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Environment

Climate Shift Drives Sardine Migration Along Northwest African Coastline

Wednesday 05 June 2024 - 15:30

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The relentless advance of climate change is etching a lasting imprint on the marine habitats of Northwest Africa, as per a pioneering study. In a vivid demonstration of the extensive ramifications of global warming, sardines and other small pelagic fish species are embarking on a northward journey along the coast, reshaping the fragile equilibrium of this crucial marine ecosystem.

The research, unveiled in the esteemed journal Scientific Reports, presents a sobering portrayal of how rising sea surface temperatures and shifting ocean currents are affecting the distribution of these vital fish populations. An international team of scientists from Senegal, France, Norway, Morocco, Mauritania, and The Gambia meticulously scrutinized a trove of data spanning over two decades, incorporating 2,363 trawl samplings and a staggering 170,000 km of acoustic sea surveys conducted between 1995 and 2015.

Their findings ring alarm bells. The southern stretch of the Canary Current Large Marine Ecosystem (CCLME), spanning from Morocco to Senegal, has witnessed substantial warming over the past 34 years. This warming trend has been accompanied by alterations in wind speed and upwelling intensity, particularly in regions where coastal upwelling was already most pronounced.

Among the most notable revelations is the northward migration of the iconic sardine (Sardinella aurita) and its pelagic counterparts. The study documents a significant shift in the northern boundary of Sardinella aurita, which has moved northward at a rate of 181 km per decade since 1995. This migration is attributed to the long-term warming trends in sea surface temperature (SST) and a decline in marine productivity in the southern regions of the CCLME.

The repercussions of this migration are profound. Sardine abundance has surged in subtropical zones while waning in the intertropical region, posing a substantial threat to these recently overexploited fish populations and complicating sustainable management endeavors.

Furthermore, the spatial rearrangements in biomass observed for sardines and other exploited small pelagic species introduce a new layer of complexity to an already precarious situation, imperiling the food security of West African nations that rely on these critical fish stocks.

The study's principal investigators stress the pressing nature of the issue, underscoring the imperative for heightened awareness, more frequent and systematic monitoring, and targeted research initiatives on small pelagic fish in West Africa. Such endeavors, they argue, are indispensable for comprehending the responses of this highly dynamic marine ecosystem, ensuring the sustainability of vital fishery resources, and safeguarding the welfare of coastal communities in the face of the climate crisis.

As Morocco, along with the rest of northwestern Africa, contends with the unprecedented impacts of global warming, including drought, desertification, and sea level rise, the study's findings resonate as a rallying cry for action. The northward migration of sardines serves as a stark reminder that the consequences of climate change are not abstract projections but tangible realities, with profound implications for the ecological and economic fabric of the region.