Fish maw is popular in Chinese cuisine, however, large numbers of illegal fishing in Mexico causing serious damage to the ecosystem there and endangering numerous of marine life, especially the vaquita (a very rare type of dolphin habitat in that area.  
It's time to rethink and say no to food ingredients that came from the unethical source. 
https://eia-international.org/ocean/preventing-the-extinction-of-the-vaquita/