Record high ocean temperatures and marine heatwaves have become increasingly common in the waters off New Zealand in the past decade.
During the same period, commercial fisheries have landed lower volumes for several fish stocks, including hoki and tarakihi.
Māori hold almost a third of commercial fisheries interests in Aotearoa, but these are constrained to certain areas. The impacts of warming seas on Māori communities’ cultural and economic future well-being are not well understood.
For many Māori, fisheries are the most significant assets. With my colleagues Tony Craig and Katherine Short at Terra Moana, we explored how changing ocean temperatures may affect Māori commercial fisheries as part of the Moana Project.
Most of the fish species of interest to New Zealand’s commercial, recreational and customary fishers are managed under the government’s Quota Management System (QMS).
It was introduced in 1986 and determines allowable fish harvests, known as “total allowable catch” (TAC). The system replaced open access with set catch limits and transferable quota rights, which means quota holders can trade and sell their catch allowance.
The impacts of climate change on the marine environment are well documented in the latest report by the Intergovernmental Panel on Climate Change (IPCC). They include marine heatwaves, more severe storms, rising sea levels and changes in salinity, stratification, circulation, oxygen levels and acidity.
Recent reviews analysed the effects of climate change on New Zealand’s commercial fisheries and found most fished species to be vulnerable to changes in temperature.
Any geographical expansion or shift in fish stocks will have major implications for Māori commercial seafood interests, given quota ownership is limited to specified management areas.