Tony Paterson, The Independent 3 Jan 08
Finnish marine biologists have identified a dangerous species of invasive jellyfish in the Baltic and raised fears that the creature has the potential to drastically reduce fish stocks in what is already regarded as one of the world's most polluted seas.
Evidence collected by scientists aboard the Aranda, a ship operated by the Finnish Institute of Marine Research, revealed that the Mnemiopsis leidyi species of jellyfish which caused huge declines in fish stocks in the Black and Caspian Seas had been sighted in the Baltic's Gulf of Finland.
Dr Markku Viitasalo, one of the institute's senior marine biologists, said yesterday that the crew of the Aranda spotted the species of combed jellyfish, which had never been seen in the Baltic before, while cruising in the eastern part of the Gulf of Finland last week. He said the species almost certainly arrived in the Baltic after leaving the waters off North and South America which are their natural habitat and entering the ballast tanks of container ships plying the Atlantic for Europe.
Dr Viitasalo told Der Spiegel magazine that the species had found its way into the Black and Caspian Seas by the same means and had almost completely wiped out fish stocks in both. The discovery followed other disturbing evidence collected by the Aranda which suggested that decades of effort invested by the countries of northern Europe in cleaning up the Baltic had made minimal impact so far.
The institute said research carried out by the ship's biologists had shown that the sea's already damaging phosphorus levels had actually risen off the coasts of Poland and Russia. "It is very important to monitor whether these efforts have had any effect and the answer is not yet," said Dr Viitasalo. Phosphorus, a by-product of agricultural fertilisers which are allowed to run off into the Baltic, and human waste promote the growth of blue algae. The weed-like substance pollutes the Baltic in summer, covering the sea's surface in acres of bad-smelling, green sludge which cuts the vital oxygen supplies needed by fish and other plant life.
Recent figures released by the Helsinki Commission or Helcom – a 10-member organisation comprised of Baltic seaboard countries which has been trying to cut the sea's pollution levels since 1974 – revealed that 730,000 tons of nitrogen and 36,300 tons of phosphorus were currently being found in the Baltic each year.
The organisation said that the amounts were enough to trigger massive algae pollution.
The Aranda's findings highlight the urgency of the latest attempt to rescue the almost completely landlocked sea. Last month the European Commission signed up to the Baltic Sea Action Plan, which aims to restore the sea to "good ecological status" by 2021.
The plan, which will be implemented from 2010, gives each of the Baltic's nine seaboard countries individual pollution reduction targets to cut phosphorus emissions by 15,250 tons and nitrogen by 135,00 tons annually. It also aims to step up efforts to protect declining fish stocks, reduce pollution caused by heavy shipping traffic and equip small communities which currently discharge their effluent directly into the Baltic, with proper sewers and waste treatment plants.
Unfortunately, the plan will do nothing to stop the Aranda's latest discovery and halt the jellyfish's spread across the Baltic.
