Epaulette Sharks: The Sharks That Can Walk On Land

SHOW NOTES

Faqih has wanted to work with sharks from a very early age [6.25]. One of his most memorable experiences is of his first time working with live sharks in the field. Accompanied by his then supervisor, with whom he was working with under the shark programme for WWF Indonesia, Faqih was heading out into the Lombok Strait in search of pelagic thresher sharks. The strait is a deep passage of water that separates the islands of Bali and Lombok. One of the local villages has a shark fishery for pelagic threshers, and Faqih and his colleagues were trying to understand how the species used the waters of the strait. This involved catching and tagging live sharks – one of Faqih’s first experiences of handling these animals in the wild. “What made it so memorable was that one of the thresher sharks we got was really weak when we pulled it up,” remembers Faqih. “We felt like if we just released it, just like that, then it wouldn’t survive.” Faqih had to take spontaneous action, jumping in the water with the thresher and taking the shark “on a little swim” to ensure water passed through the gills, and the shark could breathe. There was also a photographer on board, who dived in at the same time to capture the moment. “It was successful – the shark was released, and it was alive,” smiles Faqih. “And we did a high five in the middle of the Strait, right there in 200m deep water. It was crazy.”

Faqih’s entry into the world of marine science began in busy Tangerang, a city close to Indonesia’s bustling capital Jakarta [10.20]. Faqih’s parents would buy him encyclopaedias, which he would then search hungrily for any information on wildlife. “I think my parents were surprised that I was the only one out of four siblings that really liked reading about or looking at animals,” he laughs. Then, during Junior High, Faqih was introduced to sharks via a National Geographic documentary: “and I thought it was just so cool to work with sharks. I thought before they might be scary and everything with the sharp teeth, but then it looked so cool.” This persuaded him to pursue a career in marine biology. Faqih is now working on obtaining his masters, while leading Elasmobranch Project Indonesia, a non-profit that combines research with citizen science and community engagement to better understand and conserve shark and ray populations in the region [15.30].

EPI has two species-specific projects, one on rhino rays (which we come to at the end of the episode) and one on a particular species of our star for this episode: a walking shark known as the Raja Ampat epaulette shark. But before we zoom in on this species, we take a look at the group they belong to [18.00]. There are nine species of epaulette or walking sharks in total. Six of them can be found in Indonesia, one in Australia, and two in Papua New Guinea. But each one is endemic to the region in which they are found. And, there is one behaviour that they all seem to share: “[they] are sharks that can walk…these species are able to use their pectoral fins to walk on the surface of the seafloor,” explains Faqih. That’s where their common name, ‘walking shark’ comes from, and it’s what they’re most famous for. You can also identify them by their characteristic ‘epaulette’ pattern [19.19]. Although the exact appearance differs between species, in general all epaulette sharks have distinctive spots or blotches located just behind the pectoral fin, which echoes the ornamental shoulder pieces common on military uniforms (known as ‘epaulettes’) [21.15].

But why do walking sharks walk [27.04]? The short answer is: we don’t know for certain. “If you ask that question, it’s sort of like, ‘why does the chicken cross the road’, right?” Faqih jokes. “It’s maybe just because they want to.” But, based on his own team’s observations, Faqih believes it could be to do with foraging. “They need to sense their prey underneath the sand, or underneath the substrate. And walking, I think, is the best way for them to do it,” he says. “They can move between crevices…I normally see that they’re most comfortable walking when they look for food, when they forage.” He also notes that this doesn’t mean they can’t swim when they want to, especially when disturbed. “They will swim, and they can swim fast, so fast that you won’t even be able to chase them. The name walking shark doesn’t mean that they are slow.”

The species that Faqih works most closely with is the Raja Ampat epaulette shark, Hemiscyllium freycineti, known locally as the Kalabia [29.27]. Not much is known about this species, which is endemic to Raja Ampat. But through the Kalabia Project, Faqih and his team at EPI are trying to understand more about their ecology and behaviour, as well as potential threats to the population. “If you compare it with the species that you find in Australia, H. ocellatum, you will find basically almost nothing. And we had identified that there might be some issues and some threats socially, and maybe related to fisheries, and we started to form some research questions.”

One question they wanted to address first was whether you could use photo ID to identify individual epaulette sharks [33.00]. Some elasmobranch species, like whale sharks and manta rays, have unique spot patterns that can be reliably used to ID individuals. Faqih and his colleagues wanted to see if those distinctive epaulette patterns offered the same opportunity. The answer was yes – but with a catch. “Their patterns change as they grow. So, they have a pattern as a baby, and then as they develop into adulthood their skin grows – and so the pattern changes. But, we did find that even if they do change, even if the pattern grows, there are still similarities.” For example, the dots in the existing pattern may split up, like cells dividing. Or, they would become gradually more spaced apart. But, they maintain the original distribution and shape of the dots. Faqih and his team were able to confirm this by tagging the sharks. “They also don’t move very far…they’re only going to be around 500m radius, that’s like their home range. I think even some of them we’ve found five metres from where they were the previous year.” This makes tracking and locating specific individuals much easier.

The EPI team are also getting interesting insights into their movements, especially related to the tide [38.20]. Essentially, they have found that the Kalabia have a sort of ‘sweet spot’ in between low and high tide, where they come out to forage. “This needs further study, definitely. But the assumption is that during this moment of the perfect height of water helps them to look for food in the shallow water. The shallow water is assumed to have lots of prey diversity, lots of invertebrates. They will be able to find small crabs, small molluscs, worms, polychaetes…and then when the water is so high during the high tide, you find the black tip reef sharks hanging or patrolling around the waters in the same area.” So, they avoid predators by hiding away when the water gets too high. But, equally, they avoid times when the tide is too low: “Whenever we walk or survey the whole island during the low tide, and it’s really dry, then you won’t be able to find a single one of them.” So, it seems, for the Raja Ampat epaulette at least, it has to be just right. “And when we think of their capability of walking from tide pool to another tide pool, I’m questioning myself in the site that we’re working on. Do they really need that? Because we think that they can sense when it’s about to hit low tide and they would sort of go back to the deeper water,” wonders Faqih. An interesting question for sure.

But such tendencies also make the epaulette shark vulnerable to anthropogenic pressures [43.11]. A particular worry is climate change. Although it has been suggested that warming seas may have an impact on their physiology, the larger concern is the negative effects of habitat degradation and loss. “They’re really limited by their mobility,” explains Faqih. “We’ve established they don’t move far from their home, right? So, if something happens to a habitat or a certain area is destroyed, whether that’s because of climate change or something else, the population in that area is practically doomed, because they won’t be able to move away.” Epaulette sharks live in a variety of fragile ecosystems: coral reefs, seagrass beds, rocky reefs and mangrove forests. Such habitats are disappearing at an alarming rate and are hugely vulnerable to anthropogenic pressures.

The work of Faqih and his team is vital. Without building knowledge of species like the Raja Ampat epaulette shark, it’s difficult to determine whether a population is in decline, and the most effective ways of protecting them. “Currently, all six species of epaulette sharks are protected in Indonesia. It might bring this sense of comfort that because the species is protected, that they are safe from whatever threats out there. But that might not necessarily be the case considering that we still know so little about the species. And I’m only talking about one species that we’re working with in the Raja Ampat – what about the other five species, right? We might have threats that we don’t know just because we don’t know much about the species yet, right? So if you’re talking about management, conservation, then it’s not enough just to try to do something because if you try to do something but it doesn’t really answer or help with the issues that are happening…then that is an even worse danger, I think.”

ABOUT OUR GUEST

FAQIH AKBAR ALGHOZALI

Faqih is the co-founder and project leader of Elasmobranch Project Indonesia (EPI; Yayasan Hiu Pari Lestari). EPI is a local registered non-profit organisation working to support shark and ray conservation in Indonesia through citizen science, research and awareness campaigns. EPI also aims to map the biodiversity and distribution of shark and ray species in Indonesia with the help of citizen scientists. They are based in South Tangerang and are conducting two species-specific projects on rhino rays (giant guitarfish and wedgefish) in Karimunjawa National Park and on the Raja Ampat epaulette shark in the Raja Ampat archipelago, while also doing citizen science work and campaigns virtually.

You can find out more about the EPI here, or follow them on Instagram @elasmobranchid.

You can learn more about Faqih’s work here, or follow him on Instagram @faqihbig.