It is a low spring tide, chosen especially because it allows us to scan a vast area of the shore. Above Mawbray Banks, pilot Andrew Lysser turns the gyroplane in a circle, its rotors buzzing and clattering, and I lean out – held only by my seat-belts – and attempt to take photos of the various rows of stones below us; triangles, rectangles, straight lines and right-angles. The lines are spaced across the pebble-stippled shore, some as continuous lines, others interrupted by bands of sand.
Many years ago, while I was walking down the shore to the far-off mussel beds on the Ellison’s Scaurs with marine biologist Dr Jane Lancaster, we had come across parallel lines of boulders between which lay a fairly smooth passage of sand. My friend Ronnie Porter of Allonby, who had told me the names of the great erratic boulders and rocky scaurs on the Allonby shore, had said that these lines were known as ‘the roads’, and had perhaps been cleared to allow boats to be pulled up, or to allow baited lines to be strung across. Jane sent photos to some colleagues who speculated that they might be boundary markers for catching fish or collecting cockles. Later she forwarded two aerial photos to me, not of the parallel ‘roads’ but of a triangular shape with a linear ‘tail’ – and that of course led to further investigation.
So, in March 2014 I took the photos with me for orientation and searched the mid-to-lower shore for the geometrical shapes. As I noted then, “it was a bright morning, but the wind was eye-wateringly cold. The shore has been re-modelled by the January storms so that comforting landmarks are no longer there; sand, that once hid much of the rocky, pebbly mid-shore, has been sluiced away and moulded into domes and hollows. Stones, each formerly a little ecosystem of adherent organisms and weed, are bright with the tatters of mussel-shells and broken barnacles.”
It was thrillingly easy to find the triangle and its tail; many of the stones were greyish and rounded, others were paler granite from the Scottish side; there were several large glacial erratics which seemed to serve as markers. I spent a long time pacing the lines, noting how shallow pools of water remained trapped on the landward side of corners.
And so this led to my gyroplane flight , to understand the relationship of the stone shapes to the shore itself and to the longshore drift and line of the ebbing tide. From above I marvel at the straight dark lines, as though the marks have been stippled with a crumbling stick of charcoal upon the smeared brush-strokes of the pebbly scaurs. And now it seems obvious that the corners had been built to trap the ebbing tide, to capture fish as they attempt to follow the falling sea. Perhaps the long lines of stones served like low dams to guide the outflowing water into the traps? These structures were surely built by people who understood the often complex movements of water on the shore, where the tides and currents were influenced not just by the Moon but by the weather and the rainfall, influencing the rivers and becks that flow into the giant estuary that is the Solway Firth.
When Hale  was surveying parts of the Scottish coast for fish-traps he found similar stony structures on the shores of the Beauly Firth in North-east Scotland. Archaeologist and aerial surveyor Jamie Crawford flew over those lines of stones for his BBC Scotland ‘Scotland from the Sky’  series and – when we exchanged photographs – he agreed that the Mawbray lines indeed looked very similar.
But were the fish traps formed only of the stones, or were wooden and net structures perched on top of them?
In their archaeological investigation of fish-trapping methods in the Severn estuary, Chadwick and Catchpole  found a wide variety of traps based on stone. In some cases, small piles of stones indicated their use as anchors for wooden poles. Elsewhere, rows of stones apparently anchored lines of post-and-net structures. But they also found densely-packed lines of stones that acted as traps on their own, with a gap at a corner where the trapped fish would have been funnelled into a net or basket. Similarly, traps with nets, and traps made of walls of stone, have been found on the Irish coast. Mark Graham, of Grampus Heritage, has carried out many archaeological studies related to the Cistercians on the Cumbrian Solway coast, and he kindly pointed me to a paper about fish traps on the Irish coast, where – in Strangford Lough in the 12th century – “The concentration and intensification of the stone trap fisheries represents an investment by the Cistercian community underlining the status of the stone trap as a major economic resource. The export of fish to the home of the order (Holm Cultram on the Solway Firth, England) was part of a maritime trade corridor that linked Ireland and Britain that was utilised by Edward I to feed his army in Scotland in 1298.”  
As a suitable local ‘project’ during Lockdown3, in March 2021, I went back to the Mawbray shore with a clearer idea of what to look for. The stones are much less tightly-packed together than in the traps shown in the Severn photos – but the Solway’s tides are strong and regularly shift sediment and rocks on the shores. Stone traps or weirs at Minehead in Somerset are still in use and require frequent rebuilding; see Fig 7 in Historic England report  where a man is lifting a very large boulder! There was an area near a corner where the rocks were closely abutted, their smooth sides facing inwards. Could this have been the entrance to a funnel? So far I have seen no signs of any wood – even though wooden structures relating to the saltpans and possibly more than 250 years old are still preserved further down the coast at Crosscanonby .
Given that wooden structures such as stake nets and poke nets – all of which are high maintenance, both in positioning and cleaning [referenced in videos about haaf-netting by Annan Common Good, 8] have been commonly used along the Scottish shores even until recently – it’s quite possible that a simpler form of trap could have been used on the stonier southern side. Fish become trapped and are scooped up with hand-nets: flounder and plaice, dogfish and skate, codling and even bass…
The tide was very low, the water long drained from the middle shore, but several of the shapes were still retaining shallow pools of water. I paced one long straight row and it was nearly 200 metres long. Much further down the shore, I could just pick out more dark lines and telltale glimmers of caught water. Different rows might have led the water into traps, or been built by different fisher families.
My friend and professional photographer James Smith flew his drone over the area in 2018 and again this month and the triangle, part-rectangles, and long leading edges are clearly visible.
When were they built and by whom? There is no trace of the lines on the OS maps for 1844 or 1866, nor on the Admiralty chart for the area of 1875. A brief note in the NW Coastal Zone Rapid Assessment  states that “The trap is similar to those recorded at Nethertown and St Bees and is therefore interpreted as medieval in date” [my italics], although there is no obvious evidence for this assumption.
The traps could be older; they could be younger; they could be a mixture of ages, some re-purposed to create others. Their stories seem to have been lost even from oral history: my local enquiries have produced no answers. We will probably never know (see my article  on the Impermanence of Colonisation).
My thanks to my industrial archaeologist friend Dr Peter Stanier for tracking down some relevant papers; to Mark Graham for the paper on Irish fish traps and for discussions; and to Don O’Meara, Science Advisor and Inspector of Ancient Monuments in the North-East, Historic England for discussions.
 AGC Hale (2003) Fish-traps in Scotland: construction, supply, demand and destruction.
RURALIA V conference proceedings, January 2003. Online at http://ruralia2.ff.cuni.cz/wp-content/uploads/2018/04/16 Hale.pdf
 AM Chadwick & T Catchpole (2010) Casting the net wide: mapping and dating fish traps through the Severn Estuary Rapid Coastal Zone Assessment. Archaeology in the Severn Estuary, 21, pp47-80 https://www.gloucestershire.gov.uk/media/6097/archaeology_in_the_severn_estuary_2010-62756.pdf
 P. Montgomery & W Forsythe (2015) Intertidal fish traps in Ireland. Journal of Marine Archaeology 10, pp117-139 https://www.researchgate.net/publication/281523109_Intertidal_Fish_Traps_from_Ireland_Some_Recent_Discoveries_in_Lough_Swilly_Co_Donegal
 See also chapters 4 (Marshes and Merses) and 8 (Sea-food) in Ann Lingard (2020) The Fresh and the Salt https://thefreshandthesalt.co.uk/book/
 Historic England (2018) River Fisheries and Coastal Fish Weirs: Introductions to Heritage Assets. Swindon. Historic England. https://historicengland.org.uk/images-books/publications/iha-river-fisheries-coastal-fish-weirs/heag226-river-fisheries-coastal-fish-weirs/
 Annan Common Good https://www.annan.org.uk/haaf-netting/index.html
 Pp323-4. NW Regional Coastal Zone Rapid Assessment, Phase 2 Project; Historic England: https://research.historicengland.org.uk/Report.aspx?i=15775 .
 Ann Lingard (2021) The Impermanence of Colonisation, in Dark Mountain 10 https://dark-mountain.net/this-tidal-life/
 Saltpans at Crosscanonby https://solwayshorewalker.wordpress.com/2021/03/19/the-saltpans-at-crosscanonby/