A microscopic parasite spread by cats has been found to be the main non-fishery cause of deaths for Māui and Hector's dolphin in a new scientific study.
Toxoplasmosis has killed nine Māui and Hector's dolphins recovered in New Zealand since 2007 and is to blame for more deaths than commercial fishing.
The 18-month study was undertaken by Niwa's Dr Jim Roberts, Massey University and Quantafish, leading to a revived understanding of the dolphin's biology.
Seafood New Zealand chief executive Tim Pankhurst said the industry is doing its part to prevent dolphin deaths and welcomes the results of the study.
"It is heartening to see recognition that commercial fishing is not the most significant threat to the sustainability of the dolphins and with that, the opportunity to prevent further deaths," said Pankhurst.