The Mediterranean Sea has played host to some of the greatest civilizations that the world has ever seen. Today, it remains a hub of commerce and travel, connecting different parts of Europe, North Africa, and the Middle East. Over the years, hundreds of millions of people have lived on its shores and exploited its resources. A new study recently released has found that after centuries of exploitation, the Mediterranean Sea is running out of resources. Many formerly healthy ecosystems have been wiped out. The research was conducted by an international team of scientists, and it is unprecedented in its scope. It involved hundreds of dives over the course of three years to study ecosystems throughout the sea. The dives took place off the coasts of Morocco, Spain, Italy, Greece, and Turkey. They found that the healthiest ecosystems are in well-enforced marine reserves. Fish populations were about 5-10 times greater than those in fished-out areas. There were some areas observed where fishing is limited and not banned. In these areas, the fish populations were similar to those in areas that were completely unprotected. \"We found a huge gradient, an enormous contrast. In reserves off Spain and Italy, we found the largest fish biomass in the Mediterranean,\" said National Geographic Explorer-in-Residence Enric Sala, the paper\'s lead author. \"Unfortunately, around Turkey and Greece, the waters were bare.\" The divers observed ecosystems on the seafloor in 14 protected areas and 18 non-protected sites, where they counted fish and took biological samples. They found that fish were able to recover quickly from overfishing, but the plant life (algal forests) took much longer. This was the first baseline study of overall ecosystems, a full assessment of entire ecological communities. Their work provides a yardstick for measuring conservation efforts in the Mediterranean. The results of the study give hope to other areas throughout the world where marine reserves are established. \"The protection of the marine ecosystems is a necessity as well as a \'business\' in which everyone wins,\" Sala said. \"The reserves act as savings accounts, with capital that is not yet spent and an interest yield we can live off. In Spain\'s Medes Islands Marine Reserve, for example, a reserve of barely one square kilometer can generate jobs and tourism revenue of 10 million euros, a sum 20 times larger than earnings from fishing.\"