The lionfish is a genus of venomous fish commonly found in tropical reefs. Native to the Indo-Pacific, the fish is one of the most infamous invasive species in the western Atlantic. This voracious predator is not a threat to divers, but its introduction into exotic ecosystems can decimate juvenile specimens. In an attempt to control the spread of lionfish populations, recreational divers in the Americas have started aggressive campaigns to hunt them; in the process, many divers are stung with the lionfish’s sharp spines, which can cause very painful and sometimes complicated wounds.
Identification and Distribution
Lionfish, turkeyfish and zebrafish are common names for fish species of the genus Pterois, a subset of fish of the venomous Scorpaeniform family. Though lionfish are native to the Indo-Pacific, members of the order Scorpaenidae can be found in oceans all over the globe, even in arctic waters. Lionfish specimens are typically red with white and black stripes and have showy, spiky fins. Species include Pterois volitans, P. miles, P. radiata and P. antenata among a few others.
Western Atlantic Invasion
Since the early 1990s, invasive lionfish have wreaked havoc on local juvenile reef fish populations in the western Atlantic. Out of the nine species of Pterois, only P. volitans and P. miles are found in Western Atlantic waters, but they range from as far north as Rhode Island down to Venezuela and The Guianas.
Risk to Humans
Knowing no predators, these fish are generally docile, allowing divers to approach closely enough and making themselves easy targets for spearfishing. Unfortunately, the desperate attempts to eradicate these fish from the Americas have caused a significant rise in the incidence of lionfish puncture wounds.
The prevalence and incidence of lionfish envenomations is unknown. Treating physicians may not choose to consult a poison control center, and in the United States they are under no obligation to report these injuries to state or federal agencies. Scientific literature accounts for 108 cases of lionfish envenomations reported between 1976 and 2001, and almost all of these reports are actually from marine aquarists. It is impossible to know how often victims go untreated and how often treatment goes unreported, but the frequency of case reports seems to indicate that lionfish envenomations are not uncommon.
Lionfish culling tournaments are becoming more and more popular all over the Caribbean. Recent studies conducted by DAN staff from Cozumel, Mexico, accounted for a total of 26 cases of lionfish envenomation over four years of tournaments. Incidence of injury during these events was between 7-10 percent of participants.
Mechanism of Injury
Most lionfish-related incidents occur as a result of careless handling, usually during spearfishing or while preparing them for consumption. Lionfish have needlelike spines located along the dorsal, pelvic and anal fins, and punctures can be extremely painful and lead to rapid development of localized edema and subcutaneous bleeding. Pain can last for several hours, edema typically resolves in two to three days, and tissue discoloration can last up to four or five days. Due to edema and the venom’s inherent toxicity, puncture wounds on fingers can lead to ischemia (restriction of blood supply to the tissues) and necrosis.
Lionfish are by no means aggressive. To prevent injuries, maintain a prudent distance. If you are committed to engage in spearfishing or culling activities, avoid improvisations, and do not try to handle these animals until you learn from more experienced divers.
If you are stung, remain calm. Notify the dive leader and your buddy. The priority is to safely end your dive, returning to the surface following a normal ascent rate. Do not skip any decompression obligation.
On the surface, first aid providers should:
- Rinse the wound with clean freshwater.
- Remove any obvious foreign material.
- Control bleeding if needed. It is OK to allow small punctures to bleed for a minute immediately after being stung (this may decrease venom load).
- Apply heat. Immerse the affected area in hot water (upper limit of 113°F/45°C) for 30 to 90 minutes. If you are assisting a sting victim, try the water on yourself first to assess tolerable heat levels. Do not rely on the victim’s assessment, as intense pain may impair his ability to evaluate tolerable heat levels. If you cannot measure water temperature, a good rule of thumb is to use the hottest water you can tolerate without scalding. Note that different body areas have different tolerance to heat, so test the water on the same area where the diver was injured. Repeat if necessary.
NOTE: Thermolysis can also be a secondary benefit worth pursuing, but it tends to be less effective in cases where the venom has been injected deep into the tissues.
- Apply bandaging as needed.
- Seek a professional medical evaluation.