Assessing the reliability and utility of citizen science data for monitoring and managing sharks and rays

Sharks and rays are the most threatened vertebrate group. At greatest risk are large-bodied, shallow-water species, many of which are flagship species for marine wildlife tourism. The value of global shark and ray tourism is... [ view full abstract ]

Sharks and rays are the most threatened vertebrate group. At greatest risk are large-bodied, shallow-water species, many of which are flagship species for marine wildlife tourism. The value of global shark and ray tourism is estimated to exceed USD 500 million annually, with potential for further growth. Realizing this potential will require robust data on population distribution and status with which to inform and evaluate management interventions that address the threats to wild populations. However, obtaining accurate and timely data across Indonesia’s expansive marine ecosystems is costly and time consuming.

We present preliminary findings from a study to evaluate the accuracy and precision of population data obtained from citizen scientists. In-situ repeated measures were used to evaluate reported encounter rate estimation bias by non-specialists (recreational divers), specialists (dive professionals and guides) and experts (researchers). Crowdsourcing, machine learning and image recognition software were used to evaluate the potential of photographs, including those derived from social media platforms, to inform population assessments. We applied our findings to a 10-year data set obtained from recreational divers and tourism operators to assess long-term population trends for focal shark and ray species in Komodo National Park, Indonesia. Our findings suggest that data obtained from non-specialists and specialists can provide an accurate and precise estimate of species encounter rates, and a population status proxy to inform management planning and aid efficient targeting of research and monitoring resources.