scholarly journals Hydrology and pollution assessment in a coastal estuarine system. The case of the Strymonikos Gulf (North Aegean Sea)

2002 ◽  
Vol 3 (1) ◽  
pp. 65 ◽  
Author(s):  
A. PAVLIDOU ◽  
I. HATZIANESTIS ◽  
E. SKLIVAGOU ◽  
V. PAPADOPOULOS ◽  
V. ZERVAKIS
Keyword(s):  
Polychlorinated Biphenyl ◽  
Ecological Status ◽  
Aegean Sea ◽  
Early Spring ◽  
Early Summer ◽  
Late Spring ◽  
Nutrient Concentrations ◽  
Estuarine System ◽  
North Aegean ◽  
North Aegean Sea

Three hydrographic cruises were undertaken to study the hydrology and to estimate the ecological status of the coastal ecosystem of the Strymonikos Gulf (North Aegean Sea) impacted by the riverine waters of the Strymon River. Surface sediments were also collected in order to determine the levels of organic contaminants in the gulf. Three main water masses were identified in the Strymonikos Gulf throughout the year: a) the surface river plume water, b) the surface and subsurface Black Sea Water and c) the near bottom (>50 m) water of Levantine origin. High nutrient concentrations were recorded close to the mouth of the river, indicating a rather eutrophic environment, which was restricted near the river discharge. The salinity-nutrient correlations of the surface waters of the study area were linear, indicating that the riverine waters are the major source of nutrient in the gulf. DIN:P ratios varied seasonally from relatively higher values during winter and early spring to lower values in late spring-early summer. This led to a shift from likelihood P-limitation during winter and early spring to N-limitation in late spring – early summer. Total hydrocarbon concentrations measured in the sediments ranged from 19.2 to 95.9 μ g/g, whereas total polycyclic aromatic hydrocarbon (PAH) values varied between 107.2 and 1019 ng/g. The application of different diagnostic criteria suggests a natural terrestrial origin for aliphatic hydrocarbons and pyrolytic origin for the PAHs. DDTs displayed the highest concentrations of all the organochlorines determined, whereas polychlorinated biphenyl (PCBs) concentrations were very low. Riverine input seems to be the major source for all the compounds identified.

scholarly journals Comparative study of feeding behaviour of five Mugilidae species juveniles from two estuarine systems in the North Aegean Sea

2016 ◽  
Vol 98 (2) ◽  
pp. 283-297 ◽  
Author(s):  
Ioanna Salvarina ◽  
Emmanuil Koutrakis ◽  
Ioannis Leonardos
Keyword(s):  
Feeding Behaviour ◽  
Juvenile Fish ◽  
General Pattern ◽  
Aegean Sea ◽  
Trophic Levels ◽  
Feeding Strategies ◽  
Estuarine System ◽  
North Aegean ◽  
Estuarine Systems ◽  
North Aegean Sea

Food is an important factor for the survival of juvenile fish. Knowledge of the diet of co-existing species helps clarify their relationships with each other. A number of Mugilidae species are known to co-exist in estuarine systems, raising the question of whether they compete for food resources. The feeding behaviours of five juvenile Mugilidae species were studied in the estuaries of Strymonikos (North Aegean Sea) using stomach content analysis. It was found that the species Chelon labrosus, Liza saliens and Mugil cephalus presented high feeding activity during summer and autumn and L. ramada and L. aurata during winter and spring. The diet overlap between the species was generally moderate to low and the pair L. saliens – M. cephalus exhibited the highest overlap in Richios estuarine system. The species do not appear to compete for common resources, probably because there is not always a spatiotemporal overlap, enough food is available or they exploit different resources. Four out of the five species exhibited similar patterns of feeding strategies with varying levels of specialization at an individual level and a rather generalized pattern at the population level. This more generalized feeding strategy may permit them to co-exist. Only M. cephalus showed a more specialized feeding behaviour, with a strong preference for microalgae. The absence of a general pattern for the trophic levels according to seasons, sizes or locations, also imply the opportunistic character of the species. Both season and fish size influenced the variation in the diet composition.

scholarly journals Dissolved Oxygen and Nutrients in coastal waters impacted by the Strymon River plume, North Aegean Sea, Greece

2013 ◽  
Vol 3 (2) ◽  
pp. 71-84
Keyword(s):  
Dissolved Oxygen ◽  
Aegean Sea ◽  
Inorganic Phosphorus ◽  
Nutrient Concentrations ◽  
N Limitation ◽  
Nutrient Levels ◽  
P Limitation ◽  
North Aegean ◽  
Dissolved Inorganic Phosphorus ◽  
North Aegean Sea

Three hydrographic cruises were conducted during 1997-1999 in north Aegean Sea, in order to study the dissolved oxygen (DO) and nutrient distributions in Strymonikos Gulf impacted by the riverine waters of the Strymon River. The approaches used in this paper include a preliminary estimation of the nutrient load of Strymon River and the influence of the riverine waters upon the DO and nutrient distribution in Strymonikos Gulf. Nutrient levels recorded in Strymon River were similar with other international Rivers. The influence of Strymonas River on the DO and nutrient distributions was clearly detected during December 1997 and May 1998. On the contrary, during March 1999 the influence of Strymon River was not so clearly detected. High nutrient concentrations were recorded close to the mouth of the river. As mixing with offshore waters progressed, nutrient levels declined dramatically. Plots of atomic DIN:P (ratio of the total dissolved inorganic nitrogen to dissolved inorganic phosphorus), Si:P (ratio of dissolved silica to dissolved inorganic phosphorus) and Si:DIN ratios in Strymonikos Gulf, during the three sampling periods studied, indicated stoichiometric P-limitation in about 34%. Furthermore, the data indicated significant probable N-limitation (31.4%), while Si-limitation was not probable (2.9%). In particular, 31% of the data showed a defined P-limitation in December, whereas 30% of the data showed N-limitation. It is noteworthy that Si-limitation was not recorded. In May, the atomic DIN:P ratio indicated P-limitation in about 21% and N-limitation in about 46%. Si-limitation was not recorded. Finally, in March, the 51% of the data showed P-limitation, whereas only the 16% showed N-limitation and 8% showed Si-limitation.

Geodetic analysis of the tectonic crustal deformation pattern in the North Aegean Sea, Greece

2021 ◽  
Author(s):  
Ilias Lazos ◽  
Sotirios Sboras ◽  
Christos Pikridas ◽  
Spyros Pavlides ◽  
Alexandros Chatzipetros
Keyword(s):  
Crustal Deformation ◽  
Aegean Sea ◽  
Deformation Pattern ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea

scholarly journals Age and Growth of Red Porgy, Pagrus pagrus from the Island of Gökçeada, North Aegean Sea

2020 ◽  
Vol 35 (2) ◽  
pp. 57-63
Author(s):  
Hakan Ayyıldız ◽  
Aytaç Altın ◽  
Bayram Kızılkaya
Keyword(s):  
Aegean Sea ◽  
Age And Growth ◽  
Red Porgy ◽  
North Aegean ◽  
North Aegean Sea ◽  
Pagrus Pagrus

scholarly journals MANAGEMENT OF LATE SPRING-EARLY SUMMER PASTURE SURPLUSES IN HILL COUNTRY

1984 ◽  
pp. 199-206 ◽  
Author(s):  
G.W. Sheath ◽  
R.W. Webby ◽  
W.J. Pengelly
Keyword(s):  
Early Spring ◽  
Early Summer ◽  
Late Spring ◽  
First Year ◽  
Hill Country ◽  
Continuous Grazing ◽  
Summer Pasture ◽  
Animal Performances ◽  
Grazing Policy ◽  
Made In

Comparisons of controlling late spring to early summer pasture growth on either easy or steep contoured land with either a fast rotation or continuous grazing policy were made in self-contained farmlets for two years. Pasture control was maintained over more land by controlling steep land first and with continuous grazing. Animal performances (ewes, steers) were generally similar for the mid-November to early January treatment period, and subsequently until May shearing. In the first year better animal performances occurred in "steep control" farmlets during winter and early spring, but this was less evident in the second year. Priority control of steep land during late spring-early summer is recommended because of likely longer-term benefits in pasture composition,density and production. Quick rotation grazing through the period provides a better ability to recognise and manage pasture quantities and should be adopted if summer droughts are anticipated. For well fenced properties in summer-wet areas and with integrated stock grazing, continuous grazing during late spring-early summer may be equally suitable. Keywords: hill country, grazing management, pasture control

scholarly journals A three dimensional, full life cycle, anchovy and sardine model for the North Aegean Sea (Eastern Mediterranean): Validation, sensitivity and climatic scenario simulations

2021 ◽  
Vol 22 (3) ◽  
pp. 653
Author(s):  
ATHANASIOS GKANASOS ◽  
EUDOXIA SCHISMENOU ◽  
KOSTAS TSIARAS ◽  
STYLIANOS SOMARAKIS ◽  
MARIANNA GIANNOULAKI ◽  
...  
Keyword(s):  
Temperature Increase ◽  
Eastern Mediterranean ◽  
Larval Growth ◽  
Somatic Growth ◽  
Aegean Sea ◽  
Fish Growth ◽  
Prey Concentration ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea

We present the development of a 3D full-lifecycle, individual-based model (IBM) for anchovy and sardine, online coupled to an existing hydrodynamic/biogeochemical low-trophic level (LTL) model for the North Aegean Sea. It was built upon an existing 1D model for the same species and area, with the addition of a horizontal movement scheme. In the model, both species evolve from the embryonic stage (egg+yolk sac larva) to the larval, juvenile, and adult stages. Somatic growth is simulated with the use of a “Wisconsin” type bioenergetics model and fish populations with an adaptation of the ‘super individuals’ (SI) approach. For the reference simulation and model calibration, in terms of fish growth and population biomass, the 2000-2010 period was selected. Interannual biomass variability of anchovy was successfully represented by the model, while the simulated biomass of sardine exhibited low variability and did not satisfactorily reproduce the observed interannual variability from acoustic surveys. The spatial distribution of both species’ biomass was in relatively good agreement with field data. Additional single-species simulations revealed that species compete for food resources. Temperature sensitivity experiments showed that both species reacted negatively to a temperature increase. Anchovy, in particular, was more affected since its spawning and larval growth periods largely overlap with the period of maximum yearly temperature and low prey concentration. Finally, simulation experiments using IPCC climatic scenarios showed that the predicted temperature increase and zooplankton concentration decrease in the future will negatively affect anchovy, resulting in sardine prevalence.

scholarly journals The Confirmed Occurence of Serpent Eel Ophisurus serpens in Saros Bay (Northern Agean Sea), Turkey

2020 ◽  
Vol 78 (3) ◽  
pp. 157-164
Author(s):  
Sezginer Tuncer ◽  
Hatice Torcu Koç ◽  
Aytuğ Zilifli
Keyword(s):  
Aegean Sea ◽  
Mature Female ◽  
Female Specimen ◽  
Meristic Characters ◽  
Long Line ◽  
North Aegean ◽  
Biological Characters ◽  
North Aegean Sea ◽  
Taxonomic Studies

AbstractOne mature female specimen of serpent eel Ophisurus serpens (Linnaeus, 1758) was caught by long line by a professional fisherman at a depth of about 45 m from Ece Bight, Saros Bay, north Aegean Sea on 15 February 2016. The species was previously reported without any morphometric and meristic characters from Saros Bay. Some biological characters, such as age and diameters of otolith and oocytes, are also given. In this study, the detailed morphomeristic features, which can contribute to the taxonomic studies of serpent eel from Turkish Seas, are presented.

Macrofauna associated with the sponge Verongia aerophoba in the north Aegean Sea

1987 ◽  
Vol 24 (2) ◽  
pp. 265-278 ◽  
Author(s):  
H.E. Voultsiadou-Koukoura ◽  
A. Koukouras ◽  
A. Eleftheriou
Keyword(s):  
Aegean Sea ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea
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