Marine mammalogists get their hands (and feet) muddy with dugong grub
by: Dhivya Nair
Everyone has their “duh” moment every once in a while, when the brain does not connect with sense. Being a new field scientist at the time, here was mine:
I was definitely unprepared — I had come with sport shoes on, unsuitable footwear for the muddy intertidal area we were about to trudge through. We weren’t expecting to find much here, but still wanted to see if we could walk all the way out to the island. Here at Pulau Setindan — an island off the coast of eastern Johor, the water recedes enough when the tide is at its lowest and the island becomes accessible by foot.
So, I take my shoes off, and along we trudge. I am constantly sinking into the muddy field and am starting to wonder why we’re even doing this. “Seagrass!” I hear someone yell after trudging for what feels like an eternity. I’m trying to recall whether I’ve seen seagrass before and can’t remember having done so. In fact, I don’t recall ever thinking much about seagrass before joining MareCet as coordinator for the International Klimate Initiative (IKI) Seagrass Ecosystem Services Project.
When I finally get to the seagrass — barefooted and having given up on trying not to get too muddy — all I see is…grass? It’s a little underwhelming at first glance. Working with MareCet, I’m used to seeing larger, charismatic (and more mobile) species such as whales and dolphins.
But that’s just exactly how seagrass is viewed by most in the conservation / environmental world, and also the general public. Some refer to it as the ‘ugly duckling’ of marine conservation, with mangroves and coral reefs, its ‘sexier’ coastal cousins, getting the limelight in conservation.
But hang on, why is an NGO that usually does research on marine mammals, looking for seagrass? Is seagrass even that important? Isn’t seagrass just……grass? Well let me take you through a little of what we (marine mammal researchers) have learnt about seagrass (not marine mammals) over the past year.
More than meets the eye — seagrass, not just grass
Think lush, green expanses that are a haven for many- that’s basically what seagrass meadows are. A type of coastal marine ecosystem, seagrass meadows can be found along the coast of most continents in shallow waters. Much like how dolphins and whales are often mistaken for fish, seagrasses are also often mistaken for seaweed! Seagrass, however, are actually flowering plants that produce seeds, flowers, and fruits. Yes, seagrass is just like a typical plant that grows on land, except, they grow underwater on the sea bed.
Picture credit: Alex Bartlett, Project Seagrass
In drawing comparisons between cetaceans and seagrass, one other similarity these overlooked plants have is that their ancestors were originally land-dwelling species and have since made a home in the ocean. Despite the name-seagrass- they are more closely related to orchids and lilies.
With more than 60 species discovered worldwide, and at least 16 found here in Malaysia, seagrass come in different shapes and sizes, and their meadows can be a mix of different species. Some have single leaves as small as your fingernail, some are extremely narrow and thin and look like hair, and others may have long, tape-like leaves reaching over a metre in length! Some are even thin, “crunchy” and brittle, also tubular in strand like Syringodium isoetifolium aka noodle seagrass.
Clockwise from top left: Enhalus acoroides; Halophila ovalis; Thallasia hemprichii; Halodule pinifolia
Only worth saving, if it’s worth something?
So, we’re a little more familiar now with what seagrass is, but are they really that important? Where do marine mammals come into all of this and how crucial is it that we begin to focus more conservation efforts on these habitats?
While seemingly unassuming, these meadows are host to a whole slew of ecosystem services. Ecosystem services simply refer to what an ecosystem can give back to society, whether in the form of a product, service, or non-material value. Leave it to humankind of course, to fit a value on something before deciding whether it is worth saving. At least in the case of dolphins, the general public wants to save them simply by virtue of how cute they are. But grass isn’t very cute — so what can the so-called “ugly ducklings” offer us?
For one, these meadows act as a nursery. Think fish kindergarten for before they graduate into the big oceans, they spend their early years in the meadows where they get food and added protection under the cover of dense leaves and reduced current flows stopping them from being swept away. But not just fish inhabit these meadows; crabs, sea cucumbers, shrimp, sea urchins, sea stars and many more call seagrass home. A single acre can host upwards of 40,000 fish and 50 million invertebrates! This was news to me too, simply because at first glance, the Setindan meadow, especially at low tide, seemed so sparse of life. Cue “A Whole New World” from Aladdin, except I’m on a carpet of seagrass!
Clockwise from top left: Chocolate chip starfish; Clownfish & sea anemone; Sea urchin; Lizardfish (do you see it?)
Then there’s the carbon and oxygen cycle. Like plants, seagrass also photosynthesize, producing oxygen and sequestering carbon. They are able to store carbon in their sediment for long periods of time, effectively acting as one of Earth’s most efficient carbon sinks and inadvertently helping to mitigate climate change.
As they act like the lungs of the sea, these productive meadows also aid in sediment accretion and stabilisation. Their underground root systems help trap sediment, and dense leaves can reduce water flow, resulting in coastal protection, with the seagrass acting almost like a buffer.
All these services benefit both humans and the environment at large. It is estimated that in just one year, a football field-sized meadow is estimated to have a RM39,000 value in just the services that it provides. While this value is an estimation and can vary, the cost of losing these habitats is clear as these services include coastal protection that prevents damages to our coastlines, and nurseries that contribute to the economy via the seafood industry.
If there is SEAgrass, there must be SEAcows
While we’re on the topic of benefits, there is one other animal we haven’t quite touched on here, one that benefits but also relies on seagrass as its sole source of food. Dugongs! (Finally a marine mammal!)
Dugongs are herbivorous animals, with the main part of their diet making up, you guessed it, seagrass! Eating up to 50 kg of seagrass a day, this niche diet limits their movements and range to where seagrass is available in expansive meadows. Given it’s their sole source of grub, conserving seagrass is crucial to the dugongs’ survival. But this relationship is anything but one sided!
While they feed in the meadows, dugongs uproot the seagrass, shoots and roots leaving behind what scientists term as “feeding trails”. Almost like a vacuum cleaner hoovering a carpet of grass. The uprooting helps aid with regeneration, keeping the meadows healthy and helping to disperse seeds as they travel. So, it’s safe to say that the relationship seagrass and dugongs share is of a mutualistic kind.
Here in Malaysia, dugongs are only found in Johor, mainly off the east coast, and in very specific areas of Sarawak and Sabah. Listed as an endangered species here in the country, surveys MareCet conducted back in 2014–2018 found that there are probably not more than 100 individuals found off the Johor east coast. With such low numbers, further protection measures need to be put in place, especially from key threats like boating accidents and bycatch, which are common local causes of death for this species. In 2019, the Mersing archipelago was designated as an Important Marine Mammal Area (IMMA) by the IUCN, as it’s been observed to be an important site for the local population of dugongs’ breeding, feeding and socializing.
The Seagrass Ecosystems Services Project
Given how crucial seagrass meadows are to the survival of dugongs, the Seagrass Ecosystems Services (SES) Project presented an opportunity for MareCet to not only continue our conservation work for the dugongs, but to also learn something new. Before we get into the muddy details of this work, let’s talk about the project.
Part of the International Klimate Initiative (IKI), the SES project is the first of its kind in the Indo-Pacific region, helping to empower local communities and NGO groups to assess the services seagrass meadows provide. The information collected during the project can then be used to ensure conservation and protection of these meadows. MareCet is the official national partner for Malaysia.
To properly understand the meadows in-situ, we work with technical experts to implement research methods that help us map seagrass distribution, monitor biodiversity of seagrass meadows, determine blue carbon storage values, and assess dugong distribution. With dugongs being found only in Johor (where Peninsular Malaysia is concerned, as far as we’re aware), it was a no-brainer that our study sites would be the east coast islands off of mainland Johor, where large expansive meadows can be found in some areas.
While we have done some work on seagrass before on a previous project, most of the methods and data being collected for this project were new to us and it did really feel like we were learning so many things from scratch. As of December 2022, we have already started and completed fieldwork for two (underwater biodiversity monitoring and blue carbon sequestration) out of the four components.
Trudging through a new field (literally), and failing
As if continuously getting stuck in the mud in Setindan wasn’t enough, little did I know I would be doing that multiple times over the next year (and anticipate doing more of it come this new year). This mud business feels symbolic of what embarking on the technical research projects have felt like. Whether it was the equipment failing us constantly, or the field sites having difficult field conditions; everything has been quite the learning experience.
As marine mammal researchers, we’re more used to our subjects of study moving, tailing them from a distance. When we’re prepping field equipment, we think light, easy to float and can be towed with the boat. That’s exactly what we do with some of our acoustic equipment. It’s heavy enough that it’s able to sit in the water, but light enough that it’s easy for us to tow it with the boat as we follow our animals and record their sounds. Same with capturing footage, GoPro on a stick; simple and easy.
Seagrass however, doesn’t move, and neither does the equipment that needs to be placed in meadows. Imagine lugging a 10 kg setup for an underwater camera. Just so it’ll sink and stay in place despite strong currents. 10 kg through mud? I felt like I was training for an extreme sport competition I didn’t sign up for. Throw in the hot sun, heavy rain, wading through water against current, and having to stay on a stationary boat for hours as the waves threatened to sway my lunch out of me; marine biologists really are built different.
To top off difficulty with the equipment, we also learned how difficult it can be trying to design an experiment where tides and site changes can drastically affect the experiment. You would just have to head out to sea to look for marine mammals surfacing out of the water, but seagrass also occur in areas where it is sometimes submerged and sometimes completely exposed, i.e., the intertidal zone. For example, if we had a setup that was too tall, it wouldn’t be able to record anything once the tide recedes. If currents weren’t as strong, sedimentation would be an issue as it would be too murky. But if it was too strong, chances of our setup being lugged away would be higher! Cherry on top of the icing would have to be our skippers telling us about purported crocodile sightings in the area. That definitely had me out of the water quick as a wink.
Then there was building our setups, which I thought was most fun as I got to play Bob the Builder, except this Bob was really inexperienced.
Between failed setups that didn’t sink, PVC pipes getting stuck in the sediment, and an entire baited remote underwater video (BRUV) setup (yes, with a GoPro attached to it) being lost to the sea (OUCH!), I can’t count the number of times I have wanted to use the sledgehammer on all the equipment. I think the only thing that really stopped me was the price tag of the equipment.
But such is science, is it not? Failing, continuously, until finally something works and there’s a turtle on your camera or you finally collect your first sediment core while diving underwater. The work we have been able to experience this past year with the SES project also serves as a reminder that while difficult, our work is necessary and important, because these habitats are necessary and important. It is reminiscent of much of the work MareCet does daily with the research and outreach work on marine mammals. It’s just the study subject that’s a little different in this case.
Grass is not so green on the seaside
But as with many environments, whether terrestrial or marine, seagrass meadows also face threats, and we are losing them at alarming rates. Even more so with it being a coastal habitat and in closer proximity to us humans. Threats include things like coastal development, dredging, and industrial run-off to name a few; activities that cause disturbance to the surrounding seafloor and the water quality.
These are all threats we’ve heard of before of course. They don’t just harm seagrass but serve as threats to the environment at large. There are, however, two other threats seagrass face that perhaps our fluked friends don’t have to deal with in such dire absence; lack of legislative protection and a lack of awareness (read: interest).
Often, when we conduct outreach or just talk to people about the seagrass work that we’re doing, many ask us why. Why are you doing seagrass research, isn’t it just grass? In fact, down at our project site near Pulau Setindan, many locals give us odd looks when we tell them about our muddy adventures out to the intertidal site, followed by dismissive gestures urging us that there really is nothing out there, that we’re wasting our time, and we’ll only get stuck deep in the mud.
Lack of awareness then comes hand in hand with a lack of legislative protection. In Malaysia, seagrass is not listed as a protected habitat, but instead is only given protection by default if it happens to be within a marine park or national park (e.g., in Sarawak). With many not even knowing what seagrass is, let alone the multitude of services these habitats provide, you can imagine that getting stakeholders to prioritise protection and conservation of seagrass can be difficult.
All eyes on seagrass
But that’s exactly why projects like the SES project are so important, and crucial to furthering the conservation plight of the humble (yet mighty) seagrass. I started out this blogpost in Pulau Setindan circa 2021, and as of December 2022 we have collected sediments for blue carbon analysis as well as underwater video for biodiversity monitoring and ecosystem services valuation. Pending are some seagrass mapping and dugong distribution surveys. What have we learnt since then?
With analyses pending, the fieldwork we have done has already shown us how fluid these ecosystems are. At one time the meadow can be a lush green haven, dense and full of life; come back at a different time in the year and algal blooms or high surface sediment would cover the area, with signs of life scarce. But the meadows always seem to bounce back. Preliminary video footage has already shown an array of fish species in our study sites. The new research methods and skills we are learning from this project, whether it’s underwater video capturing or drone flying, can then be adapted and perhaps applied to the research work we do with marine mammals.
Apart from the new skills I have from playing with lots of equipment (really, I can drill lots of things now, with precision), there is of course a newfound appreciation for these meadows. Having also now dived in the seagrass meadows, I think many are missing out. The meadows offer a hide-and-seek playground of sorts, where you really must look closely to find some exciting creatures either carefully blended in with their surroundings or so small you have to turn over leaves to find them. If you ever get the chance to dive in a meadow, I highly recommend it. Pulau Sibu and Pulau Tinggi are two great locations to begin your very first seagrass diving adventures! If you’re lucky, you may even chance upon dugong feeding trails!
The ecosystem services provided by seagrass meadows are glaringly apparent. With the blue carbon potential these amazing plants have, and given the current climate state, making their protection and preservation a priority only makes sense. Seagrass is now getting industry attention as one of many nature-based climate solutions; is this what it will take to make “seagrass the new black”? Or in other words, will people start appreciating these ecosystems for what they are worth? MareCet hopes to make steps in that direction in this coming year as the project continues. We aim to take our results from the data analyses and translate that information into actionable suggestions for all stakeholders involved. Because whether you protect marine mammals or seagrass, if one gets protection, many others will benefit as well, especially in the ocean where everything is linked. Perhaps then, seagrass here in Malaysia (and everywhere else really) can get a little more of some well-deserved limelight.
As part of our efforts to give seagrass that very limelight, we hosted the Sayang Sayang Seagrass Virtual Festival back in 2020. Check out the amazing video below that highlights our meadows, and this album for more seagrass fun facts!
If you would like to support MareCet and our ongoing research and conservation efforts, please consider supporting us by purchasing one of our locally made and unique dugong plushies! Shop here!
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