The first real noticeable outcome from observations of the estuary whilst sampling, is that a large percentage of the mud is made up of China Clay. This is present as a result of being emitted by plants further up the Plym. It covers large areas, usually deposited in layers or bands, and restricts the mobility of the sediment macrofauna to the extent of it being near unhabitable. Certain common estuarine species such as Corophium volutator appear to be unusually low in number. This observation is suggested to be a reason for the poor bird population found around the estuary. Species such as Hediste diversicolor and Carcinus maenas however are found in high numbers. It is recommended that the China Clay deposits in the estuary are mapped and studied in full. Also, more work is recommended on populations of particular species such as Corophium volutator, and a 12 month study conducted on the estuarine bird population.
