Mediterraneus, or that which lies “between the lands”, has been given different names by the people who sailed on it: it was Mare Nostrum for the Romans, who took it as their own, conquering all the regions bordering this sea; and “middle white sea” for the Arabs, who subsequently ruled the Iberian peninsula and north Africa. On the shores of what is the largest continental sea in the world, major civilisations such as the Phoenicians, the Egyptians and the Greeks rose and disappeared. Over the centuries, the Mediterranean has been a privileged place not only for major cultural and commercial transactions but also for encounters and conflicts, both dividing and bringing people together.
In 2011, several countries from the three continents surrounding this sea of historical, age-old importance – Europe, Africa and Asia – came together to create the Postal Union for the Mediterranean (PUMed), which is part of the Universal Postal Union (UPU). One of the aims of this association is to enhance the potential of the postal sector in order “to boost the economic development of the countries of the Mediterranean coast”. As a way of celebrating this union, PUMed launches special issues devoted to particular joint themes. In 2016, the issue is dedicated to the fish of the Mediterranean. As a member state, Portugal has participated in this initiative since 2015. To represent this issue, species of fish found not only in the waters of the Mediterranean but also in the Atlantic, around the Azores and Madeira archipelagos, have been chosen. Thus, the eight species are divided into two groups of four elements: groupers, which belong to the Serranidae family, and tuna, which belong to the Scombridae family.
Fish belonging to the Scombridae family are pelagic fish that move in shoals, undertaking great migrations. They are considered top predators in their respective ecosystems and excellent swimmers, possessing hydrodynamic shapes that allow them to reach high speeds and to dive quickly and deeply. Included in this issue are the tuna, which can grow to lengths of three metres and weigh over 600 kilos, and three other smaller species: the bonito, which can reach lengths of over one metre and weigh over thirty kilos, and the Atlantic bonito and the mackerel, whose maximum weights are around five kilos.
Fish belonging to the Serranidae family have very different personality. They are coastal fish that live close to the sea bed – at depths of between three and 200 metres – and in rocky areas, where they tend to hide. They are generally solitary, sharing their territory with only two or three individuals of the same size. Despite being active predators, they are sedentary and slow swimmers. The souvenir sheet produced for this issue contains three smaller-sized species of groupers and the black grouper, a protected species, which can grow to lengths of over one metre and weigh over twenty kilos.
