South Island Hector's Dolphin Cephalorhynchus hectori hectori
Hector's dolphins are the smallest and rarest marine dolphins in the world and are found only in New Zealand waters.
The South Island hector’s dolphin, genetically distinct from the North Island Hectors dolphin or Maui’s dolphin, are estimated at a little over 7000 individuals. Their population has declined in number over time, down from more than 26,000 in 1970. As a result, they are listed as ‘Endangered’ by the IUCN (World conservation Union) on the Red List of Species Threatened with Extinction (www.redlist.org).
Although ranging almost the entire South Island coastline, South Island Hector’s dolphin populations are fragmented and 4 critical areas have been identified:
East coast of South Island - ClarenceRiver to WaitakiRiver
Te Waewae Bay - Sand Hill Point to Pahia Point
West coast South Island - Kahurangi Point to JacksonBay
Porpoise/Curio Bay (Catlins)- Fortrose to TautukuPeninsula
These populations do not interbreed, a behaviour that limits the gene pool and threatens their recovery. Re-building of these populations is essential to ensure population survival. Graph based on data from DoC's conservative national mortality database Jan 2000-April 2007.
Note that ‘Trauma’ includes injuries with severe impact, i.e. possible boat strike.
Threats to the South Island Hector’s Dolphin
Hector’s dolphins prefer shallow (less than 100m) waters, which brings them into direct contact with humans and poses many threats.
The biggest threat to South Island Hector’s dolphins is the use of set nets, responsible for over 60% of all known causes of reported deaths. Given that many entanglements go unreported, the actual number killed by set nets may be much higher.
Set nets, used in both commercial and recreational set net fishing, are the single most significant human threat to the survival of Hector's dolphins. These nets are used to catch fish in coastal waters where Hector's dolphins live - the dolphins get entangled in these nets and drown. Set nets are indiscriminate, killing a wide range of non-target fish, other dolphins, seals and seabirds. They are banned or heavily regulated in many countries.
Trawlers are also a threat and at least 13 Hectors dolphins have been reported dead from trawling around the South Island. On the 3rd April 2006, 3 hectors dolphins were caught by one single commercial trawl vessel.
Other human-induced threats – Cray pot entanglement, boat strikes, drift netting, tourism, marine farming, pollution, seabed mining (for sand, iron and gold) and construction.
Hector's dolphin deaths from fishing must be reduced to zero to ensure the species' survival
Who is responsible?
Data on all known set net entanglements from DoC's National mortality database (Jan 2000-April 2007) show that the recreational fishing sector is responsible for most South Island Hector’s dolphin deaths. However, the commercial sector is also responsible for dolphin deaths.
Current regulations on set nets however are largely focused on recreational net use only.
What is being done?
There is currently only one Marine Mammal Sanctuary in place to protect Hector’s dolphins. This is in place around Banks Peninsula, where many South Island Hector’s dolphins reside.
Although the sanctuary protects 80% of the dolphins in summer (when close to shore), about 60% are unprotected in winter (when they move further offshore).
Other regulations controlling set net use and other activities are in place from the Waitaki to the Waiau River mouths.
The Minister of Fisheries announced in December 2006 new measures to further protect hector’s dolphins. The new restrictions require non-commercial fishers to stay with their nets at all times when setting nets between the Waiau and Clarence Rivers. (These measures were also set for Te Waewae Bay in western Southland.) Although a good interim move, these restrictions do not go far enough to prevent all set net deaths. Many dolphins are caught by commercial fishers too (link to set net page).
The largest population of Hector's dolphins is on the West Coast, estimated at 5400 individuals. Whilst Banks Peninsula has some protection measures in place, there is no protection for this, the largest and possibly most critical population of South Island Hectors dolphins.
All critical Hector’s dolphin areas need immediate protection
Solutions
Create Havens for Hector'sclick here for brochure (PDF)
How? 1. Set Net Free Seas
The most important action we can take to protect Hector's dolphins is to remove the key threat to their survival by implementing a nationwide ban on set nets. Then we must set up safe havens to protect the dolphins from other threats to their survival.
2. Marine Mammal Sanctuaries
Once the most serious threat of set netting has been eliminated, Hector's dolphins need long-term protection in marine mammal sanctuaries so they are protected from all threats and their population can recover.
Forest & Bird proposes Marine Mammal Sanctuaries to protect key populations of Hector's dolphins in the South Island. Within each of the sanctuaries the following restrictions or regulations are proposed:
A ban on set nets and drift nets
Trawling vessels to carry vessel monitoring systems plus have observers or by-catch monitoring equipment on board
Boats to adhere to existing Marine Mammal Protection Regulations including slow vessel speeds within 300 metres of Hector's dolphins
No marine mining, littering, waste discharge, pollution.
Fishing methods and other activities that don't threaten Hector's dolphins would still be possible within the Marine Mammal Sanctuaries.
Forest & Bird invites you to comment on our proposal. Please post your comments to our Christchurch office: PO Box 2516, Christchurch 8140 or email them.
What You Can Do
Stop using set nets and encourage others to do the same
Hector's dolphins are the smallest and rarest marine dolphins in the world and are found only in New Zealand waters. 
