State of the Bay Report 2010-Final - Anchor Environmental

Anchor Environmental
differences in the fish community between sites averaged across all sample years (Global R = 0.45,
P< 0.01) and between sample years (Global R = 0.268, P< 0.05). Pairwise tests indicate that the only
significant differences between year groups were between 2005 and 2010 samples. However, it is
clear from the MDS plot that 2010 samples were similar to most sites sampled in all other years
(including some of the 2005 samples) and it is the 2005 samples that are “outliers” rather than the
2010 samples. SIMPER analyses identified higher abundance of harders, silversides, white
stumpnose and Cape sole and lower abundance of blacktail, gobies, gurnards and klipvis in the 2010
samples compared to the 2005 samples, as the dominant causes (80%) of dissimilarity between
these two sampling events.
Transform: Fourth root
Resemblance: S17 Bray Curtis similarity
2D Stress: 0.19
site
Bluewater Bay
Campsite
Smallcraft harbour
Hoedtjies Bay
Transform: Fourth root
Resemblance: S17 Bray Curtis similarity
2D Stress: 0.19
year
94
2005
2007
2008
2009
2010
Figure 10.8. Multidimensional scaling plots showing similarities between the fish communities sampled at
four sites within Small Bay during 1994, 2005, 2007, 2008, 2009 and 2010 sampling events.
Note that three replicate samples were collected at each site in each year.
State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 230