Assessment of Stocking Activities on the Native Brown Trout Populations from Nestos River (Southern Balkans) Inferred by mtDNA RFLP and Sequencing Analyses

Alien fish introductions, conducted towards the ichthyofauna enhancement in local drainages, have been occasionally proved harmful for the indigenous freshwater fish populations. The present study was designed to assess the impact of stocking activities, carried out in the past decades with fingerlings originating from Acheloos river hatcheries, on the native trout (Salmo sp.) populations of Nestos River, Greece. Trout specimens collected from several tributaries of Nestos River and were analyzed by means of PCR-RFLP and sequencing targeting the mitochondrial ND5-ND6 genes and the entire control region, respectively. It should be mentioned that trouts from Acheloos mainly belong to the marmoratus mitochondrial DNA (mtDNA) lineage, while the autochthonous trouts from Nestos belong to the Adriatic lineage. Both methodologies demonstrated that most samples from the three tributaries located at the lower part of Nestos constitute offspring of the fingerlings transferred from Acheloos hatcheries. Therefore, these tributaries have been strongly affected by stocking activities with a potential complete loss of their autochthonous trout. On the other hand, it seems that trout populations from higher altitude tributaries have not been affected by stockings. Hence, efforts should be undertaken in order to prevent the prevalence of the non-indigenous translocated Salmo in higher altitude tributaries, in conjunction with a management plan designed for the total trout populations from the area, speaking of which it has been recently included to the National Park of Rodopi Mountains.

THE CONTRIBUTION OF THE MORPHOMETRIC PARAMETERS OF AN HYDROGRAPHIC NETWORK TO THE INVESTIGATION OF THE NEOTECTONIC ACTIVITY: AN APPLICATION TO THE UPPER ACHELOOS RIVER.

In this paper the relationship between the morphometric parameters of a drainage system and the neotectonic activity is investigated. The hydrographie network of the Upper Acheloos River was chosen as the study area. The whole network and especially its western-southwestern part appears to be in the rejuvenated stage of evolution, as it is concluded by the analysis of the parameters, associated with the shape and slope of the basins, and the slope of the respective streams. Furthermore, the shape of the drainage network and the structure of the basins suggest that not only the Alpine orogenesis but also the neotectonic activity controls the morphogenetic processes in the area

Evolution of underground aqueducts in the Hellenic world

Historical and archaeological evidence shows that ancient Hellenes had developed underground aqueducts since the prehistoric times. However, innovative methods of underground aqueducts were developed in Hellas mainly during the Archaic, Classical, Hellenistic, and Roman periods. Since the well-known tunnel at the island of Samos, Hellas, was designed and begun its construction (ca. 550 bc) by Eupalinos of Megara (the first civil engineer in history), several underground tunnels (with and without well-like vertical shafts) were implemented in the country. The goal of Eupalinos tunnel was to transfer water into the town from a spring. This tunnel, representing the peak of ancient hydraulic technology, was dug through limestone by two separate teams advancing in a straight line from both sides of the mountain. Delivering fresh water to growing populations has been an ongoing problem since ancient times. Several underground aqueduct paradigms (e.g. Peisistration in Athens, Polyrrhenia in Crete), some of which are in use even today, are presented and discussed. After late Roman times and the Adrianic aqueduct a gap of about 1,700 years in construction of such hydraulic works is noted. However, a remarkable development of tunneling in Hellas appeared during the last 50 years due to the ‘cosmogony’ of the construction of infrastructure projects using modern technology, e.g. Evinos-Mornos aqueduct with 15 tunnels of 71 km total length and the diversion tunnels in Sykia to the Thessaly plain and Messochora of the Acheloos River of 17.5 and 7.5 km length, respectively. Also, very recently three small conventional tunnels and one tunnel boring machine (TBM) were constructed in Aposelemis aqueducts used for water supply of Iraklion and Agios Nikolaos cities in Crete. As a consequence, significant design and construction experiences were gained. Overall, it seems that underground aqueducts of modern societies are not very different in principle from those during antiquity.