Egypt has a coastal strip on the Mediterranean Sea that extends for 1000 kilometers, running from the Palestinian border in the east to the Libyan border in the west.
The Mediterranean Sea is an important area for biodiversity and contains 4-18% of the world's known marine species, even though it represents only about 0.8% of its oceans. Overfishing and poor regulation have compromised the environmental health of Egyptian fisheries in the Mediterranean and could threaten its diversity.
As part of the "Our Sea Around Us" initiative at the University of British Columbia in Canada and the Arab Academy for Science, Technology and Maritime Transport in Egypt, a research team reconstructed fishing data from Egyptian marine fisheries in the Mediterranean from 1920 to 2019.
The research team compared this with data reported by the Food and Agriculture Organization (FAO), which began publishing annual fishery statistics in 1950.
The study published by "Nature Middle East" revealed that significant changes in species diversity off the Egyptian coast in the Mediterranean are a result of excessive exploitation of fisheries. The authors emphasize the need for better management to combat overexploitation of fish stocks and ensure the health of marine life in the Mediterranean.
Myriam Khalef Allah, who led the study, mentioned to Nature that 3.8 million tons of fish and invertebrates were removed from Egyptian fisheries in the Mediterranean Sea from 1920 to 2019. To protect the biodiversity of this important marine resource, researchers recommend an urgent plan to improve the regulation and monitoring of commercial fishing, including reducing bottom trawling and enhancing monitoring of other activities in the region, such as recreational fishing. They also emphasized the need for new tools to assess fish stock volumes.
Recovery and Decline Over the Years
The study identified a peak in Egyptian fisheries followed by sharp declines, with one event being the construction of the High Dam at Aswan across the Nile River in the 1960s.
According to Myriam, the dam was identified as a major contributor to the collapse of fish stocks after the rapid recovery and expansion following World War II. This was due to the interruption of nutrient flow from the river to the sea, depriving fish of natural fertilizers.
The amount of fish caught decreased by half from 1962 to 1966 during the initial stages of dam construction. Data showed that sardine fish, which constituted an average of 30% of the total commercial catch between 1950 and 1965, dropped to only 4% in 1968.
The study states, "With more skilled management practices, the fate of Egyptian fisheries could have been much less precarious - and could have been more resilient in dam construction."
Fish stocks returned to pre-dam levels in the late 1980s, but fishing declined by nearly half between 2011 and 2019 after the Egyptian revolution in 2011, due to overexploitation.
Further exacerbating the decline of fish stocks is climate change, which greatly impacts the Mediterranean Sea, leading to rising temperatures and a shift towards tropical regions.
Role of the Suez Canal
The Suez Canal opened for maritime navigation in 1869, connecting the Mediterranean Sea to the Indian Ocean via the Red Sea. The passage goes through the Great Bitter Lake, which was originally more saline than the Mediterranean and Red seas, limiting the movement of species. However, it did not prevent over 400 non-native animal species from migrating to the Mediterranean, including over 100 species of Red Sea marine fish.
The lead researcher in the team, Ahmed Diab, studying aquaculture and aquatic life at the Fish Research Institute, Agricultural Research Center in Egypt, points out that temperatures are rising faster in the eastern Mediterranean, making it "ideal for many Red Sea species." Organisms from the Red Sea quickly adapt to the new Mediterranean environment due to their high-temperature tolerance.
Myriam explains that this disturbance will ultimately affect the natural habitats in the Mediterranean, disrupting the food chain as predatory organisms feed on resident species, posing a threat to habitat safety.
Diab also states that one example of predatory species invading the Mediterranean is the pufferfish, known for preying on various marine species like octopuses and small fish.
Previous studies, including one published in 2020, support Khalef Allah and her colleagues' findings. However, Mahmoud Hanafy, studying marine environment at the Suez Canal University, downplays the impact of the Suez Canal expansion on species movement between the Red Sea and the Mediterranean.
He says, "Migration is natural, especially with climate change and global warming causing marine species to move from south to north - and some species, such as jellyfish, originated in the Atlantic Ocean and not in the Suez Canal."
Overfishing
While climate change and species migration through the Suez Canal pose threats to fish stocks, one of the biggest threats to the marine ecosystem is overfishing, depleting species to a point where fish loss is hard to compensate.
