Published on 08/02/2024. Written by Dr Elisa Capuzzo, Senior Marine Ecosystem Scientist at The Centre for Environment, Fisheries and Aquaculture Science and Isla MacMillan, Data Analyst and Researcher at The Centre for Environment, Fisheries and Aquaculture Science

This report was conducted as part of the SEA project. The project is led by Hethel Innovation in collaboration with The Centre for Environment, Fisheries and Aquaculture Science (Cefas) and the University of East Anglia (UEA). The SEA project is funded by the Norfolk Investment Framework, Norfolk County Council, UK.

The link to the PDF version of the report can be found here.
Executive Summary

  • The Seaweed in East Anglia (SEA) project is a collaboration between Cefas, the University of East Anglia and Hethel Innovation Ltd. The project aims to identify steps to develop a sustainable and viable seaweed industry in East Anglia and particularly Norfolk.
  • This report scopes the farming methods and species for cultivation off Norfolk, by reviewing current practices and identifying suitable ranges of environmental conditions for growth of brown, red and green seaweed species.
  • This document collates and signposts different sources of information (peer-review and grey literature), from the UK, Europe and north-west America.
  • The information provided in this review should be considered as “guidelines” for prospective seaweeds farmers and should be critically reviewed against the local conditions of the farm site, farming methods adopted, facilities and vessel available.
  • Investigation of the four countries’ registers highlighted that there are 25 approved marine licences for commercial seaweed farming in the UK (12 England, 10 Scotland, 2 Wales and 1 Northern Ireland), however, it is unclear how many of these farms are currently operating, which species are farmed, and the methodologies used (as not all applications provide these details).
  • The report considers the following seaweed species: Saccharina latissima, Laminaria digitata, Laminaria hyperborea, Alaria esculenta, Palmaria palmata, Porphyra spp, Osmundea pinnatifida and Ulva spp. Only some of these species (e.g. S. latissima) are currently cultivated successfully in the UK while others (e.g. Porphyra spp.) are not farmed as yet due to uncertainty around the species’ life cycle.
  • Suitable values of temperature, salinity, underwater light, nutrient concentration, currents, wave height, and depth for farming of the above species were identified where possible. There was a high level of uncertainty around ranges for some of the environmental variables considered, particularly current and wave height, due to lack of observations.
  • The review highlighted that there are multiple techniques adopted for farming seaweed (longline, droppers, etc.), and different substrata to grow seaweed (e.g. twine, mesh) which are used in the UK and Europe. Methods should be chosen to suit location, farm size, yield, species farmed, end uses and environmental conditions. Therefore it is not possible to identify “one method that fits all locations”.
  • A good body of freely available ‘grey literature’ (e.g. reports, tutorials, videos), in addition to charged courses, was identified, which provides information on how to collect fertile material, nursery set-up and farming at sea, although mainly for brown seaweeds. It is difficult to keep track of these resources and the weblinks may stop working.
  • The review was completed by identifying five recommendations to support the development of a seaweed industry in Norfolk and more widely in the UK. These included: the need for more Research & Development on cultivation of additional potential species such as laver; collection and sharing of environmental data at existing seaweed farms in the UK; increased knowledge sharing between farmers around farm structure and farming methods; developing a centralised platform/repository for sharing references and information on cultivation practices; and collection of information on granted seaweed licences and annual seaweed production at the national level.

This work has been possible thanks to the Norfolk Investment Framework, Norfolk County Council.