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Invasive Lionfish, the Kings of the Caribbean, May Have Met Their Match


Scientists have devised a key to controlling the deadly lionfish in the warm waters of the southern Atlantic.

t probably started in the 1980s, with a few tropical fish hobbyists thinking they were doing the humane thing by dumping unwanted pets in the coastal waters of Florida. But introducing the lionfish, which is native to the Indo-Pacific, to the Atlantic Ocean has turned out to be one of the cruelest and most catastrophic tricks ever played on an ecosystem. Now, with the fate of numerous species hanging in the balance, a new paper in the journal Ecological Applications says that scientists have for the first time found a practical way to control the problem.

Lionfish are flamboyantly colorful fish, up to 18 inches in length, striped, and having long, fluttering venomous spines sticking out in all directions. They’re appealing to have in a fish tank. But since their release into the Atlantic, they have spread across an area of 1.5 million square miles, from Venezuela to North Carolina, with stray sightings as far north as southern New England.

In the Caribbean, according to one researcher, it’s common to see lionfish “hovering above the reefs throughout the day and gathering in groups of up to ten or more on a single coral head." She might just as well have said “hoovering,” because of the speed and thoroughness with which lionfish wipe out native fish populations. They typically flutter their fins to herd smaller fish into a group, and when they have cornered their prey, they pounce.

Because of their extraordinarily painful venom, lionfish have no natural predators. As with many other invasive species, eradication appears to be impossible. Lionfish can repopulate shallow reefs from deepwater populations lurking farther off the coast.

But the study suggests a cost-effective alternative. Getting rid of most—but not all—the lionfish on a given site appears to provide enough relief to allow for the rapid recovery of native species, including commercially important fish like Nassau grouper and yellowtail snapper.

Oregon State University researcher Stephanie Green and her coauthors started with a computer model to calculate a threshold for different habitat types—that is, how many lionfish a site could tolerate and still function normally. Then they tested the model in the field, at 24 coral reef sites near Eleuthera Island in the Bahamas.

The model didn’t make it easy on the field team. To get to the threshold, they had to remove 75 to 95 percent of the lionfish, with the help of nets and spears. On a typical reef site, which is about a third the size of a basketball court, it took about 60 minutes of dive time. Completely eradicating the lionfish would have taken 78 minutes, or 30 percent longer, and that is apparently the difference that makes the method practical.

The researchers then followed up at regular intervals for 18 months. On test sites where the lionfish population was below the threshold, native prey species quickly rebounded, with a 50 to 70 percent increase in total biomass. On sites where the lionfish remained above the threshold, native species decreased by about half.

As that suggests, leaving the lionfish alone is no longer an option, or rather, it’s an option that leaves some native species bound for extinction. But with limited funding for fisheries management across such a vast stretch of ocean, the question is where to apply the control method for the maximum benefit. Because marine reserves typically allow no taking of fish, they are in danger, the new study warns, of becoming “de facto reserves for lionfish.” Mangroves and shallow reefs that serve as nursery sites for young fish are also a likely priority for control measures.

The good news is that there is now a remedy for what had seemed like an unstoppable invasion. But it won’t come cheap, and it should serve as yet another reminder that owning pets comes with grave responsibilities.

Introducing alien species to any habitat can quickly lead to catastrophe, both for wildlife and for us: Not even counting invertebrates, such as Asian long-horned beetles, that are killing off great swaths of forest, invasive species now cost the American public $120 billion every year.

IMO: this is going to take money, great dedication and hard work.
In a related TV Documentary that showed how this was being done, they had a segment filmed elsewhere (Costa Rica?) and showed that Lion Fish were found at very deep depths (125 Ft. and below) making total eradication of this invasive species extremely difficult, especially without Gov. funding. Maybe the VI should offer a bounty on this species. Our native fish species depends on Tourism who flock here to dive and snorkel not to see barren reef systems.

Topic starter Posted : January 28, 2014 12:31 pm
Trusted Member

I don't think the VI government even has the money to give tax returns, much less pay fish bounties.

we should be organizing this privately, "lion fish cooking contests" or business sponsored events, the event where they have a contest for who catches the biggest one stuff like that will certainly help.

with robotics and electric motors becoming so cheap, maybe small submersibles with a fish harvesting system could be used; make it like a video game or something (leverage the skill sets younger people have now).

There's got to be a lot of ways to do it with out holding a hand out to the government (who will probably just look at your hand with a blank stare)

Posted : January 28, 2014 1:12 pm
Advanced Member

About the only thing the USVI government can do right now is help organize the update to the current USVI Lionfish Mgt plan (which was just recently done)... There was money allotted at one time but it was never actually funded. I can say that the related officials, like Dr William Coles, have taken a vested interest in the effort and while they can't fund, they can support and advise.

There are lots of local divers actively removing the lionfish and there have been some local derbies with prizes donated. There are a few restaurants putting lionfish on the menus, though usually just as specials, but the fishermen have to recognize them as a money-generating product to really get that volume up. Eating them, while being quite a tasty fish, has a slight complication pertaining to CFP, Ciguatera Fish Poisoning. Granted, it's much the same as eating any other reef fish, and studies are being conducted to identify high-rish areas to avoid consuming catch from (or restaurants/customers buying from). It is a fish that is being imported (from other areas, not the USVI). That's another potential market to tap to show they're a money-making product and get more fishermen involved in pulling them out for the capital!

Stephanie Green, the lady referred to in the article, has been here, along with reps from REEF, et al, since shortly after we found the first lionfish here. But again, no funding has come in directly from the government, the committed organizations have had to pay our own way, chase private donations and get involved with grant-writing, and support researchers and their grants.

The Caribbean Oceanic Restoration and Education (CORE) Foundation was created around that time, and even got it's non-profit status (2010) in order to combat this threat, and fortunately for us in the USVI, we haven't had to deal with a lot of regulations and restrictions (outside of protected waters) as far as getting divers in the water with spears, spearguns, and nets. Other locations have had to deal with this issue and have watched their reefs be overwhelmed during all the red tape or "waiting to see what happens" (expecting nature to correct itself). CORE developed training that is recognized by DFW/DPNR and PADI in safely dealing with the critter, and preserving the reef system in the process.

There are other persistent groups of divers like Caribbean Lionfish Safari and Hit-n-Miss working ardently to keep the numbers under a level that has been shown in every other location, if reached, the lionfish population explodes into unmanageable numbers, and humans are still the only consistent means of removing the ravagers. That's why the article refers to the solution not being 'cheap.' And as Alana33 points out, the fish are living as deep as 1000'!!! We have a few divers who are dive-certified to deeper depths (beyond the recreational limit of 130') and rebreather divers who are taking them at the depths they can reach, but they are limited by the amount of bottom time they can sustain and the actual depth (generally the deeper you go, the less time you have).

So far in the USVI we are light-years ahead of most of the other invaded areas that didn't get enough divers in the water soon enough. Right now, tourists can snorkel and dive and see them as just another pretty fish just like the rest of the life on the reef.

But there's no short-term fix. We'll be continuing this effort for the foreseeable future, in order to preserve our reef system, and everything connected to it. No reef means no fish, no fishing, no pretty beaches, which in turn is tourism gone. We're already on the ragged edge of sustaining our meager economy, we can't afford any more hits... so the effort, and research, continues.

Posted : February 2, 2014 11:55 am

Thanks for the great update and information!

Topic starter Posted : February 3, 2014 5:42 pm
Trusted Member


Are you referring the the act below? If so, what needs to be updated?

7 V.I.C. § 199 (2013)

§ 199. Established; definitions; subcommittee; funding; permits

(a) This section may be cited as the "Virgin Islands Native Aquatic Species Protection Act".

(b) The "Virgin Islands Native Aquatic Species Protection Act" is hereby enacted to establish, maintain, and support by appropriations to the Department of Planning and Natural Resources (DPNR), efforts to develop strategies to protect Virgin Islands native aquatic species through control of invasive species and other methods, thus benefitting our aquatic ecosystem and our economy.

(c) Definition. "Invasive Species", as similarly defined in Executive Order 13112, means an alien species or species complex whose introduction does or is likely to have an adverse impact in the Territory, causing economic or environmental harm or harm to human health.

(d) The Department of Planning and Natural Resources is instructed and given the authority to form and adopt rules, regulations and guidelines for the implementation of an Aquatic Nuisance Subcommittee. This subcommittee shall be formed within 90 days of this bill being signed into law, and initial rules, regulations and guidelines for the subcommittee shall be adopted within 90 days of the formation of the subcommittee. The subcommittee shall be comprised of the appropriate government personnel, including the Commissioner of the Department of Planning and Natural Resources, representatives from the Department of Planning and Natural Resources Division of Fish and Wildlife, Coastal Zone Management, and Environmental Protection, and community members with relevant knowledge or expertise, to ensure a wide-ranging representation of the community. At a minimum, the guidelines, rules or regulations for the operation of the Aquatic Nuisance Subcommittee must address and include the following:

(1) Implementing a Lionfish Response Management Plan that will include a strategy to: control lionfish populations through both targeted and opportunistic removal; implement a multi-tiered management approach that covers water depth below recreational diving limits and areas not frequented by water-based user groups such as recreational dive operators and spear fishermen; provide assistance and/or training for recreational and commercial fishermen, divers, and concerned citizens to encourage support in suppressing the lionfish population; and educate the public to increase public awareness of the lionfish threat; and

(2) Conducting routine monitoring of aquatic ecosystems to detect aquatic invasive species before they become widespread; and

(3) Proposing rapid response actions for other invasive species and preparing detailed rapid response plans that can be carried out quickly and effectively; and

(4) Preventing further proliferation and/or minimizing the impact of harmful aquatic invasive species by ongoing control of established aquatic invasive populations, creative methods of control, and commercialization; and

(5) Developing initiatives capable of building and expanding markets to control invasive aquatic species; and

(6) Providing a recognition system for resource users participating in the program; and

(7) Developing and implementing a sustainable long-term plan for the conservation of native aquatic species that includes immediate action to prevent the extinction of certain native aquatic species should government funds no longer be available; and

(8) Developing criteria to provide assistance to concerned citizens who provide, within reasonable guidelines, the proof needed to receive incentives, grants, loans, in-kind assistance, or any other support for their assistance in managing aquatic invasive species.

(e) The Department of Planning and Natural Resources is authorized to distribute, manage and operate the appropriations, grants, awards or other sources of funding provided, directly or indirectly related to this section, with the advice of the Aquatic Nuisance Subcommittee, to limit the proliferation of invasive aquatic species and to carry out the purpose and intent of this section.

(f) The Department of Planning and Natural Resources or the Aquatic Nuisance Subcommittee is authorized to seek any additional funding to operate, manage and mitigate any environmental and economic damage caused by invasive aquatic species.

(g) The Department of Planning and Natural Resources may issue permits to properly trained individuals to remove lionfish and other invasive species, as identified by the Department of Planning and Natural Resources, from protected waters, such as Buck Island and East End Marine Park.

HISTORY: --Added Sept. 17, 2012, No. 7407, § 1, Sess. L. 2012, p. --.

Posted : February 4, 2014 3:05 pm
Advanced Member

Let's see if I can get a link in here... the Lionfish Mgt Plan was just reviewed/updated after it's inaugural debut almost 5 years ago.

Lionfish Management Program / Reef Resilience Program

Both should go to the same place... You should be able to get the current draft. If not let me know and I'll send you the latest copy I have.

The "plan" extends out more details beyond the Act itself, and identifies some of the anchor groups or individuals responsible for various pieces and committees in order to carry out the activities described.

Posted : February 4, 2014 5:23 pm
Trusted Member

Ok no worries, I thought there was something in the code you needed amended.

Posted : February 4, 2014 8:35 pm

Five years in, efforts to control lionfish reassessed

By ALDETH LEWIN (Daily News Staff)
Published: February 17, 2014

ST. THOMAS - The proliferation of the Pacific lionfish throughout the U.S. Virgin Islands has led to a newly revised management plan.

In the summer of 2008, the territorial waters were free of lionfish.

In early 2009, divers and fishermen began to spot lionfish, first on St. Croix, then St. John and finally St. Thomas.

The zebra-striped spiny predators were first sighted off Florida in 1992. Since then, the invasive species has spread rapidly throughout the eastern seaboard and into the Caribbean.

Lionfish have a voracious appetite for smaller fish and can severely deplete fish populations that are necessary players in reefs' fragile ecosystems. It is a native of the western Pacific, and has no natural predators in the Atlantic Ocean or Caribbean Sea.

When the invasive species was first found in territorial waters, local divers and ecologist leapt on the problem, getting word out to the public about the serious economic and ecological threat the fish posed.

In October 2009, the first Lionfish Response Management Plan was presented to the public, drafted by biologist Barbara Kojis with a grant from V.I. Experimental Program to Stimulate Competitive Research.

Five years later, it was time for the plan to be updated.

The revised plan recognizes that while the lionfish population can no longer be prevented from invading the territory's reefs, strategies may help slow the growth and protect specific reefs and areas from being wiped out.

"Since the creation of the original response plan in 2009, the severity of the lionfish invasion has worsened, local circumstances have changed, and researchers, managers and citizen groups are more organized and knowledgeable about what is working and what is not," the document said.

The goal of the plan is to provide a framework for local scientists, businesses, organizations, government agencies and individuals to work together to address the lionfish problem and help save the territory's reefs.

The update was done in collaboration with the V.I. Department of Planning and Natural Resources, Divisions of Fish and Wildlife and Coastal Zone Management with assistance from The Nature Conservancy. The update included community members, organizations, agencies and businesses that are active in lionfish control and those that are concerned about the impacts of the lionfish invasion.

In October, public meetings were held and questionnaires were sent out to get input from the public. A summary was put out in December and the final document released this month.

The updated report found that a dedicated effort to remove lionfish from specific areas - like dive sites and moorings - is effective at keeping the population low.

"However, lionfish are still found in higher numbers at particular sites, at depth and following storm events. Further studies may reveal the cause of these patterns of recruitment, migration and/or habitat preferences," the report states.

A handful of fishermen have started to successfully sell lionfish in local markets and to interested restaurants, which could be a good strategy for keeping the population at bay.

While up to 12 percent of the lionfish tested have ciguatera - or fish poisoning - that amount is about the same as other reef fish. No one in the Caribbean has reported fish poisoning from eating lionfish yet, according to the management plan.

"Promoting sale and consumption of lionfish by fishermen who already know hotspots of ciguatera to avoid in territorial waters increases the success of developing a safe and reliable market for lionfish," the report said.

The document listed a series of recommendations for immidiate action, as well as a list of strategies to take over the next five years.

The short-term actions include:

- Keeping a well-maintained mooring system to allow divers to conduct regular lionfish removal activities without having to drop anchor and damage reefs.

- Ceasing the practice of feeding dead or cut up lionfish to predators like sharks and eels in an attempt to give them a taste for the invasive species. The management plan said this practice does not work and can create a dangerous situation where predators are looking for food from humans. It is against DPNR policy to feed wildlife.

- Increasing communication with legislators on the impact of the lionfish invasion.

- Offering specialty courses on the safe and effective removal of lionfish. The CORE Foundation has developed the courses and the recommendation is to make them widely available.

- Creating a system for regular exchange of information, establishing a steering committee, and finding a long-term solution to organizing regular updates to the management plan.

Strategies for the next five years include: creating uniform messages to be used in education and outreach, improving lionfish removal by coordinated spearfishing and trap fishing, using research to guide control efforts, finding sustainable incentives for spear fishermen and recreational divers to kill lionfish, exploring effective methods for control and marketing and building a framework for communication and information-sharing.

"This plan is meant to be a living document with regular updates made to reflect current information and management strategies," the report said.

The public is invited to comment or make suggested changes to keep the document up to date. The comments can be sent in through the CORE and V.I. Reef Resilience Program websites.

The plan is available at

Topic starter Posted : February 18, 2014 9:02 am

Study Focuses on Lionfish Suppression Strategies
By Bill Kossler — April 9, 2014

Preliminary results of a new study at Buck Island suggest a tightly focused lionfish removal program may be able to preserve local fisheries from this voracious, exotic Asian predator that has spread explosively throughout the region.

Oregon State University researcher Stephanie Green discusses a recent collaborative study on lionfish suppression Tuesday evening.
For the last year, the National Park Service, Oregon State University, Reef Environmental Education Foundation and the University of the Virgin Islands have been working with dive volunteers to study different approaches to suppressing the lionfish population. The last of the data is being collected this week and scientists working on the study shared the preliminary results with the CRABBS diving club Tuesday.

While lionfish have been in Florida for two decades, it was not until 2004 that one was spotted in the reefs of the Bahamas, said Lad Akins, director of operations for REEF. Now the invasive species is found from the coast of North Carolina to the cost of Paraguay and throughout the Caribbean. It has been found in all types of environments, from coastal mangroves to 1,000 feet deep. And in areas like the Bahamas where lionfish have spread unchecked, "you see up to a 95 percent reduction in fish biomass," Akins said.

With the fish so widespread, and at depths unreachable by divers, eradication is not going to happen, so the study instead will look at what sort and how much suppression it will take, and at what cost, to preserve local fish stocks, he said.

Oregon State University conservation research fellow Stephanie Green said researchers collected data on lionfish population density's relationship to what proportion of the local fish communities are eaten to home in on specific sites to target for lionfish removal. They carefully measured and laid out study sites in different depths and types of undersea terrain around Buck Island off St. Croix, she said.

Volunteer divers came out every two months and removed lionfish from the selected sites and they tracked the efficiency and cost of culling lionfish below target levels, Green said.

One part of the puzzle is how many lionfish need to be present before local fish populations begin to plummet, Green said, showing a graph of data from a number of sites indicating that any more than two or three lionfish presages a sharp drop in local fish. How often they have to be removed to keep the numbers at a manageable level is another part of the study.

On some sites, they removed every lionfish and "as soon as we stopped, three months later, the numbers were right up to where they were before we removed any lionfish," Green said. But in other locations, periodic sweeps kept the numbers down low enough.

They will be crunching the data over the summer and should have some final results over the summer, Green said. Ultimately they hope to fill in the missing variables in a formula to identify "the threshold density above which lionfish start to cause problems and things start to get bad," Green said.

"Can we use that as a target for control? I think so. If we can keep lionfish below this sweet spot we can, I think, maintain populations" of local fishes, she said. They will know more once they analyze all the data, she said.

UVI biologist Bernard Castillo shared findings about the numbers, weights, sizes and diets of the lionfish removed from around Buck Island. V.I. lionfish averaged 253 mm in length, weighing an average of 275 grams. The largest one caught weighed 584 grams.

An array of other fish and sea animals were found in the lionfish’s stomachs. The top three items in the stomachs were shrimp, damselfish and wrasse, which are the same top three items found in another study, but other areas show other contents, so it appears they "go for what is available," Castillo said.

Lionfish are a local vector for the foodborne illness ciguatera and 12 percent of the lionfish tested exceeded the FDA limit for the toxin, he said.

Green will give more details of the study and possible approaches to suppressing lionfish Thursday at 1 p.m. on the St. Croix campus of UVI in Building EVC-401 (the main theater).

Topic starter Posted : April 9, 2014 2:38 pm
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