Adriatic Sea

About Adriatic Sea

The Adriatic spans from the Balkan to the Apennine peninsula.It got it's name from an ancient port.

The east coast belongs to the Republic of Croatia, all the way from Prevlaka in the south to cape Savudrija in the west, including all islands, islets and cliffs along the coast, and the archipelago of Palagruza.

Oceanographic & Hydro Data

Depths The shallowest part of our sea is in Istria, depth not bellow 50 m. From Pula, the seabed mildly drops, making a long, narrow valley which extends from Zirje towards Italy which is called Jabucka kotlina. Towards the south, the bottom drops steeply towards the Juznojadranska dolina, where the biggest measured depth is about 1,300 metres. From Jabucka kotlina, the bottom rises to Palagruza reef where the biggest depth is 130 metres.

Tides The high and low tides have relatively small amplitudes in the Adriatic. In the southern part, the difference is rarely above some forty centimetres, while in the northern part comes to 1 metre in Istria and the Gulf of Trieste. During a strong sirocco in some narrow channels and bays, the high tide can grow considerably.The tides are of a mixed type, which means that their rhythm is semidiurnal during the new and full moon, and of a daily type during the first and the last quarter. Their amplitudes are very irregular.

Sea Currents Sea currents occur under the influence of winds, the difference in pressure, temperature, and the differences in salinity. They can be horizontal or vertical. There are also bottom currents which appear as the consequence of moving of water from warmer areas to colder ones, during which the surface layer gets cold and descends towards the seabed.The speed of currents changes in particular areas, but it also depends on time periods. The average speed of currents is about 0.5 knots, but they can also reach the speed of 4 knots.

Salinity The salinity of the Adriatic Sea is 38.30 per mill averagely. In the northern part, the salinity is somewhat lower than in the middle and southern part because of the influence of the Po River.

Sea Temperature The average annual temperature is 11 C. During the winter, the sea is the coldest and the surface temperature is about 7 C. In the spring, the surface temperature rises to 18 C. In the summer, of up to 22 to 25 C, and in the southern Adriatic and Istria up to 27 C. The thermocline is most evident during the summer, and, in the winter, the isothermal process arises. In the summer, we can notice the first thermocline at the depth of 3 to 5 metres, the next one is at about 12 metres, and yet another one at 18 metres, while below 30 metres the temperature is mostly constant throughout the year.

Waves in the Adriatic Waves occur primarily as the consequence of the blowing of winds. The bigger the reach, the higher the waves will be. Their strength depends on the configuration and the exposure of the coast. The length of the wave is the distance between two troughs. Heights of waves in the Adriatic are between 0.5 and 1.5 metres.

Meteorological Data

• Climate The climate at the Adriatic is typically a Mediterranean, with mild rainy winters, and hot and dry summers. Summer temperatures in July will be about 34 C in the northern part, while in the southern part they will rise even to 38 C. In the winter, the coldest temperatures are noticed in the northern Adriatic (up to -16 C).
• Winds bora, sirocco and north-western wind blow most often.

Bora Bora (Croatian: BURA) is a dry, cold downward wind blowing in bursts from the north-northeast to the east-northeast direction. The direction is influenced by the configuration of the shore. Bora blows mostly in the winter. In the summer, it usually lasts for a day or several hours, while, in the winter, it can blow as long as 14 days.

Sirocco (Croatian: JUGO, SIROKO OR SILOK) is a warm and moist wind which blows from the direction east-southeast to south-southwest. Its consequences are high waves and rain. It is a characteristic for the southern Adriatic. In the summer, it usually blows as long as 3 days, and in the winter even as long as 3 weeks.

Landward Breeze The landward breeze (Croatian: MAESTRAL, MAESTRAL, SMORAC) is a daily, thermic wind blowing from the direction of the northwest. It is present from the spring to the autumn, and, during the day, it often changes the direction of blowing.

Stiff Breeze The stiff breeze (Croatian: BURIN) is a wind blowing contrary to the lan dward breeze. Burin is the strongest before the dawn, and after that it stops soon. It blows during the night from the direction of the north, north-east in the northern Adriatic, and in the southern Adriatic, from the east or south-east.

Weather Data State Hydrometeorological Institute provides you with weather forecasts on VHF frequencies of coastal radio stations and harbor master's offices. They are also broadcast on FM stations or at the end of the news or within broadcasts for seamen.

• Communications Service and Nautical Radio Service The radio service for protection of human lives and safety of navigation is provided by Plovput from Split, through radio stations Split and Dubrovnik and Rijeka. According to the Global Maritime Distress and Safety System (GMDSS), the channel for automated receipt of digitalized distress calls is the channel 70, after which the communication is transferred to the operating channel of the coastal station,(16 or 10). GMDSS system has been in use since 1 st February 1999, and on the present VHF channel for distress calls, the channel 16. For a direct call to a harbor master's office, the channel 10 is used.

Sea Life

We can distinguish two types of habitats: area of the open sea where two big groups of organisms live plankton, all organisms floating i n the sea and nektons, all organisms which can actively move around. The group of benthos, or life at the bottom of the sea, includes all organisms, which are constantly or occasionally connected to the sea bottom.

In the water mass between the mentioned areas we can distinguish different belts or steps with different characteristics:

- Supralythoral is the part, exposed to the spraying of the sea.
- Mediolythoral is the area of the high and the low tide. Then comes infralitoral or the area of photophilic algae and, which in the Adriatic expands from the border of the low tide to 30-50 meters..
- Abyssal reaches 50 to 200 meters..
- Hadal or the deep sea area, which extends more than 200 meters in depth.

The Blue Flag - Blue Flag is a project for preserving the sea and coast from the year 2000 has extended throughout world. Blue Flag symbolizes preserved, safe and pleasant environment for fu n, relaxation and recreation, but it also includes an elaborated system of managing the resources, and sustainable development in tourism. Blue Flag beaches and marinas, offer quality services, have a clean seacoast, and are tidy and adequately equipped. The Blue Flag is awarded for the period of one year, and is raised at the beginning of June. For each year it is necessary to fill the questionnaire about the criteria in order to have the license extended.