The Trout Paradox: Scenarios for Managing Introduced Salmonids in New Zealand

Abstract

Introduced salmonids such as trout and salmon occupy a paradoxical position in New Zealand; celebrated as iconic sport fish yet condemned as invasive species that threaten native freshwater biodiversity. Motivated by an economic impact study of recreational fishing on Te Manahuna Mackenzie Basin hydro canals—the country's most popular salmonid fishery—we explore scenarios for the future management of trout in New Zealand. While conservationists have long highlighted the ecological harms of salmonids, their recreation and tourism significance complicates calls for eradication. In this ‘thought experiment’, we use scenario planning as a heuristic device to interrogate these contradictions, outlining two deliberately provocative scenarios: (1) Nationwide eradication of trout, enabled by emerging biocontrol technologies and intensive management; (2) A compromise strategy of ‘trout utilisation zones’, where populations are deliberately contained in artificial or highly modified freshwater systems to sustain angling, tourism, wellbeing and food security benefits while enabling biodiversity recovery elsewhere. By juxtaposing these features with the status quo, we highlight trade‐offs among ecological, socio‐cultural and economic values. Considering improbable scenarios illuminates governance tensions over the place of salmonids in New Zealand's freshwaters, and importantly, identifies technical, organisational and governance competencies required to operationalise alternative futures for their management.