Toheroa (Paphies ventricosa) are a species of large intertidal surf clam endemic to New Zealand. At the start of the 20th century, extensive toheroa populations were present on exposed west-facing surf beaches of Taitokerau (Northland), Kapiti-Horowhenua coast and Murihiku (Southland). Toheroa were a staple food for maori in these areas. The popularity of toheroa amongst european New Zealanders grew quickly leading to increased recreational harvest from the late-1800s and commercial harvesting operations (primarily for the export) began in the early 1900s.
By the mid-1900s toheroa populations declining to levels where their harvest was no longer viable. All commercial harvest ceased by 1969 and regional recreational fishery closures occurred between 1971 and 1980. Since that time, toheroa harvesting has been restricted to a limited customary take by maori and a number of recreational open days, the last of which occurred in 1993 (Oreti). Despite having been protected for 40+ years, toheroa populations countrywide have, for unknown reasons, failed to recover, with most continuing to decline.
We currently have only limited knowledge of the human and environmental parameters that may affect the distribution and abundance of toheroa today or explaining their failure to recover. This research begins the process of investigating these factors by examining the history of toheroa and identifying the environmental parameters affecting their distribution and dynamics.
This work is being done in collaboration with the kaitiaki and tohunga of Te Uri o Hau, Te Roroa, Te Rarawa, Ngati Huia and Ngai Tahu. We also appreciate the contributions of Barry Searl and Jim Te Tuhi (Ripiro) and Laurie Austin and Kevin Matthews (Ninety Mile Beach).
The following researchers are involved in this work:
Shade Smith (Triplefin Environmental Consulting), Bruce McFadgen (VUW), Huhana Smith (Te Rangitawhia Whakatupu Matauranga Ltd), James Williams (NIWA), James Crampton (GNS), Fiona McCormack, Willem de Lange, Conrad Pilditch, Ian Hogg and Chad Hewitt (UoW), Bruce Marshall (Te Papa), Yolanda Vogel and John Coster.
Students working on this project include:
Jane Cope, Jacinta Forde, Nicola Fothergill and Georgina Flowers.