Treasures of the sea

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• Home
• Executive Summary
• 1.0 Introduction
• 2.0 Methods
• 3.1 The Oceanography of the New Zealand Marine Ecoregion
• 3.2 Cetaceans, seals, and seabirds
  • 1. Subantarctic Islands (and continental shelf areas to 500m depth)
  • 2. Chatham Islands
  • 3. Chatham Rise
  • 4. Stewart Island
  • 5. South Island southern and eastern shelf edge
  • 6. Otago/Catlins Shelf
  • 7. Northeast South Island
  • 8. West coast of South island
  • 9. North coast of South Island
  • 10. Trench zone
  • 11. Coastal shelf and edge of the southeast coast and East Cape of the North Island
  • 12. Hauraki/northeast coast of North Island
  • 13. West coast of North island
  • 14. Three Kings Islands
  • 15. West coast basin
  • 16. Kermadec Islands
  • References and further reading
• 3.3 Fishes
• 3.4 Benthic invertebrates, algae, and plants
• 3.5 Information gaps
• 3.6 Future steps for the future of Biodiversity
• 4.0 Discussion
• 5.0 References
• Appendix 1
• Appendix 2
• Appendix 3
• Appendix 4

10. Trench zone

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Map ID Number: 10

Location: Canyon and trench systems running from the Kaikoura Canyon in the south up the east coast of the North Island, taking in the Nicholson Canyon, Hikurangi Trench, and north-eastward following the Kermadec Trench up to 25°S

Approximate area: 169,495km²

• Description of area
• Biological attributes
• Criteria applied
• Status and management
• State of information
• References and further reading

Description of area:

Areas of deep water. Canyon and deep trench (up to 11 km deep) systems.

Biological attributes:

New Zealand’s trench zone is an area of high productivity and consequently an attractive habitat for deep-diving species of cetacean, such as sperm whales. It is the primary New Zealand habitat for pygmy sperm whales (Kogia breviceps) and beaked whales (Mesoplodon peruvianus), which may use the trench as a north-south migration corridor. These whales forage in the trench zone, primarily for squid. There are at least 10 species of beaked whale in the area, which contribute to making New Zealand the richest country in the world in terms of beaked whale diversity (Baker 1999). Other offshore species of dolphins and whales found in the corridor include pilot whales, Risso’s dolphins (Grampus griseus), and southern right whales (Eubalaena australis). In the north there are common (Delphinus delphis) and striped dolphins (Stenella coeruleoalba), and Dusky dolphins (Lagenorhynchus obscurus) in the south. The Hikurangi Trench has the greatest number of pygmy sperm whales in New Zealand waters. In warm water years there are strandings of short fi nned pilot whales (Globicephala macrorhynchus) and more tropical species such as striped dolphins, toothed dolphins (Steno bredanensis), and dense beaked whales (Mesoplodon densirostris).

Criteria applied:

Species diversity (whales).

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Status and management:

Marine mammals have high cultural significance in New Zealand. Sperm whales in particular have great importance to Maori for bone carving and whale watching is culturally significant to most New Zealanders.

State of information:

Good.

References and further reading:

Baker (1999), Childerhouse et al. (1995), Jaquet et al. (2000).