Egyptian fisheries need urgent action to combat effects ofoverexploitation and climate change
The Mediterranean contains 4–18% of the knownmarine species in the world but poorly regulated overfishing has disrupted theintegrity of its habitat in the Egyptian fisheries and could threaten itsdiversity
Drastic changes in thediversity of the species found in the Mediterranean off the Egyptian coast area result of overexploitation of its fisheries, according to a recent study (M.Khalfallah et al. Ocean Coast. Manage. 245, 106831; 2023).
The authors argue thatbetter management is required to combat overexploitation of fish stocks and ensurethe health of marine life in the Mediterranean.
The research team fromthe Sea Around Us initiative at the Canadian University of British Columbia andthe Arab Academy for Science, Technology and Maritime Transport in Egypt reconstructedcatch data from Egypt’s marine fisheries in the Mediterranean from 1920 to2019. They compared this with data reported by the Food and Agriculture Organization (FAO), which startedpublishing annual fisheries statistics in 1950.
The Mediterranean isan important area of biodiversity and contains 4–18% of the known marine species in the world despite itmaking up about 0.8%of its oceans. Egypt has 1,000kilometres of the Mediterraneancoastline, stretching from the Palestinian border in the east to the Libyanborder in the west.
Myriam Khalfallah, who led the study, told Nature Middle East that 3.8 million tonnes offish and invertebrates have were removed from Egyptian fisheries in theMediterranean from 1920 to 2019. To safeguard the biodiversity of thisimportant marine resource, the researchers recommend an urgent plan for better regulationand monitoring of commercial fishing including limiting trawling and improvedmonitoring of other activity in the area, including recreational fishing. They alsostressed the need to use new tools to assess the volume of fish stocks.
Recovery anddecline over the years
The study identified majorpeaks in the Egyptian fisheries followed by drastic declines. Events that have ledto these fluctuations include the building of the Aswan High Dam across theNile in the 1960s. The dam was identified as one of the main contributors tothe collapse of the fisheries after the recovery and rapid expansion that followedthe Second World War. This is because it stops nutrients flowing from the riverto the sea, depriving fish of natural fertilizers, says Khalfallah.
The quantity of fish landingsdecreased by half from 1962 to 1966 during the initial stages of the buildingof the dam with data showing that sardinellas went from making up an average of30% of all commercial catches between 1950 and 1965 to only 4% in 1968.
“With more adeptmanagement practices in place, the fate of the Egyptian fisheries could havebeen far less dire – and they could have been more resilient to the damconstruction,” the study says.
The fisheries returnedto pre-dam levels in the late 1980s, but catches decreased by almost halfbetween 2011 and 2019 after the 2011 Egyptian revolution, due tooverexploitation. The decline of the fisheries has also been exacerbated byclimate change, which affects the Mediterranean heavily and has led to increasedtemperatures and tropicalization.
Migration of invasivespecies
The Suez Canal wasopened for maritime navigation in 1869, linking the Mediterranean to the IndianOcean via the Red Sea. The route passes through The Great Bitter Lake, which wasoriginally saltier than the Mediterranean and the Red Sea, which limited themovement of species. But it has not prevented more than 400 non-native animal speciesmigrating to the Mediterranean, including more than 100 species of marine fishfrom the Red Sea.
Khalfallah says thistransfer of species from the Red Sea to the Mediterranean represents a threatto biodiversity and the natural habitats of species, creating ecologicalimbalances, which are further exacerbated by the effects of climate change andrising sea temperatures.
Ahmed Diab, whostudies agriculture and aquaculture at the Fish Research Institute,Agricultural Research Centre (ARC), Egypt explains that temperatures are risingfaster in the eastern Mediterranean regions, making them “ideal for many RedSea species”.
Khalfallah says that organismsarriving from the Red Sea adapt more quickly to the new Mediterraneanenvironment because they are accustomed to high temperatures. This disturbanceof natural habitats will ultimately affect the food chain in the Mediterraneansince invasive organisms feed on resident organisms, which will pose a threatto the integrity of habitats.
One example of suchpredator species invading the Mediterranean is the pufferfish, Diab says. It isa carnivorous fish that preys on a large number of marine species such asoctopuses and small fish.
Previous studies,including one published in 2020 (G. Castellaos-Galindo et al. Nature Ecol. Evol.4, 1444–1446; 2020) support the findingsof Khalfallah and her colleagues. However, Mahmoud Hanafi, who studies marine environmentat the Suez Canal University, downplays the effectsof the expansion of the Suez Canal on the movement of species between the RedSea and the Mediterranean. “Migration is natural, especially with climatechange and global warming causing marine species to migrate from south to north–and some species, such as jellyfish, originated in the Atlantic Oceannot the Suez Canal,” he told Nature Middle East.
Overfishing
Although climatechange and the migration of species through the Suez Canal pose a threat tofisheries, one of the greatest threats to the marine ecosystem is overfishing,which depletes species to the point where it is difficult to compensate for theloss of fish.
The extent of overfishingin Egypt and other Mediterranean countries is difficult to trace. It includes fishingin an area that should not be fished or using a prohibited fishing tool.Overfishing in a specific area hinders the remaining fish from reproducing tomaintain their population. Another danger is the threat it poses to the foodchain when catching fish that another species of fish would typically feed on.
Catching small fishfor farming purposes, or ‘fishing for fry’, is one of the most serious problemsfacing Mediterranean fisheries. Hanafi considers it a crime. He says it happensmainly at the straits of northern lakes such as Lake Al-Manzala and Lake Burullus in Egypt as small fishare trying to access the nutrients in the lake.
“A sustainable fishingsystem must be implemented; one that takes into account the safety and renewalof the marine ecosystem, combatting fishing for fry, and stopping the sourcesof pollution that flow into the Mediterranean Sea, which kill fish and threatenbiodiversity,” says Hanafi.
