A Rocha Portugal Observatory Report 2009-2010

A Rocha Portugal Observatory Report 2009-2010 15
Figure 2 Number of live specimens found at the Western Marsh sampling site (4a).
At the Upper Estuary sample site (5a) all of the living specimens found (43) belonged to one of 9 species.
The highest abundance of individuals recorded was found to be Cardium edule (17 individuals in total, 14 in
the March sample). Nassarius pfeifferi was also quite commonly recorded. In January and May the number
of different species identified was similar, however in March only 3 of the most common species were
found alive (Figure 7).
Figure 3 Number of live specimens found at the Upper Estuary sampling site (5a).
At the Lower Estuary sample site (5b) 75 live specimens were recorded from a range of 13 species. The
greatest abundance of a species belonged to Tellina tenuis in the first month’s sample, but the number of
specimens of other species was more regular over the study period (Figure 8). When undertaking sampling
in May a big group of Cerithium vulgatum (around 30 individuals) was seen near to the sampling point, but
not included in graph’s data, because it was not in the sample.