Standing Advice for Seaweed Aquaculture (farming/cultivation)
Site selection
Developers must minimise impacts upon sensitive habitats, including relevant Priority Marine Features (PMFs). Where sites are proposed within or close to Marine Protected Areas (MPAs) or where an activity may impact on PMFs, additional management measures may be required to ensure the protection of relevant marine habitats and species. Additional guidance should be sought from NatureScot.
Collection of reproductive material
There is currently limited information relating to the genetic diversity of seaweed populations in Scotland. To ensure that the genetic integrity of any local seaweed populations is maintained we recommend that any collection of reproductive material for marine cultivation takes place as close to the farm as possible. The collection should take place within the same waterbody, ideally as close to the cultivation site as possible but not beyond 25km (by sea) from the site.
We understand that the quantities of reproductive material required for the cultivation of kelp species (Saccharina latissima, Alaria esculenta, Laminaria digitata) are relatively low. We do not expect these quantities to result in any significant impacts on the viability of wild populations and we would not therefore require any form of formal stock assessment for the collection of these species. However, we would nonetheless recommend that any collection of reproductive material should follow best practice guidelines as set out below:
- Avoid disturbing wildlife such as nesting birds including seabirds, especially in the main bird nesting season and also seals, especially during the pupping season by keeping an appropriate distance away. Further guidance can be found Scottish Marine Wildlife Watching Code and the Guide to Best Practice for Watching Marine Wildlife. NatureScot has published a literature review of seaweed hand-harvesting: on disturbance distances and vulnerabilities of marine and coastal birds which is also relevant.
- Vehicle access should be restricted to existing tracks and vehicles should not be used on the foreshore.
- Cut fronds (leaves) with sharp scissors or a knife, well above the point of growth and always leave the holdfast attached.
- Harvest sparsely. Take less than one third of an individual plant to allow for regrowth.
- Avoid or minimise trampling on other plants species and avoid taking ‘bycatch’ such as stalked jellyfish, brittlestars, bryozoans and blue-rayed limpets.
- If you move any rocks, replace them as you found them.
- Follow ‘Check, Clean, Dry’ biosecurity principles, checking, cleaning and drying all equipment and clothing when moving between sites to ensure that invasive species, pests and diseases are not spread to new areas.
We currently have limited understanding of cultivation techniques for any species beyond the commonly cultivated kelp species (Saccharina latissima, Alaria esculenta, Laminaria digitata). We understand that the quantities of reproductive material required to successfully culture some species is significantly greater than is required for these commonly cultivated kelp species. In principle we have no objections to the proposed cultivation of any native species and we are supportive of innovation and acknowledge that the industry will evolve in the future. However, it is likely we would require further information regarding proposals to cultivate novel species at a commercial scale. Should any applicant wish to cultivate any species beyond the well-studied and commonly cultivated kelp species then we would be happy to discuss information requirements further.
Biosecurity
A biosecurity plan should be prepared as part of any proposal and should be in place before any activity commences. This plan should set out the measures that will be taken to ensure the operation of the farm does not result in the introduction or transportation of any invasive non-native species or pathogens to or from the site. The plan should include all operations from collection of wild material and hatchery stage through to the on-growing, harvesting and processing stages. Guidance on best practice biosecurity planning can be found online in NatureScot commissioned report 748.
Non-native species
The Scottish Government’s Seaweed Cultivation Policy Statement does not allow the cultivation of non-native seaweed species in Scotland. This is to minimise the risk from non-native species.
Under the Wildlife and Countryside Act 1981 (as amended) it is an offence for a person to plant or cause any plant species to grow out with its native range. This includes species of seaweed which can grow in the marine environment.
Entanglement
The development of seaweed cultivation will create structures that may pose a threat to marine megafauna through entanglement. Applicants for seaweed farms should consider the risk of entanglement.
Small cetacean such as harbour porpoise and dolphin species are generally considered to be at low risk of entanglement.
Minke whale appear to be particularly susceptible to entanglement in fishing gear, however there are no records of entanglement of minke whale occurring in any aquaculture equipment in Scotland or the UK. Seaweed cultivation is a relatively new industry in Scotland. While some parallels can be drawn between the equipment used for seaweed cultivation and that used in the well-established mussel farming industry, there remain a number of differences and so drawing direct parallels with regards to the risk posed to minke whale by seaweed cultivation is not possible.
To improve our understanding of the risk of marine mammal entanglements, any a licence granted should commit the developer to reporting any entanglement incidences with marine mammals, including cetacean species. Should any entanglement incidents be recorded they should be reported to Marine Directorate, NatureScot and the Scottish Marine Animal Strandings Scheme.