Beneath the surface of West African waters, white grouper swim freely, caught by hundreds of canoes every day. But what do we really know about their status after decades of fishing? For the first time, researchers have cross-referenced all available data to try to shed some light on the situation.
By Laurie Henry
Cover photo: Traditional fishing in Senegal. © Wikimedia Commons
On the coasts of Mauritania, Senegal, and Gambia, the thiof is much more than just a fish: it feeds people, generates income, and sustains traditions. Highly prized by artisanal fisheries, this white grouper is at the heart of a fragile balance between human needs and marine resources. In recent years, scientists have decided to pool their data and expertise to understand the evolution of this iconic species. With the support of the FAO and European projects, they have compiled more than forty years of observations at sea, records, catches, and measurements of landed fish.
Their goal: to shed light on the actual state of the thiof stock in this region where administrative boundaries do not correspond to those of the ocean. Their findings, published in February 2025 in the journal Fishes, confirm that “fishing pressure on thiof reached unprecedented levels between 2016 and 2018,” against a backdrop of high demand and a lack of coordinated management.
Contrasting dynamics between countries
The study highlights very different exploitation trajectories between countries, even though the white grouper (Epinephelus aeneus) moves freely between Mauritanian, Senegalese, and Gambian waters.
In Senegal, thiof fishing has been practiced since the 1970s, mainly by artisanal canoes using lines, longlines, and gillnets. This long-standing exploitation has led to a collapse in the demographic structure of the stock. According to a statistical model that simply looks at the size of fish caught and applied to the period 2019–2021, the average size of fish caught has fallen to 33 cm, well below the optimal catch size estimated at around 58–60 cm. The fishing mortality indicator relative to sustainable mortality is 8.8—nearly nine times the limit that allows for stable stock renewal.