Thermaikos Gulf

Summary

Thermaikos Gulf forms an extended shelf area, which has a significant influence from rivers. Most of the particulate inputs are trapped near the river-mouth. The suspended particulate matter concentrates in nepheloid layers, at the surface and near the bottom and most of them is deposited and berried on the shelf. The fresh/salt water interface zone plays a significant role in the increase of atmospheric N2O and CH4 concentrations coming from the bacteria production in this zone. The gulf shows eutrophication events caused by the high nutrient supply, derived from the river discharges. Multiple human activities are taking place around and in the gulf as excessive urbanization, industrial activities, agriculture, fishing, mussel farming, tourism.

Policy Issue. Sustainable management of mussel culture at the area of Chalastra, Thermaikos bay.

Thermaikos Gulf is the biggest source of farmed mussels (Mytilus galloprovincialis) in Greece, representing the 88% of the country’s cultivated sea area and 80-85% of the total national production. The farms are being located in two major areas, NW of the Gulf of Thessaloniki, Chalastra (inner Thermaikos Gulf-the area under consideration for the Policy Issue) and NW of Thermaikos Gulf (estuary area of Axios- Loudias-Aliakmon rivers). Mussel farming is an activity that takes place at the area for more than 25 years, occupying an important percentage of the local population, with the mussel production of Chalastra area exceeding the 12.000tn/yr. The sea area is part of the protected area of the estuary (under the Ramsar convection) but the mussel farming is an activity compatible to the natural environment, and thus a compatible activity to the protection status. The last years, due to several reasons, as the increase of the population of the greater area of the County of Thessaloniki, the development of other Human Activities (H.A.’s: agricultural & industrial activities) and the intense increase of the mussel farming at the area, there has been an important modification to the natural environment of the Gulf that leaded to a decline of the mussel production with socioeconomic impacts to the local population (decline of mussel farmers income, unemployment, not authorized expansions of mussel cultures, negative advertisement of the products to local and international markets, etc).

Thermaikos is a U-shaped gulf situated in NW Aegean Sea – Greece

For additional information

Systems Approach Framework (SAF)

Contribution following the SAF sequence, that is the system design volume followed by the system formulation volume, the system appraisal volume and finally the system output volume.

Powerpoint presentation at the Cluster Meeting Thessaloniki 20-21 Oct 2009

Date: 2007-2011

SPICOSA local applications aim to bridge the gap between coastal stakeholders across various aspects of local economy, policies, uses, conflicts and impacts to enable the dialogue that may lead to sustainability.

Coordination by Dr. Yannis N. Krestenitis, Aristotle University of Thessaloniki

Characteristics

Marine System

Thermaikos Gulf forms an extended shelf area, which has a significant influence from rivers. Most of the particulate inputs are trapped near the river-mouth. The suspended particulate matter concentrates in nepheloid layers, at the surface and near the bottom and most of them is deposited and berried on the shelf. The fresh/salt water interface zone plays a significant role in the increase of atmospheric N2O and CH4 concentrations coming from the bacteria production in this zone. The gulf shows eutrophication events caused by the high nutrient supply, derived from the river discharges.

Watershed

The total catchments basin of Thermaikos Gulf extends to an area of ~72.000 km2, drained from four main rivers. The average discharge of the river system reaches values from 300- 350 m3s-1 and the annual discharge is estimated in 6-8 x 109 m3y-1. The solid annual discharge is rapidly reduced from 3-4 x 106Ty-1, some decades ago, to 0,6-0,7 x 106Ty-1 in the recent years.

Human Activities

Urbanization [Thessaloniki a city of 1,5 million citizens], agriculture [Thessaloniki plain, Thessalia plain], industrial [Thessaloniki industry area], tourism [E and W site of the Gulf], fisheries, aquaculture mainly mussel farming.

Impact Responses

Intensive agriculture, intensive aquaculture, overfishing, urban/industrial wastes, water cycle intervention, transboundary pollution, massive tourism, second house settlements along the coasts, public ignorance of the value of the environment,

Policy

Policy issues

  • What measures should be undertaken to reduce nutrients?
  • How Thessaloniki can have a clear water sea in its sea front?
  • How a land planning for the aquaculture can be established?
  • How fisheries can be regulated according to the carrying capacity of the system?
  • How the summer tourist invasion can be managed?

Policy changes

  • Management plan and measures for the treatment of the domestic sewage
  • Land planning of the mussel farms
  • Measures to avoid over fishing

Stakeholders and Institutional Governance

Major organisations

  • Organisation for the Master Plan and Environmental Protection of Thessaloniki
  • Thessaloniki Prefecture (Department of Agricultural Development, Department of Fishing, Department of Water Resources and Irrigation Works)

Other leading organisations

Thessaloniki Water Supply and Sewerage Company S.A. Thessaloniki

Partner Collaboration

  • AUTH University of Thessaloniki, Aegean University,
  • EREOPE University of the Aegean

Systems Studies

Long time series

Hydrochemical, -physical and phytoplankton data, river discharge and nutrient loads. Benthos, fish data. Various and large amounts of additional data e.g. meteorological, hydrodynamic, sediment, heavy metal, biological data.

Research Projects

EUROCAT [An ELOISE EU-Project]

  • European Catchment changes and their impact on the coast
  • Long-term assessment of N & P loads and heavy metals of the Axios River and their impact on the coastal system of the Thermaikos Formulation of management proposals aiming at the sustainable development of the river catchment and the coastal zone

INTERPOL [An EU Project]

  • Impact of natural and trawling events on resuspension, dispersion and fate of pollutants
  • Study of the effects of natural and anthropogenic (trawling) sediment resuspension on the biogeochemical cycles and transfer of pollutants, nutrients and key-elements in the continental shelf of the Thermaikos Gulf.

Socio-economic study

Metro-Med [An EU-MAST-III ELOISE-Project]

  • Dynamics of Matter Transfer and Biogeochemical Cycles: Their modelling in Coastal Systems of the Mediterranean Sea
  • The target of Metro-Med project is to study and simulate the mechanisms of matter transfer and of the biogeochemical cycles in the coastal ecosystems (incl. Thermaikos Gulf).

Publications

Krestenitis Y.N.,Konstantinou Z.I.,Latinopoulos D. Documentation Report for Appraisal Step implementation in SSA16 Thermaikos gulf . Aristotle University of Thessaloniki, Thessaloniki, Greece, 2010 – SPICOSA Report. [pdf, 4.2 MB]

Krestenitis,Y.N.,Konstantinou,Z.I. Scientific Report on System Output of SSA16-Thermaikos gulf, regarding the SAF methodology. Aristotle University of Thessaloniki, Thessaloniki, Greece, 2010 – SPICOSA project Output Step Report. [pdf, 2.7 MB]

Konstantinou Z., Latinopoulos D., Krestenitis Y.N. Problems and perspectives during the development of simulation models in the ICZM effort of Chalastra bay, Thermaikos gulf.. In: Liakopoulos, A., Kanakoudis, B., Anastasiadou-Partheniou, E., Tsihrintzis, B. (eds). Proceedins of the common conference of EYE and EEDYP for the Integrated Water Management under climate change conditions. pp. 495-502. University of Thessalia, Greece, Volos, Greece, 2009. [pdf, 633.3 kB]

Konstantinou Z., Latinopoulos D., Krestenitis Y.N. Science and Policy Integration for Coastal System Assesment: An ambitious Idea, the implementation in a Greek study site and problems encountered. In: Sakellariou, D.(eds.). Proceedings of the 9th Symposium of Oceanography and Fisheries. pp. 305-310. Hellenic Center of Marine Research, Athens, Greece, 2009. [pdf, 145.8 kB]

Photo: © Anthony Sigalas