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Here with a Roar!

A tenacious invader now calls the Turks & Caicos home.

By Ben Farmer, Waterfront Assistant, The School for Field Studies

I was on a drift-dive in southern Florida when I speared my first lionfish. There, I began to understand the difficulty of controlling this species which is invasive to the tropical Atlantic and devastates reef fish populations. Drift dives are perfect for seeing a lot of the reef without having to expend much energy. By the end of the dive, I was able to spear two lionfish after several attempts and a bit of determination. As exhilarating as the experience was, it became clear to me how many resources—be they dive gear, boat time or trained volunteers—are required to keep lionfish populations in check.

Although lionfish are visually stunning creatures, they are unfortunately hurting the coral reefs of the Turks & Caicos Islands.

But why do we spear and kill lionfish? After all, they are a beautiful species, coveted by aquarists the world over. The answer lies in the destruction they cause in the areas where they are invasive. Moreover, spearing has been shown as one of the most effective measures of catching lionfish.

A biological invasion happens when a species that is native to one region finds its way into another region and establishes itself. This can be a natural process, but in modern times is frequently caused by human introduction. Often, an introduced species poses no significant ecological problems in its native range but becomes a problem elsewhere. 

For example, consider the cane toad (Bufo marinus), which produces toxins that can be fatal to predators when eaten. In the cane toad’s native regions of South and Central America, many predators have adapted over time to be able to tolerate these toxins, and thus there is a natural control on cane toad populations. In Australia and other regions where cane toads are invasive, however, not all predators have these adaptations. This, as well as factors like available habitat, prey populations and means of sexual reproduction, has contributed to the cane toad population in Australia exploding from 120 to 1.5 billion. 

Zebra mussels (Dreissena polymorpha) invaded North America in 1986 from Eurasia and spread extensively, starting in the Great Lakes where humans introduced them. Now zebra mussels are so entrenched in the ecosystem that they clog water pipes and engulf underwater portions of bridges and docks across the United States. 

One of the most prolific invasions is that of the European rabbit (Oryctolagus cuniculus), which has cascaded outward to all seven continents, as well as many Caribbean islands. Since its introduction by Spanish colonizers in the 1500s, the European rabbit has devastated ecosystems due to its ability to breed quickly and consume an excess of resources. Invasions such as these cost governments extraordinary amounts of money every year, due to the ongoing toll on both native wildlife and human infrastructure, as well as the effort of controlling invasive populations.

Lionfish are one of the more recent invaders—they were the first marine fish to invade the western North Atlantic and Caribbean Sea, and came from their native range of the Pacific or Indian Oceans. First documented by a lobster fisherman in 1985 south of Fort Lauderdale, Florida, the invasion likely was a result of aquarists releasing their lionfish into Florida waters.

Lionfish possess venomous dorsal, anal and pelvic spines.

There are two species found in the Caribbean, Pterois volitans and P. miles, collectively known as the “red lionfish.” Both invasive species have an apparent ability to tolerate a wider array of habitats and temperatures than their native counterparts. However, genetic testing shows that P. volitans is the dominant species in the Caribbean and is perhaps a hybrid species. It is possible that this hybridization provided P. volitans certain traits which improved the invasion success.

High tolerance to an array of habitats and temperatures was just one factor contributing to the establishment of lionfish across the Caribbean. Another was the lack of natural predators. In the lionfishes’ native range of the Indo-Pacific, there are 12 recognized species as of 2015. All of these 12 lionfish species are eaten by predators which are able to cope with the venomous spines (lionfish have dorsal, anal and pelvic spines which release a toxin). In the Caribbean, studies have documented lionfish being eaten by sharks, groupers and moray eels. However, this predation requires human intervention (training of the predators to eat lionfish) that is difficult to maintain on a scale large enough to keep lionfish populations in check.

Lionfish also produce an enormous amount of eggs and reproduce year-round. This, coupled with the fact that their larvae can disperse hundreds of miles in the ocean, means that lionfish have taken over entire swaths of the Caribbean very quickly. Once lionfish have established in an area, their voracious eating causes sharp declines in native fish populations. Coral reefs often become less healthy as a result, because reef-associated fish are very important to the maintenance of the ecosystem.

Ben Farmer prepares to spear a lionfish using a pole spear.

Researchers at The School for Field Studies Center for Marine Resource Studies (SFS CMRS) first sighted and documented lionfish in December 2007. This sighting was on a shallow, sheltered coral reef called Jerry Camp on South Caicos. By June 2008, lionfish had been spotted in seagrass beds and deep coral reefs on South Caicos. As part of a concerted monitoring effort, SFS documented the swift spread of lionfish populations to the mangroves by 2009, and to exposed shallow reefs by 2010. The research continued, and SFS now has a dataset of lionfish catches from 2009 to 2020.

The invasion was not limited to South Caicos, either—lionfish in fact were first sighted in the Turks & Caicos Islands in an unknown location in 2006, then documented off West Caicos in 2007. I reached out to Dr. John Claydon, who was a previous center director at SFS in the 2000s and then went on to direct the Department of Environment & Coastal Resources (DECR) in Providenciales. Dr. Claydon provides some insight:

Q: You have been involved as a researcher and director in various capacities throughout the Turks & Caicos Islands, and in this time, lionfish have unfortunately become established. How did this invasion affect the livelihood of those in the TCI?

JC: It is hard to tell, but it is likely that lionfish have reduced the abundance of native species and this may affect fishers directly. It is also possible that lionfish contribute to the degradation of coral reefs, and everyone in the Islands is affected if they lose this vital natural defense against storms, and if its value as a source of food and as a tourist attraction is reduced. Not to mention the broader value of reefs for biodiversity.

Dr. Claydon brings up important points about the ecological and economic relevance of lionfish. Degradation of the reef system due to lionfish is a big potential problem for the TCI, however we have tools at our disposal. Culling, or consistent spearfishing of lionfish in an area, is the best answer currently available to controlling the lionfish population in the absence of a natural predator. When a lionfish is brought onto shore and dissected, we call it a “catch.”

I joined SFS as a waterfront assistant in Fall 2019, and soon afterwards the other assistants and I began helping Dr. Ewa Krzyszczyk with logging these lionfish catches. Dr. Krzyszczyk is professor of the Principles of Resource Management course at SFS and gets the students involved with lionfish hunts and dissections every semester. As part of field exercises, done via snorkeling or scuba diving, students help staff locate lionfish on the reefs of South Caicos. After staff spear the lionfish, students log the time and depth at which the fish are caught, as well as the fishes’ behavior. Finally, all the fish are safely brought back to the center with a cylinder called a Zookeeper. Several things are recorded there, including gut contents (what the lionfish had recently been eating), sex of the fish and body length.

As early as 2009, the DECR began lionfish “derbies” in which fishermen competed to bring in the highest number of lionfish. Hundreds of specimens were dissected, with information entered in the database. More recently in 2016, a nation-wide derby called the Lionfish Festival was hosted by the DECR and the Turks & Caicos Reef Fund, in which competitions were held in Providenciales, Grand Turk and South Caicos. Fishermen on South Caicos brought in nearly 40 fish, and SFS students assisted with measuring them. All of these fish were filleted and served at the Heritage Day Festival. Lionfish are quite tasty, after all!

Our current SFS Center Director Dr. Heidi Hertler, discusses the event here: (https://fieldstudies.org/2016/11/lionfish-derby-on-south-caicos/).

In terms of what you can do personally, some TCI dive shops will allow guests to bring speared lionfish back to their hotel restaurant for preparation. This is a great way to reduce the population of an invasive species while enjoying a great dinner—talk to a local dive shop to find out more.

Long-term research by SFS suggests that lionfish populations are decreasing on some South Caicos sites, which is likely due to culling efforts. However, these sites do not represent the lionfish population throughout the entirety of the TCI, and it is important to stay vigilant and continue monitoring. Dr. Claydon has a few thoughts on this as well:

Q: The new reality for many Caribbean reefs is that lionfish are there to stay, even accounting for culling efforts. What would you recommend as a long-term response to the issue?

JC: Localised areas of reef will benefit from regular culling, and this will be important for particularly vulnerable sites, but we are not going to get rid of lionfish completely. The lionfish invasion has helped to promote a better understanding of the value of coral reefs to people of the wider Caribbean region. We can keep using the lionfish issue to raise awareness and help protect coral reefs in other ways.

You can help support the Turks & Caicos Reef Fund lionfish project by submitting any lionfish sightings here: (https://www.tcreef.org/projects).

For additional information about The School for Field Studies, visit www.fieldstudies.org or contact us on South Caicos at hhertler@fieldstudies.org.



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On the Cover

Agile LeVin—photographer, explorer and chronicler of everything TCI on his website www.visittci.com—took this drone photo of the multi-textured wetlands of West Caicos. He was part of the expedition that investigated the site of the historic pirate attack in the area. For more information and photos, go to page 48.

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