Algae Threatens Croatian Adriatic
Date: 06-Dec-04
Country: CROATIA
Author: Igor Ilic
The algae has grown from an initial patch of 100 square metres (1,076 square feet) to an area of about 50 hectares (123 acres).
Stari Grad is one of about a dozen places in the Croatian Adriatic where two types of algae have in the last 10 years grown into dense colonies that choke life on the sea bed.
Croatia, which relies heavily on tourism along its Adriatic coast, fears the disrupted balance of the sea's eco-system could hurt its appeal for holiday makers, particularly divers in search of genuine natural biodiversity.
The algae cannot be seen on the surface and is no threat to swimmers.
The Tourism and Maritime ministry said it was aware of the problem and actively engaged in dealing with it.
BIODIVERSITY JEOPARDISED
Caulerpa Taxifolia and Caulerpa Racemosa had never been seen in the Adriatic before 1995. Other Mediterranean countries, like France, Spain or Italy, have been struggling with the algae in the last two decades, but with limited success.
Racemosa has already been found on many spots around Croatia's southern Adriatic islands, while Taxifolia has so far been found in three places -- Stari Grad and two northern Adriatic islands -- Rab and Krk.
While Racemosa is supposed to have come from the Red Sea through the Suez canal, Taxifolia is believed to have been accidentally introduced into the sea from the oceanographic museum in Monaco 20 years ago.
Particularly vulnerable to their presence is the common sea grass (Posedonia Oceanica) that supports major eco systems of the Mediterranean marine life while protecting the shores from erosion. Fauna suffers too, particularly species like sponges and sea urchins.
Local environmentalists have been pressuring the government to invest more money in the fight against tropical algae and the ecology ministry hopes to set aside 300,000 kuna ($50,000) in 2005.
CAUTIOUS APPROACH
The algae spreads by sticking to anchors, fishing nets and diving equipment. They can survive more than a week without water if in a warm and moist place, as storage houses usually are. Once back in the sea, they start developing again.
Small pieces can break off from the parent stem and be swept by the current to form a new colony on another location.
Removing the algae physically from the sea bed has so far been the only way to fight it, although with limited success.
"The algae can be hoovered or covered by black foil which would block the light they need to blossom. Unfortunately, other organisms also get affected by these methods," said Margita Mastrovic from the ecology ministry.
"What we can do is try to localise them, and we therefore react to any report on a new site of their presence," Mastrovic said.
Some experts say they should not be tampered with at all but strictly monitored.
"We should avoid interventions in nature... I believe the sea will eventually find its natural balance. Our task is to monitor the situation in order to prevent spreading that would seriously disrupt the balance of the eco-system," said Nedad Smodlaka of a local maritime institute.