Abstract
<title>Abstract</title> <p> Addressing global shark decline requires addressing multiple knowledge gaps. Traditional objectives are still widely pursued, but emerging concern regarding the prevalence, drivers, and ecological fitness implications of colour aberrations has attracted recent research attention. With recorded instances somewhat rare, citizen science platforms may inform targeted research to better understand this phenomenon, particularly its spatial and temporal occurrence. Comparing the use of the iNaturalist and Global Biodiversity Information Facility (GBIF) platforms to investigate prevalence in smallspotted catsharks <italic>Scyliorhinus canicula</italic> in the UK, we identify a recurring theme regarding licensing issues. This is a source of confusion among researchers and users that can potentially be avoided by users uploading images to iNaturalist without licensing restrictions. Researchers should preferentially use GBIF, which hosts only images without licensing restrictions. Notably, despite more initial observations on iNaturalist, usable image availability was ultimately similar for both platforms, enabling us to make broad recommendations for researchers, users, and such platforms, not least adherence to the FAIR Guiding Principles for scientific data. </p>