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Huge Potential for the Seaweed Industry

Monday 11 August 2014

The commercial harvesting of seaweed is an international industry with 35 countries participating. An estimated eight million tonnes of seaweed is produced annually with an estimated value of $(US) 6 billion.

The past 20 years has seen seaweed production double and exceeded the supply available from the harvesting of naturally occurring species.

Alternatives, such as aquaculture and the harvesting of introduced species, are seen as solutions to meeting increasing demand.

In New Zealand, we have an estimated 800 known species of seaweed. Many of these have the potential for development into commercial value and contribute to satisfying the increasing international demand.

Our temperate, nutrient rich waters provide the ideal conditions for the formation and growth of seaweed. New Zealand seaweeds are sought after internationally due to their low contamination rates and high mineral and nutrient content.

Seaweed is currently managed under the Fisheries Act 1996 and is defined under section 2 of the Fisheries Act 1996 as: “all kinds of algae and sea-grasses that grow in New Zealand fisheries waters at any stages of their life history, whether living or dead”.

It resides in three physical states: attached, free floating or beach-cast with collection or harvest dependent on the species and the physical state it resides in.

Once collected it is hung and can take up to four days in good weather conditions to dry. This process is significant as the market value of the seaweed is compromised if it is over dried or damp.

Quality is especially important as the seaweed is then turned into fertilizer, medicinal and pharmaceutical products, agar and food products, green-lipped mussel spat and feed for farmed paua.

Only a few species have currently been investigated to varying degrees for their commercial value. They include Ulva (sea lettuce), Gracilaria chilensis, Porphyra, Durvillaea Antarctica, Lessionia, Macrocystis porphyra (bladder kelp), Ecklonia radiata and Undaria pinnitifida. Bladder kelp, Ecklonia and Undaria have all been showing progress and development at varied levels in their potential contribution in commercial value.

Bladder kelp is currently the only seaweed species managed under the quota management system (QMS). It was introduced into the QMS on 1 October, 2010 within fisheries management areas 3 and 4.

It is a commonly occurring species that is found from the Sub-Antarctic Islands to the lower North Island on the east and west coasts.

Individual plants can grow up to 20 metres in length and it is one of the fastest growing seaweed species in New Zealand - growing up to one metre each day. It can occur in dense stands with maximum biomass occurring in winter.

The attached state is the only state managed under the QMS with beach-cast and free floating states monitored by the Ministry for Primary Industries (MPI) for future introduction.

The current total allowable catch (TAC) has been set at 1500 tonnes since 2011. Catch rates range from 34 to 79 tonnes a year and are valued at $15-$25 kg wholesale.

Current rates of harvest are thought to have had minimal impact on this species and its environment. MPI documents show that, due to low levels of exploitation, it is likely that all stocks are still in a virgin state and are therefore unlikely to have been over extracted.

A species that may have potential for future introduction into the QMS is Ecklonia radiata. Ecklonia is found in the more northern and warmer regions of New Zealand.

It forms dense, sub-tidal forests and can reach heights of one metre. Currently, there is little knowledge of Ecklonia and the effects of commercial harvesting and what impact it has on the surrounding environment.

A four-year research project, co-funded by the company AgriSea NZ and the government, investigated the effects of harvesting attached Ecklonia and explored the development of a fisheries plan and management framework for sustainable harvest.

AgriSea, a sustainability company, brews a natural concentrate from Ecklonia for fertilizer.

The research was conducted in Waihau Bay on the eastern Bay of Plenty by Dr Tim Haggitt. Preliminary results suggest that Ecklonia recovers at a faster rate when harvested in the spring, while autumn harvests result in slower recovery rates. The study provides encouraging support for the natural harvesting of Ecklonia, especially as overseas practice moves towards farming of the species on artificial surfaces.

A species that has great potential for future commercial value is Undaria pinnitifida. Undaria is native to Japan and has an estimated commercial value internationally of $(US)500 million.

It was accidentally introduced to New Zealand in the late 1980s through the ballast of a foreign fishing vessel. Since its introduction, it has established itself in every major port throughout the country, easily settling on any natural or artificial surface.

It is currently classified as an unwanted organism under the Biodiversity Act 1993 and is also listed as a pest by some regional councils in their regional pest management plan.

Anyone seeking to harvest Undaria commercially must apply to MPI under section 52 and/or 53 of the Bio-security Act. Due to its legislative classification Undaria has been heavily regulated.

In May 2010, MPI revised its policy on the commercial use of Undaria, which allowed for farming in selected heavily infested areas, artificial surfaces and, when cast ashore, in selected areas. However, it is prohibited for harvest when growing on natural surfaces, except when part of a programme specifically designed to control Undaria.

In 2012, MPI opened up waters within Wellington, Marlborough and the Banks Peninsula to marine farming of Undaria. However, the impacts of Undaria within the marine environment and how it interacts with native seaweed species is not well understood, therefore MPI is hesitant to allow full-scale harvesting of this species.

While the seaweed industry in New Zealand is still in its early stages of development it offers great potential for the international market.

New Zealand has a prime opportunity to offer a high quality and diverse seaweed stock to the international market.

However, government restrictions remain as there is still much to know about the impact of wide scaled harvesting of seaweed on the New Zealand marine environment. The development and exploration of seaweed farming and harvesting is sure to be followed keenly by stakeholders, researchers and the wider fishing industry.

Christopher Gibbons is an environmental consultant to the fishing industry.

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