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Hector's
Dolphin Not Out Of Danger
Or by email to: hectorsdolphin@fish.govt.nz. The following background material has been prepared by Hector's dolphin authority Liz Slooten. Liz Slooten is the Director of Environmental Science at the University of Otago. Also below is a press release Greens Co-Leader Jeanette Fitzsimon backgrounding the photo. While the photo is from the SI west coast the same methods and conditions apply on the NI west coast. NB Set nets are gillnets anchored and buoyed in place as opposed to mobile gillnets such as trawl nets or danish seine nets. Hector's dolphin is an endangered species, only found in New Zealand. The North Island population is very small (most likely fewer than 100 individuals, Russell, 1999) and has recently been listed as critically endangered on the international Red List of threatened species (IUCN, 2000). North Island and South Island Hector's dolphins are genetically different (Pichler et al., 1998). The North Island population is declining (Martien et al., 1999; Pichler and Baker, 2000), due to bycatch in gillnets (Martien et al., 1999). A sustainable level of bycatch would be about one dolphin every 5 years. A meeting of fishers, conservation groups, scientists and government officials (in Wellington in May 2000) agreed that bycatch should be reduced to zero, to allow the population to recover. The only effective way to achieve this would be to avoid overlap between dolphins and gillnets. North Island Hector's dolphins are found between Maunganui Bluff (north of Dargaville) and New Plymouth. To reduce bycatch of Hector's dolphins to sustainable levels, it would be necessary to avoid gillnetting and trawling for this whole area, out to at least 4 nautical miles offshore. The Ministry's Four Options 1. Protected area, without gillnetting, from Manukau Harbour to Aotea Harbour, to 4 nautical miles offshore. Acoustic "pingers" would be used north of this area in the hope of warning the dolphins of the nets' presence. An additional, seasonal closure is proposed for the area south to Mokau for January, February and March each year, to 2 nautical miles offshore. The total protected area in option 1 (seasonal and year-round protected areas combined) is about half of the habitat of the North Island Hector's dolphin. 2. Protected area from Manukau Harbour to Aotea Harbour, about a third of the Hector's dolphin habitat off the West Coast of the North Island. This option would require commercial gillnetters fishing north and south of the protected area to use pingers and carry observers, video cameras or other means of detecting dolphin captures. Commercial fishers using trawling and Danish seining would also be required to carry observers, video cameras or other means of detecting dolphin captures. 3. Protected area, without gillnetting, from Maunganui Bluff to Pariokariwa Point, about 40 km north of New Plymouth. This includes about 90% of the Hector's dolphin habitat off the West Coast of the North Island, and provides the strongest protection of the four options in the minister's paper. Commercial fishers using trawling and Danish seining would be required to carry observers, video cameras or other means of detecting dolphin captures. 4. Protected area slightly smaller than option 2 (similar north-south boundaries, but not as far offshore in all areas), with a maximum limit of one dolphin to be caught every five years. Commercial fishers using gillnets, trawling and Danish seining would also be required to carry observers, video cameras or other means of detecting dolphin captures. A protected area, with no gillnetting (and preferably no trawling) is the most effective way of protecting Hector's dolphin from bycatch in fishing gear. The biological evidence indicates that this protected area should be at least as large as that in option 3. The other management tools proposed in options 1, 2 and 4 (pingers, limit on bycatch) are much less effective than a protected area (Dawson et al. 1998). In addition, it would take many years to establish whether they are capable of reducing bycatch to a sustainable level. The decision basically comes down to the size of the protected area. Options 1, 2 and 4 protect the North Island Hector's dolphins in roughly a third to half of their habitat. Option 3 protects them throughout most of their range (about 90%). For these reasons, we strongly recommend option 3 or stronger protection measures. Stronger measures could include: * Extending the protected area further south, to include the area from Maunganui Bluff to New Plymouth, to 4 nautical miles out to sea * Banning trawling as well as gillnetting in the protected area * Efforts to reduce pollution For more information, see: nzwhaledolphintrust.tripo d.com/home REFERENCES: Dawson, S.M., Read, A. and Slooten, E. 1998. Pingers, porpoises and power: Uncertainties with using pingers to reduce bycatch of small cetaceans. Biological Conservation 84(2): 141-146. UCN Red Data List 2000. IUCN, World Conservation Union, Gland, Switzerland, www.redlist.org. Martien, K.K., Taylor, B.L., Slooten, E. Dawson, S.M. 1999. A sensitivity analysis to guide research and management for Hector's dolphin. Biological Conservation 90: 183-191. Pichler, F. and Baker, C.S. 2000. Loss of genetic diversity in the endemic Hector's dolphin due to fisheries-related mortality. Proc R. Soc. Lond. B. 267:97-102. Pichler, F., Baker, C.S., Dawson, S.M. & Slooten, E. 1998. Mitochondrial differences between east and west coast populations of Hector's dolphin. Conservation Biology. 12(3): 1-8. Russell, K. 1999. The North Island Hector's dolphin: a species in need of conservation. Unpub. MSc thesis, University of Auckland. Greens appalled at filleted rare dolphin Green co-leader Jeanette Fitzsimons today said protection measures may be required to protect the endangered Hector's dolphin after a professionally filleted carcass was found on a Westport beach. Ms Fitzsimons said a photograph of the mutilated dolphin had been anonymously forwarded to her by a concerned local and she had taken the issue up with the regional Conservator of the Department of Conservation. "I am told the dolphin had marks from a gill net. These are set in the sea just off river mouths and we know that two such nets were operating in the area at the time. "Hector's dolphins are a protected and endangered species and under the Marine Mammals Protection Act all deaths must be reported. Whoever found this one in their net did not report it, neither did the person who filleted it to use its meat. It was left to an anonymous member of the public. Ms Fitzsimons said that the death of even one Hector's dolphin was very significant as the population was on a knife edge. A census ten years ago estimated a total population of 1320 individuals. However they breed so slowly that this population cannot sustain more than 2.6 deaths a year from unnatural causes. Last year five deaths were reported to DOC, the year before it was nine. This year there have already been two in three months. The majority of them were killed in fishing nets. It is encouraging that a member of the public reported this death. But it is very disappointing that some have still to learn..
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