Mehmet Gökoğlu, a professor at Akdeniz University’s Faculty of Fisheries, said species migrating from the Red Sea into the Mediterranean are reshaping the marine ecosystem by competing with native species for food and habitat and placing pressure on some populations.
Gökoğlu told Anadolu Agency (AA) that the spread of Red Sea-origin species in the Mediterranean is changing not only species diversity but also feeding relationships among marine organisms.
The Mediterranean is home to a range of native species, Gökoğlu said, adding that invasive species that establish themselves in the region eventually begin using the same food sources and sharing the same habitats as native species.
He said the ability of introduced species to establish populations in a new environment indicates that they are resilient and adaptable.
“Species coming from outside are strong species. If they establish a population after entering this environment, they are resilient and strong species. Therefore, they put pressure on species in the Mediterranean,” he said.
Some Red Sea-origin species use the same food sources as native Mediterranean species, while others directly feed on the young, eggs and larvae of native species, Gökoğlu said.
He noted that this can alter the distribution and population density of some native species, adding that the integration of Red Sea species into the Mediterranean food web has created new ecological relationships.
“Species from the Mediterranean were not previously on the menu of Red Sea species. After entering the Mediterranean, they became part of their diet. Likewise, Red Sea species were not on the menu of Mediterranean species. They have now become part of their diet as well. This has brought about a change,” he said.
Gökoğlu said the effects of this change are particularly noticeable among organisms living on the seafloor, citing the Red Sea-origin pufferfish as an example.
Pufferfish feed on organisms living on the seafloor, including crustaceans and mollusks as well as octopuses, cuttlefish and squid, Gökoğlu said.
He noted that pufferfish constantly move along the seafloor, putting pressure on benthic species.
Fishermen have also observed these changes, he said.
“Pufferfish constantly move along the seafloor. They consume benthic species, including crustaceans and mollusks. Octopuses, cuttlefish and squid are also among their prey. That is why we are seeing octopus populations decline rapidly along the Mediterranean coast. Similar pressures and changes are occurring,” he said.
Gökoğlu said the use of the same resources by Red Sea species and native species gradually changes the relationships among organisms in the ecosystem, adding that the impact is not limited to a single species.
The changes caused by Red Sea-origin species have consequences not only for the ecosystem but also for fisheries, with some invasive species being put to economic use, Gökoğlu said.
However, he noted that species with no economic value still consume food and occupy habitat within the ecosystem, meaning that the inability to utilize them also represents an economic loss.
“There is competition over food and habitat. We can make use of some invasive species. There are also species, such as pufferfish, that are not utilized. There are other species that have migrated from the Red Sea to the Mediterranean but are not utilized in any way. They occupy space, and you cannot derive any economic value from them. That means you have a loss,” he said.
Gökoğlu concluded that the picture emerging as Red Sea-origin species spread throughout the Mediterranean shows that changes in the marine ecosystem are not simply a matter of new species appearing, but also involve the reshaping of feeding relationships and habitat-sharing patterns among species.
