Seagrass-Watch Magazine Issue 47 - March 2013 | Page 40

England Cornwall discovery Article by Emily Jenkinson Photography by Emily Jenkinson & Clare Marshall England EJ After centuries of shipping traffic and maintenance dredging, seagrass and its diverse faunal assemblage were found to persevere in Fowey estuary. The Fowey River is situated in Cornwall, south west England; over 33 km from its source on Bodmin Moor to the mouth of the estuary at Fowey(1), the tidal limit of the estuary approximately 8 km up river at Lostwithiel. Fowey is a deep water harbour that is a very important exporting port on the south west peninsula, being the largest in tonnage terms. It is also in the top twelve ports for non-oil product exports in the United Kingdom(2), and accommodates over 7000 visiting craft through the summer season with up to 1500 resident craft. Cargoes through the port include: the export of copper, tin and china clay; the import of coal, timber, limestone; and general cargo such as coal was unloaded at Berrills Wharf as late as the 1960s (1), and Lostwithiel in the 13th century was a key stannery town for the county’s mining industry(3). This historical and contemporary commercial interest has necessitated a maintenance of deep water channels because sediment accretion in the lower harbour from mining activity further upstream since the late 16th century has silted up the intertidal regions of the river (4). Maintenance dredging in the lower harbour in the early part of the 20th century gave access to the berths upstream by larger vessels, allowing china clay to be shipped regularly through the port. Regular dredging continues with support of annual hydrographic surveys (5), however due to historic heavy metal contamination(6) sediment removal is minimised(5). It is in areas which were possibly previously dredged that Cornwall Wildlife Trust and Fowey Harbour Commissioners have carried out a preliminary survey and assessment of the Fowey Estuary seagrass meadows (early October 2011). Snakelocks anemone (Anemonia viridis) in Zostera meadow, Fowey Estuary Anemonia viridis CM Snakelocks anemone (Anemonia viridis) has long flexuous tentacles which are a grey-brown or bright green in colour. The green variety has purple tips to the tentacles. The tentacles rarely withdraw into the col