By Richard Mithen, High-Value Nutrition National Science Challenge Chief Scientist

One of the great privileges of my job as Chief Scientist of HVN is having the opportunity to visit the many centres of science excellence in New Zealand. It was a particular pleasure to visit recently the Cawthron Institute in Nelson, and to hear about their excellent ground-breaking research to develop sustainable aquaculture systems for New Zealand. But before we get to that, let us reflect on how foods from the shoreline literally fuelled the great human migrations of prehistory.

The importance of shellfish to human nutrition dates to literally the emergence of modern humans. It is thought that between 200,000 and 125,000 years ago, while Homo sapiens were still only to be found in Africa, climatic changes resulted in much of the African continent being too cold and dry to be habitable, and the surviving populations of modern humans became restricted to narrow coastal zones. Substantial evidence of mussel consumption has been dated from sites in southern and eastern Africa from 164,000 years BCE.

Moreover, some prominent archaeologists, such as John Parkington of University of Cape Town, have speculated that it was the very rich source of lipids and proteins found in shellfish that enabled these early Homo sapiens to not only survive this dramatic period of human history but to drive technological advances. “This (viz. high value nutrition from shellfish) is the evolutionary driving force….It is sucking people into being more cognitively aware, faster-wired, faster-brained, smarter.” 100,000 years ago the first evidence for art appears in the form of ochre and geometric engravings, along with the first use of shell beads as body adornments – all potentially a consequence of changes in society and cognition arising from enhanced nutrition involving the use of shellfish.

About 80,000 years ago a small group of Homo sapiens left Africa and journeyed across the Bab-el Mandeb straits to Arabia, and began the long journey to populate India, South East Asia and Australia, a journey that took 30,000 years. It is thought that this was predominantly through the ‘southern coastal route’, and it seems likely that mussels and other shellfish were an important diet of these people on this greatest of all migrations.

Likewise, from about 20,000 years ago the first people crossed from Asia into the Americas and took a coastal route to the southern-most tip of the continent; from 15,000 years ago as the glaciers of the last ice-age retreated, people began re-colonising northern Europe, with some communities developing a maritime adaptation. Soon after the end of the ice age at 11,650 years ago, communities throughout the world were reliant on shellfish, creating huge middens at their coastal campsites. While many shell-middens have been lost by the fluctuations of sea level, archaeologists have meticulously excavated others, discovering that mussels, limpets, oysters, periwinkles and many other coastal foods were sustainably exploited over thousands of years.

The last great human migration was, of course, not coastal but a great sea voyage – that from south east Asia across the Pacific to populate Polynesia starting about 3,000 years ago. This migration finished with the arrival of Māori in Aotearoa – the last substantial land mass to be settled by Homo sapiens – and a mere 1,000 years ago. It is nice to speculate, that those early settlers may have been delighted to find an abundance of Perna canaliculus, or kūtai – the New Zealand greenshell mussel – upon their arrival. Following the Māori, the Pāhakā arrived after their own great sea voyages from Europe, including the 15 year-old Thomas Cawthron who disembarked from the Mary at Nelson in 1849.

Thomas Cawthron became a successful business man, firstly in mining and subsequently in shipping and property, and a great philanthropist. In his will he bequeathed £231,000 – practically the whole of his estate – for the development of an ‘Industrial and Technical School, Institute and Museum to be called the ‘Cawthron Institute’. This was officially opened in 1921 with Thomas Easterfield, emeritus professor of chemistry at Victoria University College as its first director.

Today the Cawthron Institute is New Zealand’s largest independent science organisation, offering expertise in aquaculture research, marine and freshwater resource management, food safety and quality, algal technologies, biosecurity and analytic testing. The current Chief Executive Professor Charles Eason leads a dynamic institute with world leading research which interfaces in a seamless manner with industry to ensure a sustainable, nutritious and safe food supply: a powerhouse of New Zealand science, technology and innovation.

But what has Cawthron done for the mussel?

The first agricultural revolution of 10,000 years ago saw the domestication of animals and crops in different parts of the world – wheat, barley, goat and sheep in the middle east, cattle in north Africa, rice, millet and soy in china, maize and beans in the Americas, and so on. Just over 100 years ago with the rediscovery of Mendelian genetics, directed breeding approaches have been applied to all our major and minor crops and livestock, and within the last 20 years modern genomic approaches have greatly accelerated these processes. Genetic improvements have gone hand-in hand with improvement in livestock husbandry and crop agronomy to result in an agriculture system that currently sustains a population of about seven billion.

While there have been developments in the husbandry of mussels, little attention has been paid to the development of improved spat – the very young mussels somewhat akin to seeds. Until a few years ago, the New Zealand mussel industry relied exclusively on the collection of wild spat for cultivation, a bit like collecting seeds from wild cereals and sowing them nearby for an easier harvest. In a collaboration with industry, the Cawthron Institute has pioneered methods to produce under controlled conditions high-quality spat of the New Zealand greenshell mussel, building upon the discovery of basic aspects of mussel biology. Spat is now supplied to a growing part of the New Zealand mussel industry by SPATnz, a company based at the Cawthron Aquaculture Park, managed by the knowledgeable and engaging Rodney Roberts. The ability to produce high quality spat under controlled conditions has opened up the opportunity for selective breeding of particular high-performance mussel genotypes, and an appealing target is to further enhance their nutritional attributes.

It is known that mussels are excellent sources of long chain omega-3 fatty acids, high quality protein, and minerals such as iodine, selenium and iron that are often deficient in our modern diets. More detailed research on health benefits is underway at Cawthron led by Dr Matt Miller in collaboration with Massey University and Plant and Food Research funded by Sanford and HVN. An important part of this programme is the inclusion of Māori researchers who are exploring Mātauranga indigenous knowledge associated with kūtai to aid hauora, improving health and social well-being.

Mussels need to eat, and they eat algae from which they obtain the long chain omega-3 fatty acids. Producing high quality mussel spat and the associated mussel breeding programmes has required the development of sophisticated methods to grow large amounts of single cell or microalgae. The Cawthron Institute has world leading expertise in many aspects of algal science and technology. It curates an international important collection of microalgae, many of which produce toxic chemicals but are being explored for the production of high-value chemicals for pharmaceutical applications. Algae itself has a tradition of use in human foods in most coastal areas of the world, and, similar to mussels, has much potential to be an important part of our diet. HVN is very pleased to be sponsoring research led by Cawthron’s Dr Tom Wheeler and colleagues in collaboration with Te Rūnanga o Ngāi Tahu and Wakatū Incorporation on the nutritional value of karengo – edible red seaweeds that are endemic to Aotearoa-New Zealand.

Mussels and other coastal foods have sustained human communities throughout our entire history. We are now entering a very rapid phase of climate change, and great challenges lie ahead in not only how to reduce greenhouse gas emissions from agriculture but how to sequester carbon from the atmosphere while retaining agricultural productivity. Mussels, algae and other forms of aquaculture will undoubtedly have an important role to play in providing a high value source of nutrition during these challenging times, just like they have done so throughout our ancient past.