Sue Daly / Thong Weed (Himanthalia elongata) English Channel, off the coast of Sark, Channel Islands, July

Linda Pitkin / 2020VISION / John dory (Zeus faber), with Sea thong (Himanthalia elongata) in the background, Porthkerris Cove, Cornwall, England, UK, June

Nick Upton / Spiny starfish (Marthasterias glacialis) among mix of Tangleweed kelp (Laminaria digitata), Thongweed (Himanthalia elongata) and Toothed wrack (Fucus serratus), Wembury, Devon, UK, August.

Nick Upton / Epiphytic red alga (Ceramium sp.) tufts growing on tips of Thongweed (Himanthalia elongata) fronds just below extreme low water on a spring tide, alongside clumps of Toothed wrack (Fucus serratus) nea...

Nick Upton / Bulbous holdfast and large spreading frond of Furbellows (Saccorhiza polyschides), a large kelp, attached to rocks very low on the shore alongside Thongweed (Himanthalia elongata) and Tangleweed kelp...

Nick Upton / Epiphytic red alga (Ceramium sp.) tufts growing on tips of Thongweed (Himanthalia elongata) fronds just below extreme low water on a spring tide, near Falmouth, Cornwall, UK.

Alex Hyde / Thongweed / Sea Thong (Himanthalia elongata) against white background. From the Isle of Skye, Inner Hebrides, Scotland, UK.

Nick Upton / Sea thong (Himanthalia elongata) mature plants and juvenile 'buttons' exposed at low tide, Crail, Fife, UK, July

Nick Upton / Sea thong (Himanthalia elongata) attached to rock alongside Toothed wrack (Fucus serratus) hanging down at low tide, Crail, Fife, UK, July

Nick Upton / Sea thong (Himanthalia elongata) mature plants and young 'buttons' exposed at low tide alongside a variety of red algae, with kelp beds in the background, Crail, Fife, UK, July

Nick Upton / Sea thong (Himanthalia elongata) mature plants and young 'buttons' exposed at low tide alongside a variety of red algae, with kelp beds in the background, Crail, Fife, UK, July

Nick Upton / Young Sea thong (Himanthalia elongata) 'buttons' on intertidal rocks exposed at low tide, Crail, Fife, UK, July