Exotic species rise, local species fall in Aegean Sea: Expert

IZMIR

An expert has called attention to the simultaneous rise in exotic fish species and reduction in local fish species in the Aegean and Mediterranean Seas due to overfishing, temperature rises, and marine pollution.

A lecturer from İzmir Katip Çelebi University, Erhan Irmak, stated that the Mediterranean Sea serves as a home to different living species as a cross-continental sea influenced by temperature variations.

As fish are cold-blooded animals, they are highly affected by even the slightest change in temperature, which leads to alterations in numbers of various fish species, the expert said.

Indicating that the fish species that pass through the Suez Canal are generally of tropical origin, Irmak said, “Consequently, when sea temperatures rise, so does the diversity of exotic species such as lionfish and pufferfish. Thus, exotic species spread throughout the Mediterranean Sea, including the southern Aegean.”

He also presented the grounds for the concurrent decline in the local species in the seas.

The expert clarified that there has been an uptick in marine pollution as a result of the excessive occupation of the coastal areas for the last 30 years. He added that the rise in turbidity brought on by land-based marine pollution is one of the primary causes of the temperature increase in the seas.

Remarking that this situation prepares the ground for the decline in local fish species of cold water, he said, “Although haddock is often located in the Aegean Sea around Izmir, they are gradually moving north and stranded in the northern Aegean currently. Since their living conditions are changing, species that prefer the cold are migrating north of the Aegean Sea.”

Irmak also drew attention to the huge effect of overfishing on the fluctuation of the number of local fish species, stating, “The species of bluefish and bonito ought to cross the straits and finish migrating, but because of overfishing, they are unable to do so. As a result, their population is drastically declining.”

The expert indicated that this year's bonito season might be extremely brief or even nonexistent, adding that it “may take four to five years for the population to recover."