SCUBA divers can collect fish and marine mammal DNA just by swimming! A few years ago, we reported on an exciting collaboration with scientists from Scripps Oceanography that uses cutting-edge technology to improve our understanding of ocean ecosystems. Results from this study were recently published in the scientfic journal, Environmental DNA. This study tested whether citizen science SCUBA divers could help monitor marine biodiversity using environmental DNA (eDNA), or tiny genetic traces organisms leave behind in seawater. eDNA filters were attached to REEF volunteer divers, who concurrently conducted REEF surveys during a REEF Field Survey Trip. The DNA captured on those filters was then extracted and sequenced, and the species detected were compared to what divers recorded visually during their surveys.

There were 17 fish species detected both by the eDNA samples and on the REEF Volunteer Fish Survey Project surveys, including the most commonly observed species. The authors found that diver-collected eDNA produced consistent results and was less affected by differences between individual divers than traditional visual surveys, suggesting it could help reduce observer bias and make large-scale monitoring more standardized. However, eDNA detected fewer fine-scale differences in fish communities and would require substantially more sampling effort to match the detail captured by human observers. Excitingly, we detected DNA from Guadalupe Fur Seal (a species previously considered extinct after most of the population was killed in 1928, was rediscovered in 1954, and is now listed as Endangered by the IUCN) in one sample, suggesting that this method can be useful for rare or cryptic species detection. Overall, the study shows that while eDNA collected by citizen scientists is a powerful and scalable tool for tracking marine life, it works best as a complement to traditional underwater surveys. Stay tuned for more on how we plan to couple REEF surveying with eDNA data collection and other high-tech tools.

Visit REEF's Publications page to read more about this study, access the paper, and information on the over 100 other scientific publications that have included REEF programs and data.