Sustainable Harvesting of Seaweed
 

http://www.ukmarinesac.org.uk/communities/infralittoral/ik5_1_2.htm


Extract from this report:


"Kelp has been harvested commercially in Brittany, Ireland,
Norway and Scotland for hundreds of years.   While the seaweed
was collected from storm and drift deposits on the beach the
impact was minimal.   Recent development in dredging techniques
led to commercial harvesting of Kelp in Norway and Brittany under strict regulatory controls (Arzel, 1996), dredging trials were also carried out in Scotland in 1991(H.T. Powell, pers.comm.)"

 

This report concludes that although the Laminaria hyperborea grew back quickly and within one year the beds were well developed and dense. The regrown biomass was made up of a greater density of smaller plants.   The stipes of these seaweeds were better suited to the extraction of alginates. However after 3-4 years the plants, although bushy were only half the size of the uncut Laminaria and the surrounding fauna and flora was species poor compared to the undisturbed areas. (Svendsen 1974, 1991)

 

This report highlights the necessity of monitoring any commercial dredging operations, and the rotation of harvested areas.   It may be that commercial mechanical harvesting can never be sustainable and  seaweed will either be hand picked from the rocks or commercially grown on rafts and ropes or in pond cultures.
 

It is now  recommended to allow a 7 - 10 year rotational period for recovery from the long lasting effects on the subsidiary flora and fauna, and the reduced biodiversity.

 

Hand Picking Seaweeds

Twelve species are presently harvested commercially in Northern Ireland.  These are collected mainly by hand pickers and divers, with boats being used for rocky access.   Vehicles are used to collect the seaweed from the beach and landing places.  See the full report cited below:
 
Seaweed Picking/Cutting

Make sure that you have permission  to pick from your proposed site.  Check that the area is clean and free from pollution.   Identify your species and check that you do not pick anything rare or endangered.  Take a species ID chart with you (A Key to Common Seaweeds - FSC) - Take care to recognise annuals and perennials.   Always cut above the stipe leaving enough of the blade for re-growth, if there are multiple blades, just take a few and leave the others to regenerate.  Rotate your collection site Check all seaweeds very careful for creatures who may also be grazing on the sea vegetables or setting up home there.



Crissy Haydon Keneck Sands 2009
   
 
RELEVANT LINKS  
In March 2007 the Environment and Heritage Services produced an assessment of Environmentally Sustainable Harvesting of Seaweed in Northern Ireland.    This document outlined the position of the EHS on Sustainable Harvesting and was produced through stake-holder agreement.  Download here.
 		 http://www.countrylovers.co.uk/wfs/wfsseaweed.htm

http://www.wildmanwildfood.co.uk/pages/seaweeds.html
   
   
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