The shores of the Mediterranean Sea are favored by jellyfish, because they are densely populated and are a constant source of "nutrients" such as nitrogen, phosphorous compounds and garbage
In the summer of 2005, bathers in Malaga, Granada and Catalonia reported a higher number of jellyfish than usual. Bathers in other parts of the Mediterranean also encountered surprising amounts of jellyfish. Thus, after over 4 billion years, a "population explosion" of jellyfish is about to occur.
Excessive fishing of predatory fish such as tuna and mackerel, an increase in water temperature and sea pollution create the ideal living conditions for the primitive animals. The Mediterranean Sea - a closed sea where these conditions are produced in a concentrated and constant manner - may become a body of viscous and burning water, so warns the European Environmental Agency.
The beaches of the Mediterranean Sea are preferred by the jellyfish, because they are densely populated and are a constant source of "nutrients" such as nitrogen, phosphorous compounds and garbage. These substances are the basic ingredients in the diet of algae and plankton - an appetizing soup that no jellyfish will refuse. Despite their delicate skin, jellyfish are carnivorous animals: they feed on the plankton, which includes larvae and eggs of many fish species.
The European Environmental Agency warns in a report it published this week, against "continuous damage" to the beaches. The report condemns the increase in the urbanization of the coastal areas and calls for increased supervision of these processes.
The human hand is involved in all the factors that allow jellyfish to reproduce. Fishing for large fish or sea turtles leaves the jellyfish without enemies. The warming water temperature provides jellyfish with more and more breeding areas. In addition, the amount of rain continues to decrease, and the rivers flow less fresh water to the sea. The jellyfish need the salt concentrations to maintain a balance between the fluids in their body and their outer body.
Jellyfish may be about to become the queens of the Mediterranean. The living conditions are so good that, in addition to the local jellyfish species, jellyfish from other regions have begun to reproduce in different corners of the Mediterranean Sea. As in many cases, man plays a role in the spread of alien species.
In Israel, the Suez Canal is the cause of the proliferation of jellyfish that approach the shores. Tens of years ago, jellyfish of the wandering filamentous species entered the sea through the canal. Over time the population spread and today a swarm of millions of jellyfish that stretches for dozens of kilometers arrives in Israel every summer.
The wandering wireworm is equipped with hunting arms with stinging cells used for protection and predation. It is an increasing nuisance to bathers at the beach, but also causes damage to fishing nets and the openings of infrastructure facilities that it blocks.
The new species of jellyfish also arrive via the Suez Canal, and additional jellyfish find their way to the Mediterranean in the hulls of ships passing through Gibraltar. To date, many species have not survived the journey, but the increase in water temperature helps them cross the Atlantic Ocean from subtropical areas to the Mediterranean Sea.
