(a) Currents

The main ocean currents which affect the northern half of the North Island are the South Equatorial Current, the Trade Wind Drift, and the East Cape Current. One arm of the South Equatorial Current flows into the East Australian, or Notonectian, Current. The latter supposedly follows a path across the Tasman in the direction of North Cape, which it rounds and affects the eastern shores of the North Auckland Peninsula. To the south of the Equatorial Current is the Trade Wind Drift, backed by the so-called south-east trade winds. It is possible that the East Cape Current (running south in a line parallel with the coast from East Cape to Wellington) forms an extension of the Trade Wind Drift. The Hauraki Gulf is well to the north of the zone of convergence of subtropical and subantarctic waters (the latter carried northward by the West Wind Drift). One part of this mixed warm and cold water passes up the west coast of the South Island and through Cook Strait; the other flows up the east coast. A difference of more than 5° C. has been recorded on either side of the zone.

Evidence from drift bottles accumulated from the work of H. C. Russell between 1894 and 1902 (Dell, 1952, p. 86) upholds the views of present workers