New research, recently published in the Ocean and Coastal Management journal, highlights the urgent need for improved management of Egyptian fisheries in the Mediterranean Sea to safeguard the region’s marine ecosystems. Scientists from the Sea Around Us initiative at the University of British Columbia and the Arab Academy for Science, Technology, and Maritime Transport conducted a comprehensive analysis of Egypt’s marine fisheries over the past century, revealing troubling signs of resource overexploitation. This unsustainable fishing practice has forced fishermen to venture further and deeper into the sea, targeting lower-tier species.
Dr. Myriam Khalfallah, who led the study, explained that Egyptian Mediterranean marine fisheries have relied heavily on trawl fishing for over a century, alongside other methods like longlining, purse-seining, and traditional multi-gear fishing. The research unearthed a startling statistic: from 1920 to 2019, a staggering 3.8 million tons of fish and invertebrates were harvested from Egypt’s Mediterranean waters. The data displayed distinct peaks in catches, often followed by sharp declines influenced by external factors and increased fishing pressure.
Early indications of trouble emerged in the mid-1920s when landings dwindled, and juvenile fish became scarcer in shallow waters, coinciding with the expansion of the trawl fleet and more frequent fishing trips. Dr. Khalfallah pointed out that these early signs hinted at an impending issue. World War II brought a temporary recovery, but the mid-1960s saw another decline due to the construction of the Aswan High Dam, obstructing the flow of vital nutrients from the Nile into the sea.
One of the hardest-hit fisheries was sardines, with their share of the commercial catch plummeting from 30% in 1950-1965 to less than 4% in 1968. Although fisheries rebounded to pre-dam levels in the late 1980s, thanks to fertilizer runoff from Nile Delta farms enriching the waters and boosting fish populations, the 2000s witnessed fluctuating catches, indicating that the resurgence was short-lived.
Dr. Khalfallah emphasized a concerning trend: a nearly 50% decline in catches between 2011 and 2019 despite growing fishing pressure. Stock assessments for commercially important species along Egypt’s Mediterranean coast confirmed overexploitation as the primary cause. Even newly established invasive species are facing overfishing pressures.
Fishing down the food web
The research findings were further strengthened by the calculation of the Marine Trophic Index, which provides insight into where most of the caught fish sit in the food chain.
Dr. Daniel Pauly, a co-author of the study and the principal investigator at the Sea Around Us, explained, “The Marine Trophic Index indicates that fishing initially targeted higher trophic levels in the food chain up until the mid-1950s, primarily due to the geographical expansion of fisheries. However, from the 1970s onwards, as available fishing grounds dwindled, excessive fishing led to a ‘fishing down’ phenomenon, resulting in lower values on the Marine Trophic Index.”
This “fishing down” trend signifies that, as predatory fish at the top of the food chain were depleted, fisheries turned their attention to progressively smaller species, eventually resorting to previously overlooked small fish and invertebrates. This, combined with shifts in species composition driven by the warming of the Mediterranean, is expected to exert increasing pressure on Egypt’s fisheries.
Furthermore, the study revealed that the average temperature of caught species has been steadily rising by 0.07°C per year since 1987, underscoring the significant influence of climate change on the marine ecosystems and fisheries in the region.
Dr. Pauly stressed the urgency of the situation, stating, “It is imperative for Egyptian authorities to take fisheries management seriously, as failure to do so would entail the loss of a vital source of food and livelihoods.”
The research paper titled “Once upon a century, the Egyptian Mediterranean fisheries (1920–2019), as affected by ‘fishing down’ and climate change” has been published in Ocean and Coastal Management.
Source: Sea Around Us