Poor Knights Islands 4.07

The Poor Knights Islands are a group of islands off the east coast of the Northland Region of the North Island of New Zealand. They lie 50km to the north-east of Whangarei, and 22km offshore halfway between Bream Head and Cape Brett. Uninhabited since the 1820s, they are a nature reserve and popular underwater diving spot. The Poor Knights Islands Marine Reserve surrounds the island. Beaglehole (1955) comments that the origin of the island name is not clear, and could be related to the Poor Knights of Windsor, or, he speculates that the islands were named is said to derive from their resemblance to Poor Knight's Pudding, a bread-based dish topped with egg and fried, popular at the time of discovery by Europeans.DescriptionThe chain consists of two large islands with a group of smaller islets between the two, the largest of which is Motu Kapiti. The islands are the eroded remnants of a 4-million-year-old rhyolitic volcano.OceanographySpring tide range for the islands is around 2m, decreasing to a neap tide of around 1m. The deep water around the island results in only moderate tidal currents. These are around the same magnitude as the prevailing shelf currents. In the general vicinity of the islands mean flows are around 0.2m/s and run toward the southeast. A remarkable feature of the region is the large internal tides that occur. These are a form of internal wave driven by the local tidal flow forcing the stratification against sloping areas of the shelf face. The surface manifestation of these waves can be seen from space. These waves generate brief highly localized accelerations. Internal wave amplitudes of around 100m have been observed, generating flow speeds as great as 0.5m/s.