State of the Bay Report 2010-Final - Anchor Environmental

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Table 8.3. W statistics at all stations sampled between 1999 and 2010 in Small Bay (1 = Undisturbed, 0 = moderately disturbed, -1 = Grossly disturbed) (Red indicates a decrease an green indicates an increase since the previous year) 1999 2004 2008 2009 2010 SB1 0.203 0.135 0.033 0.834556 0.194043 SB2 0.201 0.128 0.059 0.127981 0.21042 SB3 0.237 0.158 0.131 0.078899 0.17621 SB8 0.145 0.094 0.02 0.091269 0.072487 SB9 0.321 0.121 0.097 0.15265 0.03729 SB10 0.251 0.144 0.018 0.222488 0.213037 SB14 0.37 0.212 0.07 0.048497 0.123344 SB15 0.073 0.01 -0.067 0.043537 -0.0529 SB16 0.326 0.199 0.082 0.155185 0.148646 Table 8.4. W statistics at all stations sampled between 1999 and 2010 in Big Bay (1 = Undisturbed, 0 = moderately disturbed, -1 = Grossly disturbed)(Red indicates a decrease and green indicates an increase since the previous year). 1999 2004 2008 2009 2010 BB 20 - - 0.523014 0.121988 0.167017 BB21 0.277 0.223 0.078068 0.063047 0.162386 BB22 0.098 0.147 -0.07879 0.035334 0.109971 BB25 -0.07 0.182 0.028515 0.108905 0.290485 BB26 0.306 0.094 0.549562 0.180872 0.112742 BB29 0.083 0.266 0.419399 0.226174 0.248659 BB30 0.07 0.153 - -0.03724 0.095815 The W statistics calculated for each of the sites in Langebaan Lagoon in 2004, 2008, 2009 and 2010 were compared in Table 8.5. The long term fluctuations in the mean W statistic for Langebaan Lagoon did not correlate with physical parameters or any obvious anthropogenic discharges suggesting that the variations in the benthic community is caused predominantly by natural disturbance. The W statistic at six of the nine sites in Langebaan Lagoon reduced between 2009 and 2010. Most of the disturbance in the lagoon, particularly in the sanctuary (southern reaches), is most likely a result of the shallow nature of the lagoon and the fact that it is subject to strong currents and tidal activity. Indeed, the mud content recorded in the sediments in 2010 had reduced at most sites since 2009, suggesting increased flushing. State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 176
Table 8.5. W statistics at all stations sampled between 2004 and 2010 in Langebaan Lagoon (1 = Undisturbed, 0 = moderately disturbed, -1 = Grossly disturbed)(Red indicates a decrease an green indicates an increase since the previous year) 2004 2008 2009 2010 LL 31 0.276 0.178 0.26497 0.220529 LL 32 0.108 0.303 0.077271 0.232452 LL 33 0.216 0.099 0.415304 0.281207 LL 34 0.233 0.057 0.265976 0.247906 LL 37 0.295 0.362 0.256901 0.333258 LL 38 - - 0.166232 0.183672 LL 39 - - 0.244047 -0.06678 LL 40 - - 0.188317 0.184814 LL 41 - - 0.195189 0.032135 8.4.3 Species Diversity Indices 8.4.3.1 Spatial Analysis Mean values (± SE) for various diversity indices associated with macrobenthic communities in Small Bay, Big Bay and Langebaan Lagoon have been represented graphically in Figure 8.14. Species diversity (H’), species evenness (J), species richness (d) and the total number of species (S) is notably higher in Big Bay and Langebaan Lagoon when compared to Small Bay, but the difference is not significant (p > 0.05). These results, coupled with the W statistics and the results of the sediment analysis (see §6), indicate that macrobenthic communities in Small Bay are subject to the greatest degree of anthropogenic stress when compared to Big Bay and Langebaan Lagoon. The species diversity (represented by the Shannon Weiner Index, H’) for Saldanha Bay and Langebaan Lagoon in 2010 is represented in Figure 8.15. The diversity of species in Small Bay is lowest at the Yacht Club Basin (SB1), Mussel farm (SB9), along the Multi-Purpose Terminal (SB15) and in the middle of the bay (SB8). The low species diversity in the Yacht Club Basin is most likely due to the polluted state of this site (see §6), while the low diversity at the Multi-Purpose Terminal is most likely due to dredging that occurred in the area in 2007/08. Furthermore both the yacht club basin and the area below the ore jetty in Small Bay have been recognized as ‘key problem areas’ that suffer from reduced water movement which leads to the accumulation of fine grained particles and organic matter, to which toxic substances such as metals and hydrocarbons adsorb (CSIR 2002). The remaining five sites in Small Bay have low levels of diversity (H’ values ranging from 0.91 to 1.90). Overall the diversity in Big Bay is low to moderate (H’ values ranging between 1.4 and 2.3). The diversity of benthic macrofauna in Big Bay was lowest at sites near the ore jetty and Small Bay. The lower levels of diversity are most likely a consequence of anthropogenic disturbances that have occurred along the ore jetty (dredging) and within Small Bay (fish factory effluent, mussel farms, sewerage). Sites BB25 and BB29 both had a relatively high diversity compared to other Big Bay sites. Examination of the sediment characteristics and the concentration of contaminants provide no apparent reason for the variation in diversity between sites. State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 177
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State of the Bay 2010: Saldanha Bay
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TABLE OF CONTENTS Anchor Environmen
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11 BIRDS 234 Anchor Environmental 1
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LIST OF FIGURES Anchor Environmenta
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Anchor Environmental Figure 4.27. O
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Anchor Environmental Figure 7.3. Ch
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Anchor Environmental Figure 9.10. C
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Anchor Environmental Figure 12.1. N
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Anchor Environmental samples were c
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EXECUTIVE SUMMARY Anchor Environmen
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Anchor Environmental matter in the
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Anchor Environmental considered mos
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Anchor Environmental again in 2004,
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Anchor Environmental Populations of
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GLOSSARY Alien species An introduce
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1 INTRODUCTION Anchor Environmental
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2 STRUCTURE OF THIS REPORT Anchor E
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Anchor Environmental complicates ma
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Anchor Environmental observed deter
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Anchor Environmental 4 ACTIVITIES A
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Fish factories Small craft harbour
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Anchor Environmental Aerial photogr
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Anchor Environmental interferes wit
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Anchor Environmental Figure 4.7. Nu
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o Decrease in oxygen concentrations
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Anchor Environmental Upgrades to th
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Anchor Environmental Figure 4.9. A)
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Anchor Environmental (possibly link
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Anchor Environmental Prestedge Reti
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Anchor Environmental the constructi
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Number and types of vessels enterin
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Anchor Environmental is contained b
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Anchor Environmental include the be
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o 33 3’S o 33 10’S Saldanha Bay
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Anchor Environmental (1956) UNDER T
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Free ACtive Chlorine (mg/l) Amonia
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Faecal coliforms (org/100 ml) Chemi
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4.3.7 Storm water Anchor Environmen
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Anchor Environmental sites (concent
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Anchor Environmental Discharges fro
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Anchor Environmental Table 4.9. Det
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5 WATER QUALITY Anchor Environmenta
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Anchor Environmental Stander (1977)
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Anchor Environmental coast, result
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Anchor Environmental likely as a re
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Anchor Environmental Construction o
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Anchor Environmental Table 5.2. Per
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Counts per 100ml of sample Counts p
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Counts per 100ml of sample 10000 10
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5.6 Trace Metal Contaminants in the
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Lead(mg/kg) Mercury (mg/kg) Cadmium
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6 SEDIMENTS 6.1 Sediment particle s
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6.1.2 Sediment Particle size result
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100% 90% 80% 70% 60% 50% 40% 30% 20
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Page 125 and 126: % POC 18 16 14 12 10 8 6 4 2 0 % PO
Page 127 and 128: Percentage Percentage 1.8 1.6 1.4 1
Page 129 and 130: o 33 3’S o 33 10’S Yacht Club B
Page 131 and 132: Figure 6.12. Variation in the conce
Page 133 and 134: The concentrations of metals in sed
Page 135 and 136: concentrations are 56 and 29 times
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Page 139 and 140: Cadmium (mg/kg) 8 7 6 5 4 3 2 1 0 C
Page 141 and 142: Copper (mg/kg) 45 40 35 30 25 20 15
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Page 145 and 146: In summary, elevated trace metal co
Page 147 and 148: 6.5 Summary of sediment health stat
Page 149 and 150: 7.1 Long term changes in seagrass i
Page 151 and 152: 7.2 Long term changes in Saltmarshe
Page 153 and 154: Figure 8.1. Benthic macrofauna samp
Page 155 and 156: Table 8.1. Depth at each of the sit
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Page 159 and 160: (clustering of similar groups) (Meg
Page 161 and 162: The Big Bay samples BB 25 and BB29
Page 163 and 164: 2007/08 dredging. Other signs of th
Page 165 and 166: Wet mass per m² Wet mass per m² 4
Page 167 and 168: Big Bay Crustaceans and polychaetes
Page 169 and 170: Average number of individuals per m
Page 171 and 172: Number Individuals per m² Number I
Page 173 and 174: 8.4.2 Abundance Biomass Indices 8.4
Page 175: and percentage organic nitrogen (PO
Page 179 and 180: Figure 8.15: Variation in the diver
Page 181 and 182: percentage of mud compared to Lange
Page 183 and 184: Cu (mg/kg) Cd (mg/kg) Ni (mg/kg) Pb
Page 185 and 186: contaminants. Furthermore dredging
Page 187 and 188: areas even 5 months after the clear
Page 189 and 190: Brittle star ( Ophiuroidea spp) Sea
Page 191 and 192: 9.2 Approach and Methodology 9.2.1
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Page 195 and 196: 9.2.3 Data Analysis The similaritie
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Page 201 and 202: Plocamium spp. Ecklonia maxima Scut
Page 203 and 204: 20 40 A Group 1 B 60 Similarity C G
Page 205 and 206: Percentage Cover 80 70 60 50 40 30
Page 207 and 208: Evenness Shannon Wiener 0.9 0.8 0.7
Page 209 and 210: 2005 2008 2009 2010 Dive School Jet
Page 211 and 212: Table 9.5. Results from the SIMPER
Page 213 and 214: In general, the inter-annual differ
Page 215 and 216: The temporal distribution of M. gal
Page 217 and 218: Consistent with the previous years,
Page 219 and 220: Saldanha and Langebaan. Results fro
Page 221 and 222: The average abundance of the four m
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Anchor Environmental Figure 10.5. A
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Anchor Environmental Figure 10.7. A
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Anchor Environmental Within Big Bay
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Anchor Environmental 2008 and 2009
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Anchor Environmental the islands, b
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Anchor Environmental at Saldanha ar
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their main prey species, sardines a
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Anchor Environmental 2009). The eff
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Anchor Environmental attributed to
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Number of breeding pairs 800 700 60
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11.3 Birds of Langebaan Lagoon 11.3
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Anchor Environmental Figure 11.11.
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Anchor Environmental for the gannet
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Taxon Anchor Environmental Occurren
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Taxon Anchor Environmental Occurren
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Anchor Environmental 13 MANAGEMENT
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Anchor Environmental their operatio
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Anchor Environmental concentrations
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Anchor Environmental changes that p
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Anchor Environmental and slight imp
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Birdlife International. 2010. URL w
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Anchor Environmental penguins Sphen
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Anchor Environmental Game, E.T., Gr
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Anchor Environmental Kerwath, S. E.
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Anchor Environmental Moldan, A. 197
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Anchor Environmental Robinson, T.B.
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Anchor Environmental Tunley KL, Att
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