Danger: Invading Lionfish

They’re here!!!

Lionfish, the beautiful and venomous fish from the South Pacific, have appeared on Roatan. This invasive species has spread at unprecedented rates across the Caribbean and Eastern Atlantic over the last few years.

The Roatan Marine Park is asking for everyone’s help in reporting, capturing, and killing lionfish around Roatan. If you have seen a lionfish on one of Roatan’s dive sites, please submit a lionfish report directly to the Roatan Marine Park.

Below is a letter sent by PADI Master Instructor and marine biologist Marc Cruciani regarding the grave threat posed by invading lionfish:

Hello Everyone,

I heard that the first lionfish was sighted on the north side of the island. They are beautiful fish, and make stunning photographic models, and of course everyone wants to see one. As an invasive species and voracious predator, they also represent the one of the biggest environmental threats to the reef system. I have extensive experience with these fish, both as an aquarist and a diver, and would like to share some of this with you, and impress upon you the importance of dealing with this threat immediately.

I was an instructor in North Carolina for two years. Lionfish were known to be around, and had been for a couple of years. At the beginning of my first year, they were rarely seen, and only on the further offshore wrecks. I was as eager as anyone to see my first lionfish. By the end of the second year, I was seeing them on every dive, at every site, usually in multilple numbers. Some wrecks had populations of 30 or more, and aquarists were flocking to the coast to aquire specimens. By the time NOAA finally got into the act, it was obvious that they presented a major problem.

NOAA brought a large research vessel and a team of scientists to determine the scale of the problem. Their stated goal was to dive twice a day for a week, in the hopes of collecting about 30 fish for DNA analysis. Local divers laughed at this, we already knew how widespread the problem was. In the first two days of diving, over 80 were caught.

They are now found as far north as Rhode Island in the summer months, and have spread as far south as Nicaragua from their original starting point in Florida, wreaking havoc on local fish populations. In parts of the Bahamas, they are the predominant predator on many reefs.

Lionfish are related to scorpion fish, and eat just about anything, from juvenile groupers to cardinal fish to crustaceans. According to the lates issue of Alert Diver, they eat on average .3 ounces a day. Larger fish, up to 18 inches, can eat much more. They tend to eat smaller fish, but will eat anything they can swallow. They hunt like frog fish, and like frog fish, the mouth is the largest part, and can eat prey larger than themselves.

They have no natural predators in the Caribbean. The only fish that do eat them are some sharks and possibly the largest of groupers, both of which are in short supply on Roatan. In any case, natural predation has failed to contain them anywhere in this hemisphere.

When spawning, lionfish can produce up to 30,000 eggs, and can grow 7 inches a year, reaching sexual maturity in just a year or two. In their home environments, they spawn twice a year. For reasons yet unknown, in the caribbean they seem to spawn continuously year round. DNA analysis by NOAA indicate that Atlantic and Caribbean populations are all very closely related, coming from the same source. Considering that they were first documented in Florida in in the mid 1990’s, their range is astonishing both in scope and the short time required.

They are very hardy fish, tolerant of a wide range of water conditions, and notoriously hard to kill. They can go for months
without eating, and even the foulest of fishtanks dont seem to concern them, and are adept at hiding in small crevices. I learned this while trying to dispose of an aquarium specimen without getting stung. Lionfish stings are similar to those of scorpionfish, but much worse. Larger specimens of some species can kill a human being.

Efforts at controlling them have had mixed results at best. Once established, they are impossible to get rid of. The best bet is to keep the populations in check after the first sighting. All lionfish must be removed as soon as sighted. The prevailing strategy is to have a team of trained divers who can respond to sighting.

Under no circumstances should untrained divers be allowed to try, due to the dangers involved in handling these fish, and the skill needed to find and hunt them. The best way to hunt them is to use hand nets for smaller individuals, and pole spears or hawaiian slings for larger ones. Extreme caution must be used, as even a dead fish will still have poisonous dorsal spines.

Lionfish tend to be very territorial, once they find a good hunting ground, they are likely to stay. They also move quite slowly (except for the actually swallowing of prey, which is faster than the eye can see). They prefer to hunt at dusk and dawn, and are easiest to find at these times. The rest of the time they sit on the bottom or hide in crevices, and despite their
very colorful markings, are suprisingly difficult to spot. On the plus side, they do make good eating, similar to grouper.

All dive shops should encourage customers to report sightings so that the fish can be culled, the faster the better. This will require coordination and efforts from all the dive operations and the marine park to have any kind of impact. REEF can help with training and workshops. The man to talk to is Lad Atkins. Paula Whitfield was the original NOAA project head in North Carolina.

Some contacts for more information and resources are listed below. If there is anything else I can do to help in any way, please don’t hesitate to contact me. This is a serious problem and must be dealt with. Please distribute this letter to any interested parties and dive shops who have not received it.

Marc Cruciani
MI 183782

3 Responses to “Danger: Invading Lionfish”

  • #1
    Will Cline writes:

    Guys I have a plan for a device that will help divers kill 200 to 300 hundred fish each dive if you are in an area with lots of lion fish. It is pretty simple but the problem is that we need some kind of financial incentive for divers to go after them. I think I could attach a video camera to the device to document the number of kills.


  • #2

    Sounds interesting, can you elaborate?

  • #3

    Guys I have a plan for a device that will help divers kill 200 to 300 hundred fish each dive if you are in an area with lots of lion fish. It is pretty simple but the problem is that we need some kind of financial incentive for divers to go after them. I think I could attach a video camera to the device to document the number of kills.


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