Download FAR 2025/40 Considering ecosystem aspects when setting management targets for New Zealand’s fisheries: Insights from simulations and application to snapper and gurnard in FMA 7

Neubauer, P.; Kim, K.; Hill-Moana, T.; Langley, A. (2025). Considering ecosystem aspects when setting management targets for New Zealand’s fisheries: Insights from simulations and application to snapper and gurnard in FMA 7. New Zealand Fisheries Assessment Report 2025/40. 62 p.

We studied the implications of managing fish stocks in New Zealand by considering the wider ecosystem, instead of only focusing on individual fish species. We examined snapper and gurnard fisheries in the Tasman Bay Golden Bay areas to see what happens when fishing targets are set higher than traditional levels. Using computer simulations, we tested different management approaches that would leave more fish in the ocean than current practices typically require.

We found that keeping fish populations at higher levels led to more and bigger fish. However, this approach also meant fishers could catch 20 to 45% fewer fish, potentially reducing economic returns. Whether higher fish population targets made economic sense depended strongly on fishing costs—expensive operations benefited because they needed less effort to catch quotas, whereas cheaper operations lost money due to smaller catches.

We showed that snapper and gurnard fisheries are closely connected, with over half of snapper catches happening when boats were declaring gurnard target fishing. Managing one species differently affects the other, showing that it is important to consider multiple species together. Our study suggested that while keeping more fish in the ocean helps marine ecosystems stay productive and diverse, managers need to carefully balance environmental benefits against economic impacts on fishing communities.