Celebrating weird, wonderful and obscure sharks
SHOW Notes
Regular listeners of the World of Sharks podcast will know that we love talking about the diversity of sharks and rays. There are over 1,200 species currently known to science, each with their own unique adaptations to survive and thrive across a variety of different ecological niches. But only a handful of these are more widely known. So, we thought we’d dedicate an episode to some lesser-known species, with the help of three guests with a passion for the weird and the wonderful: deep-sea shark expert and fisheries scientist Dr Brit Finucci, shark scientist, communicator and educator Vicky Vásquez, and shark scientist, climate research manager and science communicator A-Bel Gong. For this episode, each of us is bringing to the table a species that we consider to be more obscure.
But before we get into that, we get to know our guests a bit better first by asking them for a memorable experience with the ocean. Brit goes back to when she first saw the ocean as a 12-year-old, on holiday with her family in Cape Cod [7.09]. She was keen to get out on the water from the get-go, having grown up far away from it. Her parents eventually gave in and let her go on a wildlife-watching trip, where Brit encountered whales for the first time – including humpbacks and even a sei whale. Needless to say, she was hooked! Another experience, this time at a theme park in Orlando, Florida, really set Brit apart from the rest of her family. She remembers the infamous Jaws ride with its ‘fearsome’ animatronic shark. This terrified her brother, who refused even to take baths for several weeks afterwards – but sparked in Brit what would become a lifelong fascination with sharks.
A-bel’s memorable experience is memorable for a slightly different reason [9.40]. During their undergraduate degree at the University of San Diego, A-bel attended a field trip for their Geological Oceanography course. It looked great on paper – six hours on a boat out at sea, collecting data and getting experience in the field! There was just one catch: A-bel suffers from seasickness. They watched as most of their friends left for the day shift and returned with big smiles, claiming the conditions had been idyllic. Hopeful, A-bel set off on the night shift to find a completely different story. A few hours later, the motion of the ocean had had its effect, and A-bel – who luckily had taken some seasickness medication before stepping aboard – lay down for a ‘quick’ nap to sleep it off. They slept through the entire trip, waking only once to find the boat rocking furiously and one of their coursemates violently sick over the side! After that, they decided sleep was a better option. A-bel’s experience takes us on a little tangent exploring the lesser-known side effects of seasickness medication [14.10]. Vicky remembers getting double vision, while Brit reminds us that one of the medications contains the same substance found in truth-telling serum…so you might find yourself getting a little too honest on your next boat trip!
Lastly, Vicky remembers an experience with a hungry white shark [18.38]. She grew up fishing and is very familiar with boats. Surprisingly, she originally hadn’t intended to do anything ocean related until a fishing trip to Guadalupe Island. These are prime fishing grounds for tuna and a white shark hotspot. Vicky was just about to reel in the jackpot when she felt a sharp tug. A white shark had almost eaten the entire tuna at the end of her line, leaving just the head behind! She says that she should have been gutted at losing out on such a sought-after prize, but she was so impressed by the shark’s capabilities and intrigued by its behaviour that she did a complete U-turn and decided to pursue a career in shark science.
Next, it’s time to present our obscure species of choice [22.20]. First up is Vicky with her chosen species, the goblin shark (Mitsukurina owstoni). Everything we know about this curious deep sea predator is from fisheries data, when they are brought up from the deep as by-catch. So, we only know the maximum depth at which they were caught rather than the maximum depth at which they can exist. They have been found in trawls of up to 1,300m (4,265 feet), which is pretty astounding when considering that their actual maximum depth could be even deeper. As Vicky says, you would need a lot of money and very expensive equipment – like submersibles – to observe these sharks in their natural environment. Seeing what comes up in deep-sea trawls is the most accessible way for shark scientists to learn more about them.
We do know that goblin sharks have one of the fastest-moving jaw mechanisms of any shark [25.12]. They can extend their jaw downwards, like most sharks, but can also fire it forward, too, like a slingshot. This action is so quick that the goblin shark has evolved a specially thick ligament to prevent its jaw from being ripped from its face! Vicky can attest to how quick the jaw mechanism is – she’s seen it for herself. She was part of the first team to tag a goblin shark, along with a professor who was particularly interested in filming these jaws in action. He succeeded, and Vicky says it was so fast she almost didn’t realise the event had happened until the video was later slowed down [28.36].
Aside from having lightning-quick slingshot jaws, the goblin shark could also stop hearts with its looks! A-bel tells us that the goblin shark gets its name from Japanese mythology. The tengu is a mythical creature with a long, pointed nose, angry eyes and sometimes pointed teeth, depicted in elaborate masks that are believed to protect the wearer from evil spirits [33.52]. The tengu looks similar to a goblin from Western culture, and the goblin shark shares the long, pointed rostrum and needle-like teeth. However, where tengus are bright red, the goblin shark is actually pink and blue [34.26]! Vicky explains that this is because the skin of the goblin shark is so thin it is almost translucent, meaning the blood vessels are more visible – giving it a pink body and blue fins.
With the goblin shark as our first contender, we move on to another deep-sea species. Brit wants to celebrate the white-tailed dogfish (Scymnodalatias albicauda), which she says is fast becoming her favourite species [35.23]. It’s a shark Brit has been promised for the better part of a decade, and her dreams finally came true a few months before this very podcast was recorded. A very rare member of the sleeper shark family, only a dozen specimens have ever been caught and studied. About ten years ago, one specimen was caught in New Zealand and kept in a local museum freezer. Every year, Brit would get a call saying that they would retrieve the shark and have a proper look at it – only for nothing to come of it. It almost became a joke that the shark didn’t exist! When Brit finally got to see the shark, she fell in love. A female of only about a metre long, with beautiful markings, almost like a paintbrush, had been used to brush lighter spots of colour onto a dark background.
The most exciting thing for Brit is that we know almost nothing about this little shark. We know that specimens have been caught between 150-500m – but as with the goblin shark, that’s just the depth in which the trawls that retrieved the shark were operating. They are found in very cold water off the coast of Australia and New Zealand, with some being found closer to Antarctica, and belong to the sleeper shark family, a group of sharks that live life in the slow lane – swimming at very slow speeds and generally taking a long time to grow and reproduce (the Greenland shark is perhaps the most famous member of this family!). But one of the most amazing things we know is that they are very fecund, seemingly having many young at a time. One pregnant female was found to be carrying 59 pups – the largest ever count for any shark! This is seemingly at odds with their slow and steady lifestyle, and the exact reason for this remains unknown.
Another interesting bit of information is that they have heterodonty – meaning that their top teeth differ from the bottom. The dogfish’s top teeth are narrow and pointed, almost pin-like, whereas the bottom are jagged like a cookie cutter. This must have something to do with their diet, but as so little is known about the white-tailed dogfish, the answer is still unclear. One specimen was found with a belly full of squid, which in itself isn’t unusual (many sharks eat cephalopods). But, the interesting thing is that this is a very rare species of squid, only found in one place. This could give us some insight into the life of the white-tailed dogfish, suggesting that it roams the open ocean.
For our next species, we’re moving into much shallower waters to explore A-bel’s species, the shovelnose guitarfish (Rhinobatus products) [43.10]. Guitarfish are shark-like rays with a very unusual body shape. As the name suggests, they are shaped like a guitar, with a broad, triangular, flattened head and a slender tail. They are found on the Pacific coast of the U.S., from San Francisco Bay to Baja in Mexico. They are big animals and can grow up to 5-6 feet long. They also come in different colours, from light brown to dark brown and even grey. Like all the species discussed in this episode, we know relatively little about them.
For their masters’ thesis, A-bel studied guitarfish aggregations and behaviour off the coast of San Diego, where the same individuals seemed to be showing up every summer. Surfers and snorkellers would see them, just lying on the seabed in groups. They apparently liked just hanging out together – but why? A-bel hypothesised that these gatherings served some reproductive or gestation function. For example, other elasmobranch species are known to gather while pregnant in warm, shallow areas to speed up embryonic development. The lack of baby guitarfish suggested that this wasn’t a nursing ground.
It’s important that we know more about guitarfish because they are one of the most threatened groups of elasmobranchs on the planet [50.10]. Their propensity for shallow, easily accessible environments makes them hugely susceptible to fishing pressure, and many other species are classed as Critically Endangered on the IUCN Red List of Threatened Species. Luckily, the shovelnose is faring well in comparison and is Near Threatened – but its population is decreasing.
Lastly, host Isla joins in on the weird shark action by presenting our fourth and final species, the velvet belly lantern shark (Etmopterus spinax) [51.20]. Another deep-sea species, this shark, grows to only 55cm long but has been found in depths of over 2,000m (6,000 feet)! To cope with such deep, dark waters, the velvet belly lantern shark has a few tricks up its sleeve…first, it has light-emitting organs known as photophores all over its abdomen and flanks, which scientists believe are to help it camouflage against the light coming from above – making it invisible to predators lurking underneath. Second, the velvet belly has defensive spines on its back that light up! Scientists have likened these to lightsabers used in Star Wars, which is pretty cool from a shark that is no bigger than your arm!
Which of these four species is your favourite??
About our guests
DR BRIT FINUCCI
Deep-sea shark specialist and fisheries scientist
Brit grew up in Canada but completed her PhD at the Victoria University of Wellington in New Zealand, studying the ecology of deep-sea chondrichthyans in the region. Her research described the life histories of poorly studied species caught as by-catch in deep-sea fisheries, including the prickly dogfish, longnose spookfish and black ghost shark. She is now a fisheries scientist with the National Institute of Water and Atmospheric Research and is chair of the deep water chondrichthyans working group for the IUCN Species Survival Commission Shark Specialist Group. She was also awarded the prestigious Eugenie Clark Award in 2021.
Twitter: @BritFinucci
Instagram: @britfinucci
VICKY VÁSQUEZ
Shark scientist and Executive Director, Rogue Shark Lab
Vicky Vásquez is the executive director of the Rogue Shark Lab, a nonprofit founded this month, July 2023, which is working to bring its brand of shark science into the classroom. Vicky’s research interests are focused on sharks of the deep sea, and she’s excited to share what she and her colleagues have been learning about Goblin Sharks in Tokyo Bay, Japan.
Facebook/Instagram/YouTube: @VickyShark;
A-BEL GONG
Shark scientist and Climate Research Manager, San Diego Regional Climate Collaborative
A-bel received their BA and MS from the University of San Diego’s Environmental and Ocean Sciences Department. Their research interests include shark and ray migration, movement, and behaviour using novel tracking techniques and quantitative analyses. Their master’s thesis revolved around shovelnose guitarfish and California bat rays, where they analyzed their migration along Southern California’s coast, as well as their philopatry to La Jolla, CA, a well-known aggregation site for sharks and rays, using long-term acoustic telemetry data. They plan to pursue a PhD to continue non-invasive tracking and behavioural research.
Besides research, they are extremely active in outreach, being featured on National Geographic’s “Sharks that Eat Everything” and planning and participating in events with Minorities in Shark Sciences (MISS). You may also find them involved in advocacy for LGBTQ+ identities in STEM, specifically through their year-long pandemic project, the LGBTQ+ STEM Cast.
Twitter: @Elasmabel, IG: @gong_and_a_bell
