There are thousands of seaweed species around the world growing in different climates and environments. Different seaweeds grow at different latitudes and at different depths. Like land plants, seaweeds also have seasons so when harvesting, understanding seasonality is critical to ensure the natural life cycle of the seaweed is not disrupted.
Beach Cast seaweed- this is seaweed which is collected from the beach after it’s been washed up by the tide. You can recreationally harvest seaweeds (forage) throughout NZ as long as you are not in a marine reserve. Ensure you choose clean areas of water as seaweed can become contaminated by run off and pollution in the sea. Once harvested you need to process the seaweed quickly before it starts to break down – we suggest air drying. Once dried, store in a cool dark and dry place so it doesn’t reabsorb moisture.
Wild Harvested – seaweeds may be cut from where they are growing, ideally in a way which helps them to regenerate and which does not interfere with their natural cycles. Mechanical harvesting of seaweeds is controversial due to the ‘blunt instrument’ nature of the machines that cut the seaweeds randomly as well as the damage that can be caused to the surrounding environment, which is also destroyed as the seaweed is removed mechanically.
Farmed seaweeds – typically the early life of a farmed seaweed would start in an onshore tank where a small plant is grown and later attached to a rope or some structure in the open ocean to complete its growth. Farming seaweed is more common in Asia where typically small-scale, rope grown labour intensive farms are common. Typically these farms operate under a license and will be monitored and regulated closely.
In New Zealand all seaweed harvesters who operate commercially are required to be licensed by the Ministry of Primary Industries. Although we have over 1000 species of seaweed only a small number of these are allowed to be harvested. Kelps are beach cast collected and some seaweeds ( eg, Undaria) are being wild harvested. There are a few small trials underway to explore farming opportunities, but these are in the early stages.
Globally the seaweed industry faces a challenge as there is a mismatch between seaweed demand and availability of seaweeds which are increasingly being used in new applications such as animal feeds, the biofuel, packaging industries and others. More work needs to be done to understand how larger scale seaweed farms can be established to reduce pressure on natural reserves. Seaweed grows relatively quickly, requires no fertilisation or water and absorbs enormous amounts of carbon dioxide. The establishment of seaweed farms can reduce carbon footprint, create employment in regional areas and produce high quality products. The key is ensuring that this is done in an ethical, monitored and sustainable way.
Pacific Harvest only secures seaweeds harvested from ‘clean’, uncontaminated waters.