Standard Presentation 2024 Australian Marine Sciences Association Annual Meeting combined with NZMSS

A Tale of Two Disasters - Recovery, Restoration and Future Management of the New Zealand Blackfoot Abalone (Haliotis iris) Following Earthquake-related Mass Mortality  (#305)

Shawn T Gerrity 1 , David R Schiel 1
  1. University of Canterbury Marine Ecology Research Group, Christchurch, CANTERBURY, New Zealand

In 2016 a powerful earthquake on New Zealand’s South Island caused extreme coastal uplift along 140 km of productive coastline, causing widespread die-offs of inshore communities and losses of complex habitat. This had long-lasting implications for the New Zealand blackfoot abalone, or pāua (Haliotis iris), a species of great cultural and commercial importance. High mortality of adults and intertidal-dwelling juveniles prompted a long closure to the recreational and commercial fisheries. We surveyed 26 coastal sites over 7 years to quantify abundance and size structure of the recovering pāua population. Our data depict a remarkable increase in juvenile recruitment and the build-up of large, legal sized pāua in intertidal habitats, suggesting a strong response to the fishery closure, benefits from commercial enhancement, and robust natural reproduction. As a result, the fishery was reopened in 2021 with minimal controls, and in just 3 months recreational fishers exceeded their 5 tonne catch allocation by an estimated 40 tonnes. Acute depletion of accessible pāua aggregations from shore based fishers resulted in up to a 92% reduction in legal biomass in some areas. We place this long-term study in the broader context of global abalone fishery collapse, and suggest a management strategy for the future.