New research from a study focused on Wairarapa’s coastal commercial pāua fishery will highlight the climate-associated risks to species population and growth.
The study – from the Sustainable Seas National Science Challenge – focused on the region’s commercial fishery spanning Palliser Bay to Castle Point.
Wairarapa’s coastline was chosen as it’s particularly susceptible to warming seas.
The study has involved expertise from the National Institute of Water and Atmospheric Research [Niwa], ANZ, the Pāua Industry Council and sustainability advisors Terra Moana.
Warming seas, ocean acidification, an increase in sedimentation and extreme weather events are all stressors impacting the health of pāua populations and the ability to harvest the species.
The modelling developed from this study will be used to learn more about pāua’s susceptibility to climate-associated risk.
Lead researcher from Terra Moana Katherine Short said the research would provide a better – and necessary – understanding of how the levels of these environmental stressors impact pāua.
“The model considers the environmental risks to pāua populations and pāua growth,” Short said.
“With this understanding, fishery sectors can better account for the impacts of climate change, evolve where required, and collaboratively invest in responses.”
Terra Moana partner Tony Craig grew up in Wairarapa and said the pāua export value was somewhere between $60 and $70 million.
Over his time working in the industry, Craig said tools to understand different fishing and environmental factors influencing the fishery’s health had improved.
“For example, voluntary increased size limits in fast-growing areas, sub-region management, catch effort spreading by ensuring not too much pressure is applied to particular areas and research into length at maturity and growth rates.”
With bio-economic modelling, Craig said the question being asked was, “what level of risk do I apply to my normal business model?”
“You have to understand what may happen and how you can then plan for it,” Craig said.
“Pāua don’t mind the heat to grow to their first 70-80 mm, but then for some unknown reason, they don’t like hot growing on.
“So the 21.5-degree warming line, where Gisbourne is at the moment – which is predicted to reach Kaikōura in 2060 – what is the impact of that?”
Craig said this was the level of consideration that needed to be applied for industry security.
“From a modelling point of view, how do you think about it if the northern reaches of your farm are warmer, and there’s no 125ml fish up there?” Craig asked.
“It’s not that there won’t be pāua there; there will just be lots of little ones.”
Craig said data indicated that the majority of pāua being caught off the Wairarapa coastline were above the 125mm minimum level.