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Maui's and Hector’s dolphins

INTRODUCTION

Hector’s and Maui’s dolphins are among the world’s rarest and smallest dolphins. They are an inshore coastal species with a limited home range. They are found only in New Zealand’s waters.

The Hector’s dolphin species is estimated to number between around 12000 and 19000. It is divided into two sub-species—the Maui’s and South Island Hector’s dolphins.

The Maui’s dolphin sub-species lives around the North Island’s west coast. It is estimated there are only about 55 dolphins over one year old left. The Department of Conservation (DOC) classifies them as “nationally critical”.

The South Island Hector’s dolphin sub-species live in three geographically distinct groups around the South Island. The most recent estimate for the East coast population is somewhere between 6000 and 13000 individuals. The West coast population is estimated to reach 5388 dolphins while the South coast population estimate is 630 individuals. DOC classifies them as “nationally endangered”.

Hector’s and Maui’s dolphins live for only around 20 years and breed slowly. Females don’t have their first calf until they are about seven or eight years old, and have a new calf only every two to four years. This means the species may be threatened by even occasional deaths caused by human activity.

Fishing is the greatest known human threat to Hector’s and Maui’s dolphins—responsible for about 75 per cent of reported deaths with a known cause. Set nets are the main fishing threat. Dolphins can get entangled in the fine nylon nets and drown. However, there have also been reports of dolphin captures in trawl nets.

Other human threats include marine tourism, vessel traffic, mining, construction, coastal development pollution, sedimentation, oil spills, plastic bags, marine farming and climate change. 

MANAGEMENT

A range of restrictions on commercial and recreational fishing are currently in place to manage fishing-related mortality of Hector’s and Maui’s dolphins. An overview of the management can be found here:

Management of Hector's and Maui's Dolphins Fact Sheet PDF | 124kb

THREAT MANAGEMENT PLAN

Public and government concern over the effect of human-induced mortality on Hector’s and Maui’s dolphins led to the development of a Threat Management Plan (TMP) that MFish and DOC released for public consultation in August 2007. (Note: MFish ceased to exist in July 2011, and MPI now has responsibilities for fishing legislation.)

The TMP:

  • examined all known threats to the dolphins, including fishing, boat strike, noise, pollution, mining, climate, and tourism (experts on dolphins and people from all interest groups were involved in the development of the draft TMP)
  • outlined strategies to reduce human-induced threats – including fishing threats.

This link – Threat Management Plan – takes you to the series of consultation and advice documents that led to the government’s decision to introduce new fishing prohibitions and restrictions to protect Hector’s and Maui’s dolphins in 2008. This link also provides access to the regulations for the prohibitions and restrictions which were put in place at the time.

In 2012/2013, a review of the Maui’s dolphin portion of the TMP was conducted. All the relevant documents can be found on the Review of the Maui’s dolphin portion of the TMP page.

The Department of Conservation manages non-fishing threats to the Hector’s and Maui’s dolphins. Go to the Department of Conservation website for more information.

Other consultations that have taken place regarding managing fishing-related threats to Hector’s and Maui’s dolphins include:

  • 2012 Interim set net measures in the Taranaki area to protect Maui’s dolphins
    Interim set net restrictions for commercial and recreational fishers were put in place in the Taranaki area, from Pariokariwa Point to Hawera, to protect Maui’s dolphins in 2012 while the Maui’s dolphin component of the Hector’s and Maui’s Dolphin TMP was reviewed and the nature of future possible measures decided.
Updated : 2 December 2013