Local knowledge and official landing data point to decades of fishery stock decline in West Africa

Small-scale fisheries play a pivotal role in providing food and livelihoods for millions worldwide, particularly in low-income countries in Africa. However, a common challenge in these fisheries is the relative scarcity of statistical data on the composition, abundance, and distribution of fisheries resources, which is crucial for effective management. In data-poor regions, like West Africa, local ecological knowledge has been advocated as a valid source of information for assessing stock conditions and historical performance in relation to distinct drivers of change. This approach, however, needs to be used with caution due to changes in human perceptions related, for example, to the natural state of marine environments, which is known as Shifting Baseline Syndrome (SBS). Hence, this study combines 50 years of users' perceptions and landing data from Maio island, Cabo Verde, where fishing communities dependent on fish stocks are becoming increasingly vulnerable. Our aims were i) to investigate changes in small-scale fisheries catches over the past five decades, and ii) to understand and refine the use of these data as alternative or complementary sources in local-regional fisheries management. Our results highlight the impact of SBS on users’ perceptions, which is influenced by local socio-ecological context. Significantly, our results point to a staggering decline in local stocks that may exacerbate the vulnerability of West African coastal fisheries.