鯊魚及魔鬼魚常因牠們的鰭而成為目標，但極度瀕危的圓犁頭鯆同時亦因牠們的剌而受到威脅。圓犁頭鯆的頭及背上長著一排排的小尖刺，這些刺在東南亞常被用來做製成戒指及手鐲等首飾；有些人認為佩戴這些首飾可以帶來保護。

Sharks and rays are targeted for their fins, but the critically endangered bowmouth guitarfish is also threatened by the demand for its thorns. bowmouth guitar fish has rows of spiky thorns on its head and back, and these thorns are often made into jewelry like rings and bracelets in Southeast Asia. Some believed wearing these jewelries can bring protection.

https://www.nationalgeographic.com/animals/article/thai-shark-ray