Tauranga marine scientist to study toheroa

4 December 2015

Dr Phil Ross

Dr Phil Ross will examine the influence of early Māori on the distribution of toheroa.

Dr Phil Ross, a Tauranga-based marine scientist at the University of Waikato’s Coastal Marine Field Station, has been awarded a Marsden research grant from the Royal Society of New Zealand.

Dr Ross received a Marsden Fast-Start grant, worth $300,000 over three years, to examine the influence of early Māori on the distribution of toheroa. As part of the research, Dr Ross will combine archaeology and population genetics with Matauranga Māori (Māori knowledge) to gain a better understanding of early human influences on the distribution of toheroa and the extent to which early Māori manipulated their marine environment.

“Knowledge of the effects of early human society on marine ecosystems is limited, as is our understanding of the consequences of early human practices on present day ecosystems. Early Māori were prolific users of aquatic resources and were also adept at food cultivation and translocation. After settling New Zealand, Māori domesticated and translocated numerous endemic species,” says Dr Ross.

Preliminary research suggests that the present day distribution of toheroa may result from early Māori fisheries practices, he says.

“After conducting a population genetic analysis of toheroa in order to map the dispersal of their larvae on ocean currents, initial data suggests that the toheroa of southern New Zealand may be historically derived from northern populations which led to the line of enquiry that toheroa were transplanted to locations outside their natural distribution, possibly prior to European settlement.”

Paphies ventricosa, or toheroa - which means ‘long tongue’ in Māori, is a shellfish endemic to New Zealand and of significant cultural importance to Māori. A close relation of the tuatua and the pipi; the toheroa was once an abundant shellfish in Northland, Kapiti-Horowhenua and Southland. Intense commercial and recreational harvesting over the first half of the 20th century resulted in toheroa populations declining to levels where their harvest was no longer viable.

This research challenges the idea that species distributions are largely a consequence of natural processes and recent human activity, says Dr Ross. “It will be the first study in New Zealand to look at what is effectively aquaculture by indigenous people shortly after the first colonisation of a land mass. It’s also the first study to examine the impact of early Māori on the distribution of marine invertebrates and their genetic diversity.”

A number of relevant Māori groups in toheroa regions (Northland, Kapiti-Horowhenua and Southland) will be participating in the study. Toheroa were an important food resource for Māori until their commercialisation and increased popularity as a recreational harvest resulted in the collapse of fisheries in the 1960s and 70s. Despite the fishery being closed more than 40 years ago, toheroa have failed to recover, the reasons for which remain unknown.

Although not the main focus of the study, research will also address questions about the failure of toheroa to recover from historic and present-day exploitation and will contribute important information that will aid the future restoration, management and cultivation of toheroa and other culturally and ecologically important species, says Dr Ross.

“Restoration of the toheroa fishery is desirable from an ecological perspective but is also important in terms of the ability of coastal iwi and hapu to live sustainably by harvesting locally sourced natural resources. This research will improve our understanding of the life history of toheroa and help identify life history bottlenecks preventing toheroa recovery. Ultimately it may contribute to the recovery of toheroa and Māoridom’s reengagement with this taonga resource.”

Dr Ross is a marine ecologist working at the University of Waikato’s Coastal Marine Field Station in Tauranga. His marine research is focused on understanding how communities of sea creatures respond to and recover from disturbances, particularly man-made disturbances. For the last few years his research has looked at the ecological effects of the MV Rena grounding on Astrolabe Reef.

Overall, four University of Waikato research projects were awarded Marsden funding, totalling more than $1.3million over three years.