State of the Bay Report 2010-Final - Anchor Environmental

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Number of breeding pairs Anchor Environmental Hartlaub's Gull, Larus hartlaubii, is about the 10th rarest of the world's roughly 50 gull species. It is endemic to southern Africa, occurring along the coast between Cape Agulhas and Swakopmund. It breeds mainly on protected islands but has also been found to breed in sheltered inland waters. Hartlaub’s Gulls are relatively nomadic, and can alter breeding localities from one year to the next (Crawford et al. 2003). The numbers breeding on the different islands are highly erratic, as are the total numbers in the Bay. The highest and most consistent numbers of breeding birds are found on Malgas, Jutten and Schaapen islands, with a few birds breeding Vondeling Island between 1991 and 1999. They have also been recorded breeding on Meeuw Island in 1996 and from 2002 to 2004. There are substantial inter-annual fluctuations in numbers of birds breeding, suggesting that in some years an appreciable proportion of the adults do not breed (Crawford et al. 2003). Natural predators of this gull are the Kelp Gulls, African Sacred Ibis, and Cattle Egrets, which eat eggs, chicks and occasionally adults (Williams et al. 1990). In Saldanha there is no discernable upward or downward trend over time, but there is some concern in that numbers have been at lower-thanaverage levels for the past three years (Figure 11.3). 3500 3000 2500 2000 1500 1000 500 0 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 238 1998 1999 Year 2000 2001 2002 2003 2004 2005 Total Malgas Marcus Jutten Vondeling Schaapen Figure 11.3. Trends in breeding population of Hartlaub’s Gulls at Malgas, Marcus, Jutten, Schaapen and Vondeling Islands in Saldanha Bay (Data source: Rob Crawford, Oceans & Coasts, Department of Environmental Affairs). The Swift Tern, Sterna bergii, is a widespread species that occurs as a common resident in southern Africa. Swift Terns breed synchronously in colonies, usually on protected islands, and often in association with Hartlaub’s Gulls. Sensitive to human disturbance, their nests easily fall prey to Kelp Gulls, Hartlaub’s Gulls and Sacred Ibis (Le Roux 2002). During the breeding season, fish form 86% of all prey items taken, particularly pelagic shoaling fish, of which the Cape Anchovy (Engraulis encrasicolus) is the most important prey species. Since 2001 there has been an increase in the Swift Tern population number in South Africa. This increase coincided with a greater abundance of two of 2006 2007 2008 2009 2010
their main prey species, sardines and anchovies, since 2005 however, population numbers decreased in the North and central portions of the Western Cape and increased further South, coinciding with the eastward shift of their prey species (Crawford 2009). In southern Africa, swift terns show low fidelity to breeding localities, unlike the African Penguin, Cape Gannet and Cape Cormorant, which enables them to rapidly adjust to changes in prey availability (Crawford 2009). Anchor Environmental In Saldanha Bay, Jutten Island is the most important island for breeding Swift Terns, but breeding numbers are erratic at all the islands. No long term trends are discernible, but there is some concern in that there has been no breeding for three years on any of the island (Figure 11.4). Number of breeding pairs 4000 3500 3000 2500 2000 1500 1000 500 0 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 State of the Bay 2010: Saldanha Bay and Langebaan Lagoon 239 1998 Year 1999 2000 Total Malgas Marcus Jutten Schaapen Figure 11.4. Trends in breeding population of Swift Terns at Malgas, Marcus, Jutten and Schaapen islands in Saldanha Bay (Data source: Rob Crawford, Oceans & Coasts, Department of Environmental Affairs). 2001 2002 2003 Cape Gannets Morus capensis are restricted to the coast of Africa, from the Western Sahara, around Cape Agulhas to the Kenyan coast. They breed on six offshore islands, three off the Namibian coast, and two off the west coast of South Africa (Bird Island in Lambert's Bay, and Malgas Island in Saldanha Bay), and one (Bird Island) at Port Elizabeth. The Cape Gannet is listed as Vulnerable IUCN’s ‘red data list’ due to its restricted range and population declines (Birdlife International 2011). 2004 Cape Gannets feed out at sea and will often 2005 2006 2007 2008 2009 2010
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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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Page 189 and 190: 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
Page 197 and 198: 40%, co-occurring with sponges espe
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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 229 and 230: Anchor Environmental Figure 10.7. A
Page 231 and 232: Anchor Environmental Within Big Bay
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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 267 and 268: Birdlife International. 2010. URL w
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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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