Dimitra C. Bobori

DNA barcoding analysis of fish species diversity in four north Greek lakes

Materials and methods: The present study is the first to apply DNA barcoding on identifying 37 freshwater fish species from the rich Balkan ichthyofauna. Results: The results are highly successful since in most cases barcodes cluster according to species, in agreement with morphological taxonomic studies. This is also evident based on mean conspecific and congeneric Kimura two-parameter distance values. The 5.6-fold difference between these values is lower than previous barcoding studies, possibly due to the restricted samplings and the recent taxonomy reevaluation for several species. A number of species were identified, where future work is needed: For the species Scardinius erythrophthalmus, Perca fluviatilis, and Rutilus rutilus, the divergence values found among conspecific populations could warrant their placement into different species; for Barbus and Rhodeus populations, the reported interspecific distances found were lower than expected; and for Cobitis species, the application of barcoding seems problematic, due to their complicated reproduction. Conclusion: The extension of this work to other Greek or even Balkan freshwater systems should clarify the situation.

Assessing Ecological Water Quality with Macroinvertebrates and Fish: A Case Study from a Small Mediterranean River

Biological elements, such as benthic macroinvertebrates and fish, have been used in assessing the ecological quality of rivers according to the requirements of the Water Framework Directive. However, the concurrent use of multiple organism groups provides a broader perspective for such evaluations, since each biological element may respond differently to certain environmental variables. In the present study, we assessed the ecological quality of a Greek river (RM4 type), during autumn 2003 and spring 2004 at 10 sites, with benthic macroinvertebrates and fish. Hydromorphological and physicochemical parameters, habitat structure, and riparian vegetation were also considered. Pollution sensitive macroinvertebrate taxa were more abundant at headwaters, which had good/excellent water quality according to the Hellenic Evaluation System (HES). The main river reaches possessed moderate water quality, while downstream sites were mainly characterised as having bad or poor water quality, dominated by pollution-tolerant macroinvertebrate taxa. Macroinvertebrates related strongly to local stressors as chemical degradation (ordination analysis CCA) and riparian quality impairment (bivariate analysis) while fish did not. Fish were absent from the severely impacted lower river reaches. Furthermore, external pathological signs were observed in fish caught at certain sites. A combined use of both macroinvertebrates and fish in biomonitoring programs is proposed for providing a safer assessment of local and regional habitat impairment.

Freshwater fishes of Greece: Their biodiversity, fisheries and habitats

In the present work, we review the current state of knowledge and research trends on freshwater fishes of Greece to assess a) the status of fish populations and their habitats; b) the state and priorities of fisheries science and legislation; c) priority gaps and needs in freshwater fish habitat management; and d) future strategies for freshwater fishes and aquatic resources. Freshwater fish fauna of Greece currently consists of 135 taxa including diadromous and introduced species. The taxonomy of some taxa is unclear. The distribution and origin of freshwater fishes, especially endemics, has been attributed mainly to the geological history of the country. Commercial fishing in inland waters is conducted mainly in 32 natural or artificial water systems. The total annual commercial catch for the 1988–2000 period ranged from 1,950 t in 1988 to 1,810 t in 2000 with a mean annual catch of about 1,500 t. The major part of inland catches comes from lakes, while catches from rivers are of minor importance. Aquaculture contributes greatly to the total production of freshwater fishes. The total annual aquaculture production for the period 1988–2000 ranged from 2,638 t to 3,656 t with a mean annual production of 2,832 t, 1.33 to 2.02 times higher than the traditional inland catches. Due to human activities, Greece has lost 75% of its wetland area since 1900. Today, the pressures upon the surface freshwater resources are moderate with the exception of some systems where human intervention is intense, leading to species extirpations from their type localities. Recently, surface waters have been classified under the auspices of the European Union Water Framework Directive where fishes have an essential role as indicators of the ecological integrity of running waters. Under this concept, there is an increasing emphasis on gathering biological data, to serve a broad-spectrum of environmental objects and plans such as the protection of endangered and threatened species. However, to date effective management and conservation of freshwater fishes and fisheries have not been much considered in the management of freshwaters of Greece. Existing plans for managing aquatic inland resources primarily focus on water usage and do not include specific, enforceable monitoring and management objectives, conservation actions, and control measures for aquatic habitats and fish communities, including endangered and threatened fishes. It is concluded that future efforts need to be directed to severely endangered or nearly extinct species. Furthermore, the creation of GIS-based databases for incorporating all the information on species, habitats and genetic diversity should be addressed under the guiding principle of conserving aquatic biodiversity.

Freshwater fish habitat science and management in Greece

Objectives are to (1) characterize the current status of and threats to freshwater fish habitats, native fishes, and fisheries in Greece; (2) canvas the states and priorities of fisheries science, legislation, and regulations for freshwater habitats and their fishes/fisheries; (3) indicate priority gaps in freshwater fish habitat management; and (4) comment on planning and managing strategies for freshwater aquatic resources and fishes in Greece. Freshwater fishes total 126 species (58 % endemic), 19 of which are introductions. Inland fishery production (about 700 t in 1999) has steadily decreased (due to overfishing, habitat alteration, and pollution) for the past 40 years while marine fisheries have increased from ∼12000 to 30000 t in 30 years (1964-1994). Population declines and extirpation of fish species and their habitats have been related to dam construction and operation, stream channelization, canalization, pollution, and stream desiccation, a result of water abstraction for crop irrigation and diversion of river and stream waters for potable waters supplies of urban and rural areas. Published information on habitat requirements (i.e., spawning habitat, spawning behavior, nursery areas, foraging ranges, vegetative cover, and migration) of freshwater fishes in Greece is limited. Absence of coordination among ministries and an increased market-based economy have resulted in low conservation priorities and investments for freshwater environs. Conservation programs and action plans have been implemented in Greece only recently for two endemic fish species ( Pungitius hellenicus and Ladigesocypris ghigii ) compared to 14 for other vertebrate species. Regardless of environmental statues and presidential decrees since 1970, there is no current established national action plan to improve and integrate aquatic environments and natural habitat management in a growing market-based economic strategic plan. Recommendations for the creation of an integrated, national action plan that incorporates environmental costs of protecting freshwater aquatic habitats and fish communities in sustainable economic policies and goals of Greece, an European fringe country experiencing significant competition in the international marketplace are presented.

Food web modelling on the structure and functioning of a Mediterranean lentic system

AbstractΤhe ecosystem structure of a Mediterranean lentic system (Lake Volvi, Northern Greece) was assessed and quantified for the first time, using the Ecopath with Ecosim model. Biological and fisheries-related data were collected during 2014–2015 from field surveys; moreover, operational and other data concerning fisheries exploitation were assessed by interviews. The model will (a) describe the ecological structure of the lake in terms of trophic flows (b) disaggregate the impacts imposed by fishing and other factors on the food web and (c) investigate the ecosystem’s functional changes by testing the introduction of a new fish species. Lake Volvi constitutes a mature system whose food web is characterized by “bottom-up” processes, exhibiting a “good” systemic resistance to unexpected perturbations and a rather low intensity of fisheries exploitation. Simulations from 2015 to 2025 revealed that an increase in fishing effort and/or stocking with the new species will have negligible impact on the food web and will not affect negatively the fisheries resources and top megafauna. The model presented provides key ecosystem information that is lacking for most European freshwaters systems, which can be useful in assessing their ecosystem structure and in simulating the pressure of fisheries exploitation on their food web.

Range expansion of Pachychilon macedonicum (Actinopterygii: Cypriniformes: Cyprinidae) in Northern Greece

The cyprinid freshwater fish, Pachychilon macedonicum (Steindachner, 1892), is an endemic species in the Balkan Peninsula and has a restricted distribution in Greece. Here, we report new records of the species out of its known natural range, namely at the Mpogdanas Stream (drainage area of lakes Koronia-Volvi, northern Greece), which now constitute a new eastern limit for the distribution of the species in southern Balkans. It appears that the new record is related to a human-mediated translocation.