Tales in the afterlife — revealing the secrets from marine mammal stranding events
by: Dhivya Nair & Louisa Ponnampalam, Ph.D.
P.S.: This blog post may not be suitable for weak stomachs…. you were cautioned 😉
It’s the last day of the survey season, and the team is starting much later in the day than they usually do for some reason we can no longer recall. The equipment is quickly set up and we are ready to go. Eyes are keen and scanning the water for dorsal fins, spurts, or a big splash. Well, suffice to say we weren’t expecting to find what we found.
Not even ten minutes in, and our eagle-eyed boat skipper yells out that he has spotted something afar, but not an animal. Not alive at least. Some suspect it to be just a palm frond, but a quick look through the binoculars confirms his suspicions (and eventually ours). Not too far off the coast, a flipper is seen bobbing up and down, sticking straight out of the water, piercing into the air. As the boat draws closer, the unmistakable stench and bloated look of the carcass confirms it’s in a state of decomposition. We quickly tie a rope around the animal’s tail stock so we can tow it to shore.
Strandings aren’t as uncommon as they sound. This isn’t the MareCet team’s first time dealing with a stranding; we’ve had our fair share of dead strandings over the years. But strandings always leave us with so many questions; what happened to the animal or how did it get to where it stranded? What caused its death? So, let’s dissect this shall we? (Well, not literally right now!)
Dead or alive — What is a stranding?
Marine mammal strandings are classified as a DEAD animal floating out at sea or found washed ashore, OR a LIVE animal (or group of animals) washed up on a beach and unable to get back to the water on its (their) own. In fact, all sorts of marine animals strand; whales, sea turtles, seals, sea lions, and even whale sharks!
Strandings have been recorded from as early as the 16th century with art evidence of these strandings depicting the massive animals up on land. Some of the earliest published records of strandings here in Malaysia date all the way to 1892, with a stranding of a baleen whale in Sebatu, Melaka (its skeleton is currently on display at the Labuan Marine Museum). Numerous strandings occur along the Malaysian coastline each year, but it is difficult to properly estimate a number, given that strandings can often go undetected or unreported, and even the likes of ourselves aren’t always out at sea.
Coming back to where we were earlier on the boat, upon closer inspection, we identify the carcass we have found to be a young Indo-pacific finless porpoise (Neophocaena phocaenoides). Bloated and already ripe with the smell of death and bacterial infestation, we brace ourselves; carcasses are a stinky affair after all. It is something many marine mammal researchers have to get used to, albeit unpleasant. Many of the MareCet team members can sometimes smell a carcass just by looking at a picture of one. The imagery of maggots and the feeling of warm organs stay with you for many days after a necropsy.
There are a couple of stages of decomposition of a carcass, and this porpoise is a Code 3 Carcass. Meaning the animal is decomposed and bloated, but with its organs still relatively intact, although putrefied. While necropsies don’t always promise an answer to the question of how the animal died, it gives us the chance to explore the whys and hows of the animal’s death. It allows us to collect critical biological samples that can shed light on the life of the animal and others of its species.
Fish (or in this case, marine mammal) out of water — why do they strand?
To state the obvious, marine mammals should not be up on land. While many theories and hypotheses have been made as to why they strand while alive, there is no sure-fire answer to this question.
One theory suggests topography as a factor in live strandings in certain regions. Coastal waters in some areas create a sort of trap where the echolocation mechanism these animals use doesn’t work as well as it should. Shallow waters can be especially tricky for deeper water dwelling species. The quick recession of tides can also very quickly leave an animal caught in shallow waters, making it unable to get itself back out to open sea.
Like other living beings, marine mammals are not exempt from natural causes of impairment that may lead to a live stranding, or even death. Predation, disease, and even old age are factored in when determining the possible cause of a stranding. One other intriguing hypothesis includes the social nature of marine mammals. Often thought to be a possibility with mass strandings, social pod structures and hierarchies are thought to influence highly social species in stranding events. One animal may head out into shallower waters (whether on purpose or accidentally), and the rest of the pod will follow!
Of course, a list of possible reasons for strandings isn’t complete without human influence. Noise pollution and the sounds we introduce into the seascape has been linked with detrimental effects to marine mammals, and it is no different here. Military sonar explorations have been linked to cases of mass strandings, with studies observing a change in the animals’ behaviours. Loud and fast travelling vessels may trigger animals to ascend quickly, causing what we know as decompression sickness or the bends. Apart from sound, the ever-pervasive issue of plastic pollution can also be linked to strandings, when animals ingest too much of it, causing severe and sometimes fatal gastrointestinal complications.
Silver lining in everything, not just the stomach lining!
As we carefully examine the carcass, we are on the lookout for indicators of its death, clues into the life of the animal. Dead strandings can provide a wealth of information to researchers about the species that has stranded, information that would otherwise be difficult to obtain. The finless porpoise we discovered on this day is a perfect example of this. Alive, the animal is shy and elusive; you would rarely have the opportunity to see much of its body or follow it around for long. The carcass provides the added opportunity to get an inside look into the lives and inner workings of these animals. Marine mammal researchers can contest that studying cetaceans can be quite difficult, partly due to the fact that they spend most, if not all their time, underwater. Following them constantly and seeing what they do underwater, especially at depths unreachable to us or in turbid water, is close to impossible. This is where carcasses provide an opportunity to confirm or inform questions like what the animals are feeding on as well as their estimated lifespan.
A fresh carcass allows us the chance to sample their soft organs. A look into their stomachs will give us a glimpse into the animals’ diets, allowing us to expand our understanding on where they may be feeding and if those areas overlap with areas of human activity. This in turn can assist researchers in focusing their efforts for area-based conservation for these animals. Where possible, pathological examination of the animals’ internal organs can help inform about the presence of diseases and pathogens in the environment or in the local population. Damage to their body parts, cuts and scars, wrongful ingestion; all these provide clues as to how the animal may have died and if there are conservation concerns for the species that should be considered. Skeletal remains can aid in species identification, and skin sample used for genetic work. Dead strandings can also help researchers in discovering new species records for a locality, or figuring out a species’ local distribution and range, as the likelihood of it inhabiting the seas around which it stranded, is higher. For example, the first record of the Omura’s whale (Balaenoptera omura) in Malaysia came from a stranding record of half a highly decomposed carcass that had washed ashore in Cherating, Pahang, in 2008. The second record comes from a pile of bones that are sitting idle behind an island resort on Pulau Dayang, Johor, from a whale that had washed ashore dead on Pulau Aur, Johor.
Alas, even in death, an opportunity for raising awareness and outreach stems. Some of these collected samples and remains then make it into our outreach events and exhibitions, as a means of teaching and educating people about the amazing marine mammals that inhabit Malaysian waters. People are often fascinated by the cetacean skulls and stomach content samples we put on display. Some even think cetacean skulls look rather bizarre, different from anything they have ever seen before!
Ambiguity vs. misinformation in the age of social media
We’ve discussed the possible whys of strandings; from topography differences to tide changes, predation and other natural causes, as well as possible threats from human activities. So, while a stranding can sometimes seem like big, headline-making news, it is not as pressing or end-of-the-world fear inducing as it may seem. Strandings are a challenge to decipher. With the why and how they happen often being inconclusive, this dubiety leads to misinformation when stranding events go “viral” on social media; such is quite regularly the case in Malaysia. To many here, seeing a marine mammal can seem like a novelty, hence why news about a stranding can quickly spread with false notions attached.
This was the case when in late 2021, Perlis saw multiple reports of strandings of various coastal and deep-water species (both live and dead), which caused speculations to rise. In reality, it was a mixed bag of a higher detection rate given the non-remoteness of the Perlis coastline, as well as the presence of a well-informed local community (e.g., Perlis Nature & Wildlife (PNW)) that knew to report the strandings, and not necessarily because each of those stranding events were related to the same cause (of stranding).
A large marine animal stranding on land would definitely be fodder for conversation, but the problem is when WRONG information spreads. We have seen comments on social media posts and statements in newspapers that state the wrong cause of death or reason for stranding, all without a proper necropsy being done! People then start to deduce some interesting reasons for the strandings. These include, but are not limited to: the animal must have been lost before stranding or separated from its mother, that it was starving and hence decided to come to land for food, or that it died from internal injury because fish bones were found in its stomach. Often enough, we have also found that stranded animals were misidentified in newspaper articles and social media posts. One might wonder, what is the big deal about misinformation? Well, misinformation, especially those that spread like wildfire on the internet (i.e., “gone viral”), can hurt science and conservation efforts. Drawing from our own experiences here in Malaysia, where awareness levels about marine mammals aren’t exactly high, misinformation can lead to unnecessary and unwarranted panic and draws attention away from actual conservation issues at hand. Incidences of misidentified species of stranded marine mammals published in the media has, in the past, led to the records becoming official, which, from a scientific perspective, is harmful. Such records are often difficult to rectify without having to go through layers of bureaucratic discussions.
Such incidences have driven MareCet to place an importance on outreach and raising public awareness where marine mammals are concerned. Over the years, we have conducted stranding workshops for local stakeholders (fishers, boat operators, nature guides, hotel staff) and veterinary science students, trained individuals on-the-ground to attend to live strandings and dead stranded animals, and even have resources online for what to do if one were to chance upon a stranded marine mammal in Malaysia. Most recently, we teamed up with a group of students from Taylor University’s Design School to produce an animated video on marine mammal stranding response (see videos below). The videos are available in English and Bahasa Melayu.
What can one do in the event of a stranding?
Every second counts when it comes to a live stranding, hence the added importance of knowing what to do and how to do it efficiently. The poster below identifies key steps to take when attending to a stranded and distressed animal. A great example of a live stranding rescue can be seen in the link here, showcasing team members from PNW along with a local fisherman assisting a bottlenose dolphin into deeper water, after it had live stranded on to the shallow mudflats of the Perlis coast. The local response team was quick to take action and can be seen providing shade and supporting the animal in an upright position. If the animal seems weak, stay with it as long as it is safe for you to do so, before assisting it out to sea. Strandings can be stressful and cause fatigue for the animals, combined with the fact that gravity is further pulling their mass down, where they are no longer supported by the buoyancy they have in the seawater. This is especially a problem in larger animals such as whales; being on dry land for far too long can cause organ collapse. However, PNW mobilising quickly with the virtual help of the MareCet team allowed for this dolphin to be safely returned back out to sea! Hurray!
A dead animal however, requires different action. If you’re in Peninsular Malaysia, the best thing to do is to contact local authorities or MareCet, as we will then be able to contact the authorities or head down to the site ourselves to provide assistance. Fret not! We won’t ask you to stick your hand into a carcass (unless you are willing to?), but basic information such as the date, time and location, along with some pictures would go a long way with assisting us with species identification if we are unable to head down to the site ourselves. All this information helps and contributes to science, which in turn helps us fill knowledge gaps.
In death it does not part
We’ve extracted some biological samples, perhaps even taken some parts of the bones, what then happens to the rest of the carcass, you might wonder? Out at sea, a carcass would then become part of what is termed as “whale fall”. The body of the animal slowly descends to the depths, and there, it will become a feeding ground to a range of different organisms (including deep sea bacteria!), at different stages of its decomposition. The animal and its body return to the nutrient and biological loop in the sea. On land, some disposal methods include burying, burning, or in the event of a really large and hazardous carcass, explosions (which has happened once here in Malaysia, back in the 70s, in the mangroves of Sungai Layang, Selangor, where a Bryde’s whale (Balaenoptera edeni) was burned and later exploded with dynamite!).
Though sad, the dead Indo-pacific finless porpoise we found will live on in its contribution to MareCet’s ongoing research and conservation work, as well as our outreach efforts. Strandings are a worldwide phenomenon, and more research is necessary for us to properly understand just why these animals strand or sometimes beach themselves. Our local capacity for handling these stranding events need to be improved, especially in cases where necropsies are needed in unveiling and understanding the cause of death of a stranded animal. Increased job opportunities for local veterinary science graduates in aquatic wildlife care are greatly needed, so we can have proper local expertise and guidance for a thorough handling of stranded marine mammals. In the meantime, MareCet will carry on and do our part in ensuring more awareness and education is passed on to our fellow Malaysians about marine mammal strandings, as we work towards helping to operationalise a national marine mammal stranding response network.