I have posted previously about the lionfish invasion and the threat that it poses to marine ecosystems in the Western Atlantic. In an earlier post, I noted that there is increasing evidence that regular removals can be effective in controlling lionfish infestation, allowing native fish populations to recover. Removals are being undertaken via organized efforts such “lionfish derbies” and other forms of sanctioned fishing tournaments as well as via market approaches that create commercial incentives to harvest the fish.
While marine protection agencies are generally supportive of these efforts and are indeed engaging in removals themselves, they lack the data and evidence needed to make informed decisions about the optimal mix of approaches and the level of effort and resources needed to effectively control the invasion. I recently had the opportunity to participate in a research expedition aimed at helping to address this gap. I was fortunate enough to be selected to join 29 other volunteer citizen scientists, professional/semi-professional spear fishers, and marine scientists for a fish survey and lionfish culling effort in the Flower Garden Banks National Marine Sanctuary. Situated about 100 miles off the coast of Texas, the sanctuary is home to a unique ecosystem with almost 300 species of fish, 21 species of coral, and several other invertebrate species. Lionfish are being observed with increasing frequency within the sanctuary, a cause for concern by the sanctuary’s managers. They have previously undertaken periodic culling of lionfish, but the recent effort was the first time that removals were undertaken in a systematic fashion.
Dubbed the Flower Garden Banks Lionfish Invitational, the expedition was organized by the National Oceanic and Atmospheric Administration (NOAA) and the Reef Environmental Education Foundation (REEF) with support from the National Marine Sanctuary Foundation (NMSF), Texas State Aquarium, and Oregon State University. Over the course of the three and a half day trip, we did a total of thirteen removal dives covering seven different sites within the sanctuary, each site divided into quadrants of equal size. Collectively, we removed 317 invasive lionfish ranging in size from three to seventeen inches. But the trip wasn’t just about removing as many lionfish as possible. We also collected data on the fish behavior, the amount of time and number of attempts it took to spear each fish, and the degree of effectiveness of the culling. For the latter measure, we undertook two dives on each site, with a two-hour interval in between, in order to determine whether there were any fish that had been missed during the first dive (the answer was often yes).
It was interesting to observe the differences in the level of infestation and behavior of the lionfish at the Flower Garden Banks as compared to reefs in Belize where I have previously done lionfish removals. Far fewer lionfish were in evidence than in Belize, but they tended to be much larger in size (indeed several of the fish removed qualified for new records for size). I also found that the lionfish were much more wary of divers. This is in keeping with a study that lionfish on reefs where culling takes place are changing their behavior. It was also humbling to see how my spearing skills stacked up against some of the other members of our group. I am by no means a novice at spearing lionfish, but my single-digit total for the week paled in comparison with that of two of the divers from Florida, who removed more than 100! Next time, I think I may be better off leaving the spearing to the pros and instead focus on the science and management/control aspects of the lionfish problem.
The lionfish we removed were sorted, measured, and placed in plastic bags noting the date, time, and location where they were speared. They were then frozen and brought back to shore for analysis which will include stomach content analysis, genetic testing, and testing for parasites. I did have a chance to intercept about half a dozen fish to demonstrate the process for removal and drying of fins and spines for use in lionfish jewelry.
One important aspect of the testing will be for presence of the ciguatera toxin. As I discussed in an earlier post, one of the constraints to promotion of lionfish as a seafood choice is concern over ciguatera food poisoning (CFP). In 2013, the U.S. Food and Drug Administration added lionfish to the list of reef fish covered by its CFP warning, even though there are no documented cases of CFP from consumption of lionfish, and some researchers believe that the toxin in lionfish venom may cause a false positive for presence of the ciguatera toxin. The Flower Garden Banks is a hotspot for ciguatera. So if the lionfish we removed test negative for the toxin, I’m hoping this may help convince the FDA to remove lionfish from the CFP watch list.
Another boost for lionfish as a seafood choice would be endorsement by one or more of the sustainable certification agencies. Up until now, the foremost of these groups, Monterrey Bay Aquarium’s Seafood Watch, has declined to certify lionfish, indicating that they have no basis for assessing the sustainability of a non-managed fishery. However, earlier this week the group listed Chesapeake Bay blue catfish as a “best choice”, marking the first time that they have certified an invasive species. Let’s hope that this will pave the way for addition of invasive lionfish to their list!