• SharkieSophie

I Will Be Back!

With over 1,200 species known to science, it is no surprise that there are some types of sharks and rays that many people have never even heard of! This is common for the elusive Rhinopristiformes, otherwise known as the wedgefishes, guitarfish and sawfish... Many people have never even heard of them! But these fish deserve much more notoriety because they are some of the most critically endangered animals on our planet today! In fact, some are actually so depleted, that they are already thought to be extinct!


The Rhinopristiformes have been pushed to the very brink of extinction in recent decades by habitat degradation and over-exploitation. Sawfish, guitarfish and wedgefish live in coastal waters, and so, many of their critical habitats are being repurposed by human beings. They are also fished at an unsustainable rate, as they are especially valuable in the global shark fin trade, thanks to their valuable 'white fins', which are so desired for shark fin soup (Kyne et al, 2019).


In the recent past, it was thought that the sawfish were in the greatest peril, but more up-to-date research has shown us that their wedgefish and guitarfish cousins are equally in trouble. The International Union for the conservation of Nature (IUCN) now lists 88% of Rhinopristiformes as endangered on the Red list of Threatened Species and they are considered some of the most at-risk marine animals on Earth (Kyne et al, 2019).

To learn more you can check out The Rhino-Saws.



In fact, some wedgefish are so depleted that scientists have considered them effectively extinct in the wild. For example, the clown wedgefish (Rhynchobatus cooki) had not been seen in the wild for over 23 years until it was recently discovered in a fish market in Singapore. This animal is so rare that is only known to science through a handful of specimens which have been discovered for sale in Asian fish markets (Last et al, 2016, Clark-Shen at al, 2020).


What we do know is that the clown wedgefish is the smallest of all the wedgefishes; coming in at only 1 metre from snout to tail. Thanks so some rare sightings, we know that these animals only live in a very small region in southeast Asia, in shallow habitats, like coral reefs. But that is about the extent of our knowledge! (Last et al, 2016, Clarke-Shen et al, 2020, McDavitt & Kyne, 2020).


Clown wedgefish found in a Singapore fishery in 2019 (Clarke-Shen et al, 2020)

Upon the discovery that this species is not, in fact extinct, scientists have been trying to come up with a way to learn more about these elusive creatures. As they are so rarely seen they came up with a very modern idea... using images on social media for scientific research (Mcdavitt & Kyne, 2020).


Scientists trawled through open-access images available on social media platforms like Twitter, Facebook, and Instagram, and also on Google Images, to see if they could determine if and where the clown wedgefish is still being seen (Mcdavitt & Kyne, 2020).


Images of the clown wedgefish found on social media sites (McDavitt & Kyne, 2020)

The researchers managed to find six pictures of the clown wedgefish, which had been uploaded by users located in Indonesia. The first [Image A] was by a subsistence fisherman in Lingga Island and the other five [Image B - F] came from the same fish market in Singkep Island over several different days. As all the images showed the rays for sale with their fins in tact, it seems that clown wedgefish are sometimes fished on a small scale in Indonesia, where they are used as food for the local community (Mcdavitt & Kyne, 2020).


Given so few images were found, it is clear that the clown wedgefish is far from abundant, but at least we now know that they are not extinct!


This work suggests that the distribution of the clown wedgefish might have contracted to a very small area, as their populations have declined. Not such great news... But, what is good news, is that these artisanal fishers who occasionally do catch clown wedgefish, may be able to point us towards the location of their "stronghold" - where clown wedgefish are still living and breeding in the wild. This could allow us to determine which areas need extra protections to preserve this endangered species (Clark-Shen et al, 2020, Mcdavitt & Kyne, 2020).


Locations identified by Mcdavitt & Kyne (2020) where social media users found clown wedgefish in fish markets (Image: Last et al, 2016)

Finding evidence that clown wedgefish are not yet extinct certainly gives us a beacon of hope for the future... If an animal can be so rare it is not seen for 20 + years can be rediscovered, we should feel inspired to push ever-harder to protect endangered rays. If we can all work together - from a local scale in the community, to a global scale through the internet - maybe we can turn it all around and pull these wonderful creatures back from the edge! I can't imagine a more positive and productive way to use social media platforms than that!



References

Clark-Shen N, Venkatesh B, Pei Pei CC, Xu K & Naylor GJP (2020). Not yet extinct: Rhynchobatus cooki is found after being unseen for over 20 years. Pacific Conservation Biology, 26:3. Access online.


Kyne PM, Jabado RW, Rigby CL, Dharmadi, Gore MA, Pollock CM, Herman KB, Cheok J, Ebert DA, Simpfendorfer CA & Dulvy NK (2019). The thin edge of the wedge: extremely high extinction risk in wedgefishes and giant guitarfishes. BioRxiv Preprint.


Last PR, Kyne PM, Compagno LJV (2016). A new species of wedgefish Rhynchobatus cooki (Rhinopristiformes, Rhinidae) from the Indo-West Pacific. Zootaxa, 4139:2, 233-247. DOI: 10.11646/zootaxa.4139.2.7.


Mcdavitt MT & Kyne PM (2020). Social media posts reveal the geographic range of the Critically Endangered clown wedgefish, Rhynchobatus cooki. Journal of Fisheries Biology, 97, 1846–1851. Access online.


By Sophie A. Maycock for SharkSpeak.

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