Anchovies pose some mystery

The northern Thracian Sea is considered the largest fishery in Greece, with one of the biggest anchovy stocks in the Mediterranean. Early July saw the start of another, EU-funded program in this area (budgeted at 1.3 million euros). Its aim: to solve the anchovy mystery. Scientists monitoring anchovy numbers over the last 20 years found that in some years, a drop in the population could not simply be due to overintensive fishing. Using satellite pictures in case temperature increases were the reason, scientists struggled to find the cause for the population fall. The Thracian Sea is where the cold currents sweeping in from the Black Sea and the warm currents from the south meet. Depending on their strength and the areas where they form fronts – basies, as they are called by local fishermen – they attract large numbers of pelagic fish. 160 species of fish Generally, a food chain based on the sardine and anchovy prevails in the northern Aegean. Overall, 160 species of fish have been counted in the area (not including shellfish), of which 120 are considered to be commercial. Cod, chub mackerel, bluefish, belted bonito, Atlantic mackerel and red mullet are the most common sea species that are affected by the Black Sea, to which some migrate. But while passing through the Bosporus and Dardanelles, they are fished en masse, dictating the adoption of common rules for the Greek and Turkish fishing industries. – The Thermaic Gulf and its coastal zone, from Methone in the Pieria prefecture down to Mount Pelion, which receives the beneficial effect of riverine outflows, is regarded as the second most important fishery in Greece. Pelagic fish can be found off Mount Athos. – Southern Aegean. Bogue and picarel are most common in the southern Aegean, but in smaller numbers since there are no large areas with a continental shelf (less than 200 meters deep) and there are also no riverine outflows. – The Patraic and Saronic gulfs. Respectively, these are the third and fourth largest fisheries in the country. In the Saronic Gulf’s polluted zone, fish are in short supply; but life has exploded on the edge of the zone. – Pagasitic and Euboean gulfs. Significant fisheries can be found along both. The two large plateaus of the Dodecanese and the Cyclades, the Lemnos fishery, the Amvrakikos Gulf and the Corfu area, complete the list of the country’s major fisheries. – Cretan Sea. Fishing on Crete takes place chiefly in its northern part, with commercial fish including red mullet, striped red mullet, bogue and picarel. The most common fish in all of the Aegean is cod. Research results have shown a sharp reduction in stocks of fish species that are dependent on coastal zones, including Dentex sea bream, black bream, grouper and corb. Disappearance has been total in some areas, not only because of overfishing (both professional and amateur) but because of pollution and other human activities, such as disturbance by ships. Dams Ichthyologists point out that dams across rivers cut off the food supply for sea fish. By now, the effects on the marine environment of holding back water outflow are clearly visible – including from satellite pictures – for example, off the Strymon and the Nestos river mouths. By contrast, the Evros continues its beneficial influence on Greece’s largest fishery, the Thracian Sea.