Hector's & Maui's Dolphins: Threats

The Department of Conservation and Ministry of Fisheries found gill netting to be the single biggest threat* to the survival of Hector's dolphins.

With only 55 individual Maui’s dolphins left we need immediate Government action to stop the accidental deaths of these endangered creatures. 

Gill nets:

Gill nets are used by commercial, recreational and customary fishers and are responsible for more than 60% of all known Hector’s and Maui’s deaths (where the cause of death is known). 

Gill nets are used to fish in coastal waters where these dolphins live. Dolphins, seabirds and other endangered marine mammals get tangled in these nets and drown.

A 2008 study by NIWA, the Ministry of Fisheries and fishing industry representatives estimated between 110 and150 Hector’s dolphins are killed in commercial gill nets every year. The study found that Hector’s dolphins have a very high risk of extinction unless restrictions are placed on commercial fishing,

Gill nets are banned or heavily regulated in many countries including Australia, the UK and USA.


Trawling involves pulling large nets behind boats, and, like set nets, may indiscriminately catch unwanted species. Some are so large they could hold the Cook Strait ferry.
Although a less significant threat to Hector’s dolphins than set netting, trawling does effect dolphin population. On 3 April, 2006, three Hector’s dolphins were caught by a single commercial trawl vessel around the Marlborough Sounds.

Click here to see DOC's incidents database.

*Other threats include boat strike, marine mining and pollution.