State of the Bay Report 2010-Final - Anchor Environmental

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Number of breeding pairs 26000 24000 22000 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 Anchor Environmental State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 242 1998 1999 2000 Year 2001 2002 2003 2004 2005 2006 2007 2008 Total Malgas Jutten Schaapen Vondeling Meeuw Figure 11.6. Trends in breeding population of Cape Cormorants at Malgas, Jutten, Schaapen, Vondeling and Meeuw islands in Saldanha Bay (Data source: Rob Crawford, Oceans & Coasts, Department of Environmental Affairs). Bank Cormorants Phalacrocorax neglectus, are endemic to the Benguela upwelling region of southern Africa, breeding from Hollamsbird Island, Namibia, to Quoin Rock, South Africa. They seldom range farther than 10 km offshore; their distribution roughly matches that of kelp Ecklonia maxima beds. They prey on various fish, crustaceans and cephalopods, feeding mainly amongst kelp beds where they catch West Coast rock lobster, Jasus lalandii, with Pelagic Goby, Sufflogobius bibarbatus, taken in mid-water (du Toit 2004). Total population decreased from ca. 9,000 breeding pairs in 1975 to less than 5 000 pairs in 1991-1997 to 2 800 by 2006 (Kemper et al. 2007). One of the main contributing factors to the decrease in the North and Western Cape colonies was a major shift in the availability of the West Coast rock lobster from the West Coast to the more southern regions, observed between the late 1980s and early 1990s to the turn of the century (Cockcroft et al. 2008). The abundance of lobsters was further severely affected by an increase in the number and severity of mass lobster strandings (walkouts) during the 1990s (Cockcroft et al. 2008). The Bank Cormorant has as a result of ongoing population decrease been re-classified from Vulnerable to Endangered (Birdlife International 2011). It is very susceptible to human disturbance and eggs and chicks are taken by Kelp Gulls and Great White Pelicans. Increased predation has been 2009 2010
Anchor Environmental attributed to the loss of four colonies in other parts of South Africa and Namibia (Hockey et al. 2005). Smaller breeding colonies are more vulnerable to predation which would further accelerate their decline. Birds are also known to occasionally drown in rock-lobster traps, and nests are often lost to rough seas. Count data from the Saldanha Bay area shows the dramatic decrease in the population at Malgas Island, which was previously the most important island for this species. Data suggest that some of these birds moved to other islands, with number of breeding birds increasing on Marcus and Jutten islands but there has been no recovery to peak numbers breeding in 1991 (Figure 11.7). In Saldanha Bay the declines are mainly attributed to scarcity of their main prey, the rock lobster (Jasus lalandii), which in turn has reduced recruitment to the colonies (Crawford 2007; Crawford et al. 2008c). 350 300 250 200 150 100 50 0 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 243 Total Malgas Marcus Jutten Vondeling Figure 11.7. Trends in breeding population of Bank Cormorants at Malgas, Marcus, Jutten and Vondeling islands in Saldanha Bay (Data source: Rob Crawford, Oceans & Coasts, Department of Environmental Affairs). White-breasted Cormorant Phalacrocorax carbo lucidus, also known as Great Cormorant occurs along the entire southern African coastline, and is common in the eastern and southern interior, but occurs only along major river systems and wetlands in the arid western interior. The coastal population breeds from Ilha dos Tigres in southern Angola, to Morgan Bay in South Africa. Along the coast, White-breasted Cormorants occur mainly within 10 km offshore, often near reefs. White-breasted Cormorants that forage in the marine environment feed on bottom-living, mid-water and surfacedwelling prey, such as sparid fishes (e.g. Steentjies and White stumpnose, du Toit 2004). This species forages in Saldanha Bay and Langebaan Lagoon, making it susceptible to local water quality (Hockey et al. 2005).
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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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% 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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Page 193 and 194: cover data for both mobile and sess
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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Page 231 and 232: Anchor Environmental Within Big Bay
Page 233 and 234: Anchor Environmental 2008 and 2009
Page 235 and 236: Anchor Environmental the islands, b
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Page 239 and 240: their main prey species, sardines a
Page 241: Anchor Environmental 2009). The eff
Page 245 and 246: Number of breeding pairs 800 700 60
Page 247 and 248: 11.3 Birds of Langebaan Lagoon 11.3
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Page 253 and 254: Taxon Anchor Environmental Occurren
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Page 275 and 276: Anchor Environmental Moldan, A. 197
Page 277 and 278: Anchor Environmental Robinson, T.B.
Page 279 and 280: Anchor Environmental Tunley KL, Att
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State of the Bay Report 2010-Final - Anchor Environmental

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