More than 500 studies have been carried out since 1975 on the Thermaic Gulf, focusing on issues relating to the ecological, social and financial impacts of pollution. An estimated 150,000 people are directly or indirectly dependent on the gulf for their livelihood. Three of the main economic activities in the region are mussel culture, fisheries and tourism. So it is no surprise that the detection of biotoxins, the red tide phenomenon and frequent bans on fishing have caused major problems. So far, efforts to combat pollution have been undertaken in piecemeal fashion, as highlighted in the recent case in which hundreds of dead fish were washed up along the coast. According to the vice president of the Federation of Coastal Fisheries of Macedonia, Giorgos Lydianos, the numbers of some species of fish are declining dramatically each year due to pollution and overfishing. This situation has led to some 5 percent of fishermen quitting the occupation each year. The failure of local authorities to protect the gulf from pollution prompted Prime Minister Costas Karamanlis in 2006 to make the Macedonia-Thrace Ministry solely responsible for matters relating to the development and protection of the Thermaic Gulf.