State of the Bay Report 2010-Final - Anchor Environmental

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Anchor Environmental Some of the indirect consequences of an increase in phytoplankton biomass and high levels of nutrient loading are a decrease in water transparency and an increase in epiphyte grown, both of which have been shown to limit the habitat of benthic plants such as seagrasses (Orth and Moore 1983). Furthermore, there are several studies documenting the effects that shifts in natural marine concentrations, and ratios of nitrates, phosphates and elements such ammonia and silica, have on marine organisms (Herman et al 1996; van Katwijk et al 1997; Hodgkiss and Ho 1997; Howarth et al 2011). For instance, the depletion of dissolved Silica in coastal systems, as a result of nutrient enrichment, water management and the building of dams, is believed to be linked to worldwide increases in flagellate/dinoflagellate species which are associated with harmful algal blooms, and are toxic to other biota (Hodgkiss and Ho 1997; Howarth et al 2011). The toxic effect that elevated concentrations of ammonia have on plants has been documented for Zostera marina, and shows that plants held for two weeks in concentrations as low as 125 µM start to become necrotic and die (van Katwijk et al 1997). The effects of organic enrichment, on benthic macrofauna in Saldanha Bay, have been well documented (Jackson and Gibbon 1991, Kruger 2002, Kruger et al. 2005, Stenton-Dozey 2001). Tourism and mariculture are both important growth industries in and around Saldanha Bay, and both are dependent on good water quality (Jackson and Gibbon 1991). The growth of attached algae such as Ulva sp. and Enteromorpha sp. on beaches is a common sign of sewage pollution (Clark 1986). Nitrogen loading in Langebaan Lagoon associated with leakage of conservancy/septic tanks and storm water runoff has resulted in localised blooms of Ulva sp. in the past. In the summer 1993- 94, a bloom of Ulva lactuca in Saldanha Bay was linked to discharge of nitrogen from pelagic fish processing plants (Monteiro et al. 1997). Dense patches of Ulva sp. are also occasionally found in the shallow embayment of Oudepos (CSIR 2002). Organic loading is a particular problem in Small Bay due to reduced wave action and water movement in this part of the Bay caused by harbour structures such as the Ore Jetty and the Causeway, as well as the multitude of organic pollution sources within this area (e.g. fish factories, mariculture farms, sewage outfalls, sewage overflow from pump stations, and storm water runoff). Langebaan Lagoon is also sheltered from wave action but strong tidal action and the shallow nature of the lagoon make it less susceptible to the long term deposition of pollutants and organic matter (Monteiro 1999 in CSIR 2002). There is one waste water treatment works (WWTW) in Saldanha and one in Langebaan. The WWTW in Saldanha disposes of treated effluent into the Bok River where it drains into Small Bay adjacent to the Blouwaterbaai Resort. In addition to sewage waste, the WWTW in Saldanha also receives and treats industrial waste water from a range of industries in Saldanha: Sea Harvest Hoedtjiesbaai Hotel Protea Hotel Southern Seas Fishing (no longer in operation) Bongolethu Fishing Enterprises SA Lobster Cape Reef Products TNPA -Arcelor Mittal Namaqua Sands Abattoir Duferco State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 68
o 33 3’S o 33 10’S Saldanha Bay 0m 1500m 3000m 4500m 6000m o 17 50’E Small Bay Waste water treatment works Sewage pump stations Conservance tanks Bok River Big Bay Oudepos Stofbergsfontein Club Mykonos Langebaan Langebaan Lagoon Oosterwal Anchor Environmental Figure 4.17. Location of waste water treatment works, sewage pump stations and conservancy tanks in Saldanha and Langebaan area These discharges reportedly often place the plant under considerable stress and result in the discharge of substandard effluent (CSIR 2002). State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 69
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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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Page 19 and 20: Anchor Environmental samples were c
Page 21 and 22: EXECUTIVE SUMMARY Anchor Environmen
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Page 27 and 28: Anchor Environmental again in 2004,
Page 29 and 30: Anchor Environmental Populations of
Page 31 and 32: GLOSSARY Alien species An introduce
Page 33 and 34: 1 INTRODUCTION Anchor Environmental
Page 35 and 36: 2 STRUCTURE OF THIS REPORT Anchor E
Page 37 and 38: Anchor Environmental complicates ma
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Page 41 and 42: Anchor Environmental 4 ACTIVITIES A
Page 43 and 44: Fish factories Small craft harbour
Page 45 and 46: Anchor Environmental Aerial photogr
Page 47 and 48: Anchor Environmental interferes wit
Page 49 and 50: Anchor Environmental Figure 4.7. Nu
Page 51 and 52: o Decrease in oxygen concentrations
Page 53 and 54: Anchor Environmental Upgrades to th
Page 55 and 56: Anchor Environmental Figure 4.9. A)
Page 57 and 58: Anchor Environmental (possibly link
Page 59 and 60: Anchor Environmental Prestedge Reti
Page 61 and 62: Anchor Environmental the constructi
Page 63 and 64: Number and types of vessels enterin
Page 65 and 66: Anchor Environmental is contained b
Page 67: Anchor Environmental include the be
Page 71 and 72: Anchor Environmental (1956) UNDER T
Page 73 and 74: Free ACtive Chlorine (mg/l) Amonia
Page 75 and 76: Faecal coliforms (org/100 ml) Chemi
Page 77 and 78: 4.3.7 Storm water Anchor Environmen
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Page 81 and 82: Anchor Environmental Discharges fro
Page 83 and 84: Anchor Environmental Table 4.9. Det
Page 85 and 86: 5 WATER QUALITY Anchor Environmenta
Page 87 and 88: Anchor Environmental Stander (1977)
Page 89 and 90: Anchor Environmental coast, result
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Page 93 and 94: Anchor Environmental Construction o
Page 95 and 96: Anchor Environmental Table 5.2. Per
Page 103 and 104: Counts per 100ml of sample Counts p
Page 105 and 106: Counts per 100ml of sample 10000 10
Page 107 and 108: 5.6 Trace Metal Contaminants in the
Page 109 and 110: State of the Bay 2010: Saldanha Bay
Page 111 and 112: Lead(mg/kg) Mercury (mg/kg) Cadmium
Page 113 and 114: 6 SEDIMENTS 6.1 Sediment particle s
Page 115 and 116: 6.1.2 Sediment Particle size result
Page 117 and 118: State of the Bay 2010: Saldanha Bay
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100% 90% 80% 70% 60% 50% 40% 30% 20
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% POC 18 16 14 12 10 8 6 4 2 0 % PO
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Percentage Percentage 1.8 1.6 1.4 1
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o 33 3’S o 33 10’S Yacht Club B
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Figure 6.12. Variation in the conce
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The concentrations of metals in sed
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concentrations are 56 and 29 times
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threshold of 1.2 mg/kg established
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Cadmium (mg/kg) 8 7 6 5 4 3 2 1 0 C
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Copper (mg/kg) 45 40 35 30 25 20 15
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16000 14000 12000 10000 8000 6000 4
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In summary, elevated trace metal co
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6.5 Summary of sediment health stat
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7.1 Long term changes in seagrass i
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7.2 Long term changes in Saltmarshe
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Figure 8.1. Benthic macrofauna samp
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Table 8.1. Depth at each of the sit
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these species usually provide the l
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(clustering of similar groups) (Meg
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The Big Bay samples BB 25 and BB29
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2007/08 dredging. Other signs of th
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Wet mass per m² Wet mass per m² 4
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Big Bay Crustaceans and polychaetes
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Average number of individuals per m
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Number Individuals per m² Number I
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8.4.2 Abundance Biomass Indices 8.4
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and percentage organic nitrogen (PO
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Table 8.5. W statistics at all stat
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Figure 8.15: Variation in the diver
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percentage of mud compared to Lange
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Cu (mg/kg) Cd (mg/kg) Ni (mg/kg) Pb
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contaminants. Furthermore dredging
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areas even 5 months after the clear
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Brittle star ( Ophiuroidea spp) Sea
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9.2 Approach and Methodology 9.2.1
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cover data for both mobile and sess
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9.2.3 Data Analysis The similaritie
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40%, co-occurring with sponges espe
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stands of the kelp Ecklonia maxima
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Plocamium spp. Ecklonia maxima Scut
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20 40 A Group 1 B 60 Similarity C G
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Percentage Cover 80 70 60 50 40 30
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Evenness Shannon Wiener 0.9 0.8 0.7
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2005 2008 2009 2010 Dive School Jet
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Table 9.5. Results from the SIMPER
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In general, the inter-annual differ
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The temporal distribution of M. gal
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Consistent with the previous years,
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Saldanha and Langebaan. Results fro
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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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State of the Bay Report 2010-Final - Anchor Environmental

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