THE BARRACUDA OF THE MEDITERRANEAN

The success of the yellowstripe barracuda, which has established a presence in the Mediterranean Sea, is a prime example of how an invasive species can seize on the opportunities presented by a changing climate. Aquatic species and insects find their way into the Mediterranean via the Suez Canal, often on the hulls of ships, making it the most invasive-rich water basin in the world. For a species such as the yellowstripe barracuda, which evolved in a tropical marine environment, the Mediterranean offers opportunity and challenges: it can find new prey and face fewer predators (partly because some predators, such as tuna and swordfish, have been overfished); but until recently, the cooler waters of the Mediterranean meant that it was generally confined to the southern edges of the sea. Climate-change-related factors, such as warming waters, sea-level rise and ocean acidification, are leading to a degradation of marine habitats for many marine species. However, research by the Mediterranean Experts on Climate and Environmental Change has found that the barracuda has greatly increased its distribution range in the sea over the past 30 years.