Tides on opposite sides of Cook Strait are almost out of phase
Only twenty-two kilometres separate New Zealand's islands at Cook Strait's narrowest point, yet its tides are nearly inverted: high water on one end meets low on the other. Ferries still ply Picton to Wellington across waters long called among the world's most unpredictable.
Māori name Te Moana-o-Raukawa, "Sea of Raukawa," links the strait to navigator Kupe's chase of the octopus Te Wheke-a-Muturangi. Strong tidal flows, wrecks from the Maria (1851) to TEV Wahine (1968), and whale roads shaped early European settlement in Marlborough Sounds and Kāpiti.
Te Rauparaha led Ngāti Toa migration and conquest into the region in the 1820s. From 1840, Wellington, Nelson, and Whanganui settlers treated "Cook's Strait" broadly, from Taranaki to Cape Campbell. Whaling persisted from the late 1820s into the mid-1960s, with Perano Head a principal station after 1911. Between 1888 and 1912, Risso's dolphin Pelorus Jack escorted ships near French Pass and won legal protection in 1904 after a failed shooting.
Wartime guns on Wrights Hill could range twenty-eight kilometres across the strait; thirteen smaller batteries ringed Wellington and the Sounds. Pencarrow Head held New Zealand's first permanent lighthouse, kept by Mary Jane Bennett—the country's only woman keeper—until Baring Head replaced it in 1935. Endemic Cook Strait giant wētā (Deinacrida rugosa) still embody the islands' isolation. Roughly 18,000 years ago, with seas more than 100 metres lower, the strait was a deep Pacific inlet cut off from the Tasman Sea. The ground still moves: a severe quake shook both shores in 1855, and in 2013 two shocks of magnitude 6.5 and 6.6 damaged the town of Seddon. Oddly, the middle of the strait sees almost no tidal rise and fall, and a single surge can run well beyond the usual six hours.
Source: Cook Strait
