Reliability of data collected by volunteers: a nine-year citizen science study in the Red Sea

The quality of data collected by volunteers in citizen science programs is crucial to render them valid for implementing environmental resources management and protection plans. The present study assessed the reliability of data collected by non- professional volunteers during the citizen science project Scuba Tourism for the Environment (STE), carried out in the Red Sea between 2007 and 2015. STE involved 16,164 volunteer recreational divers in data collection on marine biodiversity using a recreational citizen science approach. Through a specifically designed questionnaire, volunteers indicated which of seventy-two marine taxa surveyed were observed during their dive, giving an estimate of their abundance. To evaluate the validity of the collected data, a reference researcher randomly dove with the volunteers and filled in the project questionnaire separately. Correlation analyses between reference diver and volunteer records were performed on 513 validation trials, testing 3,138 volunteers. Data reliability was analyzed through 7 parameters. Overall results confirmed that the recreational citizen science approach can effectively provide reliable data for biodiversity monitoring. The use of a recreational approach enhances volunteer participation in citizen science projects, thus increasing the amount of sufficiently reliable data collected in a reduced time