Egyptian fisheries need urgent action to combat effects of overexploitation and climate change

Drastic changes in the diversity of the species found in the Mediterranean off the Egyptian coast are a result of overexploitation of its fisheries, according to a recent study (M. Khalfallah et al. Ocean Coast. Manage. 245, 106831; 2023). 

The authors argue that better management is required to combat overexploitation of fish stocks and ensure the health of marine life in the Mediterranean.

The research team from the Sea Around Us initiative at the Canadian University of British Columbia and the Arab Academy for Science, Technology and Maritime Transport in Egypt reconstructed catch data from Egypt’s marine fisheries in the Mediterranean from 1920 to 2019. They compared this with data reported by the Food and Agriculture Organization (FAO), which started publishing annual fisheries statistics in 1950.

The Mediterranean is an important area of biodiversity and contains 4–18% of the known marine species in the world despite it making up about 0.8% of its oceans. Egypt has 1,000 kilometres of the Mediterranean coastline, stretching from the Palestinian border in the east to the Libyan border in the west.

Myriam Khalfallah, who led the study, told Nature Middle East that 3.8 million tonnes of fish and invertebrates have were removed from Egyptian fisheries in the Mediterranean from 1920 to 2019. To safeguard the biodiversity of this important marine resource, the researchers recommend an urgent plan for better regulation and monitoring of commercial fishing including limiting trawling and improved monitoring of other activity in the area, including recreational fishing. They also stressed the need to use new tools to assess the volume of fish stocks.

Recovery and decline over the years

The study identified major peaks in the Egyptian fisheries followed by drastic declines. Events that have led to these fluctuations include the building of the Aswan High Dam across the Nile in the 1960s. The dam was identified as one of the main contributors to the collapse of the fisheries after the recovery and rapid expansion that followed the Second World War. This is because it stops nutrients flowing from the river to the sea, depriving fish of natural fertilizers, says Khalfallah.

The quantity of fish landings decreased by half from 1962 to 1966 during the initial stages of the building of the dam with data showing that sardinellas went from making up an average of 30% of all commercial catches between 1950 and 1965 to only 4% in 1968.

“With more adept management practices in place, the fate of the Egyptian fisheries could have been far less dire – and they could have been more resilient to the dam construction,” the study says.

The fisheries returned to pre-dam levels in the late 1980s, but catches decreased by almost half between 2011 and 2019 after the 2011 Egyptian revolution, due to overexploitation. The decline of the fisheries has also been exacerbated by climate change, which affects the Mediterranean heavily and has led to increased temperatures and tropicalization. 

Migration of invasive species

The Suez Canal was opened for maritime navigation in 1869, linking the Mediterranean to the Indian Ocean via the Red Sea. The route passes through The Great Bitter Lake, which was originally saltier than the Mediterranean and the Red Sea, which limited the movement of species. But it has not prevented more than 400 non-native animal species migrating to the Mediterranean, including more than 100 species of marine fish from the Red Sea.

Khalfallah says this transfer of species from the Red Sea to the Mediterranean represents a threat to biodiversity and the natural habitats of species, creating ecological imbalances, which are further exacerbated by the effects of climate change and rising sea temperatures.

Ahmed Diab, who studies agriculture and aquaculture at the Fish Research Institute, Agricultural Research Centre (ARC), Egypt explains that temperatures are rising faster in the eastern Mediterranean regions, making them “ideal for many Red Sea species”.

Khalfallah says that organisms arriving from the Red Sea adapt more quickly to the new Mediterranean environment because they are accustomed to high temperatures. This disturbance of natural habitats will ultimately affect the food chain in the Mediterranean since invasive organisms feed on resident organisms, which will pose a threat to the integrity of habitats.

One example of such predator species invading the Mediterranean is the pufferfish, Diab says. It is a carnivorous fish that preys on a large number of marine species such as octopuses and small fish.

Previous studies, including one published in 2020 (G. Castellaos-Galindo et al. Nature Ecol. Evol. 4, 1444–1446; 2020) support the findings of Khalfallah and her colleagues. However, Mahmoud Hanafi, who studies marine environment at the Suez Canal University, downplays the effects of the expansion of the Suez Canal on the movement of species between the Red Sea and the Mediterranean. “Migration is natural, especially with climate change and global warming causing marine species to migrate from south to north – and some species, such as jellyfish, originated in the Atlantic Ocean not the Suez Canal,” he told Nature Middle East.

Overfishing

Although climate change and the migration of species through the Suez Canal pose a threat to fisheries, one of the greatest threats to the marine ecosystem is overfishing, which depletes species to the point where it is difficult to compensate for the loss of fish.

The extent of overfishing in Egypt and other Mediterranean countries is difficult to trace. It includes fishing in an area that should not be fished or using a prohibited fishing tool. Overfishing in a specific area hinders the remaining fish from reproducing to maintain their population. Another danger is the threat it poses to the food chain when catching fish that another species of fish would typically feed on.

Catching small fish for farming purposes, or ‘fishing for fry’, is one of the most serious problems facing Mediterranean fisheries. Hanafi considers it a crime. He says it happens mainly at the straits of northern lakes such as Lake Al-Manzala and Lake Burullus in Egypt as small fish are trying to access the nutrients in the lake.

“A sustainable fishing system must be implemented; one that takes into account the safety and renewal of the marine ecosystem, combatting fishing for fry, and stopping the sources of pollution that flow into the Mediterranean Sea, which kill fish and threaten biodiversity,” says Hanafi.

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