by Brett Howell, 2011 PERC Enviropreneur Institute alum I have just returned from a 10-day trip to the Yucatán Peninsula in Mexico where I visited Cozumel, Playa del Carmen, and Cancun. When I planned the SCUBA trip, I expected it be a relaxing vacation. However, ever since starting to work on market-based solutions to invasive lionfish, I just could not help but turn a “vacation” into a hands-on research project.Unfortunately, invasive lionfish have become a prevalent species in Cozumel. According to my divemaster, who works for the company Dive Paradise, local dive operators have bonded together informally to begin addressing the lionfish invasion. Divemasters carry simple spear systems with them on each dive. When a lionfish is spotted, it is killed. Of the 25-30 dives I completed, lionfish were seen on about 10 of the dives, only in the shallower reef areas (45-60 feet). After it is speared, a lionfish’s spines are cut off and the fish is fed to eels or other fish. “Tourists” are not supposed to shoot the lionfish, for fear of someone being stung in the process, but our divemaster let one of the people on our boat, Eric, try his hand at the lionfish management process. According to Eric, the success of a shot really relies on the equipment being used. One spear he tried had a guidance mechanism to shoot the spear straight, whereas the other did not. Of the lionfish Eric went after, he successfully killed about half of them.One afternoon our divemaster wanted the lionfish for dinner, so he kept approximately five of them for later feasting. While I was impressed with his interest in eating the fish, despite potential ciguatera concerns (a foodborne illness from eating certain reef fishes), I was very disappointed when he would not kill a lionfish that I found. His response was that he knew that the lionfish would be there the next time he went to the dive site, and he wanted the fish to get a little bigger so there was more meat for him to eat. This is part of the challenge with trying to get people to target lionfish; we do not want people to wait to harvest invasive lionfish in the hope that they will get bigger. The process of a lionfish growing means that it has eaten more of the critical reef species that we are trying to protect.By far the most creative capture of a lionfish was a young lionfish that I found while on a night dive. Divemasters do not usually carry spears at night, so we ended up collecting the fish using one glove, a dive knife, and a plastic bag. The divemaster did the collecting. After killing the lionfish, he attempted to find an eel to feed it to, something he was unsuccessful in doing before we had to surface due to low air.