1.0 Acoustic pingers
Acoustic pingers are now used in many places around the world for the purpose of reducing bycatch of porpoises and dolphins in gillnets. The pingers either deter the animals from the nets or alert them to the nets. In either case, the pingers have been shown to reduce entanglement and death of several dolphin and porpoise species.
There are various types of pingers in use today. Each has specific acoustic characteristics. Based on New Zealand Department of Conservation (DOC) Conservation Services Levy research by Stone et al. in 1999, the Dukane Manufacturing company in the United States custom designed a pinger for use with Hector's dolphins. It is known as model Netmark 1050. This pinger, as well as others, can be obtained directly from Dukane or through New Zealand distributors.