Expert-Based Threat Analysis on Loggerhead Sea Turtle (Caretta caretta) in Central Mediterranean Sea Evidences Marine Pollution as the Priority: Gaps of Knowledge and Possible Cognitive Biases in Evaluation

We carried out an expert-based threat analysis on the Loggerhead sea turtle (Caretta caretta)—classified as ‘vulnerable’ by the International Union for Conservation of Nature—as a target species for the central Mediterranean basin. We involved a panel of 10 experts who identified 10 anthropogenic threats (named using the IUCN standard taxonomy) and assigned scores to assess, for each threats: (i) the mean pressure magnitude (PM), as a proxy for threat pressure (combining two regime attributes: extent and intensity), and (ii) the level of knowledge about these threats (knowledge magnitude, KM). Regarding PM, we observed that mean scores significantly differed among threats with ‘marine pollution and abandonment of solid waste’, ‘accidental catches with professional fishing nets’ and ‘habitat degradation’ (with modification of breeding sites), showing the highest values. ‘Pathologies’ and ‘direct persecution’ showed the lowest mean scores in PM. Regarding KM, experts assessed ‘nocturnal light pollution in breeding areas’ and ‘direct persecution’ as poorly known, evidencing as these threats deserve more effort in research about their extent and intensity as pressure attributes. Comparisons between PM and KM values evidence a significant knowledge gap for ‘habitat degradation’, a threat with high PM but medium KM. The more a threat is known in its regime, the higher its impact is perceived, suggesting cognitive biases in threat evaluation. Although threat analysis is a useful tool in the early stages of conservation projects, experts should be aware of possible weaknesses in this approach.