The Citizen Science refers to the public participation in scientific activities and research projects related with environment and its biodiversity are taking advantage of new technologies such us internet and mobile phones with recording capabilities for an easy data collection and sharing. In this paper, we presented a Citizen Science experience with the OBSEA costal-cabled video-observatory, deployed in western Mediterranean in 2009. A local biodiversity survey is going to be conducted by citizens as generic non-experienced users, high- school students, and amateur divers helping to identify and classify fishes appearing within different digital products such as time-lapse images and footages. Accordingly, we implemented a protocol for the web-based species identification supervised by scientists, in order to evaluate the different performances for each group.