The authors of this study (including REEF staff Lad Akins) examined the recent case of Indo-Pacific lionfish invading Northern Gulf of Mexico coastal waters. The authors compared traditional reef fish monitoring efforts to less traditional data including the observations of divers through REEF's Volunteer Fish Survey Project and spearfishers. They found that citizen observations documented lionfish 1-2 years earlier and more frequently than the more traditional monitoring efforts. The authors also explored the willingness of spearfishers to help minimize impacts of the invasion by harvesting lionfish. They found that spearfishers who had encountered more lionfish while diving perceived them as more harmful to the habitat than less experienced divers and were also more likely to participate in harvesting initiatives. The authors also report that encouragement from scientists and managers was a far better motivator than the desire to harvest lionfish for personal consumption. This study demonstrates the value of engaging citizens for assessing and responding to large-scale and time-sensitive conservation problems.