Anthropogenic Influence and Conservation Status of Autochthonous Fish Fauna from Lake Ohrid

Anthropogenic Influence and Conservation Status of Autochthonous Fish Fauna from Lake Ohrid

Anthropogenic Influence and Conservation Status of Autochthonous Fish Fauna from Lake Ohrid Trajce Talevski, Hydrobiological Institute, Naum Ohridski, 50, 6000 Ohrid, R.Macedonia, email: [email protected] Dragana Milosevic, Department of biology, Faculty of Science and Mathematics, University of Montenegro, Podgorica. Montenegro email: [email protected] Aleksandra Talevska, Faculty of Science and Mathematics, Institute for biology, University St. Kiril and Metodij, Skopje, R.Macedonia email: [email protected] Abstract Lake Ohrid is transboundary lake between R.Macedonia and R.Albania. It is the deepest lake of the Balkan, with a maximum depth of 297 and a mean depth of 155 m. Lake Ohrid is special as such, by far the most spectacular quality is its impressive endemism from cyprinid and salmonid fish. This paper is result of long-term researches of ichthyofauna from Lake Ohrid. The materials for researches were collected by day and nighttime’s experimental fishing with various fishing gill net. Conservation status of autochthonous fish fauna from Lake Ohrid was determinate according to IUCN (2001) and Kotellat and Freyhof (2007). Key words: anthropogenic influence, autochthonous fish fauna, conservation status, Lake Ohrid Intoduction IUCN Red List of Threatened Species (also known as the IUCN Red List or Red Data List), founded in 1948, is the world's most comprehensive inventory of the global conservation status of plant and animal species. The International Union for the Conservation of Nature and Natural Resources (IUCN) is the world's main authority on the conservation status of species. The IUCN Red List is set upon precise criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world. The aim is to convey the urgency of conservation issues to the public and policy makers, as well as help the international community to try to reduce species extinction. IUCN Red List is widely considered to be the most objective and authoritative system for classifying species in terms of the risk of extinction. The IUCN aims to have the category of every species re-evaluated every 5 years if possible, or at least every ten years. This is done in a peer reviewed manner through IUCN Species Survival Commission (SSC) Specialist Groups, which are Red List Authorities responsible for a species, group of species or specific geographic area. Species are classified in groups, set through criteria such as rate of decline, population size, area of geographic distribution, and degree of population and distribution fragmentation. • Extinct (EX) - No individuals remaining. • Extinct in the Wild (EW) - Known only to survive in captivity, or as a naturalized population outside its historic range. • Critically Endangered (CR) - Extremely high risk of extinction in the wild. • Endangered (EN) - High risk of extinction in the wild. • Vulnerable (VU) - High risk of endangerment in the wild. • Near Threatened (NT) - Likely to become endangered in the near future. • Least Concern (LC) - Lowest risk. Does not qualify for a more at risk category. Widespread and abundant taxa are included in this category. • Data Deficient (DD) - Not enough data to make an assessment of its risk of extinction. • Not Evaluated (NE) - Has not yet been evaluated against the criteria. When discussing the IUCN Red List, the official term "threatened" is a grouping of three categories: Critically Endangered, Endangered, and Vulnerable. Changes in numbers of species in the threatened categories (CR, EN, VU) from 1996 to 2009 is given in Tab.1. BALWOIS 2010 - Ohrid, Republic of Macedonia - 25, 29 May 2010 1 Table 1: Changes in numbers of species in the threatened categories (CR, EN, VU) from 1996 to 2009 (only for the major taxonomic groups on the Red List) Fishes 1996/98 2000 2002 2003 2004 2006 2007 2008 2009 Critically Endangered (CR) 157 156 157 162 171 253 254 289 306 Endangered (EN) 134 144 143 144 160 237 254 269 298 Vulnerable (VU) 443 452 442 444 470 681 693 717 810 In Macedonia in the IUCN Red List are included species from fauna and flora: Mammals - 5, Birds - 10, Reptiles – 2, Amphibians – 0, Fishes – 14, Molluscs – 0, Other Inverts – 5, and Plants 0. 5, respectively the number of total threatened species in Macedonia is 36. Investigated area Transboundary Lake Ohrid is considered to be the oldest continuously existing lake in Europe with an age of likely three to five million years. Located in a tectonic graben, the lake is amongst the few worldwide lakes existing since the Tertiary. Another peculiarity of Lake Ohrid is its extraordinary high degree of endemism, including more endemic species. Taken its size into account, Lake Ohrid has the highest degree of endemism worldwide. Therefore, Lake Ohrid is one of the very few lakes in the world representing a hot spot of evolution and a potential evolutionary reservoir enabling the survival of relict species. The proposed continuous existence since the Tertiary makes Lake Ohrid an excellent archive of long and short term environmental changes in the central northern Mediterranean region. It is the largest and deepest lake in the group and in the Aegean lake zone representing refugium for numerous species whose close relatives on Balkan Peninsula and wider in southeast part of Europe can be found only on fossil forms (Stankovic, 1960). Lake Ohrid (Fig. 1.) is located in the Sara-Pindus caustic massif. It fulfill the deepest part oh Ohrid valley (40,54' - 41,10'N and 20,38'-20,49'E) in the southwest part of Republic of Macedonia, sharing its southwestern basin with Republic of Albania. At sea level of 693.75 m it has a surface area of 358 square kilometers of which 240 belong to Republic of Macedonia and 118 to Republic of Albania. Maximal length of Lake Ohrid is 30.48 km, maximal width 15 km and means width of 11.79 km. Maximal depth is 289 m, mean depth of 164 m, volume of 58.64 cubic kilometers and retention time of about 83.6 years. Lake Ohrid is an oligotrophic, cold oligomictic, calcareous, graben, marl lake, mostly fed with spring water. The lake is supplied with water from a number of springs. The most important ones are those near the monastery of St. Naum, the well known Biljanini Izvori R.Macedonia (Biljana Springs). Considerable amount of this spring water (over 56%) originate from neighboring Lake Prespa, located on about 150 m higher sea level, and separated from Lake Ohrid by carstic massif of Galicica mountain. There are 40 tributaries (23 on Albanian and 17 in Macedonia side) flowing in to Lake Ohrid of which most are torrents and are flowing temporally The water Lake Ohrid flows out of the Lake through the river Crn Drim. Lake Ohrid belong to lakes that had been researched (more or less continuously) since the end of the 19 th century. Great number of these researches is for the systematic of enormous relict and endemic species which inhabiting Lake Ohrid. Most of the researches done later have confirmed the relictness, endemicity and sublacustrine speciation of this in most cases, unique ancient lake and its living world. Material And Methods The materials for researches were collected by day and nighttime’s experimental fishing with various fishing gill R.Albania net. Conservation status of autochthonous fish fauna from Lake Ohrid was determinate according to IUCN (2001) and Kotellat & Freyhof (2007). Figure 1. Map of Lake Ohrid BALWOIS 2010 - Ohrid, Republic of Macedonia - 25, 29 May 2010 2 Results And Disscusion The researches of fish populations from Lake Ohrid were started in beginning of XIX centaury. Attention of world scientists in this time interest the speciality of plant and animal world from Lake Ohrid. Many Balkan and world scientists (Heckel & Kner, 1858), Kottelat &Freyhof (2007), Stanković (1960), Spirkovski and all. (2009), Talevska &Talevski (2008). Talevska and all. (2009), Talevski (1996,2001,2004,2008), Talevski and all. (2009a, 2009b, 2009c, 2009d, 2009e,), Talevski & and Talevska,(2008), Tocko (1959,1982a, 1982b), Vladlkov & Petit (1930,1930 a), Vuković & Ivanović (1971) researched the biodiversity and the systematic belonging of ichthyopopulation in Lake Ohrid. Such researches were performed continuously from this time until now. The biodiversity of ichthyofauna from Lake Ohrid and its catchement area is present in Tab. 2. Fish fauna from Lake Ohrid is represented by twenty native species: Alburnoides ohridanus (Karaman, 1928), Alburnus scoranza (Heckel et Kner, 1858), Anguilla anguilla (Linnaeus, 1758),Barbatula sturanyi (Steindachner, 1892), Barbus rebeli Köller, 1925, Chondrostoma ohridanus Karaman, 1924, Cobitis ohridana Karaman, 1928, Cyprinis carpio Linnaeus, 1758, Gobio ohridanus, Karaman, 1924, Pachychilon pictum (Heckel et Kner, 1858), Pelasgus minutus Karaman, 1924, Phoxinus limaireul Schinz, 1840, Rutilus ohridanus (Karaman, 1924), Salmo aphelios, Kottelat,1997, Salmo balcanicus Karaman, 1928, Salmo letnica Karaman, 1924, Salmo lumi Poljakov, Filip & Basho 1958, Salmo ohridanus Steindachner 1892, Scardinius knezevici Bianco & Kottelat, 2005 and Squalius squalus Bonaparte, 1837. Because of human negative impact in the past period in Lake Ohrid great number of fish species are introduced. They are: Alosa falax La Capede, 1803, Carassius gibelio Bloch, 1782, Gambusia holbrooki Girard, 1859, Lepomis gibbosus Linnaeus, 1758, Oncorhynchus mykiss Walbaum, 1792, Pseudorasbora parva Temmini & Schlegel, 1846 and Rhodeus amarus Bloch, 1782 (Tab. 2.). Table 2. List of native and introduced fish from Lake Ohrid and its catchement area Lake Ohrid Fish species native introduced 1. Alburnoides ohridanus (Karaman, 1928) + 2. Alburnus scoranza (Heckel et Kner, 1858) + 3. Alosa falax La Capede, 1803 + 4. Anguilla anguilla (Linnaeus, 1758) + 5. Barbatula sturanyi (Steindachner, 1892) + 6. Barbus rebeli Köller, 1925 + 7. Carassius gibelio Bloch, 1782 + 8. Chondrostoma ohridanus Karaman, 1924 + 9. Cobitis ohridana Karaman, 1928 + 10. Cyprinis carpio Linnaeus, 1758 + 11. Gambusia holbrooki Girard, 1859 + 12. Gobio ohridanus, Karaman, 1924 + 13.

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