Dive Pacific 171 Oct- Nov 2019

Fun facts
What are the possible side
effects if injury occurs?
(1, 2, 9-13)
Mild to medium side effects:
Redness around site of injury, severe pain
(immediate throbbing), swelling and possible
discolouration of the skin where the injury
occurred, pins and needles, dizziness or
feeling faint (coupled with looking pale),
nausea, sweating, and possibly bullae (type of
blister) formation at site of stings.
• Lionfish are suction feeders, feeding on crustaceans
and fish mostly at dusk and dawn and use their cryptic
nature to their advantage by ambushing their prey (32, 40-42).
Research suggests cannibalism occurs, but this is linked to
fish size and density within an area (43).
• They can hover due to their specialized bilateral swim
bladder muscles allowing them to alter their centre of
gravity (the reason they are often seen upside down/head
down). So they can orientate themselves strategically before
striking their prey (44).
Severe side effects:
Delirium, seizures, anaphylactic shock
(if stung more than once), limb paralysis,
vomiting (watch out for dehydration) and
shortness of breath. After several weeks
you may feel a loss of sensation (anesthesia),
abnormal perception of sensation (paresthesia),
or an increase in sensation (hypesthesia).
Local necrosis (dead tissue) at site of
injury could occur.
• Lionfish can produce jets of water in the direction of their
prey when stalking which are thought to confuse or distract
the prey, and make them orientate head-first for an easy
swallow (8).
• Lionfish fins give the illusion the fish is larger than it
actually is. Specifically their pectoral fins allow it to ‘herd’
potential prey into areas of no escape. They also have been
seen to team up to hunt and alternate the fish that gets
to strike and eat the prey (45). Their pectoral fins also are
handy for flushing benthic invertebrates out of substrates
by palpation (applying pressure to determine if invertebrates
are present in the substrates) (46).
• Research has described distinct vocalization of lionfish.
They make different calls when alone (repetitive pulsecalls),
or together (multiple fish vocalize concurrently with
less rapid repetitive pulse-calls at a lower frequency), or
when agitated (hum call) (47). It is thought this calling may
have be to do with seeking a friend to hunt…
• They occupy a wide range of thermal environments, from
13 to 32°C. But about 23°C suits best. They have been found
at depths greater than 75 m (29, 32) too which means they
populate a range of habitats including reefs, mangroves,
soft bottoms, nearshore seagrass beds and near estuaries
(28, 29).
• The bacterial community found on lionfish skin is diverse
and is capable of producing antibacterial metabolites and
thus help defend the lionfish from fish pathogens (the
bacteria promotes disease resistance to its host) (30).
• Tagged lionfish movement records show they tend to
move relatively little depending on the lionfish density in
the area, body size and seascape structure (41).
• They can change their physiology to meet their energy
demands, for eg lowering their metabolism when food is
scarce (31, 32).
Actions to take:
Firstly, it is important to get the diver out of
the water as soon as possible after injury.
Pain will be most severe an hour to an hour
and a half after the venom has been injected
and persist for 6-12 hours or longer. The
persistent pain is likely due to the fact that
the toxin cannot be inactivated immediately
after injury has occurred. Immersing
the affected area in hot water, no more than
45°C for 30-60 minutes will help neutralize
the toxin and provide relief. If the spine and/
sheath is embedded it should be removed.
But when cleaning the wound use warm
saline solution as alcohol based solutions
may cause further tissue damage. The wound
will need to drain so should be left open. It
is always advisable to consult a doctor and
wise to make sure that tetanus protection
is up to date (Clostridium tetani, the bacterium
responsible for tetanus, can be found in
marine sediments.
Better safe than sorry!).
40 Dive New Zealand | Dive Pacific