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<p>We measured the <span class="inline-formula">¹⁴</span>C age of pre-bomb suspension-feeding bivalves of known age from coastal West Africa across a latitudinal transect extending from 33<span class="inline-formula">^∘</span> N to 15<span class="inline-formula">^∘</span> S. The specimens are from collections belonging to the Muséum National d'Histoire Naturelle (Paris, France). They were carefully chosen to ensure that the specimens were collected alive or that they died not long before collection. From the <span class="inline-formula">¹⁴</span>C dating of the known-age bivalves, we calculated the marine reservoir age (as <span class="inline-formula">Δ<i>R</i></span> and <span class="inline-formula"><i>R</i></span> values) for each specimen. <span class="inline-formula">Δ<i>R</i></span> values were calculated relative to the Marine20 calibration curve, and the <span class="inline-formula"><i>R</i></span> values were calculated relative to Intcal20 or SHcal20 calibration curves. Except for five outliers, the <span class="inline-formula">Δ<i>R</i></span> and <span class="inline-formula"><i>R</i></span> values were generally homogenous with weighted mean values of <span class="inline-formula">−</span>72 <span class="inline-formula">±</span> 42 <span class="inline-formula">¹⁴</span>C years (1 SD, <span class="inline-formula"><i>n</i>=24</span>) and 406 <span class="inline-formula">±</span> 56 <span class="inline-formula">¹⁴</span>C years (1 SD, <span class="inline-formula"><i>n</i>=24</span>) respectively. These values are typical of low-latitude marine reservoir age values. Five suspension-feeding species living in five different ecological habitats were studied. For localities where several species were available, the results yielded similar results whatever the species considered, suggesting that, in these locations, the habitat has only a limited impact on marine reservoir age reconstruction. We show that our measured marine reservoir ages follow the declining trend of the global marine reservoir age starting ca. 1900 CE, suggesting that the marine reservoir age of coastal West Africa is driven, at least to the first order, by the atmospheric CO<span class="inline-formula">₂</span> <span class="inline-formula">¹⁴</span>C ageing due to fossil fuel burning rather than by local effects. Each outlier was discussed. Local upwelling conditions or sub-fossil specimens may explain the older <span class="inline-formula">¹⁴</span>C age and thus the larger marine reservoir ages for these samples. <i>Bucardium ringens</i> might not be the best choice for marine reservoir age reconstructions.</p>