicesindices 666 6 600600600600 555 5 500500500500 444 4 400400400400 2 2 2 2 2 2 2 2 333 3 300300300300 n/km n/km n/km n/km kg/km kg/km kg/km kg/km 222 2 200200200200 111 1 100100100100 000 0 0000 1994199419941994 1996199619961996 1998199819981998 2000200020002000 2002200220022002 2004200420042004 2006200620062006 2008200820082008 2010201020102010 1994199419941994 1996199619961996 1998199819981998 2000200020002000 2002200220022002 2004200420042004 2006200620062006 2008200820082008 2010201020102010 YYYearsearsearsears YYYearsearsearsears European hake biomass indices European hake density indices EurEurEuropeanopeanopean hak hak hakee ebiomass biomass biomass indices indices indices EurEurEuropeanopeanopean hak hak hakee edensity density density indices indices indices 80 2,500 808080 2,502,502,50000 45 454545 2,000 40 2,000 404040 2,002,000 0 35 353535 1,500 2 1,500 2 2

2 1,500

30 2 1,501,500 0 2 2 2 30 2 2 303030 25

25 n/km 252525 n/km 1,000 n/km 1,000 n/km n/km kg/km

kg/km 1,001,001,00000 kg/km kg/km kg/km 20 202020 15 500 151515 500500500 10 101010 0 0 000 000 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 199419941994199619961996199819981998200020002000200220022002200420042004200620062006200820082008201020102010 199419941994199619961996199819981998200020002000200220022002200420042004200620062006200820082008201020102010 Years Years YYearsYearsears YYearsYearsears

Red mullet biomass indices Red mullet density indices RedRedRed mullet mullet mullet biomass biomass biomass indices indices indices RedRedRed mullet mullet mullet density density density indices indices indices 400 18,000 400400400 18,00018,00018,000 350 16,000 350350350 16,00016,00016,000 300 14,000 300300300 14,00014,00014,000 12,000 250 12,00012,00012,000

250 2 2 250 250 2 2 2 2 2 10,000 2 2 2 10,000 200 10,00010,00010,000 200200200 8,000 n/km 8,000 n/km 8,000 n/km 8,008,000 0 kg/km n/km

150 n/km

kg/km 150

kg/km 150 kg/km kg/km 150150 6,000 100 6,006,006,00000 100100100 4,000 4,000 50 4,004,000 0 505050 2,000 2,002,002,00000 0 0 0 0 0 000 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 199419941994199619961996199819981998200020002000200220022002200420042004200620062006200820082008201020102010 199419941994199619961996199819981998200020002000200220022002200420042004200620062006200820082008201020102010 Years Years YYearsYearsears YYearsYearsears

Blue and red shrimp biomass indices Blue and red shrimp density indices BlueBlueBlue and and and re re reddd shrimp shrimp shrimp biomass biomass biomass indices indices indices BlueBlueBlue and and and re re reddd shrimp shrimp shrimp density density density indices indices indices 16 900 161616 900900900 14 800 141414 800800800 700 12 700 121212 700700 600 10 600600600

101010 2 2 2

2 500 2 2 2

2 500 2 2 8 500500500 888 400

n/km 400

n/km 400400400

6 n/km n/km n/km kg/km 6 kg/km 6 kg/km 6 6 300 kg/km kg/km 300 4 300300300 444 200 200200200 2 2 100 2 2 100100100 0 0 000 000 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 199419941994199619961996199819981998200020002000200220022002200420042004200620062006200820082008201020102010 199419941994199619961996199819981998200020002000200220022002200420042004200620062006200820082008201020102010 Years Years YYearsYearsears YYearsYearsears

Deep-water rose shrimp biomass indices Deep-water shrimp density indices Deep-waterDeep-waterDeep-water r r oseroseose shrimp shrimp shrimp biomass biomass biomass indices indices indices Deep-waterDeep-waterDeep-water shrimp shrimp shrimp density density density indices indices indices 16 16 3,000 1616 3,003,003,00000 14 14 1414 2,500 12 2,502,502,50000 121212 10 2,000 10 2,002,0000 1010 2 2,000 2 2 2 2 2 2 2 2 2 8 8 1,500 8 8 1,500

n/km 1,501,500 0 6 n/km n/km kg/km n/km 6 n/km kg/km 666 kg/km kg/km kg/km 1,000 4 1,001,001,00000 444 2 500 222 500500500 0 000 0 000 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 199419941994199619961996199819981998200020002000200220022002200420042004200620062006200820082008201020102010 199419941994199619961996199819981998200020002000200220022002200420042004200620062006200820082008201020102010 Years Years YYearsYearsears YYearsYearsears

Norway lobster biomass indices Norway lobster density indices 6 NNorwayorway lobster lobster biomass biomass indices indices NorwayNorway lobster lobster density density indices indices 6 600 6 6 600600600 5 5 500 5 5 500500500 4 4 400 4 4 400400400 2 2 2 2 2 2 2 2 2 2 3 300 333 300

n/km 300300 n/km n/km kg/km n/km n/km kg/km

kg/km 2 kg/km kg/km 2 200 2 2 200200200 1 1 100 1 1 100100100 0 0 0 0 0 000 1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 199419941994199619961996199819981998200020002000200220022002200420042004200620062006200820082008201020102010 199419941994199619961996199819981998200020002000200220022002200420042004200620062006200820082008201020102010 Years Years YYearsYearsears YYearsYearsears

Figure 2.42 - GSA 19. Biomass (kg/km2) and density index (n/km2) with confidence limits (dashed lines) of the main target species estimated on their distribution depth range (Source: MEDITS 1994-2010).

Length/frequency distribution at the 95th percentile of the main target species Length/frequency distribution at the 95th percentile of the European hake, the red mullet, the blue and red shrimp, the deep-water rose shrimp and the Norway lobster is reported in table 2.16. The European hake did not show any significant trend of the sizes over time.

120 First section - Chapter 2 - Ecological aspects The red mullet did not show any significant decrease of sizes over time. During 2007, the presence of a significant fraction of juveniles was detected, as the trawl survey was conducted between late July and early August, when early juveniles could be found. The length/frequency distribution of the blue and red shrimp, the deep-water rose shrimp and the Norway lobster did not show any significant time trend. For all the species Spearman’s rho values were not significant.

Table 2.16 - GSA 19. Length/frequency distribution at the 95th percentile of the main target species (TL=Total Length, CL=Carapace Length).

Blue and red Deep-water rose Norway lobster European hake Red mullet Shrimp shrimp Year TL (cm) TL (cm) CL (mm) CL (mm) CL (mm) 1994 25.00 17.25 55.5 28.50 55.00 1995 26.25 14.75 56.00 29.00 57.00 1996 26.00 16.75 50.5 28.50 53.50 1997 34.25 17.75 53.5 29.00 52.50 1998 23.00 18.25 46.00 27.50 38.50 1999 27.00 18.25 50.00 29.50 47.50 2000 27.00 18.25 48.00 30.50 37.00 2001 29.75 19.00 52.50 29.50 50.50 2002 24.00 18.00 56.00 29.50 42.00 2003 30.25 17.75 53.00 28.50 45.50 2004 19.00 16.75 49.50 30.00 55.00 2005 21.25 16.75 53.50 30.00 49.00 2006 27.00 17.50 50.00 29.00 42.50 2007 26.50 12.25 55.50 28.50 49.50 2008 23.00 15.00 53.00 27.50 51.50 2009 30.25 17.50 49.00 29.50 53.00 2010 31.25 15.50 53.50 28.00 53.00 Spearman’s rho 0.121 -0.302 -0.108 -0.020 -0.144

Biology and spatial distribution Reproductive period The reproductive season was estimated from data collected during GRUND and MEDITS experimental surveys and from commercial catches of all fleet combined segments. The reproduction period of the main target species is reported in table 2.17. The reproductive period of M. merluccius was extended throughout the year. In M. barbatus mature individuals are concentrated from May to July. Concerning crustaceans, reproduction of A. antennatus occurs between May and September, while in P. longirostris is more continuous and moved to the summer-autumn period. Finally, the reproductive period of N. norvegicus was concentrated in spring-summer, although small fractions of mature females were also observed until October.

121 Table 2.17 - GSA 19. Reproductive period of the main target species. Data from MEDITS and GRUND experimental surveys and from commercial catches of all fleet combined segments.

Species J F M A M J J A S O N D M. merluccius X X X X X X X X X X X X M. barbatus X X X A. antennatus X X X X X P. longirostris X X X X X X N. norvegicus X X X X X X

Recruitment areas and density The recruitment indices in GSA 19 were computed from the MEDITS time series 1994-2010. In particular, the cut-off sizes used to separate the juveniles fraction for M. merluccius, M. barbatus, A. antennatus, P. longirostris and N. norvegicus were calculated in the framework of the national Nursery Project (MiPAAF). Recruitment indices highly fluctuated in M. merluccius without any temporal trend. Whilst, a significant increasing trend was observed in the recruitment indices of M. barbatus, even though values were generally negligible, with the exception of what observed during 2007-2008. As expected, the recruitment index of A. antennatus was generally very low due to the distribution of recruits on areas deeper than those investigated. However, for this shrimp higher values were recorded during 2008 and 2009. Recruitment indices highly fluctuated throughout the investigated period in P. longirostris without indication of any temporal trend. However, higher values were recorded for the deep-water rose shrimp during 2008 and 2009. Finally, the recruitment indices of N. norvegicus fluctuated throughout the study period without any temporal trend. The spatial distribution of nursery areas of the hake, the deep-water rose shrimp and the Norway lobster in GSA 19 was investigated by means of geostatistical analysis carried out on data collected in the framework of the experimental trawl surveys GRUND and MEDITS (Carlucci et al., 2009; Murenu et al., 2010). The negligible catch of M. barbatus recruits and the deep distribution of A. antennatus recruits down to 3000 m prevented the estimation of nursery areas of both species in the GSA 19. On the contrary, the main persistent nursery areas for hake and deep-water rose shrimp were observed from 100 to 250 m between Otranto and Santa Maria di Leuca in the Apulia and in the , southernmost Cape Rizzuto and northernmost Punta Stilo in Calabria (figures 2.43 and 2.44). Concerning the Norway lobster, the main areas with the highest densities of recruits were frequently observed on bottom grounds off Gallipoli and Torre Ovo from 200 to 800 m (figure 2.45). Another significant area was observed northernmost the Amendolara Bank in the Gulf of Corigliano up to 800 m.

122 First section - Chapter 2 - Ecological aspects Figure 2.43 - GSA 19. Hake nursery areas with indication of persistency.

123 Figure 2.44 - GSA 19. Deep-water rose shrimp nursery areas with indication of persistency.

124 First section - Chapter 2 - Ecological aspects Figure 2.45 - GSA 19. Norway lobster nursery areas with indication of persistency.

125 Stock assessment Merluccius merluccius - European hake The most recent stock assessment of European hake in the GSA19 was carried out in 2010. Total mortality rate (Z) was assessed according to the LCCC method using the FISAT II program (Gayanilo et al., 1996). The vector function of the fishing mortality rate (F) was evaluated by means of SURBA (Cook, 1997) using MEDITS data and ProdBiom routine (Abella, 1997). The values of Z and F (for age-classes 1-4+) varied between 0,85 y-1 (2003) and 1,44 y-1 (2008) and between 0,71 (1995) and 1,13 (2006), respectively. No significant changes in both value series were observed with time. Exploitation ratio (E), between 0,79 and 0,87, indicated overfishing conditions. The management measures proposed by EU, such as a square mesh in the cod-end and the minimum landing size, should be adopted for hake in GSA19. In addition, the knowledge of spatio- temporal distribution of the recruitment should provide useful indications to establish no-take zones (Zone di Tutela Biologica) in order to improve the exploitation status of hake in this GSA.

Parapenaeus longirostris - Deep-water rose shrimp The most recent appraisal of deep-water rose shrimp stock in GSA19 was performed in 2010. The Z values were calculated by means of LCCC method using the FISAT II program (Gayanilo et al., 1996). The vector function of F was computed by means of SURBA (Cook, 1997) using MEDITS data and ProdBiom routine (Abella, 1997). High changes were shown in both mortality rates without significant trends. Z values ranged from 2,95 y-1 (1996) to 4,84 y-1 (2008) while those of F (for age-classes 1-3) were between 2,64 and 4,36. The average E value was 0,9, indicating high overexploitation conditions for this shrimp in GSA19. A reduction of fishing effort on this demersal resource should be carried out. The adoption of a square mesh or the increase from 40 to 50 mm of rhomboidal mesh in the cod-end should favour an increase in the catches in the mid term, preserving juveniles. Since deep-water rose shrimp is a species with a short life cycle, knowledge in the recruitment fluctuation related to changes in the environmental factors are of paramount importance. However, every management measure should take into account of multispecific features of the catches in the exploitation of this demersal resource.

Nephrops norvegicus - Norway lobster The most recent stock assessment of Norway lobster in GSA19 dates back to 2009. Total mortality rate (Z) was evaluated by means of the LCCC method using the FISAT II program (Gayanilo et al., 1996). Fishing mortality rate (F) was calculated as a difference between Z and natural mortality rate (M) (Maiorano et al., 2010). Z values were rather stable throughout the study period varing between 0,78 y-1 (1995 and 1996) and 1,11 y-1 (1999). The exploitation ratio (E) ranged from 0,36 to 0,55, with an average value of 0,46, indicating an equilibrium status in the exploitation of this resource. Also for the Norway lobster the adoption of a square mesh or the increase from 40 to 50 mm of rhomboidal mesh in the cod-end should favour an increase in the catches in medium period. The eventual establishment of no-take zones along the Apulian coast, between Gallipoli and Taranto, and in the Calabria sector (Amendolara Seamount) could be of paramount importance to protect the recruitment of this .

126 First section - Chapter 2 - Ecological aspects References - Abella A., Caddy J.F., Serena F. (1997) - Do natural mortality and availability decline with age? An alternative yield paradigm for juvenile fisheries, illustrated by the hake Merluccius merluccius fishery in the Mediterranean. IFREMER Aquat. Living Resou., 10: 257-269 - Carlucci R., Lembo G., Maiorano P., Capezzuto F., Marano C. A., Sion L., Spedicato M. T., Ungaro N., Tursi A., D’Onghia G. (2009) - Nursery areas of red mullet (Mullus barbatus), hake (Merluccius merluccius) and deep-water rose shrimp (Parapenaeus longirostris) in Eastern-Central Mediterranean Sea. Estuarine, Coastal and Shelf Science, 83: 529-538. - Cook R.M. (1997) - Stock trends in six stocks as revealed by an analysis of research vessel surveys, ICES Journal of Marine Science 54: 924–933. - Gayanilo F.C., Sparre P., Pauly D. (1996) - FAO-ICLARM Stock Assessment Tools II (FiSAT II) Revised Version, User’s Guide. Computerized Information Series, FAO Fisheries, 8, Rome: 168 p. - Maiorano P., Sion L., Carlucci R., Capezzuto F., Giove A., Costantino G., Panza M., D’Onghia G., Tursi A. (2010) - The demersal faunal assemblage of the North-Western Ionian Sea (Central Mediterranean): present knowledge and perspectives. Chemistry and Ecology, 26 (1): 219-240. - Murenu M., Cau A., Colloca F., Sartor P., Fiorentino F., Garofalo G., Piccinetti C., Manfredi C., D’Onghia G., Carlucci R., Donnaloia L., Lembo P. (2010) - Mapping the potential locations of the European hake (Merluccius merluccius) nurseries in the Italian waters. In Nishida T., And Caton A.E. (Eds), GIS/Spatial Analyses in Fishery and Aquatic Sciences (Volume 4). International Fishery GIS Society: 579 p.

2.3.8 Evolution of the state of demersal resources Relini G., Sartor P., Orsi Relini L., Piccinetti C.

The analysis of the variation over time in the consistency of the resources, particularly for demersal species, is certainly not an easy process. The simple analysis of fishery statistics (information, however, not easy to obtain on a large spatio-temporal scale) is not sufficient, although supported by standardised estimations according to fishing effort, as engine power, vessel tonnage or fishing days. A proper analysis would also take into account fishing efficiency or fishing power, factors which have increased over the years. There is no doubt that the increase in fishing capacity and the technological improvement of boats and equipment, occurred particularly since the end of World War II, has led to a greater impact of fisheries on resources and the environment. Moreover, the variation in the species stock sizes can be due to natural population fluctuations (both regular and irregular), which are generally under control of climatic aspects. The North Atlantic Oscillation Index (NAO) is a widely used climatic index, whose trends have also been compared with catches and/or the recruitment intensity of certain species in the Mediterranean Sea. For example, in Liguria the catches of horned octopus are positively correlated with NAO index (Orsi Relini et al., 2006). As mentioned, the assessment of any variations in fish communities over time requires the analysis of a long series of historical data, which, for the Mediterranean Sea, is available in a standardised manner only for the last 20 or 30 years, when research on fisheries were developed. For a proper assessment and management of resources, it is very important to identify the proper baseline as far back in time as possible, regarding both the stock abundance and the fishing mortality levels (Pauly, 1995). Nevertheless, some considerations can be made by comparing observations from before and after World War II with current data. The faunal group that has undoubtedly undergone the greatest changes over time is Elasmobranches (cartilaginous fish), for which a drastic reduction is recorded, both in presence and density, especially for medium to large sized species (Ferretti et al., 2008). They show low resilience to the disturbance, leading to gradual changes in the composition of population.

127 Species such as the common smooth-hound, the and the angel shark, together with rays and small-spotted catsharks, were, until the 1980s, the target of many fisheries, constituting an important part of commercial landings for many Mediterranean fishing communities, particularly in Italy and France. In recent decades, the stock size for these species dramatically decreased and some of them (e.g. the angel fish Squatina spp.) have disappeared from many areas (Fortibuoni et al., 2009; Sartor et al., 2010). Regarding bony fish, aside from the disappearance shown by the and the clear reduction of the European eel, no other species have suffered drastic changes; in fact, none of the 247 species listed in the market of Genoa over 100 years ago (Parona, 1898) can be considered as having now disappeared. There is, however, evidence of clear variations in density over time and of variations in population structures (particularly in regard to size). The reduction in size is considered as an indicator of overexploitation of a resource. An interesting study has been conducted for the Central-northern Adriatic Sea, comparing experimental data of the (1948) with those of the MEDITS (1998) trawl surveys (Jukić- Peladić et al., 2001). Data from the Hvar survey is very important, not only because it was the first experimental trawl survey based on a standardised procedure carried out in the Mediterranean Sea, but also because the data was gathered after a period of five years of interruption of fishing, due to World War II. The work of Jukić-Peladić et al. (2001) confirms that the most important difference between the demersal assemblages in the two periods essentially consists in the reduction of the role of Elasmobranchs within the demersal assemblages. In the past, at least until the first decades of the last century, fish assemblages were characterised by a greater presence of large predators and less resilient species, which ensured more diversified and structured populations. The changes that have occurred over time have produced a reduction of the trophic connections, favouring in recent times the dominance of species placed at lower levels of the food pyramid, characterised by faster growth and greater fecundity. Analysis of the “historical” data also reveals indications that the population structure of many species was more balanced in the past (Matta, 1958), without the clear dominance of smaller specimens, typical of the current populations of many species, as the European hake, Merluccius merluccius. This aspect is common to the whole Mediterranean Sea; for example, the reports by the Scientific Advisory Committee (SAC) of the FAO General Commission for Fisheries in the Mediterranean (GFCM) have shown a status of overexploitation for most of the 14 demersal species studied (Lleonart & Maynou, 2003). The EVOMED project of the European Community (Sartor, 2011), has investigated the evolution of demersal communities over the last 100 years, from the structure of fleets to population characteristics, in various areas of the Mediterranean Sea, and has also conducted interviews with fishermen. The results for all the areas investigated confirm the changes, both in fishing capacity and efficiency, as well as the variations suffered at community structure level (Sartor et al., 2010; Sbrana et al., 2010; Maynou et al., 2011).

Red shrimp in the fisheries of the Ligurian Sea The history of red shrimp fisheries in Liguria has been reconstructed, with the help of memories on the former quantities of this resource (Relini, 2007). This is an interesting chapter in the history of fisheries, because one of the two species of relevance today is greatly reduced compared to the past, but is not extinct. Red shrimps (Aristeus antennatus and Aristaeomorpha foliacea) are now the species with greatest

128 First section - Chapter 2 - Ecological aspects value in Ligurian fisheries, with about 100-200 tonnes landed each year. This fishing activity has been carried out for around 80 years, a period of time surpassed in the Mediterranean Sea only by Algeria (Boutan & Argilas, 1927). Shrimps were one of the research topics of major interest following the discovery of trawlable bathyal sea bottoms in the late 1920s. A collaboration study on deep-water fauna was done at the University of Genoa, leaded by R. Issel, director of the Institute of zoology and his colleagues R. Santucci and A. Brian. Shrimps appeared on the market in Genoa in the 1930s, as an abundant product, consisting of the two species A. antennatus and A. foliacea (figure 2.46) in almost equal proportions. The seabeds exploited at that time were in the epibathyal zone (maximum lower limit 500 m). Issel (1930), when launching the research project on “The biology of the Norway lobster fishing grounds”, reported that six trawlers from the port of Genoa had increased the well-known field of activity of sailing trawlers (up to 150 m) in order to reach depths of over 300 m. From the very beginning, Brian began to visit the Piazza Caricamento market in Genoa to record the boxes of shrimps landed every day. He also purchased samples to investigate about ecological aspects, as the trophic support of such abundant populations. Around 10 years later, Brian (1942) reported that A. foliacea had been very common in the district of Genoa for around 10 years (the simple presence of A. antennatus has been recorded since 1846). The old fishermen of Santa Margherita Ligure relate that in 1945, when fishing resumed after the war, up to one ton of red shrimps were landed by each boat per day. From 1950 to 1960 there was a progressive reduction in yields, the fishing activity moved to greater depths and A. antennatus became dominant. Research resumed only in the 1970s, with observations on landings and, in particular, observations on board for the first time. Catches began in the springtime (April-May), would reach a peak in mid-summer and would then decline with the autumn. About 90% consisted of female A. antennatus. The concentration of shrimps in the fishing areas coincided in spring with the presence of the adults of both sexes and, from summer to autumn, the presence of females ready to spawn (Orsi Relini & Relini, 1979). With the reduction of females bearing matures eggs, the population diminished and fishing was no longer profitable. The Ligurian habits of six month mesobathyal fishing, typical of those years, coincided, however, with the reproductive season of A. antennatus. The shrimp population of the Ligurian mesobathyal beds was a particularly valuable product because the large-sized specimens were prevalent. During the 1980s, two important facts for shrimp fishing were observed, one negative and the other positive, both helpful to clarify some biological aspect of A. antennatus. In 1981, during a monitoring study (thanks to CNR funding), A. antennatus disappeared from the fishing area of Portofino. This disappearance (which fishermen had attributed to industrial waste – the red muds of Scarlino – near the island of Gorgona, from where the currents flow northwards) was fortunately of short duration, from 1980 to 1984, and occurred during a period, more than 30 years from the end of the war, in which the abundance of shrimp had declined significantly. While in Portofino there were no commercial quantities of red shrimp, fishing continued in the Western sector of the Riviera. A. antennatus reappeared in the Portofino area, although in small quantities, in the summer of 1985 and 1986, with large-sized individuals that probably originated from outlying areas. It could therefore be concluded that the shrimp did not “reside” on the fishing bottoms, but were capable of wide horizontal movements. The same conclusion could be made from the fishing in the canyon of the river Roja (on the border with France), where 14 fishing vessels from Sanremo repeated the same very short haul in turn, several times a day, daily over a period of months (Orsi Relini et al., 1986).

129 Figure 2.46 - Aristeus antennatus and Aristaeomorpha foliacea in illustrations by Alessandro Brian (1942).

An exceptional and unexpected recruitment was observed in 1987, with the appearance of a large number of small shrimps on all the bathyal bottoms, both in the Gulf of Genoa as well as off Sanremo-Ventimiglia. This event allowed fishing to resume in the east and provided fundamental indications for the study of the biology, particularly growth, of these crustaceans. The minimum size at maturity for females of A. antennatus moved from 32 mm CL to 24 mm CL; the reproductive season, which previously began in late June or July, was found to be anticipated to May. The fishing season could be extended to the entire year as had been originally. After the recruitment of 1987, which produced a peak in landings in 1988, a slow decline began in terms of catch per unit effort, which was monitored until 1995 (Fiorentino et al., 1998). The following years were those of the MEDITS surveys. In recent times in Liguria, the appearance of significant quantities of young shrimps was observed again in 1997 and in 2009, i.e. about every 10 years, considering also the episode of 1987. A similar timescale has also been noted in other areas of the Western Mediterranean Sea, for example in the Balearic Islands (Carbonell et al., 1999); this suggests

130 First section - Chapter 2 - Ecological aspects that environmental factors of a climatic nature, rather than fisheries, determine the abundance of A. antennatus. At present, August 2011, fishing on the bottoms off Portofino is thriving, with yields of 50-100 kg/day/boat. Without doubts, A. antennatus has been fished and monitored almost exclusively since the 1970s. A. foliacea has importance for Italian fisheries from Corsica southwards and from the Strait of Sicily to the : it is no longer of relevance on the “Norway lobster beds” in Liguria, where small quantities of young shrimp can be caught in the springtime. The ratio between the two species in the official statistics (approximately 5:1 in favour of A. antennatus) appears underestimated when compared with the data from the experimental surveys. The reason why when blue and red shrimp abound, A. foliacea does not participate in these occurrences, still remains to be clarified.

References - Boutan L. & Argilas A. (1927) - Les trois crevettes d’Algérie qui paraissent avoir un intérêt économique. Stat. d’aq. et de pêche de Castiglione, II fasc., Alger: 254-272. - Brian A. (1942) - I crostacei eduli del mercato di Genova (Decapoda Natantia). Boll. Pesca Piscic. Idrobiol., 18: 25-60. - Carbonell A., Carbonell M., Demestre M., Grau A., Monserrat S. (1999) - The red shrimp Aristeus antennatus (Risso, 1816) fishery and biology in the Balearic Islands, Western Mediterranean. Fish. Res., 44: 1-13. - Ferretti F., Myers R.A., Serena F., Lotze H.K. (2008) - Loss of Large Predatory Sharks from the Mediterranean Sea. Conserv. Biol., 22: 952-964. - Fiorentino F., Orsi Relini L., Zamboni A., Relini G. (1998) - Remarks about the optimal harvest strategy for red shrimps (Aristeus antennatus, Risso 1816) on the basis of the Ligurian experience. In: Lleonart J. (ed), Marine Population Dynamics, Cahiers Options Méditerranéennes, 35: 323-333. - Fortibuoni T., Giovanardi O., Raicevich S. (2009) - Un altro mare. La pesca in alto Adriatico e Laguna di Venezia dalla caduta della Serenissima ad oggi: un’analisi storica ed ecologica. Edizioni Associazione ‘‘Tegnùe di - Onlus”, Chioggia: 221 p. - Issel R. (1930) - La biologia del fondo a “Scampi” nel Mar Ligure. Scopi e piano dell’indagine. Boll. Mus. Zool. Anat. Comp. Univ. Genoa, 10: 1-3. - Jukić-Peladić S., Vrgoč N., Krstulović-Šifner S., Piccinetti C., Piccinetti-Manfrin G., Marano G., Ungaro N. (2001) - Long term changes in demersal resources of the Adriatic Sea: comparison between trawl surveys carried out in 1948 and 1998. Fish. Idrobiol., 53: 95-104. - Lleonart J. & Maynou F. (2003) - Fish stock assessments in the Mediterranean: state of art. Sci. Mar., 67 (Suppl. 1): 37-49. - Matta F. (1958) - La pesca a strascico nell’Arcipelago Toscano. Boll. Pesca. Piscic. Idrobiol., 34, 13 (1-2): 135-172 and 230-261. - Maynou F., Sbrana M., Sartor P., Maravelias C., Kavadas S., Damalas D., Cartes J.E., Osio G. (2011) - Estimating trends of population decline in long-lived marine species in the Mediterranean Sea based on fishers’ perceptions. PLoS ONE, 6 (7): e21818. - Orsi Relini L., Mannini A., Fiorentino F., Palandri G., Relini G. (2006) - Biology and fishery of Eledone cirrhosa in the Ligurian Sea. Fish. Res., 78 (1): 72-88. - Orsi Relini L. & Relini G. (1979) - Pesca e riproduzione del gambero rosso Aristeus antennatus (Decapoda, Penaeidae) nel Mar Ligure. Quad. Civ. Staz. Idrobiol. , 7: 39-62. - Orsi Relini L., Relini G., Semeria M. (1986) - Displacements of shoals of Aristeus antennatus deduced by the fishing activity of west-Ligurian trawlers. Rapp. Comm. Int. Mer Médit., 30 (2): 12 p. - Pauly D. (1995) - Anecdotes and the shifting baseline syndrome of fisheries. Trends Ecol. Evol., 10 (10): 430 p. - Parona C. (1898) - La pesca marittima in Liguria. Boll. Mus. Zool. Anat. Comp. Univ., Genoa, 3 (66): 69 p. - Relini G. (2007) - La pesca batiale in Liguria. Biol. Mar. Mediterr., 14 (2): 190-244. - Sartor P., Rossetti I., Balducci G., Lariccia M., Sbrana M., De Ranieri S. (2010) - Fishermen perceptions on the elasmobranch abundance evolution over time in the Italian trawl fisheries. Biol. Mar. Mediterr., 17 (1): 228-231. - Sartor P. (2011) - The 20th Century evolution of Mediterranean exploited demersal resources under increasing fishing disturbance and environmental change. Contratto UE N. SI2 539097. Relazione Finale: 513 p. - Sbrana M., Maravelias C., Mariani A., Maynou F., Sartini M., Sartor P. (2010) - Evomed project: fishermen interviews as source of information to reconstruct the evolution of the Mediterranean fisheries in the 20th century. Biol. Mar. Mediterr., 17 (1): 350-351.

131 2.4 Small pelagic fish in the seas around Italy Santojanni A., Angelini S., Basilone G., Biagiotti I., Bonanno A., Carpi P., De Felice A., Leonori I., Patti B., Petrillo M., Sbrana M.

Biology and ecology Small pelagic fish represent about a quarter of all fish species captured globally (Checkley et al., 2009). In the seas around Italy, the main small pelagic fish species include anchovies (Engraulis encrasicolus) and sardines (Sardina pilchardus), which are of great importance, both economically and ecologically, as well as round sardinella (Sardinella aurita) and sprat (Sprattus sprattus). In the adult stage, small pelagic fish are 10-30 cm long (Fréon et al., 2005). They have a relatively short life: anchovies can live beyond three years old and sardines six. They play a very important role in the ecosystem, since they influence the abundance of the zooplankton and phytoplankton species on which they feed. This energy, captured by the lowest levels of the food webs, is in turn made available to predators at higher levels, with the result that small pelagic fish can also produce effects on the abundance of their “natural” predators, such as fish, birds and marine mammals, as well as on fisheries. Some authors also include other larger species, with lengths of between 20 and 60 cm, in the small pelagic fish group; the term used for these in literature is in fact medium-sized pelagic fish, “as opposed to” small pelagic fish (Freon et al., 2005). With reference to Italian seas, Atlantic mackerel (Scomber scombrus), chub mackerel (Scomber japonicus), Atlantic horse mackerel (Trachurus trachurus), Mediterranean horse mackerel (Trachurus mediterraneus) and blue jack mackerel (Trachurus picturatus) can be included. If small pelagic fish can affect the expansion of other species in the ecosystem, they can in turn be influenced by others. A scarcity of food (plankton) can drastically reduce the survival of these fish, particularly as juveniles; during juvenile stages they can also be very prone to predators (e.g. jellyfish and fish). The probability of survival, particularly in the younger stages, can vary from one year to another and over the span of decades, not only due to interaction with other species but also due to environmental conditions. In conclusion, small pelagic fish populations, as well as their stocks, i.e. the population segments targeted by fisheries, are subject to considerable fluctuations over time and in terms of location, due to various factors, which are not limited to excessive fishing pressure (Patti et al., 2004; Santojanni et al., 2006; Leonori et al., 2009). Space for small pelagic fish is a complex reality. These organisms are in fact gregarious and can form schools of considerable size and various levels of aggregation, composed of one or more species, as well as carry out migrations, both vertically, along the water column, as well as horizontally, for example from the open sea to coastal areas. Other biological information that should be borne in mind for correct management of fishery activities and protection of stocks concerns reproduction. Both anchovies and sardines produce several batches of pelagic eggs in a single spawning season. In general, anchovies reproduce during the warmer months and sardines during the colder months, even if the latter are generally considered as having a reproductive season that tends to be longer than that of anchovies, covering practically most of the year. With reference to the Adriatic Sea, the reproduction period for anchovies is from April to October, with a peak in July and August; sardines, reproduce from

132 First section - Chapter 2 - Ecological aspects October to April or May, with a greater intensity in December and January, although some authors also indicated the presence of spring peak (Morello & Arneri, 2009). The horizontal migrations mentioned above may be related not only to the availability of food but also to the reproductive phase. In the Adriatic Sea, the reproduction areas for anchovies are essentially located in the western part of the basin, particularly in coastal waters. The main reproduction areas for sardines are in deep-waters off the eastern coast, approximately to the north and south of the Pomo depression. A certain separation of reproductive events is therefore observed for the two species, both in terms of time and space. It is very important for the management of stocks to know the size (and age) at which a species reaches sexual maturity. This seems to depend on various factors, including temperature and the availability of food, so that estimates of the body length at which 50% of the individuals have reached maturity tend to vary. For Adriatic anchovies, for example, this parameter has been estimated at around 8 cm.

Fishing These species are fished using: 1) seine nets for catching juveniles (no longer authorised since 2011), mainly in Sicily and the Ligurian, Tyrrhenian and Ionian seas, 2) pairs of boats with pelagic trawl nets (known as “volanti”), found almost exclusively in the Adriatic Sea, 3) purse seiners that use light sources to attract the fish (known as “lampare”), 4) boats with trawl nets, which contribute significantly to catches of species of the genera Scomber and Trachurus. On the basis of estimates provided by Irepa, landing of anchovy in 2010 amounted to 54,000 tonnes, of which 39,000 came from the Adriatic Sea; the figure reported for sardine is 16,000 tonnes, of which 8,000 came from the Adriatic Sea and 7,000 from the Tyrrhenian Sea; of the 1,000 tonnes of round sardinella, 800 came from the Tyrrhenian Sea, especially the southern part; finally, the 160 tonnes of sprat were all caught in the Adriatic. The high figures for small pelagic fish landings in the Adriatic Sea mentioned above are mainly due to the central and northern part of the area. This is particularly productive in general and various resources are shared by Italy, Croatia and Slovenia. According to the studies by CNR- ISMAR in , the average figure for the annual total of anchovies catches in the three-year period 2007-09 was 44,000 tonnes, of which 70% was attributed to the Italian fleet: this figure is close to the historical maximum recorded from 1975 to the present, namely in the period 1978- 80, when over 50,000 tonnes were landed; the historical minimum was in 1987, when there was a genuine collapse in stock, with less than 5,000 tonnes. Also according to CNR-ISMAR of Ancona, for sardines, the maximum figure for total sardine catches of sardine reached as high as 90,000 tonnes in 1981, after which there was a continuous decline until the minimum of 19,000 tonnes was recorded in 2005; the average value for the three-year period 2007-09 was 26,000 tonnes, of which, unlike with anchovy, only 14% was due to the Italian fleet. Regarding the regulation of the fishing activity, it should be noted that, in addition to the summer closure period, which includes “volanti” but not “lampare”, minimum sizes have been established for landed catches: anchovy fishing is prohibited for specimens less than 9 cm in length, without exceptions for juveniles, whereas the limit for sardine is 11 cm (reg. (CE) 1967/2006) and fishing for sardine juveniles (“bianchetto di sardina”) has been authorised with certain restrictions in the past.

133 Assessment of the state of stocks CNR-ISMAR in Ancona has been carrying out assessments for years on the state of anchovy and sardine stocks in the Central and Northern Adriatic Sea, applying population dynamics methods to temporal series starting from the mid-1970s. These methods are based on mathematical models (e.g. Virtual Population Analysis, or VPA) that mainly require capture data divided according to age classes and estimates of natural mortality rates (i.e. not due to fishing) and they produce estimates of stock biomass in the sea and of mortality rates due to fishing. According to these estimates, the anchovy stock has returned to the levels prior to the collapse in 1987 (figure 2.47), which was probably not caused by fishing alone but also by other variables connected with the environment and/or interaction with other species (Santojanni et al., 2006; Leonori et al., 2009); a clear decline in the sardine stock can be seen from the same figures, although the trend in recent years allows cautious optimism. Also in the mid-1970s, in the same area, CNR-ISMAR in Ancona began carrying out surveys at sea using acoustic methods to assess abundance (these estimates are used in the VPA calculations mentioned above) and the spatial distribution of anchovy, sardine, sprat (target species) and of other small pelagic species, the biomass of which is estimated comprehensively. Since 1987, these surveys have also covered the Southern Adriatic Sea (figure 2.48).

600,000 1,200,000

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400,000 800,000

tonnes tonnes 300,000 600,000

200,000 400,000

100,000 200,000

0 0 ‘75 ‘79 ‘83 ‘87 ‘91 ‘95 ‘99 ‘03 ‘07 ‘75 ‘79 ‘83 ‘87 ‘91 ‘95 ‘99 ‘03 ‘07

Total catches Stock biomass

Figure 2.47 - Biomass estimated with VPA and total catches of anchovy (left) and sardine (right) in the Central and Northern Adriatic Sea.

0,25000 0,21875

1340,18750First section - Chapter 2 - Ecological aspects 0,15625

0,09375 0,06250 0,03125 0,00000

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80 80

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t/nm t/nm

40 40

20 20

0 0 ‘76 ‘80 ‘84 ‘88 ‘92 ‘96 ‘00 ‘04 ‘08 ‘87 ‘91 ‘95 ‘99 ‘03 ‘07

Anchovy Sardine

Figure 2.48 - Biomass density trends (t/nm2) for anchovy and sardine in the Northern Adriatic Sea (left) and Southern Adriatic Sea (right), based on acoustic methods.

Since 2003, CNR-ISMAR in Ancona has been using a system for gathering data (Fishery Observing System, or FOS) (Falco et al., 2007) on the capture of small pelagic fish in relation to individual fishing hauls made by “volanti” and “lampare” in the Adriatic Sea: it is therefore possible to know the route of the fishing unit, its geographical location, the temperature and depths at which the nets have fished, the quantity captured and the size (average number of specimens in 1 kg) for those boats on which the FOS is installed. The study of small pelagic fish in the Ligurian and Northern Tyrrhenian seas by the former Institute of Marine environmental sciences in Santa Margherita Ligure, now known as DIPTERIS, began in 1985. Since 1998, with the introduction of the Daily Egg Production Method, or DEPM, the annual abundance of spawning stock has been assessed through an analysis of the reproductive capacity 0,25000 of adults and the natural mortality of larval forms. Following these studies, anchovy biomass 0,21875estimates are now available from 1999 to 2001 and from 2004 to 2008 (Melià et al., in press). 0,18750CIBM in Livorno has also carried out some studies on small pelagic fish in the Ligurian and 0,15625Central-northern Tyrrhenian seas, not only using population dynamics methods but also examining data from the Medits trawler surveys. Although these surveys were aimed at the assessment of 0,09375demersal resources, the net that was used (with large vertical openings) also allowed a systematic 0,06250capture of small pelagic species. The abundance indices (kg/km2) obtained from 1994 to 2008 0,03125for both anchovy and sardine were compared with the data on landed catches from ISTAT and 0,00000then Irepa, considering that the respective fishing effort remained relatively stable during that period. A positive correlation was observed between landed catches and abundance indices in the case of anchovy, but not for sardine; the latter was not the main target species of the fleet and could be thrown back into the sea when there were large catches of anchovy. Since 1997, CNR-IAMC in Capo Granitola has been gathering data on landed catches of anchovy and sardine together with the respective fishing effort, in the harbour of Sciacca, which is the main one for small pelagic fisheries in the Strait of Sicily. Since 1998, the same Institute has been conducting annual assessments of the abundance of the two mentioned species. The methodologies used for this purpose mainly involve sea surveys with the use of acoustic 0,12500

135 methods. The Daily Egg Production Method (fig. 2.49) has also been applied for various years for anchovy. An important aspect has observed in the fact that the DEPM estimates show a trend not very different from that obtained using acoustic methods, although lower levels may be given in terms of absolute abundance; this discrepancy is nevertheless expected, since DEPM only permits estimates of the portion of the population that is reproducing, whereas acoustic methods assess a wider proportion.

40,000 40,000

30,000 e 30,000

in

rd

20,000 20,000

onnes of anchovy of onnes sa of onnes

T T

10,000 10,000

0 0 ‘98 ‘00 ‘02 ‘04 ‘06 ‘08 ‘98 ‘00 ‘02 ‘04 ‘06 ‘08

Total catches Acoustic biomass DEPM biomass

Figure 2.49 - Biomass and total catches of anchovy (left) and sardine (right) in the Strait of Sicily. The anchovy biomass was estimated both with acoustic methods and DEPM.

Similarly to what was seen in the two figures for the estimates obtained for the Adriatic Sea, the abundance levels for stocks of anchovy and sardine in the Strait of Sicily show wide fluctuations (Patti et al., 2004). In general, this can include a reduction in stock levels, even over a brief period. Thus, even though if the population dynamics of the species may be heavily influenced by environmental factors and interaction with other species, the monitoring of catches and the fishing effort always provides very important information for the management of stocks.

References - Checkley D., Alheit J., Oozeki Y., Roy C. (eds). (2009) - Climate change and small pelagic fish. Cambridge University Press, New York: 381 pp. 0,25000- Falco P., Belardinelli A., Santojanni A., Arneri E., Cingolani N., Russo A. (2007) - An observing system for the collection of fishery and oceanography data. Ocean Sci., 3: 189-203. 0,21875- Fréon P., Cury P., Shannon L., Roy C. (2005) - Sustainable exploitation of small pelagic fish stock challenged by 0,18750environmental and ecosystem changes: a review. Bull. Mar. Sci., 76: 385–462. 0,15625- Leonori I., Azzali M., De Felice A., Parmiggiani F., Marini M., Grilli F., Gramolini R. (2009) - Small pelagic fish biomass in relation to environmental parameters in the Adriatic Sea. Proceedings of Joint AIOL-SItE Meeting, Ancona, 17-20 September 2007: 213-218. 0,09375- Morello E.B. & Arneri E. (2009) - Anchovy and sardine in the Adriatic Sea: an ecological review. Oceanogr. Mar. Biol. Annu. Rev., 47: 209-256. 0,06250- Patti B., Bonanno A., Basilone G., Goncharov S., Mazzola S., Buscaino G., Cuttitta A., Garcia Lafuente J., Garcia A., 0,03125Palumbo V., Cosimi G. (2004) - Interannual fluctuations in acoustic biomass estimates and in landings of small pelagic 0,00000fish populations in relation to hydrology in the Strait of Sicily. Chem. Ecol., 20: 365-375. - Melià P., Petrillo M., Albertelli G., Mandich A., Gatto M. (2012) - A bootstrap approach to account for uncertainty in egg production methods applied to small fish stocks. Fish. Res., 117-118: 130-136.

136 First section - Chapter 2 - Ecological aspects

0,12500 - Santojanni A., Arneri E., Bernardini V., Cingolani N., Di Marco M., Russo A. (2006) - Effects of environmental variables on recruitment of anchovy in the Adriatic Sea. Clim. Res., 31: 181-193. - Sbrana M., De Ranieri S., Ligas A., Reale B., Rossetti I., Sartor P. (2010) - Comparison of trawl survey and commercial data on small pelagics from the FAO Geographic Sub-Area 9 (Western Mediterranean). Rapp. Comm. int. Mer Medit., 39: 658. 2.5 The state of large pelagics Di Natale A., Addis P., Cau A., Garibaldi F., Piccinetti C., Orsi Relini L.

General The large pelagic fisheries and particularly those fishing on Scombrids have very ancient traditions in Italy. The most ancient is certainly the bluefin tuna (Thunnus thynnus) fishery, carried out since pre-historical ages, than becoming the main fishing industry in the Mediterranean Sea since the Phoenician time, using traditional tuna traps. The past century showed very relevant changes in this fishing activity, with a progressive and important reduction of the traditional tuna traps and an increasing interest by markets and consumers for other large pelagic species, especially swordfish (Xiphias gladius) and, in a reduced manner, albacore (Thunnus alalunga), but also for other species. The central geographic position of Italy in the Mediterranean Sea makes easier fishing for all large pelagic species, using all known Mediterranean métier.

Management All and tuna-like species in the Mediterranean Sea and the Atlantic Ocean are under the management and competence of the International Commission for the Conservation of Atlantic Tunas (ICCAT), based in Madrid; its competences include also other by-catch species, such as pelagic sharks. The management regulations (Recommendations) issued by the ICCAT are automatically enforced by all Contracting and Cooperating Parties (CPCs) and, being the an ICCAT Contracting Party, they are directly enforced also in Italy, in agreement with art. 12 of the Lisbon Treaty. The General Fishery Commission for the Mediterranean (GFCM), the European Commission or individual States can also adopt more restrictive regulations. Driftnet fishery for large pelagics was banned since January 1st, 2002. Periodically the ICCAT Standing Committee for Research and Statistics (SCRS) carries out the assessment of various stocks, based on the data provided by all CPCs. In Italy the research on large pelagic species is coordinated by the Direction General for Sea Fishery, often through a national ad hoc scientific coordination.

The bluefin tuna (Thunnus thynnus) fishery (BFT) Before the establishment of seasonal closures, the bluefin tuna fishery in Italy was carried out all year round. In late autumn and winter the fishery was mostly targeting intergenetic bluefin tunas belonging to the stock component staying more than one year in the Mediterranean Sea. In spring and summer the fishery was mostly targeting spawners, while in late summer and in autumn the fishery was mostly targeting juvenile bluefin tunas. This situation changed in recent years after the enforcement of seasonal closure regulatory measures. The evolution of the bluefin tuna fishery in Italy in the last century was complex. Progressively, it went from a fishery based on many traditional tuna traps and minor catches made by hand

137 lines, driftnets and harpoons to a much high variety of fishing gear starting from the ‘60s. As a matter of fact, while the number of tuna traps was decreasing mostly due to socio-economic and environmental factors, the purse-seine fishing was becoming more important, in a way that most of the production was there, replacing all other gears; the aerial spotting, started in 1978 and used up to its ban in 2006, has a fundamental importance in increasing the productivity of the purse-seine fleet. Harpoon catches decreased in parallel with the fleet decreasing, while hand-line catches were spread all around the coasts, always remaining not well defined and often including important quantities of juvenile bluefin tuna catches by non-professional fishers. The driftnet fishery was mostly targeting juvenile bluefin tunas, while the longline fishery was mostly developed at the end of the ‘60s and expanded from the ‘80s. The bluefin tuna target by the Italian fishery belongs to the Eastern Atlantic stock (BFTE). Since 1998 a bluefin quota system was enforced by ICCAT. Historically, Italy is the country reporting the highest catches in the Mediterranean Sea, with peaks over 10,000 tonnes in 1976 and 1996 (figure 2.50).

12,000

10,000

8,000

tonnes 6,000

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2,000

0

1950 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

BFT other gears BFT tuna traps BFT lines BFT purse seines BFT longline

Figure 2.50 - Bluefin tuna (Thunnus thynnus) catches in tonnes reported by Italy to ICCAT from 1950 to 2010. (Source: ICCAT data base).

The bluefin tuna quota set by ICCAT for Italy in 2011 was 1,787.91 tonnes The stock outlook is still affected by the important overfishing from the ‘90s to 2006 (figure 2.51), besides the data used were defined as not reliable by the SCRS. More recent data show a clear progressive recovery, also increased by a high recruitment induced by favorable climate factors since 2003.

138 First section - Chapter 2 - Ecological aspects F F 2-5 10+ 0.4 0.4

0.3 0.3

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0 0 1950 1960 1970 1980 1990 2000 1950 1960 1970 1980 1990 2000

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Run 13 Run 15

0,25000 0,21875Figure 2.51 - Eastern bluefin tuna (Thunnus thynnus) stock assessment, including the Mediterranean Sea. The assessment includes the fishing mortality at age 2-5 (F2-5) and up to over 10 years (F10+), the spawning 0,18750biomass in tons (SSB) and the recruitment in number. Run 13 and Run 15 are the scenarios selected by SCRS 0,15625(Source: ICCAT-SCRS 2010).

0,09375The albacore (Thunnus alalunga) fishery (ALB) 0,06250The albacore fishery has also historical roots: catches were reported by traditional tuna traps in 0,03125the last five centuries, while specific gears were developed mostly in the Tyrrhenian Sea fisheries 0,00000since the XVIII century. Actually the fishery is mostly concentrated along the southern Italian coasts, while sporadic catches are reported everywhere. Since even, the albacore fishery concerns medium-size specimens, while juveniles are practically absent in all fisheries and specimens over 120 cm are rare. The albacore fishery is carried out mostly in spring and autumn, with relevant catches also in summer. It was mostly carried out by driftnets until their ban, while now the main fishing gear is the albacore longline. Italy is the country reporting the highest catches to ICCAT in the Mediterranean Sea, with peaks over 4,500 tonnes in 2004 and 2006 (figure 2.52). 0,12500

139 5,000

4,500

4,000

3,500

3,000

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tonnes 2,000

1,500

1,000

500

0

1950 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

ALB other gears ALB longlines

Figure 2.52 - Albacore (Thunnus alalunga) catches in tonnes, riportated by Italy to ’ICCAT between 1950 andl 2010 (Source: ICCAT data base, adapted).

The state of the Mediterranean albacore stock was assessed for the first time by ICCAT in 2011 and it was considered as not overexploited (figure 2.53).

Med 5, B/Bmsy Med 5, F/Fmsy 2.0 1.0

0.8 1.5

0.6 1.0 0.4

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0.0 0.0 1970 1980 1990 2000 2010 1970 1980 1990 2000 2010

Med 8, B/Bmsy Med 8, F/Fmsy 2.0

0.6 1.5

0.4 1.0

0.5 0.2

0.0 0.0 1970 1980 1990 2000 2010 1970 1980 1990 2000 2010

Figure 2.53 - Mediterranean albacore (Thunnus alalunga) stock assessment. Med 5 and Med 8 are the scenarios chosen by the SCRS. B/Bmsy is the ratio between total biomass and the biomass at maximum sustainable yield; F/Fmsy is the ratio between total fishing mortality and fishing mortality at the maximum sustainable yield (Source: ICCAT-SCRS 2011).

140 First section - Chapter 2 - Ecological aspects The swordfish (Xiphias gladius) fishery (SWO) The swordfish fishery and particularly the harpoon fishery traditionally carried out in the Strait of Messina have very ancient traditions in Italy. The main catches, in old times obtained by harpoon fishery and also by tuna trap fishery, in the last two centuries and up to 2002, were also the result of the driftnet fishery. Swordfish driftnet catches became the large majority from the ‘60s, and then swordfish fishery also became relevant in the ‘70s, getting the majority of the catches in more recent years. The Italian swordfish driftnet fleet was the largest one in the Mediterranean Sea and it reached a peak of about 800 vessels, while the longline fishery progressively reached about one thousand vessels. The swordfish longline fishery changed in the last years, when the deep longline was introduced, substituting the traditional surface pelagic longline; this shifting induced also relevant catches of large swordfish spawners, with undefined effects on the stock status. Swordfish fishery is traditionally carried out in all Italian seas for all age classes and all year round, except for the closed season recently enforced by ICCAT. Also for the swordfish, Italy is the country reporting the highest catches to ICCAT for the Mediterranean Sea, with a peak of 13,000 tonnes in 1988 (figure 2.54).

14,000

12,000

10,000

8,000

tonnes 6,000

4,000

2,000

0

1950 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

SWO other gears SWO longlines

Figure 2.54 - Swordfish (Xiphias gladius) catches in tonnes obtained by longlines and other gears as they were reported by Italy to ICCAT from 1950 to 2010 (Source: ICCAT data base).

The Mediterranean swordfish stock was assessed again by ICCAT in 2010. According to the available data, the stock is overfished but with signs of a recent and partial recovery (figure 2.55).

141 REC SSB

140

1,400,000 100

60 1,000,000

20 1985 1990 1995 2000 2005 1985 1990 1995 2000 2005

CATCH HARVEST

20 0.6

0.5

0.4 16 0.3

0.2

12 0.1 1985 1990 1995 2000 2005 1985 1990 1995 2000 2005

Figure 2.55 - Mediterranean swordfish (Xiphias gladius) stock assessment. The red line shows age 5+ group, while the green line shows the age 10+ group. REC: Recruitment in number of individuals;SSB: Spawning Stock Biomass in thousands of tonnes; CATCH: Total catch in thousands of tonnes as officially reported to ICCAT; HARVEST: Fishing mortality (F) (Source: ICCAT-SCRS 2010). 0,25000 0,21875 The0,18750 fishery of small tuna and tuna-like species The0,15625 Italian fishery is also getting relevant quantities of Atlantic bonito (Sarda sarda), bullet tuna (Auxis rochei), (Euthynnus alletteratus), skipjack tuna (Katsuwonus pelamis), Mediterranean spearfish (Tetrapturus belone) and other species having small interest or which 0,09375 are uncommon (Di Natale et al., 2009). The catches of all these species before the enforcement of0,06250 the EC Data Collection Framework were not well known, because often they were not included in0,03125 the statistical system. Their fishery is usually artisanal but having a high socio-economical relevance;0,00000 after the driftnet ban, the fisheries are carried out mostly by longlines and handlines. The assessment of the various species and stock were never carried out. The total combined catches reported by Italy to ICCAT peaked up to 7,000 tonnes in 2002, but it is commonly believed that they are heavily underestimated (figure 2.56).

0,12500

142 First section - Chapter 2 - Ecological aspects 8,000

7,000

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tonnes 4,000

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0 1960 1961 1962 1963 1965 1966 1967 1968 1969 1970 1971 1972 1973 1975 1976 1977 1978 1979 1980 1981 1982 1983 1985 1986 1987 1988 1989 1990 1991 1992 1993 1995 1996 1997 1998 1999 2000 2001 2002 2003 2005 2006 2007 2008 2009 2010 1964 1974 1984 1994 2004

Pelagic sharks Small tunas Other tuna-like

Figure 2.56 - Catches in tonnes of pelagic sharks (15 species), small tunas (3 species) and other tuna-like species (5 species, including the Mediterranean spearfish) as reported by ICCAT to ICCAT from 1960 to 2009 (Source: ICCAT data base). 8,000 The 7,00large0 pelagics fishery in the Adriatic Sea The fishery6,000 for large pelagic species in the Adriatic Sea has a long history particularly for the bluefin5,00 tuna,0 which was historically caught for more than a century by simple tuna traps along the North-westerntonnellate 4,000 Adriatic coast. Since over 60 years there is a purse-seine fishery from March to October targeting juvenile bluefin tunas. This fishery originated in Trieste, then developed also 3,000 in Porto Garibaldi, , and Pescara with various results and with technological adaptations2,000 to the characteristics of the different vessels (usually having a modest size), the hauling1,00 systems0 and the fish-schools searching tools.

Actually, 0the Italian purse seine fishery in the Adriatic Sea is no longer carried out, because no quota is available, while a Croatian fleet has still been active fore more than 10 years, and this fleet transfer 1960 all catches1962 1964 1966 to1968 fattening1970 1972 cages1974 1976 to1978 sell1980 them1982 1984 later1986 on1988 the1990 market.1992 1994 1996 A long1998 2000 line2002 fishery2004 2006 was2008 2010 developed about5-Sharks all (other) year - WS roundH in Fano5-Sharks and(other) San - SDS Benedetto5-Sharks del (other) , - ALV and then2-Tu naprogressively (small) -LT A 5-Sharks (other) -SY T 5-Sharks (other) - SBL 4-Sharks (major) - POR 2-Tuna (small) - BON reduced due 5-Sharksto the (other) quota -SY Csystem. Other5-Sharks bluefin(other) - GA Utuna fisheries4-Sharks exist (major) are - BSH activein the2-Tuna Adriatic (small) - BLT Sea, 5-Sharks (other) - SPZ 5-Sharks (other) - DGZ 3-Tuna (other) - TUN 1-Tuna (major sp.) - SPF with troll lines5-Sharks or pole (other) lines - SMD with bait,5-Sharks both (other) as professional - DGS 3-andTuna (other)sport - MSPfishery. Bluefin1-Tuna tuna (major catches sp.) - SKJ were very variable5-Sharks in(other) the - SHAdriaticO Sea,5-Sharks reaching (other) -CC Pover 1,0003-Tu natonnes (other) - KAinW some years for the Italian catches only. The bluefin tuna fishery carried out by some pelagic longline vessels from Sicily in South Adriatic Sea showed the possibility to catch also swordfish, a species not fished before by Adriatic fishers because they were not using any fishing gear able to catch it. Currently the longline swordfish fishery is carried out in North and central Adriatic Sea by the same longliners targeting bluefin tuna. The traditional albacore fishery is carried out by pelagic longliners in South Adriatic between September to November, targeting 4 to 8 kg albacores. Sporadic catches of larger size albacore of little tunny are reported by small purse seiners and tuna longliners. The Atlantic bonito fishery is opportunistic and carried out mostly by recreational fishers. The large pelagics fishery risks to disappear in the Adriatic sea because of new regulatory measures impeding the existing activities besides the presence of biological resources; in

143 recent years, fishing efforts and catches by vessel are conditioned by regulations and not by the abundance of target species. As far as concerns the species biology is concerned, the presence of bluefin tuna spawners is well known in South and central Adriatic Sea and, according to the literature, mature bluefin tuna were fished also in the Gulf of Fiume. The Adriatic Sea, thanks to its high productivity and the abundance of small pelagics, is a trophic concentration area, used mostly by juvenile bluefin tunas. The correlations between central-southern Adriatic swordfish and Ionian Sea swordfish is not known, but juvenile swordfish-of-the-year are frequently caught by the albacore fishery in fall.

The large pelagics fishery in the Southern Italian Seas The Ionian Sea, the Strait of Sicily and the Tyrrhenian Sea are historical areas for the large pelagic fishery and many activities in this sector were originated in the southern Italian seas. Bluefin tuna fishery was carried out with tuna traps along the coast, but some years ago even the last tuna trap in Favignana was closed down after a series of low catches. Since the ‘60s a fleet of powerful tuna purse seiners was developed mostly in Campania and Sicily, large vessels using tuna seines that were the most productive sector of the Italian tuna industry. These vessels were targeting big bluefin tuna spawners in May-July and the fleet was then moving to the Ligurian Sea and the targeting juveniles in late August-October. More recently, due to more strict ICCAT rules, this fleet was considerably reduced and the individual quota can be reached in one single day of activity by a vessel during the one-month fishing season established by ICCAT (15 May-15 June). Bluefin tuna catches, that before were all landed, allowing also important statistical records, are now moved into fattening cages which are located in the South Tyrrhenian Sea or abroad. At the same time, a tuna pelagic longline fleet was progressively developed, initially active in late winter, spring and autumn targeting adult bluefin tuna and now active only in the first six months of the year, getting important catches. Minor catches are obtained by the harpoon fishery in the Strait of Messina and by thousands of very small vessels with hand lines or troll lines, spread everywhere and difficult to monitor and control, often managed by non-professional fishers. The albacore fishery also showed important changes. Traditionally carried out in the central- southern Tyrrhenian Sea, this fishery was progressively extended to the Ionian Sea areas, at the beginning along the areas off Catania and then to the Calabrian and Apulia waters, while no catches were made in various decades in the Strait of Sicily. The albacore fishery was historically carried out by driftnets (“palamitare” and “alalungare”), while now is exclusively using surface longlines with small-medium hooks. Important amounts of albacore catches in the last decade are from the Lybian fishing grounds, but all those fish are landed at the home ports in Sicily. The swordfish fishery is carried out since centuries in the southern Tyrrhenian Sea and in the Strait of Messina. The traditional harpoon fishery is limited now to a very few vessels, while the historical driftnets fishery (“spadare”), which were diffused everywhere in Campania, Calabria, Sicily and Apulia including all minor islands and which was able to provide the majority of the fish for the market, is now banned. At the same time, even the swordfish by-catch usually obtained by the tuna traps disappeared along with those traps. The swordfish longlines, initially developed by fishers in Catania areas, were spread everywhere but particularly in Trapani areas. Currently swordfish longliners are active all year round (except for

144 First section - Chapter 2 - Ecological aspects the closed season), bringing on the national market medium-big swordfish. The fishery carried out by small vessels with longlines equipped with small hooks for illegally catching juvenile swordfish, which was very common in the past, is now considerably limited. The small tunas and tuna-like species, including the Mediterranean spearfish in recent times, are also very important in the southern Italian seas. The small tunas fishery is carried out by hundreds of small vessels using hand lines or longlines and it has a very high socio-economic relevance, particularly for Sicilian and Calabrian coastal communities.

The large pelagics fishery in Sardinia The large pelagic fishery in Sardinia concerns almost exclusively bluefin tuna, which is caught by traditional tuna traps. The origin of this fishing activity in the isle is at the end of the XV century, under the Spanish domination. Only two out of the original 24 Sardinian tuna traps are currently active, one on the Isle of San Pietro and the other in Portoscuso, the last remaining active traps in the Mediterranean Sea. The typical “di corsa” trap type was substituted by the Spanish trap type in the ‘90s, because it is more easy to maneuver it, allowing for a higher number of fishing operations (“mattanza”) and, consequently, to more properly manage the delivery of fresh tuna on the market. The actual trap is made of 5 chambers: big, “bordonaro”, bastard, chamber and death chamber. The bluefin tuna quota attributed to the two Sardinian traps in 2011 was 140 tonnes. Catches in number of tunas from 1950 to 2010 shows a variable trend between 1950 to 1970, followed by a negative trend until 1980, when the trap activity was interrupted (figure 2.57).

4,000

3,500

3,000

2,500

2,000

1,500

1,000

500

0 1950 1955 1960 1965 1970 1975 1980 1995 2000 2005 2010

IP PS

Figure 2.57 - Bluefin tuna (Thunnus thynnus) catches in number of individuals in the Sardinian traps of Isola Piana (IP) and Portoscuso (PS) in 1950-2010.

The trap fishery restarted again in the early ‘90s, with a private management which paid much more attention to the economic results compared to the previous management. Since that time there is a constant production increasing, with reached a peak of 250 tonnes in 2010. The large part of the catches is sold fresh on local and Italian markets. The export to Japan had an important role for relaunching the trap activity in the ‘90s (figure 2.58). The two tuna traps are currently employing a staff of about 400, either directly or indirectly employed; furthermore,

145 0,25000 0,21875 0,18750 0,15625

0,09375 0,06250 0,03125 0,00000

0,12500 they attract a high number of tourists and visitors in the area, also through country festivals and gastronomic events such as “Girotonno”.

2010

2009

2008

2007

2006

2005

2004

2003

0% 20% 40% 60% 80% 100%

Japan Italy Spain Canning Other

Figure 2.58 - Main markets of bluefin tuna (Thunnus thynnus) caught by Sardinian traps.

The large pelagic fishery in the Tuscany-Ligurian area Bluefin tuna, swordfish, Atlantic bonito and bullet tuna are the most important large pelagic species in this area. The bluefin tuna is fished since prehistoric times in the Ligurian Sea, but written documents are related mostly to tuna traps since the XVII century. Among the traps which were active in the past century (Porto S. Stefano, Enfola and Bagni di Marciana on Elba Isle, Baratti and Camogli) (Parona, 1919), only the latter is still set and used according to ancient traditions. As a matter of fact, it is a type of trap diffused with many replicates from Marseille to Monterosso, targeting juvenile bluefin tunas which are the main component of the stock in this area. This small tuna trap (“tonnarella”) survived thanks to its artisanal structure and the daily activity able to provide over 40 different species of pelagic fish. 0,25000Since the mid-‘70s purse-seine fisheries was developed in the offshore areas, with high catches 0,21875(up to 1,000 tonnes in 1999); this activity was carried out not only by a few local vessels, but 0,18750also by French tuna fleets and those from the southern Italian areas, which were used to close their fishing season in the Ligurian Sea in late summer and fall. A variable portion of annual catch 0,15625 was obtained by pelagic longliners or as a driftnet fishery by-catch or by sport fishers, but the current regulations and particularly the minimum size of 115 cm caused an almost total reduction 0,09375of these fisheries (Orsi Relini et al., 2010). Juvenile bluefin tunas, belonging to 1 to 4 age classes, 0,06250usually found an important trophic area in the Ligurian Sea, thanks to two main food sources: 0,03125small pelagic species and krill (Meganyctiphanes norvegica). 0,00000The swordfish fishery was initially introduced in the Ligurian Sea in the ‘50s, by pelagic longliners. The traditional fishing season was from May to December, slightly anticipated in the Tuscany areas and in the Elba Isle, with the highest peak in August-September, delayed along the western Ligurian areas where the highest activity and catch were reported from August to October. The

146 First section - Chapter 2 - Ecological aspects 0,12500 total number of vessels was always very limited, but actually there are about 55-60 vessels in all the area, almost all carrying out the recently developed deep-longline swordfish fishing. Driftnet fishery (“spadare”) was very common in the late ‘90s. The total Ligurian driftnet vessels were 17 in 1990, but many other vessels were coming from the southern Italian areas to the Ligurian Sea from August to September for closing their fishing season; this too high fishing pressure, which also included a by-catch of cetaceans and other protected species, certainly contributed to the creation the Ligurian marine mammal sanctuary.

References - Di Natale A., Srour A., Hattour A., Keskin Ç., Idrissi M., Orsi Relini L. (2009) - Regional study on small tunas in the Mediterranean including the Black Sea. Studies and Reviews. General Fisheries Commission for the Mediterranean, 85. FAO, Rome: 132 p. - Iccat (2011) - Report for Biennal period, 2010-11. Part 1 (2010),1, Madrid: 391 p. - Iccat - Scrs (2011) - Report for Biennal period, 2010-11. Part 1 (2010),2, Madrid: 265 p. - Orsi Relini L., Palandri G., Garibaldi F., Relini M., Cima C., Lanteri L. (2010) - Large pelagic fish, swordfish, bluefin and small tunas, in the Ligurian Sea: biological characteristics and fishery trends. Chem. Ecol., 26: 341-357. - Parona C. (1919) - Il tonno e la sua pesca. Venezia. R. Comitato Talassografico Italiano, Memoria LXVIII: 259 p. 2.6 Clam fishery with dredges Arneri E., Piccinetti C.

Commercial clam fishery has been taking place in the Adriatic Sea for more than two centuries, whilst manual collection for subsistence has been active for millennia. The first written record of clam fishing (C. gallina) along the Adriatic Sea is found in 1792 (Olivi). In that period clams caught in the were exported to the Papal Territories. A constant and continuous technological evolution, starting from rowing boats with manual rakes, brought in the last forty years to hydraulic dredges (Froglia, 1989). Hydraulic dredgers are rather homogeneous fishing vessels, their present number is about 700 (Tab. 2.18). The crew is normally of 2. The gross saleable production of this fishing fleet is 4.7% of the entire Italian saleable fish production (Tab. 2.19). The overall annual landings are about 30.000 tonnes (11,5% of the entire Italian landings of marine fisheries). The main harvested species is the baby clam (Chamelea gallina) but also razor clam (Ensis minor) and smooth clam (Callista chione) are landed.

Photo by M. Martinelli.

147 Table 2.18 - Hydraulic dredgers by region, 2009.

N GT Engine Power (kW) Lazio 22 217 2,302 Campania 15 154 2,084 Puglia 76 819 7,544 Abruzzo 103 1,597 11,148 Molise 9 96 967 Marche 218 3,363 23,201 Emilia Romagna 54 785 5,610 Veneto 162 1,821 17,875 F.V.Giulia 41 437 4,770 Total 700 9,289 75,500

Source: MiPAAF.

Most of the fleet is concentrated in the Adriatic Sea and in particular in Marche (31%) and Veneto (23%). In the Tyrrhenian Sea the few hydraulic dredges harvest mainly razor clams (Ensis minor) in shallow waters (2 to 6 metres).

Table 2.19 - Summary of statistics per , hydraulic dredger, 2009.

Average value per vessel Fishing days in a year 87 Daily landings (kg) 321.3 Daily revenue (euro) 1036.1 Annual landings (t) 28 Annual revenue (thousands of euro) 90 Wholesale price per kg (euro) 3.22

Source: elaboration of Irepa data.

Moreover in the Thyrrenian Sea there are 144 fishing vessel using manual dredges (rakes) targetting “telline” (Donax trunculus, wedge shells).

Table 2.20 - Fishing boats authorised to use manual dredge by region.

N GT Engine Power (kW) Toscana 22 24 224.09 Lazio 86 120 1644.8 Campania 36 46 540.55

Source: MiPAAF.

Fishing days for this category of fishing boats range between 96 to 126 with an average daily production (landings) of 29 kg per vessel and a total annual value of about 26,600 Euro. Wedge shells “telline” can reach 10 Euro/kg wholesale price.

148 First section - Chapter 2 - Ecological aspects Table 2.21 - Average values per fishing boat with manual dredge, in Campania and Lazio, 2009.

Average value per vessel Fishing days 95.7 Daily landings (kg) 29.3 Daily revenue (euro) 278 Annual landing (kg) 2,807 Annual revenue (euro) 26,623 Wholesale price (euro) 9.48

Source: elaboration of Irepa data.

The present management of dredge fisheries is the result of a long process of refinement and negotiation among the National Administration (Italian Directorate for Fisheries) and local fishermen organized in consortia “Consorzi di Gestione” on a fishing district (Compartimento Marittimo) basis. General rules are decided at national level by the Italian Directorate for Fisheries of MiPAAF, whilst locally Consortia can adopt stricter regulations in particular regarding: • gear characteristics, fishing time and daily quotas per vessel; • restocking with juveniles • rotation of fishing areas inside the fishing district; • market policies to avoid drop in prices due to oversupply; • control, surveillance and sanctioning; Moreover the Consortia cooperate with the Administration and with research Institutions towards a rational management of this resource. In this context the Consortia establish daily quotas (below the maximum limit set by the national law) equal for each vessel in order to tune the total amount landed with resource availability and market demand. Thus the number of hours spent fishing daily, the quota landed per vessel and the area are decided in advance for the entire fleet. Some areas from time to time are closed to fishery and are restocked with seed (juvenile individuals) from other areas, in order to let them grow. In this way this fishing activity has much in common with extensive fish farming. The Consortia have a day to day knowledge of the state of the resource which is annually improved by a general prospection carried outd by a research Institute, performed with a sampling gear similar to the commercial dredge (Paolini et al., 1998; Froglia, 2000). Overall clam fishing with dredges had a great development in recent times as it responds to the social and economic needs of modern fishermen: reduced time at sea and high mechanization of fishing operation, together with a form of co-management which enables quick decision in order to tune the catch to the situation of the resource and of the market demand.

References - Froglia C. (1989) - Clam fisheries with hydraulic dredges in the Adriatic Sea. In Marine invertebrate fisheries: their assessment and management. (Caddy J.F., ed), pp. 507-524. John & Sons: New York. - Froglia C. (2000) - Il contributo della ricerca scientifica alla gestione della pesca dei molluschi bivalvi con draghe idrauliche. Biologia Marina Mediterranea 7: 71-82. - Paolini M., Piccinetti C., Soro S. (1998) - Stock di vongole (Chamelea gallina, L.) nel compartimento marittimo di (1984-1995). Biologia Marina Mediterranea 5: 404-411.

149 2.7 Biodiversity: a great heritage 2.7.1 Marine biodiversity Boero F.

After a long period of junction with the Indo-Pacific basin, the Tethys, the ancient sea located in the space now occupied by the Mediterranean Sea, almost dried up during the Messinian crisis. Around five million years ago, Atlantic waters entering from the Strait of Gibraltar flooded the Tethys basin and the Mediterranean Sea was formed. Several Atlantic species joined some Tethyan relicts (i.e., species that survived the Messinian crisis), and a series of endemic species evolved from these, due to the original features of the basin (higher salinity and surface temperature than Atlantic waters) and geographical separation from the original populations. The Adriatic Sea, in the meantime, maintained alternating connections with the and the . Very recently, the opening of the Suez Canal allowed hundreds of tropical species from the Indo- Pacific basin to enter the Mediterranean Sea, where they found favourable conditions thanks to global warming. Today, the Mediterranean Sea is a very unique bio-geographical crossroads and Italian biodiversity provides ample evidence of this (see Bianchi et al., 2004, for a summary).

How many species inhabit the Italian seas? The Italian peninsula, with its continuation in Sicily, crosses the Mediterranean Sea from North to South, dividing its western and eastern portions. This geographical position ensures that Mediterranean biodiversity is well represented in Italian waters. According to Coll et al. (2010), about 17,000 known species live in the Mediterranean Sea. The biodiversity of the Italian seas reaches comparable numbers, amounting to 13,543 species, of which 1,116 are protozoans, 9,655 animals (536 vertebrates), 949 macrophytes, 1,781 microphytes and 42 fungi (Relini 2008; 2010). The list continues to grow due to the arrival of non-native species (especially fish, molluscs, crustaceans, and macro algae), mainly dwelling surface waters, whereas the discovery of native species new to science, regards either quite inconspicuous or deep sea organisms. Indeed, the exploration of deep-waters is leading to the discovery of many new species and current figures without doubt underestimate the true biodiversity levels of the Italian seas.

Physical oceanography and biodiversity Atlantic water enters from Gibraltar with a surface current that reaches the eastern part of the Mediterranean Sea, it then returns as Levantine intermediate water and exits from the Strait of Gibraltar. This great circulation, from west to east on the surface and from east to west at depth, involves the first 500 m of the water column. Mediterranean deep-waters are formed at the surface, in the “cold engines” that trigger north-south vertical circulations. The , the Northern Adriatic, and the Northern Aegean are the coldest areas of the Mediterranean Sea and their dense, oxygen-rich waters descend to the deep, pushing deep-waters, poor in oxygen and rich in nutrients, towards the surface. The Western Mediterranean deep-water is formed in the Gulf of Lion, while that of the eastern basin is formed alternatively in the Northern Adriatic or Northern Aegean Seas. The “cold engine” areas of the Mediterranean Sea are home to endemic cold-water species that are very sensitive to global warming. The failure of one of

150 First section - Chapter 2 - Ecological aspects these cold engines (that of the Northern Adriatic Sea) to operate triggered the so-called Eastern Mediterranean Transient and the formation of the deep-waters of the eastern basin shifted to the Northern Aegean Sea. In a global warming scenario, the malfunctioning of the Mediterranean cold engines could lead to an anoxic crisis in the deepest part of the sea, with serious repercussions on the biodiversity of the Mediterranean Sea (Boero et al., 2008).

Lists of species The list of Mediterranean species is constantly growing due to the addition of new discoveries to former ones. Although it is very easy to add species to the list, it is much more difficult to remove them and, in fact, there are no documented cases of extinction in the Mediterranean Sea. The newly arrived warm water species swell the lists, whereas the decline of cold water ones, due for example to diseases caused by the deepening of the summer water stratification, is more elusive. The lists of endangered species should not be influenced by the excessive importance given to conspicuous or charismatic species, as is currently the case. This problem could be solved by chronogeonemy, which is based on taxonomic literature (Bologna, 2004) and evaluates the time intervals for the sightings of species. The absence of sightings for very long periods supports the assumption of extinction, which should then be assessed through surveys in the known area of distribution. It is reasonable to consider a species as being endangered if it has not been sighted for a sufficiently long period. These practices would lead to a much different assessment of the specific biodiversity of the Mediterranean Sea than the current one and represent a new challenge to the study of biodiversity.

Habitats The Habitats Directive specifies that habitats themselves should be targets for biodiversity management and protection activities at a European level. The classification of Mediterranean marine habitat types, however, is compromised by idiosyncrasies connected with the specialisations of the compilers. Some are too generic (e.g. those of the Habitats Directive itself), whereas others are too detailed (e.g. that of the RAC-SPA) for being of use either to biodiversity managers or to ecologists (Fraschetti et al., 2011). Despite these problems, the decision to focus on habitats is the most rational one for biodiversity management because, if implemented properly, it will also allow species that are still unknown to be managed and protected, through the management and protection of their habitats. For this reason, marine habitats should be mapped with the same level of detail that is used for terrestrial habitats. Marine habitat classification is done exclusively in terms of seabed types and does not take the water column into consideration, although pelagic habitats are far from homogenous. Fronts, gyres, eddies and more stable currents contain communities of species that are distributed by the current systems, connecting the benthic habitats through biological cycle dynamics (mobility of larvae, juveniles, adults, and asexual propagules).

Biodiversity and ecosystem functioning Knowledge of marine biodiversity allows ecosystem functioning to be interpreted and understood. The connection between biodiversity and the functioning of ecosystems is not clear. Most biodiversity is composed of inconspicuous and rare species, of little apparent importance in determining the functioning of ecosystems, which normally depend on a few structurally and functionally important species. The important species, however, are not always the same. For example, over the last 30 years, the biodiversity of the Adriatic Sea has passed through a series of phases that have also changed the functioning of the ecosystems.

151 During the early 1980s (figure 2.59, a), a phase in which fish were dominant gave way to a phase characterised by the prevalence of jellyfish (particularly Pelagia noctiluca) (figure 2.59, b), followed in turn by dinoflagellate blooms (the red tides of the late 1980s) (figure 2.59, c) and by bacteria (mucilages in the 1990s) (figure 2.59, d) up to a period, which still continues today, of rapid alternation between the dominance of these components, with lower numbers of both benthic and pelagic fish species (figure 2.59, f). Thaliacean blooms occasionally limit the proliferation of microbes (figure 2.59, e). These periods have been studied in isolation, with little attention paid to the “history” of the system to understand its dynamics. It is highly probable that the impact of industrial fisheries, with the use of high-powered vessels, plays a critical role in causing this series of phase shifts and intensifies the impact of other anthropic activities and of global warming.

Figure 2.59 - The history of the Adriatic Sea from the 1980s up to the present (see text for explanation) (art by Alberto Gennari, graphics by Fabio Tresca).

Tendencies History does not stop, and the Mediterranean Sea is undergoing significant changes. The most important ones are: • The malfunctioning of the “cold engines” – the Northern Adriatic Sea has already stopped supplying deep-waters to the Eastern Mediterranean Sea, having been replaced by the Northern Aegean Sea. The worst-case scenario, in a period of global warning, involves an interruption the functioning of all “cold engines”, with widespread anoxia in the deepest parts of the basin.

152 First section - Chapter 2 - Ecological aspects • Tropicalisation and southernisation – the arrival of hundreds of tropical species and the northward spread of southern species is changing the biodiversity and the functioning of ecosystems. • Decline of coldwater species – species endemic to the “cold engine” areas are at risk of extinction. • Fewer fish, more jellyfish – the removal of fish provides space for the proliferation of jellyfish (cf. box “From a fish to a jellyfish ocean”). • Alteration of habitats – Anthropic pressures change coastal and even deep-water habitats.

Future research Italy still has sufficient human resources to study its own marine biodiversity in terms of species and habitats. A national strategy is required, however, to obtain results that can allow the protection and management of this heritage.

References - Bianchi C.N., Boero F., Fraschetti S., Morri C. (2004) - The wildlife of the Mediterranean. In: Minelli A., Chemini G., Argano R., Ruffo S. (eds), Wildlife in Italy. Touring Editore, Milano e Ministero dell’Ambiente e della Tutela del Territorio: 248-335. - Boero F., Féral J.P., Azzurro E., Cardin V., Riedel B., Despalatovi M., Munda I., Moschella P., Zaouali J., Fonda Umani S., Theocharis A., Wiltshire K., Briand F. (2008) - I - EXECUTIVE SUMMARY OF CIESM WORKSHOP 35 “Climate warming and related changes in Mediterranean marine biota”. CIESM Workshop Monographs, 35: 5-21. - Bologna M.A. (2004) - Rarity and extinction of species. In: Minelli A., Chemini G., Argano R., Ruffo S. (eds), Wildlife in Italy. Touring Editore, Milano e Ministero dell’Ambiente e della Tutela del Territorio: 390-419. - Coll M., Piroddi C., Steenbeek J., Kaschner K., Ben Rais Lasram F. (2010) - The Biodiversity of the Mediterranean Sea: Estimates, Patterns, and Threats. PLoS ONE 5(8): e1184. - Fraschetti S., Guarnieri G., Bevilacqua S., A., Claudet J., Russo G.F., Boero F. (2011) - Conservation of mediterranean habitats and biodiversity countdowns: what information do we really need? Aquatic Conservation, Marine and freshwater Ecosystems, 21: 299-306. - Relini G. (ed) (2008) - Checklist della Flora e della Fauna dei mari italiani (I parte). Biol. Mar. Mediterr., 15 (Suppl. 1): 385 p. - Relini G. (ed) (2010) - Checklist della Flora e della Fauna dei mari italiani (II parte). Biol. Mar. Mediterr., 17 (Suppl. 1): 387-828.

2.7.2 Biodiversity and fisheries Relini G., Orsi Relini L., Lanteri L., Franco A.

Biodiversity, i.e. the variety of forms, organisation and functions under which life manifests itself, from genes to populations and from species to ecosystems, interacts greatly with fisheries in a reciprocal way: it both influences fisheries and is conditioned by fisheries activities. The variety of organisms and habitats allows the exploitation of a wide range of resources and since Palaeolithic times has led humans, particularly in the Mediterranean Sea, to invent the most varied fishing equipment and systems. This diversity of fishing methods forms the basis an important cultural heritage, with traditions that are unfortunately disappearing due to pressure from globalisation and European fishery policies, which do not consider resources of modest size and distribution. To gain an idea of the number of species and large systematic groups of interest to fisheries in Italy, reference may be made to the two volumes by FAO, which contain identification sheets for the species targeted by fisheries in the Mediterranean and the Black Sea (Fisher et al., 1987). The sheets cover 15 large systematic categories and 906 species, 806 of which are found in Italian

153 seas and 521 considered edible (64.64%). Some species are fished for other uses, for example sponges, red coral, hermit and sea cucumbers, the later being used as bait. The checklist of flora and fauna of the Italian seas (Relini, 2008; 2010) contains 4,657 species from the 15 systematic groups covered in the FAO manual, 806 of which are fished and 521, as mentioned, are considered edible: thus only 11.18% of Italian species are deemed edible. Elasmobranchii is the group with the highest percentage of species considered edible (90%). However this group also includes rare species and species that are never brought to market, with differences from one fishing community to another. Oil is extracted from the liver of certain sharks, both for therapeutic and lubrication purposes, and the dried skin (sharkskin) is used as a very fine abrasive. 39% of bony fish are considered edible; this does not mean that all these species are normally consumed, because some of them are difficult to find and opinions on their edibility, and therefore their value, can vary in different areas. For example, the African armoured searobin, Peristedion cataphractum, is normally eaten in Sicily, but is discarded at sea in Liguria, the damselfish (Chromis chromis) which is a targeted species in the South, where it is caught using pots, is not brought market in Liguria. Blotched and common picarel (genus Spicara) are appreciated in Western Liguria but not so much in Genoa and the East. Many species could be used for human consumption but are discarded at sea, with a considerable waste of protein. For example, grenadiers (rattails), a target species for deep sea fisheries in the Atlantic Ocean, are thrown back into the sea in Italy. In other cases, inappropriate regulations do not permit the use of the fish, as in the case of the ocean sunfish (Mola mola). The most important species for fisheries in terms of quantity and commercial value, i.e. those listed in groups G1, G2 and G3 of the EC data collection regulation for fisheries, amount to over 120. In reality, the first group includes around 50 selaceans, most of which have no commercial value, but are mainly of naturalistic or conservation importance. Group G1 includes 9 bony fish, 4 decapod crustaceans, 49 elasmobranchs plus other shark-like selachii (not better defined) and Istiophoridae (only one species of which is considered in Italy). Group G2 includes 19 bony fish, 2 crustaceans and 7 cephalopods, plus grey mullets (not considered in Italy) and Venus clams (only one species in Italy is considered for EC data collection). Group G3 includes 21 bony fish, 2 decapod crustaceans and 1 bivalve mollusc (Pecten jacobaeus). This division into three groups has been made on the basis of the importance of the species and the details and collection frequency of the information to be gathered in the collection of data on fishing. The impact of fisheries on biological diversity can have numerous aspects: above all, the effects of overfishing, with a qualitative and quantitative reduction in species, change in population structures, decrease in spawners, loss of genetic diversity etc.; the physical impact on ecosystems, with changes to the substrate and precious (sensitive) ecosystems that are sometimes beyond recovery; and an excessive input of nutrients through mixing of the seabed and the dumping of discard; the possible spread of disease and alien species, as happened with the seaweed Caulerpa taxifolia. These effects can be particularly drastic in Italian seas, and more generally in the Mediterranean sea, where, in addition to a high biodiversity (Coll et al., 2010) that has produced multiple lists of protected species and habitats, illegal and highly destructive fishing practices are still carried out, such as European date fishing, which involves rock demolition, the use of explosives and trawling on seagrass beds. Although these practices may be considered as dying out, due to an increase in education and environmental awareness, it should be noted that many fishing activities are not single-species and selective, i.e. other species are caught in addition to the target species and

154 First section - Chapter 2 - Ecological aspects then discarded in the sea, causing irreparable damage; these can also include protected species. In regard to fishery target species, a considerable and sustained fishing pressure affects the reproductive potential of the targeted populations, bringing it to critical levels, often very close to collapse; the first to be eliminated by this are the larger broodstock, which are also the most fertile fish. With the elimination of top predators, food webs and energy flow in the ecosystem are simplified; the reduction of genetic diversity leads to lower resilience and less stability in the ecosystem, and a reduced capacity to adapt to natural changes in the environment, particularly climate changes. The seriousness of the phenomenon is not always fully understood, just as the extent of the impact of fisheries on biodiversity remains little known, particularly the genetic impact, since up to now this study has only been carried out for a few species. There is a risk that serious damage may remain unobserved due to lack of data. The current situation, in which a large number of species are overexploited, clearly indicates that the present rate of capture is not sustainable for many stocks. The application of regulations for sustainable fisheries that respect the environment is therefore urgent. Many such regulations are provided in the FAO Code of conduct for responsible fisheries. There is already widespread agreement (Tudela, 2000; RAC/SPA, 2003) on the positive role that protected marine areas can play, not only for the conservation of biodiversity, but also for fishery resources, particularly coastal resources. Fishery restricted areas are also important in this context, providing a spatial/temporal closure of fishing and the construction of artificial habitats (artificial reefs), with a dual purpose of protection and restocking. With the advance in knowledge there is a growing conviction that the safeguarding of fishery resources and activities for their capture should be part of a precautionary and ecosystem approach (Boero, 2009) and therefore linked to biodiversity conservation. Policies for fisheries and for the conservation of biodiversity should proceed hand-in-hand. Fisheries should also be managed in such a way as to contribute to stop the loss of biodiversity, as indicated in the Communication from the EC Commission (EEC, 2006). Regulation No (CE) 1967/2006 concerning management measures for the sustainable exploitation of fishery resources in the Mediterranean Sea moves in this direction, indicating sensitive habitats that require protection.

References - Boero F. (2009) - Recent innovations in marine biology. Mar. Ecol., 30 (suppl. 1): 1-12. - CEE (2006) - Communication from the Commission. Halting the loss of biodiversity by 2010 - and beyond. Sustaining ecosystem services for human well-being. SEC 607, 621. Brussels: 1-15. - Coll M., Piroddi C., Steenbeek J., Kaschner K., Ben Rais Lasram F., et al. (2010) - The Biodiversity of the Mediterranean Sea: Estimates, Patterns, and Threats. PLoS ONE, 5: e1184. - Fischer W., Bauchot M.L., Schneider M. (eds) (1987) - Fiches FAO d’identification des espèces pour le besoins de la pêche (Révision 1). Méditerranée et mer Noire. Zone de pêche 37. 1. Végétaux et Invertebres. 2. Vertébres. Publication préparée par la FAO (Project GCP/INT/422/EEC), Rome: 1530 p. - RAC/SPA - Regional Activity Centre for Specially Protected Areas (2003) - Effects of fishing practices on the Mediterranean Sea: Impact on marine sensitive habitats and species, technical solution and recommendations. Project for the Preparation of a Strategic Action Plan for the Conservation of Biological Diversity in the Mediterranean Region (SAP BIO): 116 p. - Relini G. (ed) (2008) - Checklist della Flora e della Fauna dei Mari Italiani (Vol. I). Biol. Mar. Mediterr., 15 (Suppl. 1): 385 p. - Relini G. (ed) (2010) - Checklist della Flora e della Fauna dei Mari Italiani (Vol. II). Biol. Mar. Mediterr., 17 (Suppl. 1): 387- 828 + 68. - Tudela S. (2004) - Ecosystem effects of fishing in the Mediterranean: an analysis of the major threats of fishing gear and practices to biodiversity and marine habitats. FAO, Fisheries Department, Rome: 44 p.

155 2.7.3 Elasmobranchs Serena F.

Elasmobranchs are characterized by a K-selected life strategy (Hoenig & Gruber, 1990). They reach maturity relatively late, generally produce only few offspring, show low natural mortality rates and a very slow population growth rate (Ricklefs, 1979). Indeed they have low resilience and slow recovering rates. An almost linear relationship between size of the adult stock and recruitment they produce was observed, even though in some cases a reduction in the stock that may generate a compensatory mechanism which favours the increase of individual fecundity was observed (Holden, 1977). During their life elasmobranchs, move from mating areas to areas where offspring will be born or where egg cases will be laid down (nursery areas). During their growth young individuals will search for appropriate feeding areas (Serena et al., 2010). There are few fisheries targeting elasmobranchs. In many cases however elasmobranch species are part of the by-catch of fisheries targeting other species. Due to the general low commercial value of elasmobranch species and difficulties of identification, the lack of reliable statistics of both commercial landings and individuals discarded at sea is rather common. This leads to difficulties for the assessment of the state of exploitation and the choice of effective management measures. Data collected in the frame of stock assessment programs as trawl surveys (Bertrand et al., 1997) and in the EU Data Collection Framework are fundamental to estimate absolute and/or relative biomass values of fish stocks, as well as for the definition of reference points. The collection of historical time series of catches and abundance allows the monitoring of their evolution in time (figure 2.60).

70

60

50

2 40

kg/km 30

20

10

0 1994 1996 1998 2000 2002 2004 2006 2008 Years

Figure 2.60 - Trend index of elasmobranch biomass caught in GSA9, in the MEDITS project.

The poor information on elasmobranchs has precluded up to now in many areas the concrete use of sound assessment models both of analytical and/or dynamic ones. With mere information on some biological features such as survival rates and mean fecundity at age it is still possible to apply demographic models as life tables or Leslie matrices (Hoenig & Gruber, 1990; Simpfendorfer, 1999). To estimate survival rates information on natural mortality rate M, that can be derived making use of direct estimations or through the use of empirical equations, is required. Hoenig (1983) proposed an equation that relates longevity and natural mortality rate. In many cases, as the estimate of longevity is difficult, the empirical Pauly equation (Pauly, 1980), mainly based on growth parameters, is also used for elasmobranchs.

156 First section - Chapter 2 - Ecological aspects As regards their depth preferences, most Mediterranean elasmobranchs can be allocated in three bathymetric ranges: while Raja clavata and Scyliorhinus canicula are well represented along a very wide bathymetric range, Dasyatis pastinaca, Mustelus mustelus, Raja asterias, etc., mainly live over the continental shelf, and Galeus melastomus, Centrophorus granulosus and Etmopterus spinax prefer the shelf slope or much deeper bottoms. Some elasmobranchs are abundant over the whole Mediterranean sea (S. canicula, R. clavata, Torpedo marmorata, R. asterias) while others are only common in the Western area (Torpedo nobiliana, Rostroraja alba, Oxynotus centrina) or in the Eastern area (S. acantias, R. radula, R. naevus, R. brachyura); some species seem to be confined to restricted areas, such as Hexanchus griseus and R. miraletus in the Tyrrhenian Sea, M. mustelus in the Adriatic; R. brachyura and R. undulata in the Aegean Sea. Pelagic elasmobranchs include many species characterized by a large size (mako, , porbeagle, violet sting ray, etc.) that often constitute an important part of the by-catch of tuna or swordfish fisheries. Information of such catches in the Mediterranean is scarse and hence, the impact of fishing activity on these stocks is hard to evaluate. As regards to their life strategy, elasmobranchs are among the first stocks that may show signals of suffering as soon as fisheries start to develop. Such species are in general positioned at the highest levels in the food webs and a reduction of their abundances will have unavoidable consequences on the trophic relationships and over the whole ecosystem, as well as a damage of economic interests. In many Mediterranean areas, mostly in the seas facing the more industrialized countries, intense fisheries lead to the rarefaction of some species (Ferretti et al., 2008) with evident consequences on the conservation state of marine biodiversity (Cavangh & Gibson, 2007). With the aim of limiting the mentioned phenomenon, FAO (1998), following the guidelines of the Code of conduct for a responsible fisheries, launched the action IPOA-Sharks suggesting the enforcement of national plans for the sharks conservation (FAO, 2006). UNEP-MAP (2003) published the action plan for the Mediterranean. The European Comunity in 2009 made his own official Plan aimed at the conservation and management of sharks in fisheries. Italy wrote its own guidelines and the two ministries MiPAAF and MiATTM, closely collaborated for the enforcement of assessment programs on the exploitation and conservation state of elasmobranchs in Italian seas.

References - Bertrand J., Gil de Sola L., Papakostantinou C., Relini G., Souplet A. (1997) - An international bottom trawl survey in the Mediterranean: the MEDITS Program. ICES CM 1997/Y: 03 16. - Cavangh R.D., Gibson C. (2007) - Overview of the Conservation Status of Cartilaginous Fishes (Chondrichthyans) in the Mediterranean Sea. IUCN, Gland, and Malaga, Spain. Vi + 42 p. - Commission of the European Communities (2009) - Communication from the commission to the European parliament and the council on a European Community Action Plan for the Conservation and Management of Sharks. Brussels, 5.2.2009. - FAO (1998) - The International Plan of Action for Conservation and Management of Sharks. Document FI: CSS/98/3, Consultation on Management of Fishing Capacity. Shark Fisheries and Incidental Catch of Seabirds in Longline Fisheries. Rome 26-30 October 1998. - FAO (2006) - Report of the FAO Expert Consultation on the Implementation of the FAO International Plan of Action for the Conservation and Management of Sharks. Rome, 6-8 December 2005. FAO Fisheries Report. No. 795: 24pp. - Ferretti F., Myers R.A., Serena F., Lotze H.K. (2008) - Loss of Large Predatory Sharks from the Mediterranean Sea. Conservation Biology 22: 952-964. - Hoenig J.M. (1983) - Empirical use of longevity data to estimate mortality rates. Fish. Bull. U.S. 81: 898-903. - Hoenig J.M. & Gruber S.H. (1990) - Life-history patterns in the elasmobranchs: implications for fisheries management. In: Elasmobranchs as living resources: advances in the biology, ecology, systematics and the status of the fisheries. Edited by Pratt, H.L. Jr., S.H. Gruber and T. Taniuchi. NOOA Tech. Rep. NMFS, 90: 1-16.

157 - Holden M.J. (1977) - Elasmobranchs. In: Gulland J.A. (ed), Fish population dynamics, Chap. 9. John Wiley & Sons, New York. - Pauly D. (1980) - On the interrelationship between natural mortality, growth parametres and mean environmental temperature in 175 fish stocks. J. Cons. Int. Explor. Mer. 39 (3): 175-192. - Ricklef R.E. (1979) - Ecology, 2nd ed. Chiron Press, New York: 966 p. - Serena F., Mancusi C., Barone M. (eds) (2010) - Field identification guide to the skates (Rajidae) of the Mediterranean Sea. Guidelines for data collection and analysis Biol. Mar. Mediterr., 17 (2): 204 p. - Simpfendorfer C.A. (1999) - Mortality estimates and demographic analysis for the Australian sharpnose shark, Rhizoprionodon taylori, from northern . Fish. Bull. 97: 978-986. - UNEP MAP RAC/SPA 2003. Action Plan for the Conservation of Cartilaginous Fishes (Chondrichthyans) in the Mediterranean Sea. Ed. RAC/SPA, Tunis: 56 p.

Box 2.1

From a fish to a jellyfish sea Boero F.

Global fisheries trends show that fish stocks are gradually becoming depleted. Large species are rapidly diminishing and fishing is becoming concentrated on smaller-sized species, a phenomenon known as “fishing down the food web” (figure 2.61). This reduction coincides with an increase in gelatinous macrozooplankton (Cnidaria, Ctenophora and Thaliacea), which is perhaps enhanced by global warming.

Figure 2.61 - Left: an ocean with abundant large fish is becoming an ocean with smaller fish. Right: an ocean with smaller fish and large gelatinous macrozooplankton populations (art: Alberto Gennari, graphics: Fabio Tresca).

The total pelagic biomass, if measured as a whole, may even not have varied, but its composition changed radically: gelatinous plankton biomass is replacing that of fish. The case of the alien Ctenophora Mnemiopsis leidyi (figure 2.62), which arrived in the Black Sea in the early 1980s, provided the first proof of the impact of carnivorous gelatinous macrozooplankton on fish populations.

158 First section - Chapter 2 - Ecological aspects Mnemiopsis consumes the crustacean zooplankton on which juvenile fish feed, and is therefore a competitor to them. Moreover, by also feeding on fish eggs and larvae, Mnemiopsis exerts significant predatory pressure on fish. The impact on fisheries alone may be below the tolerance thresholds of target species but, combined with other impacts, could contribute to the collapse of the stocks. The impact of gelatinous predators is continuously increasing and should be given serious consideration, also in order not to blame excessive fishing alone for the depletion of fish resources. Figure 2.62 - The ctenophore Mnemiopsis leidyi, alien to the Black Sea and now also present in Italian waters (art by A. Gennari).

Gelatinous macrozooplankton in Italy in 2009-2011 The “citizen science” project Occhio alla Medusa (“Watch for jellies”, promoted in Italy through the initiative of research scientists from the University of , CoNISMa and CNR-ISMAR and through Focus magazine) has compensated for the lack of institutional research on gelatinous plankton, allowing its presence to be quantified along the 8,500 kilometres of Italian coastline during the period 2009-2012. The results of the four surveys show that jellyfish were extremely abundant in the four years of research and had a very high diversity. The distribution of species, moreover, was not uniform neither in space nor in time. This initiative, which was the focus of intense media coverage, also led to the identification of new species for Mediterranean fauna (the scyphozoan Catostylus tagi, of Atlantic origin) and Italian Figure 2.63 - The “Occhio alla medusa” campaign poster for 2011. fauna (the scyphozoan Phyllorhiza punctata, which entered the Eastern Mediterranean from the Suez Canal and has reached Italian shores).

159 The largest jellyfish species in the Mediterranean Sea, the scyphozoan Drymonema dalmatinum, was found again, after not being sighted in our seas for decades. The poster for the 2011 edition of the “Occhio alla medusa” campaign (figure 2.63) shows the main species of gelatinous macrozooplankton currently found in the Mediterranean Sea, including those that have recently arrived.

From jellyfish to “jellyfish eaters” The abundance of gelatinous macrozooplankton would appear to present an opportunity for the growth of species that use them as a food source, such as large marine , ocean sunfish and Cornish blackfish, as well as Atlantic mackerel and even tunas. The shift from fish to jellyfish may therefore be followed by a subsequent reduction in gelatinous plankton populations due to an increase in their predators. The situation in which a “sea of fish” is becoming “a sea of jellyfish” could eventually lead to a “sea of jellyfish eaters” (figure 2.64), such as large marine turtles or ocean sunfish. Forecasting the future is tenuous in fields such as ecology, which are subjected to non-linear dynamics with several variables interacting, being difficult to model while using methods developed for linear systems with few variables. The ecosystem approach to fisheries biology appears extremely necessary in this context, and it is quite clear that jellyfish should be included among the variables to be considered.

Figure 2.64 - Left: from large fish to small fish (yesterday). Centre: from small fish to jellyfish (today). Right: from jellyfish to jellyfish eaters (tomorrow) (art by Alberto Gennari, graphics by Fabio Tresca).

160 First section - Chapter 2 - Ecological aspects Box 2.2

Alien species and fisheries in Italian seas Andaloro F.

Alien species: a threat to biodiversity Alien species now represent one of the most serious threats to biodiversity in almost all terrestrial and marine environments on the planet, with consequences for the economy, health and culture of the affected countries. According to the EU Biodiversity Strategy (2011), 22% of Europe’s indigenous species are threatened by alien species. The need to prevent and counter the spread of alien species, already stressed in the Convention on Biological Diversity (UN 1992), has become a target of the latest conference of the Convention of Contracting Parties (Nagoya, 2010) and has been incorporated by the EU Biodiversity Strategy. Recommendations on alien species in the Mediterranean Sea were made by the Barcelona Convention (UNEP/ MAP) and more recently by the Marine Strategy Framework Directive (2008/56/EC). The numerous international commitments regarding alien species include GIPS (Global Invasive Species Programme), ISSG-IUCN (Invasive Species Specialist Group of the International Union for Conservation of Nature), ERNAIS (European Research Network on Alien Invasive Species) and DAISIE (Delivering Alien Invasive Species Inventories for Europe).

Alien species in the sea In the past, the sea was the environment least affected by alien species, since the pathways of voluntary or involuntary introduction are very limited. More recently, globalisation and the shipping traffic growth have led to an increase in alien species in all the seas on the planet, given that they become established more easily in stressed and overexploited environments. The introduction pathways of alien species can be voluntary or involuntary. As far as the sea is concerned, voluntary routes include marine species introduction for aquaculture and aquaria and other forms of species imports such as live bait. Involuntary routes include the ballast water of ships and the fouling of hulls, with import of live or dead animals also providing a possible pathway for the involuntary introduction of alien pathogens.

Non-native species in the Mediterranean Sea The Mediterranean Sea is now one of the seas most afflicted by biological invasion in the world, both in terms of the number of species (Costello et al., 2010) and the rate of invasion (Zenetos, 2010). The high number of alien species in the Mediterranean Sea is mainly caused by their migration through the Strait of Gibraltar and the Suez Canal, as well as by introductions. Atlantic migration - The profound geomorphologic and climatic changes in the Mediterranean Sea from the Cambrian period up to present have influenced its biodiversity. In zoogeographical terms, autochthonous and endemic species, according to Por and Dimentman (1985), are to be found among the fauna of the Messinian period (which survived the salinity crisis), whereas the other species are considered as pseudo-endemic, having arrived from the Atlantic following the opening of the Mediterranean Sea during the Pleistocene epoch. Due to this relatively recent colonisation, the Mediterranean Sea cannot be considered as an autonomous zoogeographical region and shows a higher receptivity

161 towards alien species than other highly competitive and specialised environments. Due to the low of its biodiversity, it is preferable to use the term non-indigenous species (NIS) rather than alien species for the Mediterranean Sea. - In 1902, 33 years after the opening of the Suez Canal, which was built by the architect Ferdinand de Lesseps, Atherinomorus lacunosus, the first fish species from the Red Sea to be caught in the Mediterranean Sea, was found in Haifa. Since then, discoveries of Indo-Pacific species in the Eastern Mediterranean Sea have been frequent and the phenomenon has been described by Por as “Lessepsian migration”. The completion of the Aswan Dam in 1971 changed the salinity of the formerly hyposaline Nile Delta, increasing the establishment of Lessepsian species in the Levant. The scale of the problem - Despite increasing scientific efforts, there is no certain data on the number of NIS in the Mediterranean Sea, due to the difficulty of validating many occurrences and differences in opinion among experts. There have only been single occurrences for many species, others are rare and those that are established (and complete their life cycle in the Mediterranean Sea) account for no more than 20% of the species discovered. According to Coll et al. (2010), of the 17,000 marine species that make up Mediterranean biodiversity, 600 are NIS, a figure that is probably underestimated, according to data from RAC/SPA and the European Environment Agency, which assess them to be around 1,000. According to ISPRA, 45% of NIS in the Mediterranean Sea have migrated through the Suez Canal, 9% through the Strait of Gibraltar, 16% have been introduced by maritime traffic, 8% through aquaculture and fish keeping and 22% are of other or unknown origin. Most NIS in the Mediterranean Sea have tropical or subtropical affinity, and the rapid increase in discoveries over the last 30 years has therefore also been attributed to climate change, a phenomenon described as the tropicalisation of the Mediterranean Sea (Andaloro & Rinaldi, 1998; Bianchi, 2007).

The impact of non-indigenous species on Italian fisheries The NIS of most interest to fisheries belong to the groups of fish, crustaceans and molluscs. Of the 149 non-indigenous fish species identified in the Mediterranean Sea, only 45 have been found in Italian waters (27 of Atlantic, 14 of Indo-Pacific and 4 of doubtful origin), but there has only been a single occurrence for 25 of these species. Of the 71 non-indigenous crustacean species identified in the Mediterranean Sea, 16 have been found in Italian waters (9 are of Atlantic and 7 of Indo-Pacific origin), but only 5 are of commercial value and there has been only a single occurrence for 9 other species. Of the 163 non-indigenous mollusc species sighted in the Mediterranean Sea, 35 have been found in Italian waters (10 of Atlantic and 25 of Indo-Pacific origin), but only 10 are of commercial value and 12 have only been found once. The impact of non-indigenous species on fisheries can be direct, due to their capture in addition to or instead of indigenous species, or indirect, through changes caused to the habitat, interaction with fishing gears and, in certain cases, their toxicity sometimes with lethal effect on consumers. Catches of non-indigenous species in Italian seas should still be considered occasional, although certain species are not rare. There are recurrent catches of Lessepsian species, such as bluespotted cornetfish (Fistularia commersonii) and dusky spinefoot (Siganus luridus), and of Atlantic species, such as lesser amberjack (Seriola fasciata), which can even reach the market in some cases.

162 First section - Chapter 2 - Ecological aspects The three species introduced by aquaculture are an entirely separate case: the Japanese carpet shell (or Manila clam, Ruditapes philippinarum), which has practically replaced the grooved carpet shell (Ruditapes decussatus), in the Northern Adriatic, the Japanese (Crassostrea gigas), which competes with the European flat oyster (Ostrea edulis), and the kuruma prawn (Marsupenaeus japonicus), which is now frequently caught in certain areas. The situation is very different in the Eastern Mediterranean Sea, where, in terms of biomass, catches of Indo-Pacific species now almost match those of indigenous species, as in Lebanon, where NIS account for 37% of fish production (Carpentieri et al., 2009). Changes to habitats caused by NIS can have serious consequences for fisheries: this has been the case with the seaweeds, Caulerpa racemosa and Caulerpa taxifolia, which have caused serious problems to coastal fisheries in some areas. In certain periods of the year these seaweeds shed their branches, which get caught in gillnets, and they also alter the benthic communities, with consequences that are probably harmful to indigenous species. The toxicity of certain alien species can have an impact on fisheries. This is the case with Ostreopsis ovata and other harmful algae, and with the caulerpaceae, which contain the toxin caulerpenyne. The toxicity of these alien algae can be harmful to the organisms that eat them and can make species such as , and sea urchin inedible. There are also toxic NIS, such as tetraodontiformes, which contain tetrodotoxin; pufferfish and lagocephalus belong to this order. The pufferfish found in Italian seas include Diodon hystrix, Chilomycterus reticulatus, Sphoeroides marmoratus and Sphoeroides pachygaster, but only the last of these has been caught frequently. A greater cause for concern is the spotted rough-backed blowfish , which has caused a deaths in the Eastern Mediterranean Sea, but has never been sighted in Italian seas. The sale of tetraodontidae is, however, prohibited in Italy. Fishermen play an important role in the struggle against bioinvasions, as they represent the most important source of information, and it is thanks to them that many species have been found and identified.

National efforts against alien marine species In Italy, the Ministry of the Environment and Protection of Land and Sea (MiATTM), in association with ISPRA, started compiling a database, maps and a tissue bank of NIS in Italian seas in 2000; it also carried a study on ballast water in some sample ports. The MiATTM, as part of the “Mediterranean strategy to prevent the transfer of marine organisms through ballast water” (UNEP/MAP/2011), is creating an early warning system for certain ports, selected on the basis of risk analysis. The MiPAAF, with technical assistance from ISPRA, has created a register of exotic species introduced in aquaculture, in accordance with Regulation 708/2007/EU.

163 References - Andaloro F. & Rinaldi A. (1998) - Fish biodiversity change in Mediterranean sea as tropicalisation phenomenon indicator. In: Enne G., D’angelo M. e Zanolla C. (eds), Prooceding of international seminar: Indicator for assessing desertification in the Mediterranean. Porto Torres: 201-206. - Bianchi C. N. (2007) - Biodiversity Issues for the forthcoming tropical Mediterranean Sea. Hydrobiologia, 580: 7-21. - Carpentieri P., Lelli S., Colloca F., Mohanna C., Bartolino V., Moubayed S., Ardizzone G. (2009) - Incidence of lessepsian migrants on landings of the artisanal fishery of south Lebanon. Marine Biodiversity Records, 2: e71 - Coll M., Piroddi C., Steenbeek J., Kaschner K., Ben Rais Lasram F., et al. (2010) - The Biodiversity of the Mediterranean Sea: Estimates, Patterns, and Threats. PLoS ONE 5(8): e1184. - Costello M.J., Coll M., Danovaro R., Halpin P., Ojaveer H. Miloslavich P. (2010) - A census of marine biodiversity knowledge, resources and future challenges. PLoS ONE, 5(8): e12110. - Por F. D. & Dimentman C., (1985) - Continuity of Messinian biota in the Mediterranean basin. In: Stanley D. J., Wezel F. C. (eds), Geological Evolution of the Mediterranean basin. Springer-Verlag, Berlin: 545-557. - Zenetos A. (2010) - Trend in alien species in the Mediterranean. An answer to Gail 2009 “Talking stock: inventory of alien species in Mediterranean Sea”. Biological invasion, 12: 3379-3381.

164 First section - Chapter 2 - Ecological aspects