Effects of exotic and translocated fish species in the inland waters of Turkey

Transcription

1 Rev Fish Biol Fisheries (2006) 16:39 50 DOI /s y ORIGINAL PAPER Effects of exotic and translocated fish species in the inland waters of Turkey Deniz Innal Æ Füsun Erk akan Received: 4 August 2005 / Accepted: 10 June 2006 / Published online: 28 July 2006 Ó Springer Science+Business Media B.V Abstract Throughout the world a number of problems have arisen following the introduction of new fish species; impacts of introductions are not limited to biological and ecological effects but may also have socioeconomic implications. Exotic and translocated fish species have become established in various parts of the inland waters of Turkey since the 1950s. The present paper reviewed ecological and economical effects of introduced freshwater fish of Turkey. Keywords Exotic fish Æ Translocated fish Æ Inland waters of Turkey Introduction Globally, the biodiversity of freshwater systems is rapidly deteriorating as a result of human activities. The introduction of exotic species and the translocation of native species from one drainage system to another in the same country are widely accepted methods for enhancement of many natural waters around the world. Many D. Innal (&) Æ F. Erk akan Department of Biology, Hacettepe University, Beytepe Ankara, Turkey innald@yahoo.com F. Erk akan erkakan@hacettepe.edu.tr exotic species often appear in natural waters where these fish were unknown before. Introductions could be the result of accidents such as the careless release of live specimens from home aquaria, dumping unused bait fish or escapes from nearby aquaculture facilities. Other causes of exotic introductions include the negligent transfer of fertilized eggs of unknown species during stocking, opening connective channels with introduced fish to native habitats or simply undocumented stocking (Cowx 1998). The impact of introduced species is a neglected, worldwide ecological problem, especially in freshwater systems. Freshwater fish fauna are highly differentiated and isolated, particularly compared to marine fish. For this reason the introduction of freshwater fish, which is common worldwide mainly for aquaculture and angling related purposes, is especially harmful in terms of biodiversity. Fish species have been introduced in Turkey since the 1950s to promote angling diversity (Innal 2004a). A total of 25 exotic species have been introduced as eggs, fry or fingerlings for different purposes over the last five decades. Some of these fish have been used only in closed systems while others have been released into open inland waters throughout the country. Fourteen native species and members of two genus (Mugil and Liza) have also been translocated from their original systems to habitats

2 40 Rev Fish Biol Fisheries (2006) 16:39 50 elsewhere in Turkey. Gambusia sp. is possibly one of the earliest deliberate exotic introductions although there are no exact records. The aim of this paper is to describe these introducions and annotate known ecological and economic influences. The government s responsibility for both inland and marine fisheries and their management in Turkey is vested in the Ministry of Agriculture and Rural Affairs, the Ministry of Environment and Forestry and DSI (State Water Works). In the management of fish populations in Turkey, fish stocking plays a central role. Fish stocking in Turkey is primarily financed by the state and other agencies, e.g., hydro-electric power companies, universities and fisherman or fisheries organizations. Government fish culture is organized by the Fisheries Research Department and its eight aquaculture stations. The fish farms owned by fisheries associations and companies produce juveniles for commercial stockings. The state s fish cultivation stations are involved in comprehensive activities for many species and strains covering development of brood stock, egg hatching and juvenile rearing, using intensive artificial cultivation and natural food pond methods. Although many of the problems resulting from the introduction of non-native species into aquatic ecosystems have been highly publicized, comparatively little effort has been made to help the public understand or solve the problems created by this activity. Recent information on species introductions were collected by the Ministry of Environment and Forestry, State Water Works (DSI), Ministry of Agriculture and Rural Affairs, Ministry of Health Malaria Control Department, and other organizations involved with this matter. Fish introductions in Turkey In the following section we provide a map of Turkey showing water drainages where introductions have occurred (Fig. 1). Current available information on the status of introduced and translocated fish species is given in Tables 1 and 2. We also present selected data on the date and purpose of fish introductions derived from the literature and/or anecdotal evidence. Exotic fish introductions Family: Acipenseridae Acipenser baeri Brandt 1869 Siberian sturgeon is a potential candidate for commercialization and species diversification in Turkey, but further efforts are needed to establish hatchery techniques, i.e. the artificial propagation and juvenile production (Rad et al. 2003). This species is not currently found in natural aquatic habitats in Turkey. Family: Centracanthidae Lepomis gibbosus (Linnaeus 1758) This species was first recorded in Ipsala Canal (Edirne) in 1982 (Erk akan 1983). It was reported in the rivers Strymon (Kerkini) and Evros, probably after the release of fry or fingerlings by the Bulgarians (Economidis et al. 2000). Sası and Balık (2003) reported the species in Topçam Dam Lake (Aydın), Dirican and Barlas (2005) reported the species in Dipsiz and Çine streams. Family: Cichlidae Tilapia sp. Varieties of this species were introduced into the Adana and Hatay Region in the late 1970s (Çildir 2001). Tilapia rendalli, T. zilli, and Oreochromis aureus are found in cage culture in Seyhan Dam Lake and O. niloticus is found in Çukorova University s fisheries stations. Tilapia escaped from culture stations to Seyhan River and maintained viable populations (Dikel and Çelik 1998; Gökçe et al. 2003; Çelik and Gökçe 2003). O. mossambicus was introduced in Köyceğiz Lake (Çalıskan and Yerli 2000). Family: Coregonidae Coregonus laveratus (Linnaeus 1758) This species was introduced in Lake Iznik in 1954, but the first 3-year old fish was only caught 21 years later. Low production of this species was attributed to a number of factors including too few larvae stocked, stocking of larvae at too great a depth over unsuitable substrate, lack of suitable spawning sites with the right bottom and temperature regime, and the absence of a fully

3 Rev Fish Biol Fisheries (2006) 16: Rivers Lakes Source: General Command of Mapping-Turkey Fig. 1 Map of Turkey showing water drainage 1) Hamam Lake, 2) Kayalı Dam Lake, 3) Meric River, 4) Gala Lake, 5) Sultanko y, 6) Altınyazı, 7) Bu yu kçekmece Dam Lake, 8) Sapanca, 9) _Iznik, 10) Uluabat Lake, 11) Kaz Dag ları National Parks, 12) Kayabog azı Dam Lake, 13) Marmara Lake, 14) Demirko pru, 15) U rkmez, 16) Topçam, 17) Yaylakavak, 18) Mumcular, 19) Kemer Dam Lake, 20) Ko yceg iz Lagoon, 21) Kepez Water Products Station, 22) Karacao ren I dam Lake, 23) Go lcu k, 24) Burdur, 25) Eg irdir, 26) Beysehir, 27) C ivril Lake, 28) Selevir, 29) Porsuk Dam Lake, 30) Yedigo ller (Ku tahya), 31) Abant Lake, 32) Yedigo ller National Parks, 33) Filyos-Devrek Creek, 34) C amkoru Pond, 35) C ubuk II, 36) Bayındır Dam Lake, 37) Mogan Lake, 38) Kesikko pru, 39) Hirfanlı, 40) Damsa, 41) Mamasin, 42) Apa Dam Lake, 43) Go ksu Lagoon, 44) Ayrancı, 45) Seyhan, 46) Akko y, 47) Sarimsaklı Dam Lake, 48) Kızılırmak River, 49) Gelingu llu, 50) Almus, 51) Belpınar, 52) Yedikır, 53) Sarayo zu Dam Lake, 54) Bafra Lakes, 55) _Ikizdere and Fırtına Rivers, 56) Van, 57) Nazik Lake, 58) Nemrut Krater Lake, 59) Keban, 60) Cip, 61) C at Dam Lake developed pelagic fishery in the lake (Coad 1996a). Family: Cyprinidae Carassius auratus (Linnaeus 1758) The goldfish is found in park and garden ponds in various parts of Turkey. It is now common in many natural aquatic habitats. The original agent of introduction of this species in Turkey is unknown, but probably related to early introductions for aesthetic purposes. It was first introduced in the early 1990s in Eğirdir Lake (Izci 2004). It has also been reported in Keban Dam Lake (Duman and S en 2002), Kızılırmak River (Kayseri) (Aydın and Kuru 2003), Karacaören I Dam Lake (Becer and Ikiz 2001). Carassius carassius (Linnaeus 1758) This species was introduced in in EgirdirLake and 1995 in Lake Beysehir. The original agent of introduction is unknown, but it is suspected that these are unofficial and therefore private introductions made by personnel from the Kepez Aquaculture Products Station (Antalya) (Çildir 2001). It has also been reported in Karacaören I Dam Lake, Yedigölller (Kütahya) Lake, Hamam Lake (Kırklareli-Igneada), Marmara Lake (Izci 2004), Kayaboğazı Dam Lake (Alas et al.1998). Nazik Lake (Çetinkaya et al. 1999), Uluabat Lake (Balık and Çubuk 2001), Mumcular Dam Lake (Yılmaz 2004).

4 42 Rev Fish Biol Fisheries (2006) 16:39 50 Table 1 Introduced and translocated freshwater fish species in Turkey Species Native Introduced Translocated Hatchery closed systems Free water released Acipenser baeri + + Anguilla anguilla Atherina boyeri Lepomis gibbosus + + Tilapia rendalli Tilapia zilli Oreochromis aureus Oreochromis niloticus Oreochromis mossambicus + + Clarias gariepinus Clarias lazera Coregonus laveretus + + Carassius auratus + + Carassius carassius + + Carassius gibelio + + Ctenopharyngodon idella Cyprinus carpio Hypopthalmichthys molitrix + + Pseudorasbora parva + + Tinca tinca Alburnus chalcoides Alburnus tarichi Aphanius mento _Ichtalurus punctatus + + Ameiurus nebulosus + + Morone chrysops Morone saxatilis Mugil sp Liza sp Sander lucioperca Perca fluviatilis Gambusia affinis Gambusia holbroki Oncorynchus mykiss Salvelinus fontinalis Salmo salar Salvelinus alpinus + + Salmo trutta labrax Salmo trutta abanticus Salmo trutta macrostigma Silurus glanis Carassius gibelio (Bloch 1782) Sası and Balık (2003) reported that the first records of this species were given as Carassius auratus and Carassius auratus gibelio from Lake Gala and Büyükçekmece Dam Lake, respectively, from the Thrace region of Turkey. Özuluğ et al. (2004) reported there may have been two methods of introduction into this region: (1) they may have naturally dispersed through river systems from Greece and Bulgaria; or (2) they may have been intentionally introduced by people. Fishermen admitted in discussions that this species was introduced intentionally from Kayalı Dam Lake to Büyükçekmece Dam Lake. However they think that it was originally introduced in the course of fish stocking, especially together with Cyprinus carpio, and that C. gibelio was not discovered until now because of problems with identification. This species inhibits Kayalı Dam, Tunca Rivers, Sarıcaali Pond, Çöpköy Pond, Bülbüldere Pond, Ibriktepe Dam, Meriç River, Gala Lake, Çamlıca

5 Rev Fish Biol Fisheries (2006) 16: Table 2 Date and purpose of introductions Species Family Date of introduction Purpose of introduction Acipenser baeri Acipenseridae 1995 Research for aquaculture Anguilla anguilla Anguillidae 1955 Recreational fishing Atherina boyeri Atherinidae 1987 Recreational fishing Accidental Lepomis gibbosus Centracanthidae 1980s Accidental Tilapia rendalli Cichlidae 1970s Research for aquaculture Tilapia zilli Cichlidae 1970s Research for aquaculture Oreochromis aureus Cichlidae 1970s Research for aquaculture Oreochromis niloticus Cichlidae 1970s Research for aquaculture Oreochromis mossambicus Cichlidae 1970s Research for aquaculture Clarias gariepinus Clariidae 1990s Ornament Accidental Clarias lazera Clariidae 1990s Ornament Accidental Coregonus laveretus Coregonidae 1954 Recreational fishing Carassius auratus Cyprinidae 1990s Ornament Accidental Carassius carassius Cyprinidae 1990s Ornament Accidental Carassius gibelio Cyprinidae 1990s Accidental Ctenopharyngodon idella Cyprinidae 1985 Biological control Cyprinus carpio Cyprinidae 1950s Recreational fishing Hypopthalmichthys molitrix Cyprinidae 1960s Accidental Pseudorasbora parva Cyprinidae 1980s Accidental Tinca tinca Cyprinidae 1960s Recreational fishing Alburnus chalcoides Cyprinidae 1969 Improvement _ of wild stocks Alburnus tarichi Cyprinidae 1954 Recreational fishing Aphanius mento Cyprinodontidae 1990s Accidental Ichtalurus punctatus Ictaluridae 1990s Recreational fishing Ameiurus nebulosus Ictaluridae 1960s Doubtful Morone chrysops Moronidae 1999 Aquaculture (Farm escape) Morone saxatilis Moronidae 1999 Aquaculture (Farm escape) Mugil sp. Mugilidae 1950s Aquaculture (Farm escape) Liza sp. Mugilidae 1950s Aquaculture (Farm escape) Sander lucioperca Percidae 1955 Recreational fishing Perca fluviatilis Percidae 1995 Research for aquaculture Gambusia affinis Poecilidae 1920s Biological control Gambusia holbroki Poecilidae 1920s Biological control Oncorynchus mykiss Salmonidae 1969 Recreational fishing, aquaculture (Farm escape) Salvelinus fontinalis Salmonidae 1990s Aquaculture (Farm escape) Salmo salar Salmonidae 1990s Aquaculture (Farm escape) Salvelinus alpinus Salmonidae 2000s Research for aquaculture Salmo trutta labrax Salmonidae 1990s Improvement _ of wild stocks Salmo trutta abanticus Salmonidae 1980s Improvement _ of wild stocks Salmo trutta macrostigma Salmonidae 1990s Aquaculture (Farm escape) Silurus glanis Siluridae 1969 Improvement _ of wild stocks Creek, Kavaklı Stream, Kınıklı Stream, Büyükçekmece Dam Lake, Pond of Istanbul Technical University. It was introduced into Eğirdir Lake at the beginning of the 1990s (Çildir 2001) and Çivril Lake (Balık et al. 2004). Ctenopharyngodon idella (Valenciennes 1844) This species was introduced into Lake Pamvotis Hatchery during the 1980s and from there it was transferred to some lakes and rivers, including the Evros River in the Thrace region (Economidis et al. 2000). Grass carp have been introduced in various reservoirs and canals of Turkey for control of excessive growth of aquatic plants. DSI has a hatchery in Edirne-Ipsala (Thrace region) Izmir-Ürkmez, Elazığ-Keban and Adana-Seyhan to produce Ctenopharyngodon idella, but the population has not been maintained. This species was introduced into Marmara Lake (Manisa), Seyhan Dam Lake (Adana), Belpınar Ponds (Tokat), Sarayözü Ponds (Amasya), Cip Dam Lake (Elazığ), Çat Lake (Malatya), Sultan Köy reservoir (Edirne), Altınyazı Reservoir (Edirne), Karademir Reser-

6 44 Rev Fish Biol Fisheries (2006) 16:39 50 voir (Tekirdağ), Gala Lake (Edirne), and Yaylakavak Reservoir (Aydın) (Anonymous 2001). It was also introduced into Alaplı pond by Ankara University for biological control (Kırkağaç and Pulatsu 2001). Pseudorosbora parva (Temminck & Schlegel 1846) This species was introduced accidentally into many European drainages, including the Thrace region of Turkey. The first records of P. parva in Turkey were reported by Erk akan (1984) from the Thrace region. In addition, this species was introduced into the Antalya Basin (Küçük 1997) and Karacaören I Dam Lake (Becer and Ikiz 2001). It has also been introduced into Gelingüllü Dam Lake (Ekmekçi and Kırankaya 2004). The authors observed it in Filyos-Devrekcreek in Hypopthalmichthys molitrix (Valenciennes 1844) Economides et al. (2000) reported that the silver carp has been widely introduced in Europe specifically to control excessive phytoplankton growth in natural waters. It was introduced to Bulgaria during the 1960s and escaped into Greek areas of the Evros (Meriç) River. Although no official documentation supports its occurance in Turkey, it probably inhibits parts of the Evros River in Turkey through natural colonization from Grece. Family: Ictaluridae Ameiurus nebulosus (Le Sueur 1819) This species was recorded from the Tigris- Euphrates basin in Turkey (Erençin et al. 1971) However, this probably was a misidentification of a native species of Glyptothorax from the family Sisoridae (Coad 1996b). Ichtalurus punctatus (Rafinesque 1818) This species was introduced in early 1990s into Lake Eğirdir (Çildir 2001).This species inhabits rivers and streams and prefers clean, well oxygenated water. Therefore, these introductions were unsuccessful. It is assumed that there was no impact on Lake Egirdir from these introductions (Çildir 2001). Family: Moronidae Morone chrysops (Rafinesque 1820) and Morone saxatilis (Walbaum 1792) Hybrid striped bass (Morone chrysops $ Morone saxatilis #) were cultured in Kemer Dam Lake, Aydın (Güner et al. 2006). Family: Percidae Sander lucioperca (Bogutskaya & Naseka 1996) The first recorded introductions of this species were in Eğirdir Lake and Marmara Lake in DSI is responsible for the introduction of Sander lucioperca into Apa Reservoir (Konya), Ayrancı Reservoir (Konya), Çubuk 2 Dam Lake (Ankara), Demirköprü Dam Lake (Manisa), Mamasın Dam Lake (Nigde) Sarımsaklı Dam Lake (Kayseri), Hirfanlı Dam Lake (Kırsehir), Damsa Dam Lake (Kırsehir), Seyhan Dam Lake (Adana), Lake Gölcük (Isparta), Selevir Dam Lake (Afyon) (Anonymous 1988) However, there is no evidence that deliberate introductions of this species in other inland waters of Turkey. Family: Poeciliidae Gambusia affinis (Baird & Girard 1853) and Gambusia holbroki Girard 1859 These species are possibly one of the earliest deliberate introductions of freshwater fishes in Turkey although there are no exact records of early introductions. Gambusia was brought to Turkey by the French for controlling malaria and was introduced into Lake Amik (Oztürk and Ikiz 2004). Family: Salmonidae Oncorynchus mykiss (Walbaum 1792) This species was probably first introduced in Turkey in 1969 into Yedigöller (Bolu) National Research Park (Uysal and Alpbaz 2002). Since 1969 Fry and fingerlings of rainbow trout are released to water bodies by the Ministry of Agriculture and Rural Affairs, General Directorate of State Hydraulic Works, to some internal forest waters by General Directorate of National Parks and Game Wildlife. Approximately 2 million trout is produced annually from six trout hatchery

7 Rev Fish Biol Fisheries (2006) 16: stations (Bolu-Gölköy, Elazığ-Keban, Antalya- Kepez, National Parks of Yedigölller, Nif Mountain and Baldıran Trout Breeding Stations that was privatized) (Anonymous 2001). Salmo salar (Linnaeus L. 1758) and Salvelinus fontinalis (Mitchill 1814) Karatas et al. (2003) reported that Atlantic salmon (Salmo salar) farming started on the Black Sea coast of Turkey in Eggs were imported from Norway and raised in incubators at the Sapanca Hatchery of the Fisheries Faculty of Istanbul University from where they were transported in tanks to the Black Sea and placed in cages for rearing. S. fontinalis has been cultured commercially in the eastern Black Sea region of Turkey as a secondary species on rainbow trout (Oncorhynchus mykiss) farms (Basçınar et al. 2003). S. salar and S. fontinalis now occasionally appear in inland waters of Black Sea coast apparently after escaping from fish farms. Salvelinus alpinus (Linnaeus 1758) This species was introduced into Atatürk University, fishery research center, in order to test performance and weight conditions (Haliloğlu et al. 2002). Translocated fish Family: Anguillidae Anguilla anguilla (Linnaeus 1758) This species was transplanted into Burdur Lake (Anonymous 1996). However, these introductions were unsuccesful (Anonymous 1996). Family: Atherınidae Atherina boyeri (Risso 1810) Altun (1999) reported this species in Büyükçekmece and Küçükçekmece Lakes, _ Iznik Lake, Sapanca Lake, Köyceğiz Lake and Güzelhisar River. It was first noticed in large numbers at Lake _ Iznik in Local fishermen are responsible for the introduction of this species. The authors observed it from Hirfanlı Dam Lake, Beysehir Lake and Mogan Lake in Family: Clariidae Clarias gariepinus Burchell 1822 This species lives naturally in lakes, fishponds, streams, and natural ponds in both deep and shallow waters. Catfish are found along the Mediterranean region extending from Hatay to Antalya and around Eskisehir (Yalçın et al. 2001). It was probably introduced in streams and canals of the Eskisehir region. Clarias lazera (Cuv and Val 1840) Clarias lazera is of high economic significance and is consumed especially in the southern part of Turkey. It was transplanted into Göksu Lagoon (Ergene et al. 1999) and the Sakarya River. The agent of introduction and date is unknown. Family: Cyprinidae Alburnus tarichi (Bogutskaya 1996) Alburnus tarichi is an endemic cyprinid species of the Lake Van basin. This species was stocked in Burdur Lake, Turkey as a potential food fish (Aksıray 1982). However, factory wastes depleted oxygen levels in the bottom layers of the lake, reducing the available habitat and productivity (Aksıray 1982). Alburnus chalcoides (Guldenstaedt 1772) This species was transplanted by DSI. The first recorded transfers were into Akköy Dam Lake (Kayseri) in 1969, Isparta Gölcük Lake in , Sarımsaklı Dam Lake (Kayseri) in , Bayındır Dam lake (Ankara) in 1971, Gölköy (Bolu) Lake in 1975 (Anonymous 1988). It has successfully maintained populations in these areas. Cyprinus carpio (L. 1758) This species is one of the first transplanted species of Turkey. Transplantation started in the 1960s by the Ministry of Agriculture and Rural Affairs and Ministry of Environment and Forestry and DSI. Successful populations derived from escapes and releases remain in many inland waters resulting in a highly productive fishery in Turkey.

8 46 Rev Fish Biol Fisheries (2006) 16:39 50 Tinca tinca (L. 1758) This species is wide-spread in Europe and adjacent regions. It resides in rivers and lakes flowing into the Black Sea, Thrace and Northern Anatolia. Local fishermen are responsible for the introduction. This species successfully maintains populations in Turkish inland waters. Transplantation studies of T. tinca have been conducted in areas of poor quality water. Therefore, tench could become important in dammed lakes in the future in Turkey for cleaning and mineralization of the waters (Yılmaz 2002). It was introduced into Kayaboğazı Dam Lake (Alas et al. 1998), Kesikköprü Dam Lake (Altındağ et al.1998), Porsuk Dam Lake (Yılmaz 2002), Çivril Lake (Balık et al. 2004), Bayındır Dam Lake (Altındağ et al. 2002), Çamkoru Pond (Innal 2004b). Family: Cyprinodontidae Aphanius mento (Heckel 1843) Çildir (2001) reported a form of this species that was introduced into Nemrut Krater Lake in 1980s where it was not found earlier. It was possibly introduced accidentally along with Gambusia. Family: Percidae Perca fluviatilis (L. 1758) DSI has a hatchery in _ Izmir-Ürkmez to produce Perca fluviatilis. This species was introduced into Ürkmez Dam Lake ( _ Izmir) in order to test performance and weight conditions (Anonymous 2001). Family: Salmonidae Salmo trutta labrax (Pallas 1811) This species is endemic to the Eastern Black Sea regions. Aydın and Yandı 2002 reported Spawning areas of this species in Turkish rivers have been destroyed by pollution, illegal fishing, deforming river beds and construction of dams. Improvement of wild stocks The Ministry of Agriculture and Rural Affairs, Central Fisheries station started to produce fingerlings. Salmo trutta abanticus (Tortonese 1954) and Salmo trutta macrostigma (Dumeril 1858) Salmo trutta abanticus is endemic to Lake Abant. The authors observed it was transplanted for improving wild stocks to Abant Lake and the nearest creeks by the DSI and the Ministry of Environment and Forestry. S. trutta macrostigma was cultured on some farms in Turkey. Family: Siluridae Silurus glanis (Linnaeus 1758) Two Silurus species inhabit in Turkish freshwaters: Silurus glanis has a wide range and Silurus triostegus inhabits the Euphrates Basin. Because of its economic importance, S. glanis has attracted interest as a potential species for fish culture. Introduction started in Kemer Dam Lake (Aydın) in , Almus Dam Lake (Tokat) in , Yedikır Reservoir (Amasya), Cip Dam Lake (Elazığ), (Anonymous 1988, 2001) DSI is responsible for all introductions. This species was transplanted from Terkos Lake to Büyükçekmece Dam Lake by fisherman in 1989 (Meriç 1992). Successful populations still occur in Turkish inland waters. Discussion The number of introduced fish has apparently increased in recent years and the variety of freshwater fish fauna has changed in Turkey. The Ministry of Environment and Forestry, Ministry of Agriculture and Rural Affairs, DSI, Fishery Science Faculty of Universities and local fisherman are responsible for many introductions. It may have started in Burdur Lake, where there was no economically productive fish species until Murat the III, Sultan of Ottoman, in (Aksıray 1982). Introductions were primarily driven by the need for economical stocks in order to find suitable fish species for this lake. As a result of these investigations, Anguilla anguilla was stocked, but the original population has not maintained (Anonymous 1996) and another eco-

9 Rev Fish Biol Fisheries (2006) 16: nomical fish species Alburnus tarichi from Van Lake was found to be suitable for Burdur Lake. This species is bred by artificial insemination in the lake. However, factory wastes have depleted oxygen levels in the bottom layers of the lake reducing the available habitat and this economically valuable stock could not reach an adequate self-sustaining level (Aksıray 1982). The mosquito fish was introduced into fresh water systems in Turkey for malaria control as an important alternative to pesticides. Gambusia affinis, introduced in various habitats for mosquito control, is known to be a threat to other fish. The species presence should be regarded as a serious threat to populations of A. anatoliae transgrediens in Lake Acı (Wildekamp and Valkenburg 1994). Çildir (2001) reported that in 1955 approximately 10,000 young Sander lucioperca (= Zander) of cm length imported from Austria were translocated into Lake Eğirdir by the Hydro Biological Research Institute (University of Istanbul). The apparent aim was to improve the fisheries of the lake. The fishery was widely practiced in central Europe at the time before transplantation and ten fish species were reported to exist in the lake: Cyprinus carpio, Vimba vimba, Capoeta pestai, Acanthorutilus handlirschi, Thylognathus klatti, Aphanius chantrei, Cobitis taenia, Orthrias angorae, Schizothorax propyhlax and Pararhodeus niger. Of these S. prophylax and P. niger were apparently misidentified since these fish are not among the fauna of Turkey. However they are presumed to represent Phoxinellus zeregi and P. anatolicus, respectively. Twenty three years later in 1978 the only significant population left in the lake (apart from Zander) was carp (Cyprinus carpio), Vimba vimba and Varicorhinus pestai (= Capoeta pestai). Zander is the only species with a large stock, while carp and Vimba vimba catches have declined sharply. Most recent data evaluations indicate while P. anatolicus, O. angorae, Seminoemacheilus lendli and Hemmigramocapoeta kemali are still surviving in some numbers, Phoxinellus egridiri, P. handlirschi, P. zeregi are suspected to have gone extinct. After introduction of Zander to Beysehir Lake, the number of fish species have been decreasing drastically. The three species presumed extinct were endemic to Turkey. Cyprinus carpio was first cultured in Turkey at the beginning of 1960s. It successfully maintains populations from escapes and releases throughout Turkey. In the beginning of 1990s the introduction of carp (C. carpio) in Kara Lake (Nigde) threatened an endemic Toros amphibian, Rana holtzi (Innal 2004a). At the beginning of 1970s DSI started to stock Silurus glanis and Alburnus spp in some reservoirs. Oncorynchus mykiss was introduced into Yedigölller (Bolu) National Research Park (Uysal and Alpbaz 2002). The Ministry of Environment and Forestry, Ministry of Agriculture and Rural Affairs, DSI are responsible for later introductions of this trout. Dammed lakes have been used for rainbow culture in Turkey, but insufficient oxygen levels have impacted these populations. Stocked trout have influenced the native salmonid Salmo trutta abanticus in Abant Lake (Innal 2004a). Trout aquaculture grew rapidly in Turkey. Species originally introduced for aquaculture eventually escaped from the confinement of their ponds or cages and often but not always colonized natural waters. Salmon have been cultured Black Sea region as alternatives for rainbow trout since After the 1970s, technological and economic development have brought marked changes in the condition of the Turkish lakes and rivers which have been significantly affected by damming of rivers, clearing of obstructions, dredging, flood control measures, regulation of water levels and stream flows, water pollution and forest ditching. The stocks of many valuable river-spawning migratory fish species have been seriously damaged by the river damming and construction operations. The introduction of tench (Tinca tinca) is not of commercial importance in Turkey owing to its slow growth rate and tasteless flesh. However, it is used for cleaning carp pools and aiding mineralization in aquatic systems of poly-culture. This species is used for this purpose in Turkey. Transplantation studies of T. tinca have been conducted in areas of poor quality water. It has caused a decline in the catch of carp (Cyprinus carpio). Carp cannot maintain

10 48 Rev Fish Biol Fisheries (2006) 16:39 50 economical populations in sympatry with Tinca tinca, since there is competition between T. tinca and C. carpio in Kayaboğazı Dam Lake. Tench are very well adapted and has been the dominant population for some time. In order to increase the density of mirror carp, it will be necessary to control the tench population in this lake (Alas et al. 1998). Carp has been stocked in Çamkoru pond since reservoir construction, but in competition with tench, Carp has not maintained viable populations (Innal 2004b). Various fish species are used in Turkey for experimental studies in weed and organic matter control, physiology, ecology, genetics, medical and other disciplines. Oreochromis and tilapia were introduced into Adana and Hatay Region by Çukurova University. DSI cultivates Ichtalurus punctatus, an exotic herbivorous fish used to control aquatic vegetation. However, introductions have so far been unsuccessful. DSI has hatcheries in Edirne, _ Izmir, Elazığ and Adana to produce Ctenopharyngdon idella, but its growth, condition and performance is not yet known. There were new records of introductions for the Thrace region of Turkey in the beginning of 1980s. The main route for alien freshwater fish immigration seems to lead from Greece and Bulgaria via the River Meriç, but also by intentional stocking of foreign fishes. Lepomis gibbosus and Pseudorasbora parva are exotic species recently reported from Thrace region (Erk akan 1983, 1984). Pseudorasbora parva and Lepomis gibbosus have become widespread in lakes and reservoirs of Turkey and the effects of their presence on these systems are still unknown. At the end of 1980s Atherina boyeri was noticed in _ Iznik Lake. It previously occurred in Marmara Lagoons. Recently it has been found to inhibit _ Iznik Lake, Mogan Lake, Hirfanlı Dam Lake and Beysehir Lake. Local fishermen were responsible for these introductions and it has become common and abundant and seems to be expanding to other reservoirs. At the beginning of 1990s Carassius sp. was introduced into our fresh water systems. The Carassius gibelio population increased rapidly in Eğirdir Lake, and now it is the dominant fish species. Fishing pressure on this species is insufficient. The silver crucian carp population and those of other cyprinids, such as the common carp, Cyprinus carpio L., 1758 and Vimba vimba L., 1758, in the lake may be negatively affected in the future (Balık et al. 2004). Yılmaz (2004) reported that Carassius carassius is competing with Cyprinus carpio for food and space in Mumcular Dam Lake and Izci (2004) reported that C. auratus has been used for balance of carnivore/omnivore fauna and as an alternative to S. lucioperca for fisherman in Eğirdir Lake. At the end of 1990s trout (Salvelinus fontinalis, Salmo salar and Salvelinus alpinus) and Hybrid striped bass production were started. The escape of fish from aquaculture facilities also may be harmful to the environment. References Aksıray F (1982) Environmental factors limiting the spreading out of Chalcalburnus tarichi (Pall, 1881) breeded in Burdur Lake (In Turkish with English summary). Atatürk Univ J Sci Fac 1(1):20 28 Alas A, Yılmaz F, Solak K (1998) Adaptation and competition of tench (Tinca tinca L., 1758) implanted to the Kayaboğazı Dam Lake (Tavsanlı-Kütahya). The Proceedings of the First International _ Symposium on Fisheries and Ecology Altındağ A, Shah SL, Yiğit S (2002) The growth features of tench (Tinca tinca L., 1758) in Bayındır Dam Lake. Turk J Zool 26: Altındağ A, Yiğit S, Ahıska S (1998) The growth features of tench (Tinca tinca L., 1758) in the Kesikköprü Dam Lake. Turk J Zool 22: Altun Ö (1999) Morphological variations observed on the Sand Smelt (Atherina boyeri Risso, 1810) populations (In Turkish with English summary). Turk J Zool 23(3): Anonymous (1988) Bulletin of water products DSI (State Water Works). Republic of Turkey, Ankara, 73 pp Anonymous (1996) Report on Burdur. Prime Ministry State Planning Organization. Republic of Turkey, Ankara, Reference No: 2463, 96 pp Anonymous (2001) Bulletın of statistics DSI (State Water Works). Republic of Turkey, Ankara, 571 pp AydınDÖ, Kuru M (2003) Karyotype of the Carassius auratus (L., 1758) live in Kızılırmak (Kayseri Turkey) (In Turkish with English summary). Gazi Univ J Edu Fac 21(3):33 37 Aydın H, Yandı I (2002) The general status of spawning areas of Blacksea trout in the East Blacksea Regions (Salmo trutta labrax Pallas, 1811) (In Turkish with English summary). Ege Univ J Fish Aqu Sci 19 (3 4): BalıkI, Çubuk H (2001) Selectivity of gillnets on fishing roach (Rutilus rutilus L., 1758) and shad (Alosa maeotica Grimm, 1901) in lake Uluabat (Apolyont)

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