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Scientist: Half of All Mediterranean Organisms are Invasive Species

Sea is becoming increasingly tropicalized due to climate change, pollution and overfishing

A huge number of invasive species are flooding the Mediterranean Sea and rapidly transforming marine biodiversity in the area, particularly near the Israeli coast, according to at least one expert.

Dr. Alvaro Israel, a senior scientist at Israel’s National Institute of Oceanography, has been monitoring marine life for the past three decades. He says the transformation could force people living in surrounding areas to change their diets as native fish are increasingly displaced by foreign invaders.

“Fifty percent of the species today [are invasive] and not natural to the Mediterranean Sea, which has also influenced fisheries in the area because [many] were overfished,” Israel told The Media Line. “We have a huge number of invasive species coming particularly from the Indo-Pacific Ocean through the Suez Canal and arriving eventually in the [Israeli] part of the Mediterranean.”

The Mediterranean is one of the most complex marine ecosystems in the world and is home to roughly 17,000 species, according to extensive studies carried out in the region. It is also considered to be a hotspot for bio-invasions. Hundreds of marine species – including the puffer fish, which is rare to temperate zones such as the Mediterranean – have lately been encountered in the area thanks to east-west marine currents.

At the root of many of the most dramatic changes are overfishing and pollution, although acidification and rising sea temperatures are also contributing to the shift.

“There’s a consensus within the international scientific community that because of climate change – increasing temperatures and carbon dioxide [levels] – [the waters] of the Mediterranean are getting tropicalized,” Israel said, referring to the growing number of warm-water species in the region.

“There are constant changes in biodiversity worldwide, and that’s because of the movement of marine organisms from one place to another, which happens quite easily now because of maritime transportation and other key vectors,” he explained.

“[We] will have to eat different kinds of fish,” he affirmed, qualifying this by adding that “we don’t have enough data and we’re still working on it.”

The veteran scientist underlined that the National Institute of Oceanography had been tasked by the Israeli government with conducting a lengthy study of marine life in the Red Sea and eastern Mediterranean following the discovery of the Tamar gas field, located some 80 km. (50 miles) off the Israeli coast. The findings are expected to be published by the end of this year and will include recommendations to promote conservation and avert marine life deterioration.

Research carried out by the Mediterranean Information Office for Environment, Culture and Sustainable Development (MIO-ECSDE) in 2013 found that 10-15% of all species in the Mediterranean were invasive. But according to the University of British Columbia’s Sea Around Us research initiative, as of 2016, half of all trawlers’ catches in Israel were made up of non-native organisms.

Similarly, a study published in the American journal Science Advances last month argued that unregulated fishing and poaching were the single biggest threat to marine life in many of the world’s oceans. The research team, led by the University of Helsinki’s Dr. Enrico Di Minin, placed the Arabian Gulf in the top 10% of areas at risk.

Jon Corsiglia, senior communications manager for the Sustainable Ocean Initiative at the non-profit World Resources Institute, told The Media Line that there were a number of sustainable practices that could be implemented to at least halt the process.

“Generally, unsustainable fishing, ocean warming and ocean acidification, and plastic pollution are top threats to the health of the global ocean and the life therein,” Corsiglia explained.

“The biggest things people and governments can do to help are, one, to fully enforce fisheries management laws and stamp out illegal fishing – people can also seek out certified sustainable seafood when they buy fish and seafood by looking for ecolabels like the Marine Stewardship Council,” he said.

“Two,” he continued, “[we can] reduce our carbon dioxide emissions. And three, [we can] consume less plastic and demand that the companies we buy from move to a circular economy model so that less plastic is produced and therefore less plastic ends up in the ocean.”