KUALA LUMPUR, July 25 — The combination of sun, sand and crystal-clear waters may promise the perfect tropical getaway, yet beneath the surface lies a hidden danger that many beachgoers may be unaware of.
What looks like a harmless piece of translucent ‘plastic’ drifting in the sea could actually be a jellyfish. While most jellyfish species are harmless, some are venomous and capable of delivering painful, and sometimes dangerous, stings.
Experts warn that jellyfish could be the “biggest winners” from climate change and the El Niño phenomenon as the warmer temperatures may accelerate their growth and create conditions favourable for them to thrive.
Scientific studies document around 20 to 34 types of jellyfish species in Malaysian waters, mostly from the Scyphozoa and Cubozoa classes.
Among them is the box jellyfish, regarded as one of the world’s most venomous marine animals, whose sting can inflict excruciating pain, trigger cardiac arrest and, in severe cases, cause death within minutes.
A study published in the ‘Journal of Travel Medicine’ in July 2011 by the International Society of Travel Medicine reported three fatal box jellyfish stings in Malaysia between 2000 and 2010, all involving tourists.
As for more recent cases, on Nov 19 last year, a two-year-old Russian boy died four days after being stung by a box jellyfish while swimming with his family in shallow waters at Pantai Cenang in Langkawi.
Following the incident, the Langkawi District Civil Defence Force reported that a total of 102 jellyfish sting cases were recorded in the island’s waters over the past three years, with 2024 registering the highest number at 73 cases.
On Aug 21 last year, a seven-year-old girl died after being stung by a box jellyfish while swimming off Pantai Sawangan in Kuala Penyu, Sabah. In another case, which also occurred in August last year, about 30 children were stung by jellyfish while participating in an open-water race at Teluk Senangin beach in Lumut, Perak.
Increase in jellyfish blooms
Universiti Putra Malaysia (UPM) Faculty of Biological Science senior lecturer Dr Wan Mohd Syazwan Wan Solahudin said the increase in jellyfish blooms around the world, including Malaysia, over the past few decades is a cause for concern due to their impact on the ecosystem and humans.
(A jellyfish bloom refers to a massive, rapid explosion in the population of jellyfish in a specific marine area.)
“Some species, particularly the Portuguese Man O’ War, Irukandji and Chironex sp., can cause severe symptoms, complications and even fatalities from their harmful stings.
“In Malaysian waters alone, over 700 cases of jellyfish stings, both fatal and non-fatal, have been reported since the early 2000s,” he told Bernama.
Wan Mohd Syazwan said jellyfish could benefit from climate change as the rising ocean temperatures can stimulate the recruitment of juvenile jellyfish and accelerate their growth. These conditions are particularly favourable during El Niño events, when warmer waters, reduced oxygen levels and ocean acidification create an environment that allows jellyfish populations to flourish.
“Adult jellyfish may also expand their range in temperate and subtropical regions as they are more tolerant of low-oxygen (hypoxic) conditions compared with competitors such as fish and shellfish. This is due to their lower oxygen and food demands,” he said.
He said in temperate regions, warmer temperatures have been linked to the increased numbers of multiple jellyfish species, while in Malaysia, jellyfish blooms are frequently reported during the warmer months from January to September.
He said aside from climate-related effects, jellyfish blooms are also caused by human activities such as overfishing, and an increase in human-made structures such as fishing stakes, fish cages and jetties.
He added that the blooms may also negatively disrupt economy-driven human activities as most sting cases often involve beachgoers – beach closures can hinder recreational activities and cause losses in tourism revenue.
More research, public awareness needed
Wan Mohd Syazwan said jellyfish blooms are not new in Malaysia and historical records have indicated that at least 65 cases of jellyfish blooms occurred in Malaysian waters from the early 1960s to the present, with at least five jellyfish species identified as the culprits.
“Despite their frequent and massive blooms, jellyfish have not been a priority for scientific research in Malaysia until recently, when local scientists from UPM, Universiti Malaya and Universiti Sains Malaysia started studying the causes of the phenomenon, including how local environmental changes can affect jellyfish populations and why they only thrive at certain times,” he said.
He said the researchers are still in need of more information on why jellyfish thrive in certain areas and whether it is due to climate change or other human factors.
“We also need to learn more about the life and behaviour of jellyfish so that we can predict where they’ll be and when.
“This information is urgently needed so we can better manage and reduce the impact of their blooms on the marine environment and human well-being amid climate shifts,” he said.
Meanwhile, Associate Prof Dr Ahmad Khaldun Ismail, an emergency physician and clinical toxinologist at Hospital Canselor Tuanku Muhriz, Universiti Kebangsaan Malaysia, said greater public awareness, better-trained first responders and wider emergency preparedness remain crucial to reducing fatalities related to jellyfish stings.
“Prevention is always better than cure. But if a sting happens, knowing what to do within the first few minutes can determine whether someone survives,” he told Bernama in an interview.
He believes many deaths can potentially be prevented if beachgoers recognise cardiac arrest early and begin cardiopulmonary resuscitation (CPR) immediately while waiting for an ambulance.
CPR important
Dr Ahmad Khaldun said unlike most jellyfish species, box jellyfish possess an extremely potent venom capable of attacking the heart and nervous system.
“Severe box jellyfish envenomation can stop the heart within minutes, leaving only a narrow window to preserve brain function.
“If the heart stops, you have roughly four minutes before brain damage begins. Without CPR for about 10 minutes, the chances of meaningful recovery become very slim.
“In the Russian toddler’s case, CPR was not continuously performed during transport (to the hospital), resulting in prolonged oxygen deprivation,” he said.
He also urged beach operators and local authorities to ensure lifeguards and first responders are trained in basic life support (BLS).
He said these personnel are often the first people approached during emergencies and should be capable of recognising severe envenomation, assessing vital signs, activating the 999-emergency response, performing CPR and sustaining resuscitation until the ambulance crew arrives.
“The local authorities also should be more proactive in reporting jellyfish incidents so beaches with repeated cases can be clearly identified and warning signs installed,” he said.
Dr Ahmad Khaldun also advised swimmers, especially families with children, to wear protective stinger swimsuits made from Lycra material when entering waters known to have jellyfish activity, adding that in the past, mandatory protective suits had reduced jellyfish stings among participants of an international swimming event in Penang from around 90 percent to just five percent.
He also urged the public to abandon unproven first-aid practices such as applying urine, sand or soft drinks to stings.
“Instead, visible tentacles should be rinsed away gently using seawater before seeking immediate medical treatment,” he said.
Antivenom remains limited
Dr Ahmad Khaldun, who is also the founding consultant and advisor of Southeast Asia Remote Envenomation Consultancy Services, said Malaysia does not manufacture its own antivenom.
He said the box jellyfish antivenom is manufactured solely in Australia. It is imported and stocked only in hospitals located in coastal areas with a documented incidence of severe box jellyfish envenomation.
“Currently, only hospitals in Sabah, Penang and Langkawi maintain supplies. Each hospital stores only a small number of vials because the antivenom is rather expensive, has a shelf life of about two years and is used only in severe cases,” he said.
A patient may require between one and three vials, while the cost of each vial was previously around RM4,000 to RM6,000.
Not every jellyfish sting requires antivenom, Dr Ahmad Khaldun said, noting that the Australian product is currently the only proven treatment, although its effectiveness continues to be evaluated. — Bernama
