The picture in the period between 1960 & 1980 is one of accelerating erosion & a downward trajectory for the health of the foreshore environment. Naturally occurring events like the "big freeze" in 1962/63 had a catastrophic impact on foreshore health and biodiversity. Human activities had an equally damaging effect during this period. The sustained use of toxic chemicals like tributyltin (an anti-fouling paint for boats) had an observable effect on aquatic life. Much like the damage of the post-war agrochemical boom of the 1950’s, tributyltin is highly toxic to marine life and participants noted that many sea grasses around the island began to disappear when it was used. Fishing and leisure vessels traditionally always moored in the Pyefleet channel to the west of the island, accessed via the channel between the Monkey Beach and Cobmarsh Island where some of the last eel grass grew on the island. With potentially a large number of boats coated with tributyltin being moored in the harbour, the cumulative effect of the daily wash of the tides could have played a key part in spreading the chemical along the shoreline, ultimately destroying the last remnants of the protective sea grasses. By 1980 sea-level rise was extending tidal reach & increasing the destructive capacity of erosion. Displaced material from the reducing marshes was settling in more sheltered areas, causing accretion & the sedimentation of creeks. Similarly, shell & hard matter that had been contained in the foreshore were extending nearby beaches & facilitating processes like longshore drift, itself a factor in blocking some creeks & reducing their navigability. As the tideline rose, areas that had been historically terrestrial in their grasses were joined by transition zone species, as the salinity of the environment increased. Flora such as phragmites reeds were joined by saltmarsh varieties like puccinellia, suaeda maritima, & spartina in places like Hove Marsh. Erosion in East Mersea had started forming taller cliffs at Cudmore as the depth of foreshore sediments reduced, meaning areas of marshland to the west of the cliffs had almost disappeared. The period also saw the disappearance of the last traces of some former creeks including Cumber Gut, which was observed as little more than a shallow drain on an ebbing tide.