A Rocha Portugal Observatory Report 2009-2010

14 A Rocha Portugal Observatory Report 2009-2010
A considerably large number of empty Bittium reticulatum shells were recorded. No living specimens were
found, but numbers of these shells were greater at almost all sampling points than other similar small-sized
species such as Hydrobia, Turbonilla or Rissoa. Only the sampling site in Alvor gave equal or higher numbers
of Hydrobia sp. than Bittium reticulatum.
Table 4 Total number of living specimens found during this study in the Alvor Estuary 2010.
January March May
Species 4a 5a 5b 6a 6b 4a 5a 5b 6a 6b 4a 5a 5b 6a 6b
Abra tenuis 6 3
Calyptrea chinensis 1
Cardium edule 1 2 1 14 2 1 1 2 2 1
Cerithium vulgatum 1 1 1 1 10
Cyclope neritea 5 1 6 4
Gibbula umbilicalis 2 4 2
Haminoea navicula 2 2
Hydrobia acuta 1
Hydrobia neglecta 60
Hydrobia ulvae 3 6 120 12 3 9 3 24
Jujubinus striatus 1
Lepidochitona cinereaus
(Polyplacophora)
1 3
Loripes lacteus 43 8 21
Mesalia mesal 5 10 4 4 2 5 15
Monodonta lineata 1 1 1 2 1 2 2
Nassarius pfeifferi 1 2 1 5 8 3 8 1 6
Nassarius reticulatus 2 2 1 1 2
Ostrea edulis 1
Paphia aurea 1
Paphia rhomboides 1 3
Scrobicularia plana 1 7 4
Spisula subtruncata 1
Tapes decussatus 1 1
Tellina tenuis 1 10 8 6 7 1
Venerupis senegalensis 1
Results by sampling site
At the Western Marsh (4a) a total of 101 living specimens from 8 species were recorded from the samples.
As it can be seen in Figure 6 the highest number of living specimens (54) was obtained in January
comprising largely of individuals of Loripes lacteus (43 specimens). In general the number of species
recorded at this site was lower than at other sample sites in the Alvor Estuary. Hampel et al (2009) in her
studies also found lower number of species in salt marsh habitat than in the estuary.