S Diversification of dense mats in shorter timescale than would occur naturally

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1 Appendix vii - SWOT workshop output Yellow group S Recycling nutrients onto farmland S Diversification of dense mats in shorter timescale than would occur naturally S Ecological benefits of mudflats remaining exposed (pre 1960 s levels) S Facilitate representative bodies of agriculture to continue to lead the direction of travel in the catchment through persuading farmers that there is engagement in the issue from a range of bodies S Would give partnerships extra oomph with the farming community S A pilot would help to identify where algae is beneficial to invertebrate communities S (algae) not a great advert. Appearance to visitors to Poole would result in improvements to tourism and amenity,; improvement to aesthetic value of the harbour; smells avoided O Business/employment opportunity S Saltmarsh communities would not suffer from smothering by detached weed O floating reedbeds could be an alternative measure, less disturbance O (A pilot) would allow a (full) cost benefit analysis O Interreg funding could be an option O Landowners would understand the impacts of shoreline dead algae and recycling opportunities W NT has tried harvesting algae but the cleanness of the algae is a significant problem O alternative green manure for agriculture, algae could have intrinsic value O could use existing expertise in the marine industries; assets and technology O sustainable funding through S106 O Cost benefits to biodiversity of removal could be evaluated T Holes Bay in particular has a different environment to the rest of the harbour, potential warm water inputs from STW? Which probably exacerbates the problem?; whilst Holes Bay is a hotspot the algae has a very non uniform distribution (seasonally, annually and geographically) S Is perceived as a problem for the CLA members O Wider opportunity for (investigation) other products (uses?)? W only a pilot would allow investigation of the effectiveness of methodologies. W requires a proof of Concept before a pilot W Need to know specifics of timing, location before

2 W risk associated with destruction of habitat are too great W examples provided of other countries are not pertinent to the unique position in the harbour, the protected nature of the site W cant prove that algae can be removed after it has smothered mudlfats W would leaves or whole plant be removed? Would the holdfast be uprooted and so lead to disturbance of the sediments? W The algae is fast growing would cutting make it bloom/ regrow from the holdfast and so negate improvements from the algal removal W becomes a political distraction from the main problem (of nutrient inputs) W environment presents many constraints, much of it is inaccessible W a small pilot would not necessarily reveal the impacts on biodiversity at a harbour scale W risk of cut material floating off and smothering salt marsh and so be more damaging W unknown if the floating pieces of algae responds differently after being cut W short-lived impact on the volume of algae e.g. example for Poole Park Lake W if businesses are encouraged to invest, its not sustainable because the longterm aim is to reduce algae not viable to encourage investment in a business model (that will not allow growth and inevitably end); weak business model,; unsustainable future supply. W suitable condition for algal growth vary W algae is the primary input some food chains; W; don t know to what extent the algae is a food source, could algal removal result in food depletion? W removal does not resolve the problem, cannot reduce its vigor W uncertainty over the economic disbenefits W don t know what the tourists think T would removed algae be classified as waste by EA T S106 funding needs to be sustainable, 80yr+ harvesting would require revenue funding and so not be eligible T Lack of consensus T not financially viable T unknown if the infraction with the EU is Habitats/WFD/UWWTD T is there a wider demand from farmers? Would they pay for the harvester? T unknown if there is a significant impact on businesses.

3 T tourism impact mainly on boats not on harbour beaches

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6 Blue group T Cost is main constraint? reducing P availability may help limit the algal issue S water temperature can be limiting, climate change may increase growth T birds are feeding in algal areas in preference to bare mud T if reduced to bare mud then there may not be sufficient time of invertebrates in sediments to recover, so will impact on bird diversity T will take 2-3 years for the invert community to recover W 3 year programme (for pilot?) to allow for recovery? Most cost effective to remove gradually over time e.g. 1Ha per day for 100 days? need to establish what benefit is wanted/valued? Who/businesses? Are disadvantaged by algae e.g. BoP Poole Park Lake, Lilliput marina S maybe cleansing of upper shore smelly or washed up (decomposition?) S algae mats stop annual saltmarsh plant growth S may satisfy aesthetic concerns without impacting too much on the ecology, allows colonisation by larger spp such as crabs? dominated by smaller inverts on upper shore S limited reports of problems from the RYA Bluee lagoon main problem area W less of an issue for boats using the channel, mainly a problem in the shallows S those addressing the cause would like to see symptoms addressed (see results) T need to address the core symptom, is it the (problem) on the upper shore? W will harvesting on the upper shore help growth of the saltmarsh?? when the N is broken down, where does it restabilise? W In poole harbour don t see the salt marsh growth reducing T algae will need to to be removed several times a year to keep up with it but this may cause more damage to species W Pubeck side the access is limited and so is the visual impact (of algae), Poole side is more visible W key question is is it getting worse? W is the impact enough to attract money to fund?

7 W greatest density is in the South West but less visible so would need reporting to publicise benefits as not visual O is shared research an option? Working with other harbours and estuaries W no studies have been done on the impact of clearance, only very small scale, so impact of long term benefits/ disbenefits (unknown?) W does algae provide the nutritional requirements of birds? T need to be aware of the removal of algae on salmon populations particularly during migration time (same applies to sea trout) T timing of removal is important to many populations including fish and invertebrates. (consider ) breeding cycles? headwater streams are useful in removal of N O oysters for removal of N?; W amount of N removal is small (from shellfisheries) PH is already largest oyster faming (area) in the country (is) seeded W, does N cause an issue? O road cutting/ road verges/ agricultural buffer strips, can these nutrients be recycled? W need a benefit that will pay for harvesting or a study W (various) practicalities of harvesting- odour, noise, traffic W education, may need to publicise and educate if the trial is visual (visible?)

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