John Hayes

John Hayes

Senior Scientist – Freshwater Fisheries and Ecohydraulics Research

Role at Cawthron

John is a senior scientist in the Coastal and Freshwater Group and is responsible for managing freshwater fisheries and ecohydraulics research and consulting programmes.

Technical skills, experience and interests

  • Recreational trout and salmon fisheries
  • In-stream habitat modelling with the in-stream flow incremental methodology (IFIM) and with process-based models
  • Native fish ecology and distribution modelling
  • A bioenergetics-based whole-lifetime growth model for trout
  • World-leading process-based models integrating river hydraulics, invertebrate drift dispersion, bioenergetics-based trout growth and carrying capacity
  • Best paper in Transactions of the American Fisheries Society award in 2001 for a paper on a whole-lifetime bioenergetics growth model for drift-feeding brown trout
  • Communication of fisheries and ecohydraulics science to the public
  • Regular contributor to Fish and Game New Zealand magazine 
  • Co-authored ‘The Artful Science of Trout Fishing’ with Les Hill, acclaimed fishing photographer

Professional affiliations

  • New Zealand Freshwater Sciences Society
  • American Fisheries Society


  • PhD (Zoology). University of Canterbury, 1984
  • BSc (Hons, Zoology). University of Canterbury, 1979


    John Hayes