South Island Hector's

The South Island Hector’s dolphin is the smallest marine dolphin in the world – and its uniquely ours.

Quick Facts: South Island Hectors

• Hector’s dolphin is found off the coast of the South Island. An identical but genetically distinct subspecies, Maui’s dolphin, is found off the North Island's west coast.
• Hector’s dolphins are very slow breeders and typically only have one calf every two or three years.
• They are easily identified by their rounded dorsal fin, which looks like a Mickey Mouse ear.
 

With an estimated population of less than 8000, Hector’s are listed as endangered by the IUCN (World Conservation Union).

Although found off almost the entire South Island coastline, Hector’s dolphin populations are much smaller than they were several decades ago and they are highly fragmented, making them particularly vulnerable. Isolated populations typically do not interbreed, limiting the gene pool and threatening their recovery.

To rebuild these populations, we need to establish protected “corridors” of coastal waters so that the currently isolated populations can intermingle and widen their gene pool.

Major threats: gill nets & trawlers

Hector’s dolphins usually prefer shallow waters (less than 100 metres deep), which often brings them into direct contact with coastal fishers.

Gill nets are the biggest threat to the dolphins, responsible for more than 60% of all known reported deaths, where the cause of death is known. Many entanglements are not reported, so the actual number of dolphins killed by set nets may be much higher.

The National Institute of Water and Atmospheric Research (NIWA), the Ministry of Fisheries and the fishing industry estimate that 110 – 150 Hector’s dolphins are killed in commercial set nets alone every year. Gill nets are banned or heavily regulated in many countries. Commercial trawlers have also been known to catch Hector’s dolphins in trawl nets.

What is being done?

In May 2008, new measures to protect Hector’s dolphins were announced. The new regulations came into force on 1 October and include:

Protection measures Problems

New marine mammal sanctuaries

- Clifford and Cloudy Bay
- Catlins coast
- Te Waewae Bay

Extension of the existing Banks Peninsula sanctuary from 4 nautical miles from the coast to 12 nautical miles.
 

  • The Banks Peninsula sanctuary still fails to protect Hector’s dolphins in winter, when they range further offshore than the sanctuary boundaries.
     
  • Flounder nets are still allowed inside the Banks Peninsula sanctuary.
     
  • There is no sanctuary on the West Coast of theSouth Island, despite the fact that 70% of Hector’s dolphins live there – and 41% of reported deaths since 2000 occurred there.
     

Gill netting

Set nets are banned within 4 nautical miles of the coast in the South Island (except West Coast). This applies to most regions inhabited by Hector’s dolphins.

Recreational set netting is banned off the West Coast out to 2 nautical miles offshore and commercial set netting is banned only between December 1 and February 28.
 

  • Gill net measures do not protect dolphins in offshore waters.In May 2009 a Hector’s dolphin was killed in a commercial set net off Kaikoura. It was caught in waters deeper than 100m, in an area exempted from the fishing restrictions.
  • Dolphins off Banks Peninsula, are still at risk further than 4 nautical miles offshore (research shows their distribution sometime extends to 20 nautical miles).
     
  • Few fishing restrictions off the West Coast where most dolphins live.
     
  • Gill netting is still allowed in waters around the top of the South Island and in Cook Strait.Since January 2009, a South Island Hector’s dolphin has been sighted numerous times in the Wellington harbour and along the Kapiti coast.
     

Trawling Bans

Trawling is banned within 2 nautical miles in all regions (except West Coast).
 

  • Dolphins outside these areas may still be at risk.
     

Solutions

Hector’s dolphins living outside fishing restriction areas need immediate protection. Most urgently, a response is needed to the death of a Hector’s dolphin in a commercial gill net in Kaikoura. Greater fishing restrictions should be placed around fishers operating in these deeper waters. 

1. Gill net-free seas
The most important action we can take to protect Hector's dolphins is to remove the key threat to their survival and implementing a nationwide ban on gill nets.

2. Marine Mammal Sanctuaries

Another solution is to establish a marine mammal sanctuary off the West Coast to protect the largest population of dolphins, and the Banks Peninsula sanctuary should be extended to protect Hector’s dolphin in winter.