Nylon nets infused with barium sulfate or other metal compounds that have acoustical detection features for reducing small cetacean bycatch. These may reduce small cetacean and sea turtle bycatch by increasing the likelihood that these animals would “bounce” off the netting. Experimental results show that they can be effective in reducing the bycatch of harbor porpoise and greater shearwater (Trippel et al., 2003), though it has not been ascertained if this is due to their acoustic reflectivity or increased stiffness over conventional gillnets.