Estimating illegal catches in data-poor S-fisheries: Insights from multispecies shellfish poaching in galician small scale fisheries

The opaque nature of illegal, unreported, and unregulated (IUU) fishing means that the data on catches are scarce or unreliable, making it difficult to estimate the volume of illegal fishing and the number of individuals who practice it. In this work, we develop the use of quantification methods for IUU fishing in data-poor fisheries and provide estimates for the main shellfish species exploited in S-fisheries in Galicia (NW Spain). To make the estimates, we use a model whose primary input is the Confiscations per unit of policing effort (CPUPE) index, which relates the sanctions imposed for poaching, estimated poaching, and confiscations carried out by the Enforcement Forces. The estimates for the period 2012–2020 are 660.2 t of illegal catches of different species and an average number of 1,766.2 poachers/year. These estimates provide evidence that makes it possible to analyse tendencies in illegal fishing, to establish assessment baselines and to highlight potential improvements in the fight against IUU fishing in small-scale fisheries.