State of the Bay Report 2010-Final - Anchor Environmental

Anchor Environmental
Figure 8.17. MDS of Saldanha Bay and Langebaan Lagoon benthic macrofauna abundance (2010)
with superimposed circles representing depth (Increasing circle size = deeper) ....... 181
Figure 8.18. MDS of Saldanha Bay and Langebaan Lagoon benthic macrofauna abundance (2010)
with superimposed circles representing abiotic factors: Particulate Organic Carbon
(POC), Particulate Organic Nitrogen (PON), % Gravel and % Mud (Increasing circle size
= larger measurement). ........................................................................................... 182
Figure 8.19. MDS of Saldanha Bay benthic macrofauna abundance (2009) with superimposed
circles representing concentrations of select metals: Cu, Cd, Pb and Ni. Circle size is
proportional to magnitude of concentration (increasing circle size = larger
concentration) ........................................................................................................ 183
Figure 8.20. Two-dimensional PCA ordination of the environmental variables (metals, POC and
PON; transformed and normalized) for Saldanha Bay 2010...................................... 183
Figure 8.21. Benthic macrofauna species frequently found to occur in Saldanha Bay and Langebaan
Lagoon, photographs by: Charles Griffiths. .............................................................. 188
Figure 8.22. Benthic macrofauna species frequently found to occur in Saldanha Bay and Langebaan
Lagoon, photographs by: Charles Griffiths. .............................................................. 189
Figure 9.1. Positions of the eight rocky intertidal study sites in Saldanha Bay. ........................... 192
Figure 9.2. The rocky shore study sites in 2009 from top right to left bottom: Dive School, Jetty,
Schaapen Island East, and Schaapen Island West. .................................................... 193
Figure 9.3. The rocky shore study sites in 2009 from top right to bottom left: Iron Ore Jetty, Lynch
Point, North Bay, and Marcus Island. ....................................................................... 194
Figure 9.4. Top left to bottom right: High shores at Dive School, Iron Ore Jetty, Schaapen West
with blue green algal cover, and at Marcus Island. .................................................. 197
Figure 9.5. From top right to bottom left: Mid shores at Jetty, Schaapen East showing rock
depression with orange sponge and Ulva spp., Iron Ore Jetty with dense Balanus
glandula cover (insert showing Afrolittorina knysnaensis nestling among barnacles),
and Mytilus galloprovincialis, B. glandula and Ulva spp. partially growing on mussels
recruits at Marcus Island. ........................................................................................ 198
Figure 9.6. Low shore at the sheltered site Dive School dominated by the algae Gigartina
polycarpa (top left), Ralfsia verrucosa and Ulva spp.(top right), the anemone
Pseudoactinia flagellifera (bottom left), and the sea urchin Parechinus angulosus in
rock pools with sparse cover of the indigenous mussels Aulacomya ater and
Choromytilus meridionalis (bottom right). ............................................................... 199
Figure 9.7. Top: Low shore at the semi-exposed/exposed site North Bay showing mussel band and
emerging kelp Ecklonia maxima. Bottom: Low shore at the exposed site Marcus Island
with the mussel bed overgrown by red algae and patches of ‘pink’ encrusting
corallines in between. The limpet Scutellastra cochlear, which is associated with the
encrusting corallines, is fringed by a narrow garden of fine red algae. ..................... 202
Figure 9.8. The mean abundance (number/0.5 m 2 ) of the most important mobile species at the
eight rocky shores in 2010. ...................................................................................... 202
Figure 9.9. Dendrogram (top) and multi-dimensional scaling (MDS) plot (bottom) of the rocky
shore communities at the eight study sites in 2010. The circles in the MDS plot
indicate a 40% (black) and 50% (red) similarity level. See text for further explanation.
............................................................................................................................... 203
State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 14