B5. Mediterranean and Black Sea, FAO Statistical Area 37

49 B5. MEDITERRANEAN AND BLACK SEA FAO Statistical Area 37 Figure B5.1 - The Mediterranean and Black Sea (Area 37) by Jordi Lleonart * INTRODUCTION The Mediterranean (Figure B5.1) is a semi-enclosed sea with a surface of about 3.3 million km2, contributing 0.8 percent to the total world marine surface. Due to its geographical position, being placed at a relatively narrow range of latitudes (from 30ºN to 46ºN) in the temperate zone of the Northern Hemisphere, the Mediterranean Sea shows a marked seasonal cycle. Water masses are Atlantic through the Strait of Gibraltar proceeds stratified in summer, but the deep-water (below to the eastern Mediterranean progressively losing 400 m) temperature is 13±0.3ºC throughout the nutrients and increasing in salinity through year. The low precipitation in the summer period evaporation. It eventually goes back out to the is the main characteristic of the Mediterranean Atlantic to form the high saline component of the climate. The Mediterranean has a negative water Atlantic circulation. This makes for a large budget: the loss of water through evaporation is number of habitats with many small local stocks greater than the inputs due to rain and river and species whose stock trends cannot be runoff, hence the contribution of about individually described here but show up as 1 700 km3/year of Atlantic water trough the Strait dissimilarities between sub-areas (Garibaldi and of Gibraltar balances these losses (Oliver, 2003). Caddy, 1998). The system of basins includes water ranging from The Mediterranean has been globally considered Atlantic origin in the Western Mediterranean to as an oligotrophic sea (Margalef, 1985; Estrada, warm-temperate hypersaline water in the Levant 1996; Stergiou et al., 1997b). Normally, the basin, hyposaline waters in the Black Sea, and gradual decrease in nutrient would result in a cold-temperate estuarine conditions in the boreal west to east decrease in productivity, but there Azov Sea. Surface water entering from the are local exceptions resulting from a north-south Figure B5.2 - Annual nominal catches ('000t ) by ISSCAAP species groups in the Mediterranean and Black Sea (Area 37) 2 000 35- Herrings, sardines, anchovies 24- Shads Other ISSCAAP Groups 1 500 34- M iscellaneous demersal fishes 33- M iscellaneous coastal fishes 32- Cods, hakes, haddocks 1 000 500 0 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 Source FAO * FAO, Marine Resources Service, Fishery Resources Division 50 productivity gradient evident also from satellite subsequently increased to 1.5 million tonnes in imagery of chlorophyll A, due to incoming 2001 and 2002, after some small fluctuations. nutrients from northern rivers (notably the Small pelagics account for approximately Rhone, Po and Black Sea inflows into the 50 percent of total Mediterranean catches. Aegean). These anthropogenic effects on Anchovy (Engraulis encrasicolus) with fisheries production have been described by 59 percent of small pelagics catch, and sardine Caddy, Refk and Do Chi (1995). (Sardina pilchardus) with 16 percent are the The continental shelf is mostly a narrow coastal most abundant. Other small pelagics are sprat fringe with the exceptions of the Adriatic Sea, (Sprattus sprattus), sardinella (Sardinella aurita) Gulf of Gabès, northern Black Sea south of Sicily and Azov sea sprat (Clupeonella cultriventris). and gulf of Lions, and represents only 23 percent The substantial increase in European anchovy of the total area. catches from 1960 to the mid 1980s (Figure The fisheries of the Mediterranean have shown a B5.3) partly reflects increased effort from Turkey surprising resilience to fishing compared with in the Black Sea that was added to that of the some areas of the Atlantic. This is especially former Soviet Union fleet previously dominating noteworthy since formal and coordinated the fishery. As with sprat catches, it could reflect measures for fisheries management are largely eutrophication of the Black Sea environment by absent in most Mediterranean countries, though incoming rivers (Mee, 1992; Zaitsev, 1993). The more frequent activities and a revision of the collapse of anchovy, sprat and Azov sea sprat in terms of reference of the GFCM (General 1990 is the result of the introduced ctenophore Fisheries Commission for the Mediterranean) and species Mnemiopsis leidy in the Black Sea. A its Scientific Advisory Committee (SAC) is subsequent increase of catches did not reach the intended to remedy this from 2000. Farrugio et former levels. The sardine series shows a smooth al. (1993), Farrugio (1996), Anon. (2001), Bas increasing trend to late 1980s (282 000t in 1988) (2002), Oliver (2003) and Lleonart and Maynou and a subsequent moderate decrease to about (2003), among others, have reviewed 187 000t in 2002. Mediterranean fisheries. Mixed bottom fisheries using small mesh trawls, gillnets, trammel nets, traps, pots and dredges PROFILE OF CATCHES capture a large suite of demersal fish and invertebrates of high value for the fresh fish Nominal catches in Area 37 increased from market, with no single species making up more slightly over 0.7 million tonnes in 1950, to near than 10 percent of the total demersals. However, 2 million tonnes between 1982 and 1988 (Figure in those areas where trawl fleets operate B5.2 and table D5). Catches subsequently regularly, despite the inherent complexity of declined steeply to 1.3 million tonnes as a result multispecies catches, there is an identifiable of the collapse of the sprat and anchovy fishery in series of target species which in biomass or in the Black Sea (Figure B5.3). Total catches have economic terms, constitute an important basis of production. The species considered demersals Figure B5.3 - Annual nominal catches ('000t) of (more than 100, although some of them show a selected species in ISSCAAP Groups 24 & 35, pelagic behaviour) represent around 40 percent of Mediterranean and Black Sea (Area 37) total reported catches in the Mediterranean and 800 European pilchard (=Sardine) Black Sea. Hake (Merluccius merluccius), red 700 European anchovy mullets (Mullus spp.), blue whiting European sprat (Micromesistius poutassou), whiting (Merlangius 600 Sardinellas nei Azov Sea sprat merlangus), anglerfishes (Lophius spp.), Pagellus 500 spp., bogue (Boops boops), picarels (Spicara 400 spp.) striped venus (Chamelea gallina), Octopus 300 spp., cuttlefish (Sepia officinalis), red shrimp 200 (Aristeus antennatus), Norway lobster (Nephrops norvegicus) and deepwater rose shrimp 10 0 (Parapenaeus longirostris), are the main 0 demersals. 1950 1960 1970 1980 1990 2000 Source FAO 51 By-catch species include species not registered catches, but their economic value is far greater. individually in official catches or not always Catches of bluefin tuna increased from the mid present but that together can represent a 1960s to the mid 1990s, but then significantly significant proportion of catches such as small dropped (Figure B5.7). The bluefin tuna fishery sharks (Carbonell et al., 2003). in the Mediterranean is a matter of concern because of the marked expansion of the But there are also other local and/or well priced species caught in relatively small quantities like some species of flatfishes, Scorpaenidae, Figure B5.4 - Annual nominal catches ('000t) of Sparidae, Triglidae, Mugilidae, Serranidae, and selected species in ISSCAAP Group 56, some invertebrates. The last by-catch group is Mediterranean and Black Sea (Area 37) from time to time also relatively abundant but not Clams, cockles, arkshells, etc. always high priced species such as some 60 Scombridae and Carangidae, or from species with Striped venus low market acceptability like bogue or picarels (Spicara spp.). Discards are also important, and 40 the reasons for discarding diverse: illegal sizes, non-commercial species or sizes, or market reasons (Carbonell et al., 1998; Lleonart and 20 Maynou, 2003). It is worth noting the spectacular increase in 0 catches of striped venus, Chamelea gallina, 1950 1960 1970 1980 1990 2000 mainly in the Adriatic, reaching a maximum in Source FAO 1993 (Figure B5.4). This could reflect the Figure B5.5 - Annual nominal catches ('000t) of interaction of fishing with the transition from selected species in ISSCAAP Groups 45 & 57, oligotrophic conditions in the early period to Mediterranean and Black Sea (Area 37) close to mesotrophic conditions. 30 Cephalopod catches (Figure B5.5) show a 25 Deepwater rose shrimp maximum around 1990 that could in part reflect Common octopus Common cuttlefish 20 reduced abundance of large predatory fish as Common squids nei speculated by Caddy and Rodhouse (1998), but in most cases these are components in a mixed 15 groundfish fishery. The onset of deep water 10 trawling off the slope areas in the mid-1980s appears to explain the sharp rise in deepwater 5 rose shrimp catches, which are speculated to have benefited from a reduction in the biomass of 0 large hake in slope areas. 1950 1960 1970 1980 1990 2000 Source FAO Most of the gadoids, and other semi-pelagic Figure B5.6 - Annual nominal catches ('000t) of species such as bogue and picarel (Spicara spp.), selected species in ISSCAAP Groups 32 & 33, as well as red mullets (Mullus spp.), have shown 60 Mediterranean and Black Sea (Area 37) steady increasing trends over the whole time Surmullets (=Red mullets) nei 50 period, except for declines of several species in European hake the last few years. More remarkable is the case of Whiting hake which after reaching historic maxima in the 40 Bogue Picarels nei mid 1990 (more than 52 000 t), catches have dropped by more than half in 2002. The whiting, 30 only present in the Eastern Mediterranean, shows 20 also this general pattern with maximum around 1990 (Figure B5.6). 10 The prominent large pelagics are bluefin tuna 0 (Thunnus thynnus) and swordfish (Xiphias 1950 1960 1970 1980 1990 2000 gladius). They represent 3 percent of total Source FAO 52 farming/fattening activities of wild specimens, japonicus), and Atlantic mackerel (Scomber which contributes to increase the fishing pressure scombrus).

Load more