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February 1, 2010

Hector's Dolphin: Still Declining

Protections have not been enough to allow the species to recover

Humane Society International


    Found only in New Zealand. Steve Dawson


    Still at risk of entanglement in fishing nets. © Steve Dawson

Hector’s dolphin is found only in New Zealand. A management plan (called a “threat management plan” because the species is considered Critically Endangered by the International Union for Conservation of Nature (IUCN)) prepared by the New Zealand Ministry of Fisheries and the Department of Conservation shows that deaths in fishing nets are the most serious impact on the species.

New protection measures were implemented in 2008 by the Minister of Conservation Jim Anderton. These new protection measures are a major improvement, providing at least some protection for most parts of the distribution of Hector's dolphin. Unfortunately, they are still not enough to allow the species to recover.

Bad news

Research just published in the scientific journal "Aquatic Conservation: Marine and Freshwater Ecosystems" indicates that the species is still declining. This research was carried out by Drs. Liz Slooten and Steve Dawson from Otago University in New Zealand. They showed that the population on the south coast of the South Island is likely to recover to its original population size in about 250 years and is currently about half this size. All other populations are expected to continue to decline or to take more than 1,000 years to recover to half of their original population size. Dr. Slooten says, "Hector's dolphins are no longer doing a nose-dive, but there will not be any meaningful recovery in the next 50 to 100 years unless more is done to protect them. The most likely outcome is that they will continue to decline, just at a slower rate than before." This is supported by information from independent observers placed on fishing boats. So far, no significant decrease in the number of dolphins caught has been detected.

Better protection needed

Much better protection, and much better monitoring of the effectiveness of the protection measures, is needed to ensure that fishing does not continue to cause declines in the populations of Hector's dolphin. Too many areas have been left unprotected. Protection in several other areas includes less than a third of the offshore range of the dolphins, for only a few months of the year. Most areas either have no protection from entanglement in trawl nets, or trawling is prohibited for less than a third of the offshore range of the dolphins. This means there is still considerable overlap between Hector's dolphins and trawl fisheries.

With the fishing threat only half solved, several new impacts may be added soon. There are two proposals for invasive research, one of which involves dolphins being caught, removed from their group and from the water, brought onboard a boat to have holes drilled in their dorsal fins and a tag bolted on. The other involves biopsy sampling, which has caused problems for other small dolphin species.

As if that's not bad enough, there is a proposal to place 200 tidal turbines in the entrance to a harbour used by North Island Hector's dolphins, also known as Maui's dolphins. Only about 100 dolphins remain in this population, which is genetically distinct and a separate subspecies. The idea of putting tidal turbines in an area with a Critically Endangered dolphin, found only there, is as potentially damaging as proposing to build a holiday resort in the remaining habitat of the giant panda or the snow leopard.

How to help

Please write to The Honorable John Key, Prime Minister of New Zealand, urging him to improve protection for Hector's dolphin by reducing the amount of gillnet and trawl fishing in dolphin habitat and by declining the applications for tidal turbines and invasive research.