During the mid 19th century Auckland and Northland Māori dominated shipping trade. In 1851 51 vessels were registered and 30 smaller vessels licensed. By 1857 there were 37 schooners. The fleet increased steadily during the Tasman trade boom of 1853–56. Māori paid customs duties to the government and invested heavily in vessels, so suffered considerably when a dramatic market slump hit New Zealand especially effecting the Auckland–Waikato–Hauraki area. During the musket war period and for a time afterwards, Maori, isolated from their tribal support by these devastating conflicts, hid in isolated places, living off patches of vegetables they grew in tiny gardens. This practice was very common in Taranaki which had been devastated by Waikato attacks in particular. European explorers, such as Dieffenbach, often stumbled upon these survivors while exploring. He described these as hotbeds for rats and vermin.