Comparison of local knowledge and researcher-led observations for wildlife exploitation assessment and management

The use of local knowledge observations to generate empirical wildlife resource exploitation data in data-poor, capacity-limited settings is increasing. Yet, there are few studies quantitatively examining their relationship with those made by researchers or natural resource managers. We present a case study comparing intra-annual patterns in effort and mobulid ray (Mobula spp.) catches derived from local knowledge and fisheries landings data at identical spatiotemporal scales in Zanzibar (Tanzania). The Bland-Altman approach to method comparison was used to quantify agreement, bias and precision between methods. Observations from the local knowledge of fishers and those led by researchers showed significant evidence of agreement, demonstrating the potential for local knowledge to act as a proxy, or complement, for researcher-led methods in assessing intra-annual patterns of wildlife resource exploitation. However, there was evidence of bias and low precision between methods, undermining any assumptions of equivalency. Our results underline the importance of considering bias and precision between methods as opposed to simply assessing agreement, as is commonplace in the literature. This case study demonstrates the value of rigorous method comparison in informing the appropriate use of outputs from different knowledge sources, thus facilitating the sustainable management of wildlife resources and the livelihoods of those reliant upon them.