Bowmouth Guitarfish
Rhina ancylostoma
It’s a shark… It’s a ray… It’s the bowmouth guitarfish!
Key Features & Appearance
Though the bowmouth guitarfish resembles a shark it is a species of ray. Specifically, it is a species of wedgefish within the order Rhinopristiformes which are known as the “rhino rays”. Reaching a maximum size of 2.7m/9ft, it has a broad rounded snout, large pectoral fins, and a long body and tail. On the top it is grey-brown with white spots whilst on the underside it is white, and it has ridges by the eyes and along the back which are covered in thorns.
Habitat & Distribution
Though rare, they are found widely distributed in the western Indo-Pacific Ocean from shallow waters to 70m. They are bottom dwelling, preferring sand and mud bottoms but often associate with reefs.
Diet
They typically feed on crustaceans and molluscs found on the ocean floor and so have undulating rows of flat, ridged teeth in order to crush their prey's shells.
Reproduction
They are viviparous meaning they give birth to live young which have developed inside the female's body. These pups are 45-50cm at birth and reach maturity at 1.8m for females and 1.64m for males.
Threats
It is targeted for both its meat and its fins. Wedgefish fins are some of the most valued in the shark fin trade and are considered the best quality for human consumption. The species is also caught incidentally when other species are being targeted, but is often then kept and utilised. In the last few years a new threat has been noticed, the trade of their thorns for use in jewellery, particularly rings, due to the belief that the thorns have protective powers. These threats have led to the species undergoing declines of greater than 80% across its range in the last 45 years. The wedgefish along with two other families of rhino rays, the giant guitarfish and sawfish, are the most threatened families of fish.
Status
It was classified as “Critically Endangered” by the International Union for Conservation of Nature (IUCN) Red List of Threatened Species in 2019.
Fun Fact
The pups have dark brown markings that fade as they grow up!
Works Cited
Boldrocchi, G. et al. (2023) ‘Annual recurrence of the Critically Endangered Bowmouth Guitarfish (Rhina Ancylostomus) in Djibouti Waters’, Biology, 12(10), p. 1302. doi:10.3390/biology12101302.
Georgia aquarium (2023) Bowmouth guitarfish. Available at: https://www.georgiaaquarium.org/animal/bowmouth-guitarfish/ (Accessed: 24 April 2024).
International Thai National Parks (no date) Rhina Ancylostoma, Bowmouth guitarfish, Thai National Parks. Available at: https://www.thainationalparks.com/species/rhina-ancylostoma (Accessed: 24 April 2024).
Kyne, P.M. et al. (2020) ‘The thin edge of the wedge: Extremely high extinction risk in wedgefishes and giant guitarfishes’, Aquatic Conservation: Marine and Freshwater Ecosystems, 30(7), pp. 1337–1361. doi:10.1002/aqc.3331.
Moore, A. (2017) ‘Are guitarfishes the next sawfishes? extinction risk and an urgent call for conservation action’, Endangered Species Research, 34, pp. 75–88. doi:10.3354/esr00830.
Purushottama, G.B. et al. (2022) ‘Catch composition, reproductive biology and diet of the bowmouth guitarfish Rhina Ancylostomus Bloch and shneider, 1801 (Batoidea: Rhinidae) in the Eastern Arabian Sea, India’, Indian Journal of Fisheries, 69(3). doi:10.21077/ijf.2022.69.3.117929-01.
Pytka, J.M., Moore, A.B. and Heenan, A. (2023) ‘Internet trade of a previously unknown wildlife product from a critically endangered Marine Fish’, Conservation Science and Practice, 5(3). doi:10.1111/csp2.12896.
Pytka, J.M. et al. (2023) ‘A tangled web: Global review of fishing interactions with Rhino Rays’, Reviews in Fish Biology and Fisheries, 34(1), pp. 131–160. doi:10.1007/s11160-023-09821-3.
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