Abstract
With the collapse of global populations, New Zealand has one of the last wild abalone fisheries. The blackfoot abalone ( Haliotis iris) supports important customary, commercial and recreational harvests, but environmental stressors and overfishing have prompted restoration and stock enhancement efforts. We used field surveys to quantify effects of the 2018 commercial outplanting of 167,000 hatchery‐raised juvenile abalone following the catastrophic Kaikōura earthquake. We tested alternative enhancement methods by outplanting swimming larvae and rocks with settled post‐larvae. Annual surveys at seven sites found that outplanted juveniles comprised 12% of the sampled population after three years, amid unexpectedly high natural recruitment. Recaptured outplants grew well at c. 25 mm yr −1 but showed poor growth at two densely populated sites. After three years, >50% of recaptured individuals had likely reached sexual maturity. Outplanting 200,000 competent swimming larvae into natural habitats had no effect after three months compared to controls. However, the outplanting of rocks settled with larvae resulted in a significantly greater density of small (≤15 mm) recruits compared to controls, signalling potential for this method as a practical and scalable enhancement strategy. The insights from this research help clarify the benefits and limitations of three stock enhancement methods and inform future efforts.