Status of alien species in the Mediterranean and Black Sea

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12 The changes in the Black Sea ecosystem that have occurred since the 1960s due to the concurrent impacts of eutrophication, overfishing, climatic fluctuation and alien species invasions have been studied extensively. A synthesis provided recently in State of the Environment Report (BSC, 2008) examines the changes in pelagic and benthic ecosystems. The Black Sea’s biodiversity clearly reflects its geological history. Brackish water fauna known as “Caspian relics” originated from the Neoeuxinian Lake, and the components of this fauna are found only in waters with low salinity. Some bivalves, such as Dressenia, and fishes, such as gobies and sturgeons, are good examples. Another group of species is called “cold water relics” and includes ctenophores (Pleurobrachia), copepods (Calanus), and fishes such as spiny dog fish, sprat, flounder and whiting (Zaitsev and Mamaev, 1997), (Öztürk and Öztürk, 2005). This group is the second oldest inhabitants of the Black Sea, entering the sea between the Neoeuxine Lake Period and the early stage of the formation of the Istanbul Strait (Bosphorus). After the Istanbul Strait (Bosphorus) established a connection with the Mediterranean Sea about 7 000–10 000 years ago, the salinity of the Black Sea rose gradually and soon the Mediterranean species were established in the Black Sea. Today, 80 percent of total fauna in the Black Sea is of Mediterranean origin. According to Slastenenko (1959), the Black Sea received more than one third and about one fifth of its fauna from the Aegean Sea and the Mediterranean Sea, respectively. The last group of species is called “alien species”, which includes those introduced either intentionally or unintentionally by human activities from the various seas and oceans of the world. 1.2 Vectors for the alien species in the Black Sea In recent years, the Black Sea has become home for a large number of alien plants and animals. There are three main vectors for alien species to reach the Black Sea. These are: a) shipping activities, which is the most common way; b) intentional or unintentional introduction by humans; c) Mediterranization, which means that Mediterranean originated species pass all ecological barriers in the Turkish Straits and penetrate to the Black Sea. 1.2.1 Shipping activities The most common way of invasion of alien species is via ocean-going ships. Marine organisms usually travel either as a part of the fouling attached to ship hulls either in tank sediment or in ballast water. (Zaitsev and Mamaev, 1997; Zaitsev and Öztürk, 2001; Öztürk 2002a;b; Gomiou et al., 2002; Streftaris et al., 2005). Shipping activities are intense in the Black Sea mainly due to the Caspian petrol transportation from Novorossisk, the Russian Federation, to the Mediterranean countries via Turkish Straits (Figure 3). It is also known that the largest unintentional pathway for the transport of marine organisms is the ballast water of commercial vessels and a typical commercial bulk vessel may carry over 30 000 metric tonnes of ballast water to provide stability and trim adjustment during a voyage (cited in Wonham et al., 2000). Hundreds of algal and animal species, both microorganisms and even smaller organisms, are known to travel by attaching themselves to the hulls of the ship. Most of them are attached to the living substrate such as algae, clams and barnacles. However active non-sessile forms can also be found, such as amphipods, shrimps, crabs and fishes. When the ship is in motion they hide in barnacles and other similar shelters, so as not to be swept away by the current. Ballast water pumped to tanks to stabilize a ship when it is not carrying any cargo. When ships fill their ballast tanks in ports or sometimes in certain areas, suspended matter and various planktonic organisms are also pumped into the tanks with the water. Many organisms survive the trip in the ballast water or sediment, sometimes as spores and eggs. Upon arrival at the ship’s destination, the ballast water is discharged into the sea and the organisms find themselves in a new environment. If the
13 conditions are favorable to their particular needs, the organisms may survive and even become naturalized. The huge number of ocean-going ships means that many new species are introduced into new environment constantly. Figure 3 – Main shipping routes in the Black Sea 1.2.2 Intentional or unintentional introduction by humans Several alien species have been introduced to the Black Sea for aquaculture or other reasons. The mosquito fish Gambusia affinis is a good example of this type of introduction. This fish is well known for its ability to feed on neuston larvae and mosquito eggs, including those species which transmit malaria. It was, thus, introduced to the wetlands to combat malaria in the entire Black Sea basin. After the fish was adapted and reproduced, Gambusia turned to euryhaline species. Today Gambusia is widespread in the Black Sea basin. There are several examples of intentional introduction to the Black Sea. 1.2.3 Mediterranization effects This is a relatively new phenomenon and the reason for the invasion of the Mediterranean originated species to the Black Sea seems to be related to water temperature rise as a consequence of climate change (Oğuz, 2005). Even though the Turkish Straits (Istanbul and Çanakkale Straits) serve as an ecological barrier for these species due to totally different oceanographic peculiarities of the Black Sea from the Mediterranean Sea, some phyto and zoo plankton species penetrate to the Black Sea (Georgieva, 1993; Kovalev, 2006; Selifinova et al., 2008). Because of the temperature rise due to the climate change, some Mediterranean fish species have also penetrated into the Black Sea, such as sardine, bouge and wrasse, in recent years. 1.3 Alien species in the Black Sea Twenty-six alien species from the Black Sea have been described by Zaitsev and Mamaev (1997). According to Zaitsev and Öztürk (2001), there are 59 species of alien marine organisms in the Black Sea and only a few species have been well studied, in terms of the impacts on fisheries, such as whelk Rapana and a ctenophore Mnemiopsis leidy. Çinar et al. (2005) reported 20 alien species from the Turkish part of the Black Sea. Alexandrov et al. (2007) reported 240 alien species from the Ukrainian
Page 1 and 2: GENERAL FISHERIES COMMISSION FOR TH
Page 3 and 4: iii PREPARATION OF THIS DOCUMENT Th
Page 5 and 6: v CONTENTS EXECUTIVE SUMMARY ......
Page 7 and 8: vii LIST OF FIGURES Figure 1 - The
Page 9 and 10: EXECUTIVE SUMMARY 9 Biota of the Bl
Page 11: 11 Figure 1 - The Black Sea The pre
Page 15 and 16: 15 This species comes originally fr
Page 17 and 18: 17 depends on the size of the comb
Page 19 and 20: 19 respectively. The former two ass
Page 21 and 22: 21 Figure 7 - Anchovy catch and cte
Page 23 and 24: 23 these lessepsian migrants need t
Page 25 and 26: 25 these organisms. They need to be
Page 27 and 28: 2. STATUS OF ALIEN SPECIES IN THE M
Page 29 and 30: 29 Table 2.1 - List of alien specie
Page 31 and 32: 31 increasing steadily until 1999 (
Page 33 and 34: 33 Figure 16 - Catch of Rapana veno
Page 35 and 36: 35 Marmara Sea interactions should
Page 37 and 38: 37 Mediterranean Sea (Figure 19). S
Page 39 and 40: 39 Figure 20 - Main routes of shipp
Page 41 and 42: 41 Figure 22 - The Suez Canal (Por,
Page 43 and 44: 43 vessel-transported and 4 percent
Page 45 and 46: 45 Mediterranean ichthyofauna and t
Page 47 and 48: 47 Species name Fisheries* Aquacult
Page 49 and 50: Syrian Arab Republic 49 Saad (2005)
Page 51 and 52: 51 Iskenderun Bay, Penaeus kerathur
Page 53 and 54: 53 4. HARMFUL ALIEN SPECIES AND IMP
Page 55 and 56: 55 Table 4.3 - Harmful alien specie
Page 57 and 58: 57 empty niches to establish themse
Page 59 and 60: 59 Besides C. taxifolia, C. racemos
Page 61 and 62: 61 According to the protocol concer
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REFERENCES 63 Akçali, B. and Cirik
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65 Gravez, V., (eds). First Interna
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67 Düzgünes, E., Şahin, C., Baş
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69 of YugNIRO Complex Researches in
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71 Lasram-Rais, B.F. and Mouillot,
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73 Öztürk, B., Poyraz, Ö. and Ö
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75 Shiganova, T.A., Tarkan, A.N., D
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77 Yokes, B. and Galil, B.S. 2006b.
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Species Origin Vector Gibborissoa v
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Species Origin Vector Chrysallida m
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Species Origin Vector Caloria indic
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Species Origin Vector Tellina valto
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87 Appendix 2 (a): List of lessepsi
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Appendix 2 (b): List of non-lesseps
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91 Appendix 3: Species number and d
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Species 93 Origin Aegean Marmara Bl
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95 Champsodon nudivittis (Ogilby, 1
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Saurida undosquamis Scomberomorus c
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Sillago shiama Siganus rivulatus Si
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Marsupenaeus japonicus Melicertus h
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Mnemiopsis leidyi Rhopilema nomadic
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Status of alien species in the Mediterranean and Black Sea

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