Department of Statistics

Case study: The pāua of statistics

Kathy Ruggiero helped a pāua researcher investigate whether adjusting water flow and food rations affected the shellfish’s growth.

Pāua are raised in tanks at OceaNZ Blue in Northland.

Commercial pāua growing is a $380 million-a-year business for New Zealand. But mature black-footed pāua (Haliotis iris) – the larger pāua whose meat and shells are prized – become stressed when water temperatures rise over 20 degrees, and their growth slows dramatically.

University of Auckland MSc student Daniel Tyler investigated how water flow rate, feed amounts and temperatures might interact to influence pāua growth, first at the university’s Leigh Marine Laboratory and then at OceaNZ Blue, the country’s largest pāua farm.

Daniel admits he was daunted by the amount of data generated by his Leigh experiment. He brought “pages and pages” to Kathy, who showed him how to analyse it, using the software packages JMP and R, and interpret it.

Says Kathy, “I sat with him and talked through each step, telling him what I was doing and why. This coaching is important – supervisors want students to learn practical skills.” Daniel took what he had learned and applied it to his larger-scale experiment at OceaNZ Blue.

And the results? Daniel says the research showed that neither flow rate nor feed ration had a significant effect on summer growth. However, there was evidence to suggest that increasing water flow and food over cooler months could improve pāua growth, and his thesis outlines other lines of enquiry.