Built around oyster work
The Mersea Harbour Protection Trust describes Packing Marsh as a former centre for grading and packing oysters for London and European markets in the nineteenth century. The island is crossed by a series of oyster pits running roughly across the shoreline.
Those pits are part of the same working system as the restored Packing Shed: oysters could be held, sorted and prepared close to the productive beds and navigable creeks rather than carried immediately onto the main island.
A marsh that has physically shrunk
Historic mapping used by the harbour-protection project shows substantial loss around the island’s margins. The Trust calculated a 35% loss of marsh between 1888 and 1997, followed by a further 13% decrease around the perimeter between 1997 and 2014.
Shell dumped from the oyster industry, including slipper-limpet shell, has helped form harder ridges around parts of the island. The harbour-protection account identifies the slipper-limpet shell as material cleared from nearby oyster beds in the 1930s and 1940s. Later sand and gravel accumulated around the marsh edge, while the old pits remained visible in its interior. That accidental protection sits beside more deliberate modern shoreline management.
The 2021 recharge
Work began at Packing Marsh on 7 November 2021. Over three days the dredger Sospan Dau placed 5,000 cubic metres of sand and gravel on the island. The material was part of the wider 98,000-cubic-metre harbour recharge completed in January 2022. The project’s construction update records the sequence of dredging and placement.
The four-and-a-half-acre island
Packing Shed Marsh Island was used by the Tollesbury & Mersea Native Oyster Fishing Company for oyster handling and storage. At its busiest, more than sixty fishermen worked there, with oysters being cleaned and graded for despatch to London and continental markets.
The fishery company bought the freehold of the four-and-a-half-acre island in August 1914 for £215. The restored Packing Shed remains owned by the company and is leased to the community trust.