18 – Pelagic Cnidaria and Ctenophora
195
distributions. Box jellyfish, for example, are generally
restricted to coastal and near-shore island localities. In
contrast, stings from Irukandji jellyfishes have been reported from nearly every coastal and island/reef locality
where recreational activities take place throughout the
GBR (Box. 18.2). Curiously, the moon jellyfish (Aurelia
spp.) is one of the commonest species globally, but is
only sporadically found in the GBR region, where it may
occur in dense but short-lived blooms. However, the majority of jellyfish species have only been reported from
one reef or island but this is probably more due a paucity
of studies than a reflection of their true abundance. In
general, the dangerous species have received the most
attention but some are yet to be formally classified.
A hot topic of modern jellyfish research is bloom
dynamics, or the cycles and triggers of jellyfish blooms.
Most jellyfish are capable of exploiting perturbed
ecosystems, whether through pollution (especially
eutrophication), overfishing, species introductions, or
climate change. They have changed little in design in
over 600 million years, suggesting that they are tolerant
of changes in pelagic assemblages and environmental
BOX 18.2 IRUKANDJI SYNDROME
About 50 stings each year in the Great Barrier Reef region send people to hospital with a
bizarre constellation of symptoms known as ‘Irukandji syndrome’. At least 10 species of
jellyfish have been linked with the syndrome. The initial sting is typically mild, and is followed after a 5–40 minute delay by any or all of the following: severe lower back pain,
nausea and vomiting, cramps, spasms, muscular restlessness, difficulty breathing, profuse
sweating, or a feeling of impending doom. Irukandji syndrome is not usually fatal, but it
can be; more frequently it resolves entirely or, rarely, results in permanent heart damage.
The best prevention against Irukandji stings is a full-body lycra suit (or neoprene wet
suit), which provides good protection for about 80% of the body’s skin surface. It is still
possible to be stung on the hands, feet, or face, but this rarely happens compared to the
larger body surfaces. For those wishing additional protection, gloves, booties, and hood
are recommended.
Irukandjis are more prevalent on days with dense ‘jelly button’ or ‘sea lice’ blooms,
especially if salps are present (see Chapter 14). These sorts of days only occur a few times
a year, but it is wise to avoid the water if possible.
Treatment priorities for known or suspected Irukandji stings:
1. If the person is already feeling systemic symptoms, call ‘000’ for an ambulance,
then douse the sting well with vinegar. Rest and reassure the patient.
2. If systemic symptoms have not yet onset, douse the sting site well with vinegar
and monitor the patient for 30–40 minutes to see if symptoms develop; if so, call
‘000’ for an ambulance.
Treatment priorities for box jellyfish stings:
1. Call for help
dial ‘000’ for ambulance or get a lifeguard
2. Treat the victim
provide emergency care (CPR if necessary)
3. Treat the sting
douse sting area with vinegar
4. Seek medical aid
transport to hospital
195
distributions. Box jellyfish, for example, are generally
restricted to coastal and near-shore island localities. In
contrast, stings from Irukandji jellyfishes have been reported from nearly every coastal and island/reef locality
where recreational activities take place throughout the
GBR (Box. 18.2). Curiously, the moon jellyfish (Aurelia
spp.) is one of the commonest species globally, but is
only sporadically found in the GBR region, where it may
occur in dense but short-lived blooms. However, the majority of jellyfish species have only been reported from
one reef or island but this is probably more due a paucity
of studies than a reflection of their true abundance. In
general, the dangerous species have received the most
attention but some are yet to be formally classified.
A hot topic of modern jellyfish research is bloom
dynamics, or the cycles and triggers of jellyfish blooms.
Most jellyfish are capable of exploiting perturbed
ecosystems, whether through pollution (especially
eutrophication), overfishing, species introductions, or
climate change. They have changed little in design in
over 600 million years, suggesting that they are tolerant
of changes in pelagic assemblages and environmental
BOX 18.2 IRUKANDJI SYNDROME
About 50 stings each year in the Great Barrier Reef region send people to hospital with a
bizarre constellation of symptoms known as ‘Irukandji syndrome’. At least 10 species of
jellyfish have been linked with the syndrome. The initial sting is typically mild, and is followed after a 5–40 minute delay by any or all of the following: severe lower back pain,
nausea and vomiting, cramps, spasms, muscular restlessness, difficulty breathing, profuse
sweating, or a feeling of impending doom. Irukandji syndrome is not usually fatal, but it
can be; more frequently it resolves entirely or, rarely, results in permanent heart damage.
The best prevention against Irukandji stings is a full-body lycra suit (or neoprene wet
suit), which provides good protection for about 80% of the body’s skin surface. It is still
possible to be stung on the hands, feet, or face, but this rarely happens compared to the
larger body surfaces. For those wishing additional protection, gloves, booties, and hood
are recommended.
Irukandjis are more prevalent on days with dense ‘jelly button’ or ‘sea lice’ blooms,
especially if salps are present (see Chapter 14). These sorts of days only occur a few times
a year, but it is wise to avoid the water if possible.
Treatment priorities for known or suspected Irukandji stings:
1. If the person is already feeling systemic symptoms, call ‘000’ for an ambulance,
then douse the sting well with vinegar. Rest and reassure the patient.
2. If systemic symptoms have not yet onset, douse the sting site well with vinegar
and monitor the patient for 30–40 minutes to see if symptoms develop; if so, call
‘000’ for an ambulance.
Treatment priorities for box jellyfish stings:
1. Call for help
dial ‘000’ for ambulance or get a lifeguard
2. Treat the victim
provide emergency care (CPR if necessary)
3. Treat the sting
douse sting area with vinegar
4. Seek medical aid
transport to hospital