Seaweed Harvesting Workshop 2015

Transcription

1 Seaweed Harvesting Workshop 2015 Sustainable harvesting of bladderwrack Rhiannon Inkster, Christine Rolin, Josh Laing & Lesley McEvoy

2 Who are we? Intertidal Zones The Shetland Seaweed Growers Project will run from June 2014 until December 2016 at the NAFC Marine Centre. It is funded by the Coastal Communities Fund which aims is to promote sustainable economic growth and jobs in coastal communities. During the project we have worked together with a variety of aquaculture companies and food and drink businesses throughout Shetland including: Scottish Sea Farms Ltd.; East Voe Shellfish Ltd., COPE Ltd, The Shetland Distillery Co. Ltd., Artisan Island Cheese, Shetland Fudge Company, Mirrie Dancers Chocolatier, Saxavord Restaurant, Shetland SeaSalt Company.

3 Why are we interested in seaweed? Seaweed plays a vital role in the marine ecosystem, providing habitats fo marine species and playing an important role in the coastal processes that take place around us. It has been harvested traditionally in Shetland on a small scale for hundreds of years and used in traditional crofting practices. There has been increased interest in seaweed and seaweed related products recently. Seaweed is already used in a surprising number of everyday products such as foods, cosmetics, fertilisers and medicines. Unlike other crops used for producing biofuels, seaweed does not require valuable arable land or freshwater. As a result there is now strong interest in using it for biofuels.

4 What is the purpose of this workshop? To demonstrate small-scale, sustainable harvesting techniques for the bladderwrack (Fucus vesiculosus).

5 Intertidal Zonation Different zones have different physical properties: Splash zone High tide zone Mid tide zone Low tide zone Usually dry unless extremely high tide. Little vegetation grows here. Flooded during high tides Covered and uncovered twice daily by tides Usually underwater and only exposed at extremely low tides

6 Seaweed Morphology Here is a basic illustration of Fucus vesiculosus, explaining some of the terminology used when describing seaweeds. Glossary Frond the blade of a seaweed. Paired vesicles Midrib Receptacle Frond Holdfast Stipe Midrib Receptacle The part of the seaweed that attaches it directly to the substrate. Stalk or stem of a seaweed frond. A thickened ridge along the midline of a frond Fertile, swollen areas at the tips of seaweed fronds containing the fruiting portion during reproduction. Holdfast Stipe Vesicle Small fluid- or air-filled bladder.

7 Bladderwrack ( Fucus vesiculosus ) Where can you find it... From the North Atlantic to the Canary Isles It prefers sheltered shores look for bays and voes Most common in the mid-tidal zone (0.5 3m below high tide line) It is found below some tougher wrack species such as spiral wrack (F. spiralis) among serrated wrack (F. serratus) and egg wrack (Ascophyllum nodosum). How does it look Round vesicles on either side of midrib, usually paired Forked areas at the tips become swollen during the reproductive season (Autumn). Flattened fronds with a short stipe Olive green to brown colour Prominent midrib Smooth edges

8 Not to be confused with Spiral wrack (mid-high shore) F. Spiralis Olive green to light brown in colour The seaweed is flattened when not reproductive F. spiralisis smooth to the touch and has smooth edges Noteable midrib Fronds do not lie neatly, are usually spirally twisted Often found without air bladders Ends of fronds are Y-shaped When reproductive Y-shaped ends become swollen, surrounded by a distinct thin band of darker sterile tissue Horned wrack Fucus ceranoides Olive green to brown in colour Fronds feel leathery to the touch and are flattened Fronds are thin with smooth margins Lacks spherical airbladders but has distinct elongated air bladders that run either side of the mid rib Midrib set in between elongated airbladders Ends of fronds are forked

9 Not to be confused with Serrated wrack (lower shore) F. serratus Olive green to light brown in colour Fronds are flattened with an obvious serrated saw like edge Like other fucoids it has a prominent midrib Lacks airbladders During periods of reproduction, frond tips become slightly swollen and have a bumpy texture. Fronds can also have an orange tinge. Two-headed wrack Fucus distichus Olive green to yellow in colour Fronds are tough and rigid Fronds are narrow, partially flattened and smooth edged A midrib is clearly visible Lacks airbladders Tips of fronds are Y shaped When seaweed is reproductive, Y shaped ends are swollen and lumpy Frond flattened when seaweed is not reproductive

10 Not to be confused with Channel wrack (high shore) Pelvetia caniculata Olive brown to green in colour, but can look black when exposed for long periods Thin fronds found in tufts and grow no bigger then 15cm Fronds are rolled. Fronds are rolled inward forming a channel on the surface nearest the rock and a smooth ridge on the other side of the curled frond. Channels help prevent desiccation. Airbladders absent Lacks midrib Evenly forked ends When reproductive forked ends appear beady and knobbly and orange in colour Egg wrack (mid-low zone) Ascophyllum nodosum Olive green to golden/ pale brown in colour Fronds are long and have large egg shaped airbladders placed at regular intervals along the frond The frond between the airbladders is flattened and strap-like No midrib Often found with epiphytic reddish filamentous seaweed growing on fronds When reproductive, receptacles grow from the seaweed frond. These structures are lumpy and lightly coloured

11 Seaweed Identification Exercise Can you identify the different seaweeds in the pictures below from the species factsheets?

12 Why Why we we need need to to have harvest sustainability sustainably Seaweeds are a very important part of the shore ecosystem as they create habitats in which other marine life can find food and shelter. Seaweeds also help protect the coast against erosion and storms. Overharvesting can therefore have negative impacts on the environment (Fig1). Seaweed can be harvested manually using hand held tools or mechanically using machines or large cutters. Harvesting seaweed by hand and rotating harvest areas is thought to be the least damaging to the ecosystem and allow seaweed stands to recover faster. Overharvesting can lead to changes in habitat, species composition and coastal processes. Fig. 1: Potential Impacts of Commercial Wild Seaweed Harvesting from Scottish Seaweed Policy Statement Consultation Document, By using sustainable harvesting techniques we can help safeguard future resources.

13 Scottish legislation Recommendations: Although the recent Scottish Government seaweed consultation may lead to changes, harvesting wild seaweed by hand is not regulated at present and a Marine Licence is not required. However, if a vehicle or vessel is being used to harvest wild seaweed, then it does become a licensable activity. At present, the only legal requirement for hand-harvesting wild seaweed is to gain the permission of the landowner. In most cases, this will be the Crown Estate Scotland but the land may also be privately owned. If the Crown Estate Scotland is the landowner, licences for wild harvesting are issued based on the impacts on seaweed sustainability, habitats and the implications for coastal processes. Specifically, consideration will be given to the harvesting methods, frequency, species, area and harvest regime. Guidance may be developed to promote good practices and mitigate against negative environmental impacts. Removing flora and fauna from any environment will always affect that habitat to some degree. However, any impact is likely to be reduced if sustainable harvesting methods are employed. Gain permission from the landowner and check if you require a Marine Licence. Promote good practices and mitigate against negative environmental impacts. Therefore.. Only harvest a fraction of the seaweed stock. Leave whole plants and rotate the harvest areas to allow regeneration in Norway only 20% of the seaweed in an area is harvested to allow regeneration and not harvested again for 5 years. in Canada no more than 30% of bladderwrack should be harvested and harvesters are required to carry licences.

14 How to harvest sustainably Harvest from no more than 30% of the plants Cut above the holdfast to allow new shoots to grow Allow 2 5 years to regenerate before further harvest Rotate harvest areas to allow regeneration Monitor and assess the area to ensure recovery Harvesting equipment and checklist Cut Full risk assessment Permission from landowner Protective clothing Sheathed knives Harvest baskets

15 Health and Safety Do a full risk assessment of the area and your planned activity. Assess the selected area before the collection date. Make sure to note any hazardous areas to avoid during harvesting. Plan your collection time, checking tide times beforehand. Always let someone know: -Where you are going -Who you are with -When you will return Monitor your surroundings continuously and leave if risks increase. Be careful to avoid slips, trips and falls. Have a first aid kit nearby just in case. Test your footing before shifting your weight, especially over seaweed. Wear appropriate clothing and protective equipment non-slip footwear/waders, gloves, lifejacket, suncream etc. Take a mobile with you, but remember: sometimes no mobile signal.

16 Further reading Algaebase: Listing the World s Algae The Marine Life Information Network Bunker, F.D., Maggs, C.A., Brodie, J.A. & Bunker, A.R. (2010). Guide to Seaweed of Britain and Ireland. Marine Conservation Society Seaweed ID book. Environment and Heritage Service (2007). Environmentally Sustainable Seaweed Harvesting in Northern Ireland. Halm, T & Kautsky, L. (2003). Differences in life-history characteristics are consistent with the vertical distribution pattern of Fucusserratus and Fucusvesiculosus (Fucales, Phaeophyceae) in the Central Baltic Sea. Journal of Phycology 39: James, M.A (2010). A review of initiatives and related R & D being undertaken in the UK and internationally regarding the use of macroalgae as a basis for biofuel production and other non-food uses relevant to Scotland. Report by FRM Ltd for Marine Scotland. Maine Seaweed Council (2014). Harvester s Field Guide to Maine Seaweeds. Scottish Government (2013). Draft Seaweed Policy Statement Consultation Document. Scottish Government (2013). Draft Seaweed Policy Statement Consultation Document Environmental Assessment Report.