T. W. Downes’ article from the Transactions of the New Zealand Institute, first published in 1918, gives a comprehensive account of eeling and eel weirs.
Tame Saunders gave this account of the annual eel migration at Lake Wairarapa, published in Te Ao Hou magazine in 1965.
The annual tuna migration and harvest still happens today. This site has photographs and information on the harvest.
Best, Elsdon. Fishing methods and devices of the Māori. Wellington: Te Papa Press, 2005 (originally published 1924).
Guthrie-Smith, W. H. Tutira: the story of a New Zealand sheep station. Auckland: Godwit, 1999 (originally published 1921).