Sea lettuce problem update ~ 15 May 2017

We hope to be wrong, but we fear the sea lettuce blooms, which are the scourge of St Aubin’s Bay, will be back in force this year. Here is a brief report on what’s happening (or not) at the moment and why it matters. 

Download as a PDF: SOS Jersey – Sea Lettuce Problem Update – 17 May 2017

Introduction

The now annual sea lettuce blooms in St Aubin’s Bay are a blight. They adversely affect the local ecology, Islanders who live and work along the Bay, and local and incoming tourism.

Yet again, the relevant States Departments have let us down by not acting sooner on the sea lettuce issue. We are amazed they do not appear to listen to experts and blunder on regardless.

After a period of our queries not being replied to, Michael du Pré, Chair of SOSJ, has finally received word about trials which are due to go ahead and about which we have reservations, which are outlined in this brief report.

This report also looks at what is happening this year (the short answer is ‘nothing of any consequence’) and includes the news release sent to local media; the release contains some details not included elsewhere in the text, so please have a look at it too.

Because this is short, the facts are very simply put, so we apologise for any seemingly simplistic statements. We are happy to answer specific questions; our contact details are in the footer of each page.

We also invite you to read our previous reports on the sea lettuce; they are short and not technical. Links to those reports and to more detailed pages are included at the end.

We also sincerely hope real progress will be made soon and that SOSJ can focus on other important shoreline issues.

In Brief

Sea lettuce thrives in the conditions of St Aubin’s Bay:

• Tidal flows were (of course) affected when the reclamation area around La Collette was built; the resultant flows suit the sea lettuce
• The Bay is shallow, sheltered and sunny; during spring tides there is a lot of warmed, shallow water ‘sitting’ in the inter-tidal region, which helps promote sea lettuce growth
• The water entering the Bay from runoff and the Bellozanne sewage works outlet at First Tower is high in nitrates and other chemicals which help sea lettuce to grow

We know how much the sea lettuce affects Islanders and tourists – the evidence is right in our faces (and up our noses); Visit Jersey’s comment last summer that tourists could go elsewhere on the Island was unhelpful.

In addition, the ecology of the Bay is being badly affected; for example, the Bay’s seagrass (Zostera noltii, also known as dwarf eelgrass) has to compete for nutrients, light and oxygen when the sea lettuce blooms. While sea lettuce benefits some species, the seagrass has a much more important role locally, forming the basis of an important ecosystem which includes algae, invertebrates, juvenile fish and Brent geese. It is also important in stabilising sediments and reducing wave energy.

Seagrass does not recover well once damaged, so we must at the very least preserve what we have, and preferably facilitate more growth of the beds. Seagrass is just one example of what is being affected by sea lettuce blooms, and we will cover those on another occasion.

SOS Jersey, an entirely voluntary and unfunded body, has been campaigning on the issue of the sea lettuce blooms in St Aubin’s bay for many years now. The relevant (paid) States departments have been dragging their feet on the issue, with current Ministers, until summer 2016, being happy to blame the problem squarely in the French.

Happily, there is some (though not enough) acknowledgement now that the problem is partly home grown: that is, Jersey has helped create the conditions leading to sea lettuce blooms. We hope to see a truly integrated solution to ameliorating our nitrate-rich waters being developed very soon.

While scientific research shows furrowing can contribute both to stopping sea lettuce sporelings taking hold so much, and to enhancing the environmental conditions needed for good seagrass growth, local trials still need to take place. We understand the DoI/ Environment are, based on discussions with Tony Legg last autumn, to commence with trialling furrows. But, and it’s a big but, we are concerned that they are in the wrong place: data collected from this trial will be of no help in terms of our sea lettuce problems.

News Release

SEA LETTUCE – DFI TO CONDUCT FURROWING TRIALS IN ST AUBIN’S BAY ~ Is the States response to the sea lettuce problem too little, too late (and in the wrong place?)

SOS Jersey understand the Department of Infrastructure (DfI) will soon be starting furrowing trials to retard the growth of sea lettuce (Ulva lactuca) in St Aubin’s Bay. While we commend action on this issue, we believe the DfI will have wasted another year whilst St Aubin’s Bay becomes blighted with sea lettuce once again. Briefly, here is why we think this:

• Wrong place: The use of furrows trials at the west end of St Aubin’s Bay, away from the seagrass and where the sea lettuce blooms, is designed to fail: the beach profile, drainage conditions, and angle to prevailing wave action in the area to be trialled are will generate unhelpful data. This was pointed out to the Departments by marine expert Tony Legg in a meeting last November. The trials should take place in the centre of the Bay by the First Tower outfall.

• Wrong time: The trial should have started on the two sets of spring tides in April (a few hours a day on three or four consecutive days on each tide) and then again on May’s spring tides.  Instead, the DfI will be starting later this month when the sea lettuce will have already started to take hold.

• Testing the furrows: The DfI intend, as a first step, to make a few furrows ‘to determine the structural integrity over a few tides’. The furrows suggested by Tony Legg and SOS Jersey will be extremely shallow and will nearly disappear after a few tides. The surface will be raised a few centimetres only, to ‘flick away’ the juvenile Ulva on the retreating tide before it ‘sets’.  A much smaller percentage of seagrass will be affected by this than is currently affected by heavy plant moving up and down the beach. This information was carefully set out in the EIA which was done (as a favour to DfI) by Tony Legg last summer.

Currently summer and autumn season Ulva ‘swamps’ the seagrass; the assertion that the Ulva has no detrimental effect on seagrass is absurd and SOSJ wish to see a move to protect the seagrass beds by reducing the sea lettuce.

One conclusion is that this is a case of the relevant Departments wanting to be seen to do something, but knowing that their approach will be ineffective – then they can say, ‘It won’t work.’

We suggest that since it is now too late to have any effect for 2017, that the DfI start work properly, in the right area, at the right tides, as discussed by Tony Legg with both relevant Departments in November 2016. (SOSJ were not allowed to attend the meetings.)

Conclusion & Recommendations

Sea lettuce is going to be a problem again this year and the trials looking at how to at least partly deal with the problem should have started before now. While we have very recently been assured trials are to commence, due to ground conditions, the planned use of an area to the far west of St Aubin’s Bay will not achieve any of the desired results and will fail.

We would like to see:

The furrowing trials taking place where recommended by expert Tony Legg. A trial of as few as two furrows, in the right conditions, in the centre of St Aubin’s Bay will a) give evidence of all these projected outcomes and b) cause no long-term damage risks; these assertions are backed by scientific evidence from studies elsewhere.

An integrated approach to the Island’s ecology and water runoff nitrate load; things are beginning to happen in this direction, and while we still see a distinct lack of communication between different departments, we hope the situation will continue to improve.

Local expert knowledge being taken on board and not discarded or misinterpreted in the way that it currently is.

Finally, we would like to reiterate that, despite what is said about SOSJ, we are on the same side as the DoI and the Environment and want to see the end of the sea lettuce menace and all the problems it brings.

Links

Sea lettuce reports: http://sosjersey.co.uk/sea-lettuce/

Sea lettuce posts: http://sosjersey.co.uk/category/concern/pollution/sea-lettuce/

About sea lettuce: https://en.wikipedia.org/wiki/Sea_lettuce

About seagrass: https://en.wikipedia.org/wiki/Zostera_noltei

Interesting trials: http://www.int-res.com/articles/meps2005/298/m298p123.pdf; http://www.nationalgeographic.com/people-and-culture/food/the-plate/2016/12/the-future-of-fine-scotch-whisky-may-rest-on-restoration/; http://www.bbc.co.uk/news/uk-england-hampshire-39645107

More links on request – please say what you particular area to do with sea lettuce you are interested in.