Kaimoana in the Hauraki Gulf

The discovery of tetrodotoxin (TTX) in the grey side-gilled sea slug is of particular concern to iwi who live around the Hauraki Gulf. Māori are concerned TTX may get into the food chain. Larn Wilkinson from the Hauraki Māori Trust Board points out that large numbers of iwi in the area rely on kaimoana as a food source. Toxins appearing in marine life may have a huge impact on the way iwi gather kaimoana, eat and live. A further concern is that these highly toxic slugs may be dangerous for tamariki (children) walking along the beach. Larn says the discovery of TTX is something they really need to be aware of so they can minimise and reduce the impact of any effects.

Dr Shaun Ogilvie

Dr Shaun Ogilvie (Ngāti Awa, Te Arawa) is a Māori research scientist, employed by the Cawthron Institute as a Māori Development Consultant. Shaun’s work is to make connections between people and to bring science, research and Māori organisations together.

Shaun thought it was important for local iwi to know about the discovery of TTX in the Hauraki Gulf. He approached the Hauraki Māori Trust Board (HMTB) and gave them a briefing on what the Cawthron Institute scientists had found. The HMTB realised the importance of the issue and wanted to be involved in further research.

I love being able to take new discoveries out into communities and talk about them.

Dr Shaun Ogilive

A collaborative study

The Cawthron Institute and the HMTB formed a collaborative study in 2010. Their aims are to determine the risk of TTX getting into seafood that people are harvesting and to determine what the risks are for people who are consuming kaimoana.

This study involved setting up a sampling survey of kaimoana species. Local iwi member Dave Hammond became the main field technician for collecting kaimoana samples. Every month, Dave collects samples that are commonly eaten, such as pipi, mussels, oysters and cockles. He then sends those to Cawthron Institute where they are analysed for TTX.

Results to date

The results of the survey have shown positive results for four species. However, as the level of positive results for three of the species is barely measurable, they’re not a concern for people harvesting and eating them.

The fourth species (pipi) showed low positive results over 4 months. In this case, the levels of TTX did warrant a recommendation of caution in terms of eating too much. A risk analysis suggested that, if you were to eat 5 kilograms of pipi all at once, you would risk being seriously ill. Since people do not usually eat this quantity, the scientists considered pipi were still safe to eat.

Local Māori knowledge helps scientists

The collaboration between Cawthron Institute and the HMTB has also been beneficial to the Cawthron scientists. They have been able to talk to iwi, including elders, and to members of the HMTB. They’ve discovered a wealth of knowledge – a database of environmental information based on stories that have been passed down through generations. A search through this database for poisoning and toxic events showed no record for anything like the dog deaths and slugs washed up on the beaches. This may indicate that the discovery of TTX is an unprecedented event.

At a hui held at Manaia in January 2012, Cawthron scientists described TTX and its effects to HMTB members and local iwi. Some of the people mentioned that, in the past, they had experienced numbness in their lips after eating pipi. Consequently, they had decided to stop eating pipi for 3 months.

Although this collaborative study was due to finish in June 2012, there was a general consensus at the hui that they’d like to see the study continue, if funding allows. Presently, there are only three sampling sites on the Coromandel. They would like the study spread further geographically to see if TTX is in other areas around Coromandel and Auckland.