Saldanha Bay and Langebaan Lagoon

State of the Bay 2006: Saldanha Bay and Langebaan Lagoon

Technical Report

Prepared by: L. Atkinson, K. Hutchings, B. Clark, J. Turpie, N. Steffani, T. Robinson & A. Duffell-Canham

Prepared for: Saldanha Bay Water Quality Trust

August 2006

Photograph by: Lyndon Metcalf

Anchor Environmental Consultants CC STATE OF THE BAY 2006: SALDANHA BAY AND LANGEBAAN LAGOON

TECHNICAL REPORT

Prepared by: L. Atkinson, K. Hutchings, B. Clark, J. Turpie, N. Steffani, T. Robinson & A. Duffell-Canham

AUGUST 2006

Prepared for:

Copies of this report are available from: Anchor Environmental Consultants CC PO Box 34035, Rhodes Gift 7707 Tel/Fax: ++27-21-6853400 E-mail: [email protected] http://www.uct.ac.za/depts/zoology/anchor

TABLE OF CONTENTS

EXECUTIVE SUMMARY...... 5

1 INTRODUCTION...... 10

2 STRUCTURE OF THIS REPORT...... 13

3 BACKGROUND TO ENVIRONMENTAL MONITORING ...... 14 3.1 MECHANISMS FOR MONITORING CONTAMINANTS AND THEIR EFFECTS ON THE ENVIRONMENT...... 14 4 RANKING SYSTEM...... 17

5 WATER QUALITY ...... 19 5.1 WATER TEMPERATURE ...... 19 5.2 SALINITY ...... 21 5.3 DISSOLVED OXYGEN...... 23 5.4 CURRENTS AND WAVES ...... 25 5.5 MICROBIOLOGICAL MONITORING...... 27 5.6 HEAVY METAL CONTAMINANTS ...... 31 5.7 SUMMARY OF WATER QUALITY IN SALDANHA BAY AND LANGEBAAN LAGOON...... 33 6 SEDIMENTS ...... 34 6.1 SEDIMENT PARTICLE SIZE (MUD – SAND – GRAVEL)...... 34 6.2 PARTICULATE ORGANIC CARBON (POC) AND NITROGEN (PON)...... 36 6.3 TRACE METALS ...... 40 6.4 HYDROCARBONS...... 41 6.5 SUMMARY OF SEDIMENT HEALTH STATUS OF SALDANHA BAY ...... 46 7 BENTHIC MACROFAUNA ...... 47

8 INTERTIDAL INVERTEBRATES (ROCKY SHORES)...... 55 8.1 HISTORICAL STUDIES...... 55 8.2 BASELINE STUDY CONDUCTED IN 2005...... 60 8.2.1 Findings of the Baseline Survey 2005 ...... 63 9 FISH COMMUNITY COMPOSITION AND ABUNDANCE ...... 65 9.1 SEINE NET SURVEYS...... 65 9.2 GILL NET SAMPLING...... 71 9.3 ROTENONE SAMPLING OF CRYPTIC FISHES...... 71 9.4 OVERALL STATUS OF FISH IN SALDANHA BAY AND LANGEBAAN LAGOON...... 72 10 BIRDS ...... 74 10.1 INTRODUCTION ...... 74 10.2 BIRDS OF SALDANHA BAY AND THE ISLANDS ...... 74 10.2.1 National importance of Saldanha Bay and the islands for birds...... 74 10.2.2 Ecology and status of the principle bird groups ...... 75 10.3 BIRDS OF LANGEBAAN LAGOON ...... 81 10.3.1 National importance of Langebaan Lagoon for birds ...... 81 10.3.2 The main groups of birds and their use of habitats and food...... 82 10.3.3 Interannual variability in bird numbers ...... 84 10.4 OVERALL STATUS OF BIRDS IN SALDANHA BAY AND LANGEBAAN LAGOON...... 85 11 MANAGEMENT AND MONITORING RECOMMENDATIONS...... 86 11.1 WATER QUALITY ...... 86 11.1.1 Temperature, Salinity and Dissolved Oxygen...... 86 11.1.2 Chlorophyll a and Nutrients...... 86 11.1.3 Currents and waves ...... 86 11.1.4 Microbiological monitoring (Faecal coliform)...... 86 11.2 SEDIMENTS ...... 87 11.2.1 Particle size, Particulate Organic Carbon and Trace metals...... 87 11.2.2 Hydrocarbons...... 87 11.3 BENTHIC MACROFAUNA ...... 87 11.4 ROCKY INTERTIDAL ...... 87 11.5 FISH...... 87 11.6 BIRDS ...... 88 12 REFERENCES...... 90

APPENDIX I: Percentage cover of intertidal species at eight study sites in Saldanha Bay region

APPENDIX II: Detailed descriptions of rocky intertidal fauna and flora occurring at eight sampling stations in Saldanha Bay, 2005 and statistical analyses.

APPENDIX III: Number and mass of fish caught in seine net hauls in Saldanha Bay and Langebaan Lagoon, October 2005.

Anchor Environmental Consultants CC

EXECUTIVE SUMMARY Regular, long-term environmental monitoring is essential to identify and to act pro-actively in minimising negative human impacts on the environment (e.g. pollution), and in so doing maintain the beneficial value of an area for all users. This is particularly pertinent to an area such as Saldanha Bay –Langebaan Lagoon, which serves as a major industrial node and port while at the same time supporting important tourism and fishing industries. The development of the Saldanha Bay port has significantly altered the physical structure and hydrodynamics of the Bay, whilst all developments within the area (industrial, residential, tourism etc) has the potential to negatively impact on ecosystem health. Various methods are available to monitor the health of the environment, including measuring of physical parameters (e.g. water temperature, oxygen levels, and circulation patterns), actual pollutants (e.g. heavy metals, hydrocarbons, microbiological indicators) and biological components of the ecosystem (e.g. birds, fish, and invertebrates). Nearly all measurable parameters exhibit substantial natural variability, and it is essential that environmental monitoring is conducted over the long term (years-decades) at sufficient frequency to enable identification of anthropogenic induced changes. In this report, available data on a variety of physical and biological parameters for Saldanha Bay are summarised and where possible trends and areas of concern are identified. Recommendations for future monitoring are made with a view to developing a comprehensive environmental monitoring program for Saldanha Bay are also provided.

Water Quality Aspects of water quality (temperature, salinity and dissolved oxygen, nutrients and chlorophyll concentrations) are often measured in an attempt to understand the origin of a body of sea water and the impacts it has on the physical and biological processes in the environment. Investigation of the available long-term data sets of temperature, salinity and dissolved oxygen suggest no evidence of long-term trends (neither increases nor decreases) in these parameters that can solely be attributed to anthropogenic factors. Natural, regional oceanographic processes appear to be the dominant processes driving the variation in water temperature, salinity, dissolved oxygen, nutrients and chlorophyll concentrations observed in Saldanha Bay. However, there is clear evidence of altered current strengths and circulation patterns within the Bay which are ascribed to the construction of the ore jetty and causeway. The water entering Small Bay appears to remain within the confines of the Bay for longer periods than was historically the case (i.e. an increased residence time). There is also an enhanced clockwise circulation and increased current strength flowing alongside unnatural obstacles (i.e. enhanced boundary flow for example alongside the ore jetty). The wave exposure patterns in Small Bay and Big Bay has also been altered as a result of harbour developments in Saldanha Bay. The extent of sheltered and semi-sheltered areas has increased in both Small and Big Bay.

Coastal waters in Small Bay have faecal coliform counts in excess of safety guidelines for both mariculture and recreational use. Considering the likely growth of mariculture and tourism industries on Saldanha Bay, it is imperative that steps be taken to remedy this source of pollution into the Bay. Improvements to storm water and sewerage management methods are urgently required in the Small Bay area. Big Bay and Langebaan Lagoon should continue to be monitored with serious consideration to upgrade sewage and storm water facilities in these areas.

The Mussel Watch Programme records concentrations of Cadmium, Copper, Lead, Zinc, Iron and Manganese present in the flesh of mussels. The data collected through this programme in Small Bay indicate that there does not appear to be significant increases in concentrations of heavy metals in the flesh of mussels in Saldanha Bay. The quality of the water can be considered suitable for mariculture purposes and heavy metal accumulation is currently not a concern. However, owing to high concentrations of certain heavy metals in the sediments of the Bay, continuous monitoring of metal concentrations in mussel flesh is strongly recommended particularly following any dredging events.

Sediments The distribution of mud, sand or gravel within Saldanha Bay is influenced by wave action, currents and mechanical disturbance (e.g. dredging). Under natural circumstances the

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 5 Anchor Environmental Consultants CC prevailing high wave energy and strong currents would tend to flush fine sediment and mud particles out the Bay, leaving behind the heavier, coarser sand and gravel. Obstructions to current flow and wave energy can result in greater deposition of finer sediment (mud). Large- scale disturbances (e.g. dredging) of sediments, re-suspends fine particles that were buried beneath the sand and gravel. Contaminants (trace metals and toxic pollutants) are largely associated with the mud component of the sediment and can have a negative impact on the environment. Accumulation of organic matter in benthic sediments can also give rise to problems as it depletes oxygen both in the sediments and surrounding water column as it decomposes. Historically, it was reported that the proportion of mud in the sediments of Saldanha Bay was very low, to the extent that it was considered negligible. Reduced water circulation in the Bay and dredging activities has resulted in an overall increase in the mud fraction in sediments in the Bay. The most significant increases in mud content in the surficial (surface) sediments has been observed following dredging events, however, with time (several years), significant proportions of the mud has either been flushed out or re-buried beneath sand and gravel, and the sediment composition has returned to one mostly dominated by sand and gravel. The most recent studies investigating the sediment particle size in Saldanha Bay (2004) indicate that the sediment in the Bay is currently predominantly made up of sand and is not considered to contain high levels of contaminants, except in the most sheltered parts of the Bay (e.g. Yacht Club Basin). Continued monitoring of sediment particle size is recommended, however, as this provides a good indication of changes in circulation, wave action and extent of flushing in the Bay.

Particulate Organic Carbon (POC) and Nitrogen (PON) are present at elevated levels in the sediments in certain areas of the Bay, notably near the Yacht club basin and the Mussel farm. It is considered most likely that the origin of the POC and PON is associated with waste discharge from the fish factories and faecal waste from the mussel rafts. Accumulation of organic waste, especially in sheltered areas where there is limited water flushing, can lead to anoxic conditions and negatively impact on the marine environment as has been seen from the nature of the organisms inhabiting the sediments in the affected areas. Data collected in 2004 indicate generally low organic matter concentrations occurring in Saldanha Bay, except at the Yacht Club Basin and Mussel farm sites. Organic levels should thus continue to be monitored on a regular basis, especially in Small Bay.

Contaminants (trace metals and toxic pollutants) are commonly associated with fine sediments and mud, and have begun to reach high levels (in some cases exceeding acceptable threshold levels) in areas of the Bay where fine sediments have been observed to accumulate. This is believed to be due either to naturally occurring high levels of the contaminants in the environment (e.g. in the case of Cadmium) or due to impacts of human activities (e.g. Lead, Copper and Nickel associated with ore exports). While such trace metals are generally non-threatening when buried in the sediment, they can become toxic to the environment when re-suspended as a result of mechanical disturbance (e.g. dredging). Following the most recent major dredging event in 1999, Cadmium concentrations in certain areas in Small Bay were observed to exceed internationally accepted safety levels, while concentrations of other trace metals (e.g. Lead, Copper, Nickel) were observed to approach such levels. Most have returned to natural or close to natural level since this time, as fine sediments along with the associated contaminants have either been flushed out of the bay or have been reburied, but nonetheless are likely to become a serous risk again following any future dredging events. Regular monitoring of trace metal concentrations is strongly recommended to provide an early warning of any future increases.

Hydrocarbons measured in the sediments of Saldanha Bay in 1999 were reported to be very low and not considered an environmental risk. No poly-cyclic, poly-nuclear compounds or pesticides were detected in sediments of Saldanha Bay and no further monitoring of these aspects has been conducted since.

Benthic macrofauna Soft-bottom benthic macrofauna (animals living in the sediment that are larger than 1 mm) are frequently used as a measure to detect changes in the health of the marine environment resulting from anthropogenic impacts. Measures of species abundance and biomass (the numbers and mass of species making up the benthic community) and species diversity (how

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 6 Anchor Environmental Consultants CC many different species are present) are investigated from studies conducted prior to development of Saldanha Bay and compared to more recent data in order to interpret the overall health of the marine environment. Available pre-development benthic macrofauna data of Saldanha Bay and Langebaan Lagoon were unfortunately collected using different methods to those of more recent studies. However, taking into consideration these different sampling techniques, it is nonetheless evident that there has been a significant change in the nature of the benthic communities in the Bay. The most dramatic change is observed in Small Bay where there has been a substantial increase in crustaceans (mudprawns, sandprawns, amphipods and isopods) and tongue worms, resulting in an overall decrease in species diversity (redeuced number of species present and hence a negative impact on the environment). The abundance of crustaceans has similarly increased in Big Bay over time, although the species diversity (number of species present) appears to have remained fairly consistent. The sea pen (Virgularia schultzei), a species highly sensitive to disturbance and pollution, disappeared from both Big and Small Bay after monitoring first commenced in the 1970’s, but have since returned to Big Bay in recent years which is encouraging for this area at least. Benthic macrofauna present in Langebaan Lagoon were measured in 1975 and again only in 2004. There appears to have been a dramatic decrease in both species abundance and diversity over this time period. In 1975, healthy numbers of as many as six species were found to occur in Langebaan Lagoon, however, data collected in 2004 indicate an almost complete dominance by crustaceans with a small amount of polychaetes occurring in the Lagoon. Previous reports had indicated that the anthropogenic changes occurring in Saldanha Bay had imposed limited impacts on Langebaan Lagoon, however, recent benthic macrofauna data provide sufficient reason for concern for the Lagoon environment. It is strongly recommended that regular benthic macrofauna monitoring continue in Langebaan Lagoon.

Rocky intertidal Species occurring in the intertidal rocky shore zone are readily impacted on by negative changes in the environment. No known studies examined the rocky intertidal species composition in Saldanha Bay prior to 1980, at which time the alien, invasive Mediterranean mussel (Mytilus galloprovincialis) had already begun to displace indigenous species from the rocky shore. Studies conducted in 1980 at Marcus Island compared to the status in 2001, clearly show strong links between the invasion of the Mediterranean mussel and changes in the intertidal rocky shore communities observed. The zones of the intertidal area most impacted on by the invasive mussel are at the high shore, however, local species like the black mussel and ribbed mussel have been displaced from the low shore by the highly competitive Mediterranean mussel. It is considered most likely that the Mediterranean mussel was first introduced with ballast water discharged by ore carriers visiting Saldanha Bay and has since spread along the coast as far as Namibia and to Port Elizabeth.

As a component of this State of the Bay evaluation, baseline conditions (the current status) of the rocky intertidal communities present at eight sites in Saldanha Bay was recorded. Rocky intertidal communities inhabiting a series of sites spanning a wave exposure gradient (a major driving factor of rocky shore communities) were sampled in Small Bay, Big Bay and Outer Bay as part of this study. Overall, rocky intertidal communities on shores sheltered from high wave impact were dominated by algae (seaweed) species, while more exposed sites had high a high biomass of mussels (mostly the invasive Mediterranean mussel). Generally these communities were health apart from the presence of the Mediterranean mussel.

Fish Good baseline scientific data on fish communities within Saldanha Bay and Langebaan currently exists, from which future changes can be assessed. Analysis of data from seine-net surveys, conducted approximately 10 years apart show significant changes in abundance for some species over time, but given the limited data set it is not possible to assess the implications of the changes present i.e. whether these changes are a result of natural anthropogenic processes. It is recommended that the seine-net surveys should be continued as one monitoring method. Seine-netting is very effective at sampling juveniles of many species that inhabit near shore surf-zones and as such provide an indication of the health of the environment as well as of the adult stocks. The frequency of sampling should be increased and the timing of future surveys should be standardized to enable identification of

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 7 Anchor Environmental Consultants CC natural seasonal or inter annual patterns. Trends in the abundance and composition of larger species not vulnerable to capture in seine nets can be monitored in a cost-effective manner by sampling anglers’ catches.

Birds Saldanha Bay, Langebaan Lagoon and the associated islands provide important shelter, feeding and breeding habitat for at least 53 species of seabirds, 11 of which are known to breed on the islands. The islands of Malgas, Marcus, Jutten, Schaapen and Vondeling support breeding populations of African Penguin (a red data species), Cape Gannet, four species of marine cormorants, Kelp and Hartlaub’s Gulls, and Swift Terns. The islands also support important populations of the rare and endemic African Black Oystercatcher. The diversity of birds utilising Saldanha Bay and the islands are considered low, however, this region supports substantial proportions of the total population of many of these species. Regular surveys of breeding populations of these birds have been conducted. Ket findings from these surveys include: • Annual counts of breeding African Penguin pairs indicate that there has been an overall decrease in population size at most of the islands in the Bay (Vondeling Island being an exception). The decrease in numbers has been attributed to migration to other islands (Robben and Dassen Islands) and a reduced availability of anchovy, which is the primary food source for these birds. The decreased numbers of African Penguin in the Saldanha Bay region are unlikely to be as a result of anthropogenic developments here. • Overall populations of Kelp Gulls have increased in Saldanha Bay region, this being attributed to an increase in food (invasive mussel) availability. • Hartlaub’s Gull and Swift Tern populations vary erratically, with numbers fluctuating widely each year. There have been no long-term increases or decreases in populations of these birds. • Populations of Cape Gannets and Cape Cormorants also vary each year, however, there appears to have been a slight increase in total populations in the area. • Bank Cormorant numbers have shown steady declines since 1991, which could be related to increasing numbers in other areas, however, the overall total population decline is of concern. • Numbers of Crowned Cormorants are either stable or increasing. This species is not considered to be threatened in the region. • White-breasted Cormorants are recent arrival in the Bay (first sighted in large numbers on Schaapen Island in 1995), but has since shown a steadily decline with only two breeding pairs being counted in 2004. These birds are highly sensitive to disturbance and the observed decrease in numbers is likely to be as a result of increased human activity in the region. • The increasing numbers of African Black Oystercatchers in the region have been attributed to the increasing abundance of invasive mussel, a favoured prey item of this bird.

Langebaan Lagoon and its associated warm, sheltered waters and abundance of prey, provides an important habitat for migrant waterbirds, specifically from the Palearctic region of Eurasia. As much as 98% of the waterbirds present in the Lagoon during summer months are migrant species with only an average of 2% being resident during the remainder of the year. Langebaan Lagoon has been identified as the most important wetland for waders on the west coast of southern Africa. Annual counts of the numbers of waders over the period 1975 to 1980 showed stable summer populations, but large variations in the number of migrants that remained over winter. Subsequent to 1980, data show a dramatic downward trend in the numbers of Palearctic waders at the Lagoon with similar decreasing trends being echoed by resident waders. The likely cause of this decrease in both migrant and resident waders (the latter being of most concern) has been attributed to the siltation of the Lagoon reducing the amount of suitable feeding grounds and increasing levels of human disturbance.

In summary, it can be said that developments in Saldanha Bay and Langebaan Lagoon during the past thirty years have inevitably impacted on the environment. This State of the Bay Report aimed to examine long-term trends in available data sets to highlight long-term changes in the environment. Most parameters investigated in this study, with the exception of

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 8 Anchor Environmental Consultants CC fish (very limited available data), indicated some degree of negative impact occurring. Decreasing populations of resident waterbirds in Langebaan Lagoon and decreased numbers of White-breasted and Bank Cormorants are perhaps of greatest concern. However, the decreased numbers of birds may well be a reflection of poor fish, benthic macrofauna, sediment and water quality. Negative environmental conditions imposed on the water quality or sediments, will, in time, negatively impact on the top predators (birds and fish) of the system. A holistic approach in monitoring and assessing the overall health status of the Bay is essential, and regular (in some cases increased) monitoring of all parameters reported on here is strongly recommended.

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 9 Anchor Environmental Consultants CC

1 INTRODUCTION

Saldanha Bay is situated on the west coast of South Africa, approximately 100 km north of Cape Town and is directly linked to the shallow, tidal Langebaan Lagoon. The Bay and Lagoon are considered to be one of the biodiversity “hot spots” in the country and an area of exceptional beauty. However, the history of the area has been one tainted with both exploitation and abuse, the environment being the loser in both instances.

Figure 1.1. Saldanha Bay and Langebaan Lagoon showing the extent of development (grey shading) and conservation areas (dark blue and yellow shading).

The first mention of Saldanha Bay in history occurred in 1601 when Joris van Spilbergen unintentionally transferred the name “watering place of Saldanha” (the name given to Table Bay at the time) to Saldanha Bay (Axelson 1977). In 1623, an Icelander by the name of Jon Olaffsson entered Saldanha Bay in search of whaling opportunities, only to find that French sailors had already commenced with such lucrative activities in the Bay.

Shortly after his arrival in Table Bay in 1652, Jan van Riebeek sent a small vessel to explore the possibility of local trade opportunities in Saldanha Bay (Axelson 1977). At this stage the French had already virtually hunted out the seal population, which fetched a high price for their skins. However, the abundance of sheep, fish (4000 harders being caught in a single day) and bird’s eggs rendered the Bay sufficiently valuable for the Dutch East India Company to erect markers denoting their possession of the Bay in 1657 (Axelson 1977). A shortage of freshwater, however, limited development or permanent European colonization in Saldanha Bay, although four small communities eventually became established in Langebaan Lagoon.

Saldanha Bay was reported to be “rich in fish” and although the price for fish was deemed “poor”, there are records of a fish trading post being established at Oosterwal, Langebaan Lagoon in the early 1700’s (Axelson 1977). A commercial fishing industry was slow to

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 10 Anchor Environmental Consultants CC develop in Saldanha Bay, however, by the early 1900’s fishing was considered a growing industry. In 1903 a rock lobster fishery was introduced in Saldanha Bay with the North Bay Canning Company and the Saldanha Bay Canning Company being established in the early 1900’s (Axelson 1977). With increasing catches of sardines in the vicinity of the Bay, canning companies soon expanded their business to incorporate sardine canning. In 1948 the North Bay Canning Company was absorbed into Southern Seas Fishing Enterprises, while in 1964 Sea Harvest Corporation was formed, subsequently becoming the largest fishing operation in Saldanha Bay, operating a fleet of deep-sea trawlers and providing an onshore fish packing and freezing facility.

The first whaling factory was eventually built in 1909 at Donkergat, followed by a second in 1911 at Salamander Bay. In 1930 however, the international price for whale oil plummeted, resulting in the closure of both these factories. Whaling activities were re-established for a short period between 1960 and 1967, after which, no further whaling took place in Saldanha Bay (Axelson 1977).

The establishment of fish processing factories and the substantial growth of the fishing industry in Saldanha Bay resulted in an ever increasing number of pelagic fishing vessels harbouring in the Bay and offloading their catch. During the early 1970’s, the methods employed to offload the catch involved releasing substantial amounts of water, loaded with organic matter (biological waste and fish factory effluent), back into the Bay (known as “wet offloading”). Within a short period of time the marine environment within the Bay began showing severe signs of organic overloading and in 1972 a mass mortality event of marine organisms (fish and shellfish) brought the pollution situation to attention. By 1974 official waste management practices (primarily “dry offloading” of the catch) were being implemented by the fish factories to reduce the amount of organic loading in the Bay (Christie and Molden 1977). The effects of fish factory effluent continue to be closely monitored in Saldanha Bay on a regular basis.

Saldanha Bay, being considered the only natural harbour of significant size on the west coast of South Africa, was targeted for development, and in 1971 was upgraded into an international port (Fuggle 1977). The primary purpose of the port at that stage was to facilitate the export of iron ore as part of the Sishen-Saldanha Bay Ore Export Project. The first major development in the Bay was a causeway built in 1973 that linked Marcus Island to the mainland, providing shelter for ore-carriers. During 1973 and 1974 the General Maintenance Quay and Rock Quay were built, making up the iron ore jetty. Between 1974 and 1976 extensive dredging was conducted to accomodate a deep-water port for use by large ore-carriers. The iron ore jetty was built with the initial intention of being used for export of ore, however, was later extended to provide for the import of oil. The construction of the iron ore jetty essentially divided Saldanha Bay into two sections: a smaller area bounded by the causeway, the northern shore and the ore jetty (called Small Bay); and a larger , more exposed area adjacent called Big Bay, leading into Langebaan lagoon (Figure 1.1). A multi- purpose terminal had been added to the jetty by 1980 and a small-craft harbour was built in 1984 to cater for the increase in recreational and tourism activities in the Bay. Due to the increase in heavy industries in the area in the 1990’s (Namakwa Sands, Saldanha Steel), the multi-purpose terminal was extended in 1998. During each phase of development undertaken in Saldanha Bay (summarized in Table 1.1), dredging and submarine blasting has been necessary. Development of the causeway and iron-ore jetty in Saldanha Bay greatly modified the natural water circulation and current patterns (Weeks et al. 1991) in the Bay. This led to reduced water exchange and increased nutrient loading of water within the Bay.

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 11 Anchor Environmental Consultants CC

Fish factories Small Bay Multipurpose terminal Small craft harbour Iron ore jetty

Mussel rafts Causeway Big Bay Marcus Island

Langebaan Lagoon

Figure 1.2. Map of Saldanha Bay indicating anthropogenic developments established since 1973 referred to in text.

Table 1.1: Summary of major development in Saldanha Bay Year Development 1973 Causeway built linking Marcus Island and mainland 1973 – 1974 General Maintenance Quay and Rock Quay 1974 – 1976 Iron-ore jetty 1980 Multi-purpose terminal added to Iron-ore jetty 1984 Small craft harbour 1997 Most recent dredging of Small Bay 1998 Multi-purpose jetty extended

In addition to the increasing fish factory effluent and the structural modifications of the Bay, the establishment of mussel mariculture ventures (of the Spanish mussel Mytilus galloprovincialis) in the sheltered waters of Small Bay in 1984, exacerbated the pollution and organic loading problems in the area (Stenton-Dozey et al. 1999).

Industrial development in and around Saldanha Bay has been matched with increasing tourism development in the area, specifically with the declaration of the West Coast National Park, Langebaan Lagoon being declared a National Wetland RAMSAR site and establishment of holiday resorts like Club Mykonos and Blue Water Bay. The increasing tourism capacity results in higher levels of impact on the environment in the form of increased pollution, traffic and disturbance.

The first symposium on research in the natural sciences of Saldanha Bay and Langebaan Lagoon was initiated by the Royal Society of South Africa in 1976 in an attempt to summarise the various research studies being conducted in the area. The majority of studies reported on at the symposium were conducted before construction of the causeway, resulting in the subsequent proceedings from the symposium providing an indication of baseline conditions of

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 12 Anchor Environmental Consultants CC the natural environment prevalent in Saldanha Bay and Langebaan Lagoon prior to any large- scale development. With ongoing development and modifications to the natural environment of the Bay, increasing concerns for the overall health of the environment began to arise. Several studies, both academic and through private industry, were commissioned to detect changes (both positive and negative) occurring in the natural environment of Saldanha Bay and Langebaan Lagoon. These included studies on water quality; sediment particle size, distribution and contamination levels; benthic macrofauna assemblages; and species of fish and birds present. The majority of these studies were conducted over relatively short periods of time (one to two years) and focused on specific biological aspects.

The Saldanha Bay Water Quality Trust (SBWQT) identified the need to collate the findings and recommendations of studies conducted in the Bay prior to significant anthropogenic modifications and to develop an index for regularly monitoring the State of the Bay. The State of the Bay report aims to present a comprehensive assessment of the environmental health status of Saldanha Bay and Langebaan Lagoon using studies conducted from historic times through to present day.

2 STRUCTURE OF THIS REPORT

This report draws together all available information on water quality and aquatic health of Saldanha Bay and Langebaan Lagoon. The emphasis has been on using data from as wide a range of parameters as possible that are comparable in both space and time and cover extended periods which provide a good reflection of the long term environmental health in the Bay. The report is composed of twelve chapters each of which addresses different aspects of the health of the system. Chapter One provides a general overview of man’s association with Saldanha Bay and the associated anthropogenic impacts on the system. Chapter Two provides an outline of the structure of this report (this chapter). Chapter Three provides background information to anthropogenic impacts on the environment and the range of different approaches to monitoring these impacts, which captures the differences in the nature and temporal and spatial scale of these impacts. Chapter Four describes the ranking system employed for the purposes of this report, to provide a gauge against which to monitor the state of the environmental parameters measured in Saldanha Bay and Langebaan Lagoon. Chapter Five summarises available information on water quality parameters that have historically been monitored in the Bay and Lagoon and reflects on what can be deduced from these parameters regarding the health of the Bay. Chapter Six summarises available information on sediment monitoring that has been conducted in Saldanha Bay and Langebaan Lagoon with further interpretation of the implication of the changing sediment composition with time and/or related to dredging events. Changes in benthic macrofauna evident in Saldanha Bay and Langebaan Lagoon are presented in Chapter Seven while Chapter Eight addresses changes that have occurred in the rocky intertidal zones in and around Saldanha Bay over the past 20 years and introduces a rocky intertidal baseline survey results, conducted in 2005. Chapter Nine summarises all available information on the fish community and composition in the Bay and Lagoon, as deduced from both seine and gill net surveys, and provides baseline data on a seine net fish survey conducted in 2005. Chapter Ten provides detailed information on the status of key bird species utilising the offshore islands around Saldanha Bay and both resident and migrant waders utilising the feeding grounds in Langebaan Lagoon as well as providing an indication of the national importance of the area for birds. Chapter Eleven provides a tabulated summary of the key changes detected in each parameter reported on with a ranking category for each parameter. Furthermore, recommendations for future environmental monitoring are provided and some indication of management measures to be considered.

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3 BACKGROUND TO ENVIRONMENTAL MONITORING

Pollution is defined by the United Nations Convention on the Law of the Sea as ‘the introduction by man, directly or indirectly, of substances or energy into the marine environment, including estuaries, which results in such deleterious effects as harm to living resources and marine life, hazards to human health, hindrance to marine activities, including fishing and other legitimate uses of the sea, impairment of quality for use of the sea water and reduction of amenities’. A wide variety of pollutants are generated by man, many of which are discharged to the environment in one form or another. Pollutants or contaminants can broadly be grouped into five different types: trace metals, hydrocarbons, organochlorines. radionuclides, and nutrients. Certain metals, normally found in very low concentrations in the environment (hence referred to as trace metals) are highly toxic to aquatic organisms. These include for example mercury, cadmium, arsenic, lead, chromium, zinc and copper. These metals occur naturally in the earth’s crust, but mining of metals by man is increasing the rate at which these are being mobilised enormously over that achieved by geological weathering. Many of these metals are also used as catalysts in industrial processes and are discharged to the environment together with industrial effluent and waste water. Hydrocarbons discharged to the marine environment include mostly oil (crude oil and bunker oil) and various types of fuel (diesel and petrol). Sources of hydrocarbons include spills from tankers, other vessels, refineries, storage tanks, and various industrial and domestic sources. Hydrocarbons are lethal to most marine organisms due to their toxicity, but particularly to marine mammals and birds due to their propensity to float on the surface of the water where they come into contact with seabirds and marine mammals. Organochlorines do not occur naturally in the environment, and are manufactured entirely by man. A wide variety of these chemicals exists, the most commonly known ones being plastics (e.g. polyvinylchloride or PVC), solvents and insecticides (e.g. DDT). Most organochlorines are toxic to marine life and have a propensity to accumulate up the food chain. Nutrients are derived from a number of sources, the major one being sewage, industrial effluent, and agricultural runoff. They are of concern owing to the vast quantities discharged to the environment each year which has the propensity to cause eutrophication of coastal and inland waters. Eutrophication in turn can result in proliferation of algae, phytoplankton (red tide) blooms, and deoxygenation of the water (black tides).

It is important to monitor both the concentration of these contaminants in and their effects on the environment as this can ensure that major negative effects on the environment and human health can be averted before they arise.

3.1 Mechanisms for monitoring contaminants and their effects on the environment

The effects of pollutants on the environment can be detected in a variety of ways as can the concentrations of the pollutants themselves in the environment. Three principal ways exists for assessing the concentration of pollutants in aquatic ecosystems - through the analysis of pollutant concentrations in the water itself, in sediments or in living organisms. Each have their advantages and disadvantages. For example, the analysis of pollutant concentrations in water samples is often problematic owing to the fact that even at concentrations lethal to living organisms, they are difficult to detect without highly sophisticated sampling and analytical techniques. Pollutant concentrations in natural waters may vary with factors such as season, state of the tide, currents, extent of freshwater runoff, sampling depth, and the intermittent flow of industrial effluents, which complicates matters even further. In order to accurately elucidate the degree of contamination of a particular environment, a large number of water samples usually have to be collected and analysed over a long period of time. The biological availability of pollutants in water also presents a problem in itself. It must be understood that some pollutants present in a water sample may be bound chemically to other compounds that renders them unavailable or non-toxic to biota (this is common in the case of heavy metals).

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Another way of examining the degree of contamination of a particular environment is through the analysis of pollutant concentrations in sediments. This has several advantages of the analysis of water samples. Most contaminants of concern found in aquatic ecosystems tend to associate preferentially with (i.e. adhere to) suspended particulate material rather than being maintained in solution. This behaviour leads to pollutants becoming concentrated in sediments over time. By analysing their concentrations in the sediments (as opposed to the water) one can eliminate many of the problems associated with short-term variability in contaminant concentrations (as they reflect conditions prevailing over several weeks or months) and concentrations tend to be much higher which makes detection much easier. The use of sediments for ascertaining the degree of contamination of a particular system of environment is thus often preferred over the analysis of water samples. However, several problems still exist with inferring the degree of contamination of a particular environment from the analysis of sediment samples.

Some contaminants (e.g. bacteria and other pathogens) do not accumulate in sediments and can only be detected reliably through other means (e.g. through the analysis of water samples). Concentrations of contaminants in sediments can also be affected by sedimentation rates (i.e. the rate at which sediment is settling out of the water column) and the sediment grain size and organic content. As a general rule, contaminant concentrations usually increases with decreasing particle size, and increases with increasing organic content, independent of their concentration in the overlying water. Reasons for this are believed to be due to increases in overall sediment particle surface area and the greater affinity of most contaminants for organic as opposed to inorganic particles (Phillips 1980, Phillips & Rainbow 1994). The issue of contaminant bioavailability remains a problem as well, as it is not possible to determine the biologically available portion of any contaminant present in sediments using chemical methods of analysis alone.

One final way of assessing the degree of contamination of a particular environment is by analysing concentrations of contaminants in the biota themselves. There are several practical and theoretical advantages with this approach. Firstly, it eliminates any uncertainty regarding the bioavailability of the contaminant in question as it is by nature ‘bio-available’. Secondly, biological organisms tend to concentrate contaminants within their tissues several hundred or even thousands of times above the concentrations in the environment and hence eliminate many of the problems associated with detecting and measuring low levels of contaminants. Biota also integrate concentrations over time and can reflect concentrations in the environment over periods of days, weeks, or months depending on the type of organism selected. Not all pollutants accumulate in the tissues of living organisms, including for example nutrients and particulate organic matter. Thus, while it is advantageous to monitor contaminant concentrations in biota, monitoring of sediment and water quality is often also necessary.

Different types of organisms tend to concentrate contaminants at different rates and to different extents. In selecting what type of organism to use for biomonitoring it is generally recommended that it should be sedentary (to ensure that it is not able to move in and out of the contaminated area), should accumulate contaminants in direct proportion with their concentration in the environment, and should be able to accumulate the contaminant in question without lethal impact (such that organisms available in the environment reflect prevailing conditions and do not simply die after a period of exposure). Giving cognisance to these criteria, the most commonly selected organisms for biomonitoring purposes include bivalves (e.g. mussels and oysters) and algae (i.e. seaweed).

Aside from monitoring concentrations of contaminant levels in water, sediments, and biota, it is also possible, and often more instructive, to examine the species composition of the biota at a particular site or in a particular environment to ascertain the level of health of the system. Some species are more tolerant of certain types of pollution than others. Indeed, some organisms are extremely sensitive to disturbance and disappear before contaminant concentrations can even be detected reliably whereas others proliferate even under the most noxious conditions. Such highly tolerant and intolerant organisms are often termed biological indicators as they indicate the existence or concentration of a particular contaminant or contaminants simply by their presence or absence in a particular site, especially if this

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 15 Anchor Environmental Consultants CC changes over time. Changes in community composition (defined as the relative abundance or biomass of all species) at a particular site can thus indicate a change in environmental conditions. This may be reflected simply as an overall increase in biomass or abundance of all species, as a change in community structure and/or overall biomass/abundance but where the suite of species present remain unchanged, or as a change in species and community structure and/or a change in overall biomass/abundance (Figure 3.1). Monitoring abundance or biomass of a range of different organisms from different environments and taxonomic groups with different longevities, including for example invertebrates, fish and birds, offers the most comprehensive perspective on change in environmental health spanning months, years and decades.

The various methods for monitoring environmental health all have the advantages and disadvantages. A comprehensive monitoring programme typically requires that a variety of parameters be monitored covering water, sediment, biota and community health indices.

(a) Abundance/biomass changes, composition remains the same

(b) Species present remain the same, community composition changes and overall abundance/ biomass may also change, composition remains the same

Figure 3.1. Possible alterations in abundance/biomass and community composition. Overall abundance/biomass is represented by the size of the circles and community composition by the various types of shading. After Hellawell (1986).

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4 RANKING SYSTEM

For the requirements of the Saldanha Bay and Langebaan Lagoon State of the Bay monitoring programme a ranking system has been devised that incorporates a range of different measures of ecosystem health from contaminant concentrations in seawater through change in species composition of a range of different organisms (Table 4.1). Collectively these parameters provide a comprehensive picture of the State of the Bay and also a baseline against which future environmental change can be measured. Each environmental parameter incorporated within the ranking system was allocated a health category depending on the ecological status and management requirements in particular areas of Saldanha Bay and Langebaan Lagoon. An overall Desired Health category is also proposed for each environmental parameter in each area, which should serve as target to be achieved or maintained through management intervention.

Table 4.1. Ranking categories and classification thereof as applied to Saldanha Bay and Langebaan Lagoon for the purposes of this report. Health category Ecological perspective Management perspective

No or negligible modification from Relatively little human impact Natural the natural state

Minimal alteration to the physical Some human-related environment, the biodiversity and disturbance, but ecosystems Good integrity of the environment remains essentially in a good state, largely intact however, continued regular monitoring is strongly suggested Significant change evident in the Moderate human-related physical environment and disturbance with good ability to Fair associated biological communities; recover. Regular ecosystem sensitive species may be lost, while monitoring to be initiated to tolerant or opportunistic species are ensure no further deterioration beginning to dominate. takes place. Extensive changes evident in the High levels of human related 6 physical environment and disturbance. Urgent Poor 6 6 6 associated biological communities, management intervention is majority of sensitive species lost, required to avoid permanent and tolerant or opportunistic damage to the environment or species dominate. human health.

Various physical, chemical and biological factors influence the overall health of the environment. Environmental parameters or indices were selected that can be used to represent the broader health of the environment and are feasible to measure, both temporally and spatially. The following environmental parameters or indices are reported on:

Water Quality: Water quality is a measure of the suitability of water for supporting aquatic life and the extent to which key parameters (temperature, salinity, dissolved oxygen, nutrients and chlorophyll a, faecal coliform and heavy metal concentrations) have been altered from their natural state. Water quality parameters can vary widely over short time periods and are principally affected by the origin of the water, physical and biological processes and effluent discharge. Water quality parameters provide only an immediate (very short term – hours to days) perspective on changes in the environment and do not integrate changes over time.

Sediments: Sediment quality is a measure of the extent to which the nature of benthic sediments (particle size composition, organic content and contaminant concentrations) has been altered from its natural state. This is important as it influences the types and numbers of organisms inhabiting the sediments and is in turn, strongly affected by the extent of water

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 17 Anchor Environmental Consultants CC movement (wave action and current speeds), mechanical disturbance (e.g. dredging) and quality of the overlying water. Sediment parameters respond quickly to changes in the environment but are able to integrate changes of short periods of time (weeks to months) and are thus good indicators or short to very short-term changes in environmental health.

Macrofauna: Benthic macrofauna are mostly short lived organisms (1-3 years) and hence are good indicators of short to medium term (months to years) changes in the health of the environment. They are particularly sensitive to changes in sediment composition (e.g. particle size, organic content and heavy metal concentrations) and water quality.

Rocky intertidal: Rocky intertidal invertebrates are also mostly short lived organisms (1-3 years) and as such are good indicators of short to medium term changes in the environment (months to years). Rocky intertidal communities are susceptible to invasion by exotic species (e.g. Mediterranean mussel), deterioration in water quality (e.g. nutrient enrichment), structural modification of the intertidal zone (e.g. causeway construction) and human disturbance resulting from trampling and harvesting (e.g. bait collecting).

Fish: Fish are mostly longer lived animals (3-10 years +) and as such are good indicators of medium to long term changes in the health of the environment. They are particularly sensitive to changes in water quality, changes in their food supply (e.g. benthic macrofauna) and fishing pressure.

Birds: Birds are mostly long lived animals (6-15 years +) and as such are good indicators of long term changes in the health of the environment. They are particularly susceptible to disturbance by human presence and infrastructural development (e.g. housing development), and changes in food supply (e.g. pelagic fish and intertidal invertebrates).

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5 WATER QUALITY

The temperature, salinity (salt content) and dissolved oxygen concentration occurring in marine waters are the variables most frequently measured by oceanographers in order to understand the origins, physical and biological processes impacting on, or occurring within a body of sea water. Long-term data series of these three variables exist for Saldanha Bay and these are discussed in some detail below. Other measurable physical and chemical variables such as nutrient levels (specifically dissolved nitrate – a limiting nutrient for phytoplankton growth), chlorophyll concentration (a measure of primary production), current strengths and circulation patterns have been reported on in various studies and the key findings or trends are also summarised in this chapter.

5.1 Water temperature Water temperature records for Saldanha Bay and Langebaan Lagoon were first collected during 1974-75 as part of a detailed survey by the then Sea Fisheries Branch, Department of Industries (now Marine and Coastal Management, Department of Environmental Affairs and Tourism). The survey was initiated to collect baseline data of the physical and chemical water characteristics prior to the development of the Bay as an industrial port. The findings of this survey were published in a paper by Shannon and Stander (1977). Surface water temperatures prior to the construction of the iron ore/oil jetty and Marcus Island causeway varied from 16-18.5°C during summer (January 1975) and 14.5-16°C during winter (July 1975). During both periods, higher temperatures were measured in what is now the northern part of Small Bay and within Langebaan Lagoon, whilst cooler temperatures were measured at sampling stations in Outer Bay and Big Bay. The water column was found to be fairly uniform in temperature during winter and spring (i.e. temperature did not change dramatically with depth) and the absence of a thermocline (a clear boundary layer separating warm and cool water) was interpreted as evidence of wind driven vertical mixing of the shallow waters in the Bay. A clear shallow thermocline was observed at about 5 m depth, during the summer and autumn months at some deeper stations and was thought to be the result of warm lagoon water flowing over cooler sea water. The absence of a thermocline at other shallow sampling stations was once again considered evidence of strong wind driven vertical mixing. Shannon and Stander (1977) suggested that there was little interchange between the relatively sun- warmed Saldanha Bay water and the cooler coastal water through the mouth of the Bay, but rather a “slopping backwards and forwards tidal motion”.

The Sea Fisheries Research Institute continued regular monitoring (quarterly) of water temperature (and other variables) in Saldanha Bay until October 1982. These data were presented and discussed in papers by Monteiro et al. (1990) and Monteiro and Brundrit (1990). The temperature time series for Small Bay and Big Bay is shown in Figure 5.1. This expanded data series allowed for a better understanding of the oceanography of Saldanha Bay. The temperature of the surface waters was observed to fluctuate seasonally with surface sun warming in summer and cooling in winter, whilst the temperature of deeper (10 m depth) water shows a smaller magnitude, non-seasonal variation, with summer and winter temperatures being similar (Figure 5.1). In most years, a strong thermocline separating the sun warmed surface layer from the cooler deeper water was present during the summer months at between 5-10 m depth. During the winter months, the thermocline breaks down due to surface cooling and increased turbulent mixing, and the water column becomes nearly isothermal (surface and deeper water similar in temperature) (Figure 5.1). Unusually warm, deeper water was observed during December 1974 and December 1976 and was attributed to the unusual influx of warm oceanic water during these months (Figure 5.1).

Warm oceanic water is typically more saline and nutrient-deficient than the cool upwelled water that usually occurs below the thermocline in Saldanha Bay. This was reflected in the high salinity (Figure 5.2), and low nitrate and chlorophyll concentration (a measure of phytoplankton production) measurements taken at the same time (Monteiro and Brundrit 1990). Monteiro et al. (1990) suggested that the construction of the Marcus Island causeway and the iron ore/oil jetty in 1975 had physically impeded water movement into and out of

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Small Bay, thus increasing the residence time and leading to systematically increasing surface water temperatures when compared with Big Bay. There appears to be little support for this in the long-term temperature time series (Figure 5.1) and although the pre- construction data record is limited to only one year, Shannon and Stander (1977) show Small Bay surface water being 2°C warmer than that in Big Bay during summer, prior to any harbour development. It is likely that the predominant southerly winds during summer concentrate sun warmed surface water in Small Bay, whilst much of the warm surface layer is driven out of Big Bay into the outer Bay by these same winds.

22 1 m 10 m

)

14 Temperature (C 12

Apr-74 May-74 Jul-74 Aug-74 Sep-74 Oct-74 Dec-74 Jan-75 Feb-75 Mar-75 Apr-75 Jul-75 Oct-75 Jan-76 Mar-76 Jun-76 Sep-76 Dec-76 Mar-77 Jun-77 Aug-77 Oct-77 Dec-77 Mar-78 Jun-78 Sep-78 Jan-79 Apr-79 Jul-79 Oct-79 Jan-81 Apr-81 Jul-81 Oct-81 Jan-82 Apr-82 Jul-82 Oct-82 94 Apr 97 Feb

Big Bay water temperature

1 m 10 m 22

18 ) 16

14 Temperature (C 12

8 Apr-74 May-74 Jul-74 Aug-74 Sep-74 Oct-74 Dec-74 Jan-75 Feb-75 Mar-75 Apr-75 Jul-75 Oct-75 Jan-76 Mar-76 Jun-76 Sep-76 Dec-76 Mar-77 Jun-77 Aug-77 Oct-77 Dec-77 Mar-78 Jun-78 Sep-78 Jan-79 Apr-79 Jul-79 Oct-79 Jan-81 Apr-81 Jul-81 Oct-81 Jan-82 Apr-82 Jul-82 Oct-82 94 Apr Feb 97 Mar-99 Apr-99 May-99 Jun-99 Jul-99 Aug-99 Sep-99 Oct-99 Nov-99 Dec-99 Jan-00 Feb-00

Small Bay water temperature Fig. 5.1: Water temperature time series at the surface and at 10m depth for Big Bay and Small Bay, Saldanha Bay

More detailed continuous monitoring of temperature throughout the water column at various sites in Outer Bay, Small Bay and Big Bay during a two week period in February-March 1997, allowed better understanding of the mechanisms causing the observed differences in the temperature layering of the water column. The summer thermocline is not a long-term feature, but has a 6-8 day cycle. Cold water, being more dense than warmer water, will flow into Saldanha Bay from the adjacent coast when wind driven upwelling brings this cold water near to the surface. The inflow of cold, upwelled water into the Bay results in a thermocline, which is then broken down when the cooler bottom water flows out the Bay again. This density driven exchange flow between Saldanha Bay and coastal waters is estimated to be

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 20 Anchor Environmental Consultants CC capable of flushing the bay within 6-8 days, substantially less than the approximately 20 day flushing time calculated based on tidal exchange alone by Shannon and Stander (1977). The influx of nutrient rich upwelled water into Saldanha Bay is critical in sustaining primary productivity within the Bay, with implications for human activities such as fishing and mariculture. The fact that the thermocline is seldom shallower than 5 m depth means that the shallower parts of Saldanha Bay, particularly Langebaan Lagoon, are not exposed to the nutrient (mainly nitrate) import from the Benguela upwelling system. As a result these shallow water areas do not support large plankton blooms and are usually clear.

The most recent monitoring of water temperature in Saldanha Bay was conducted by the CSIR (Monteiro et al. 2000) over the period March 1999-February 2000. This was the most intensive long-term temperature record to date, with continuous measurements (every 30 minutes) taken at 1 m depth intervals over the 11 m depth range of the water column where the monitoring station was situated in Small Bay. The average monthly temperature at the surface (1m) and bottom (10 m) for this period is shown in Figure 5.1. These data confirmed the pattern evident in earlier data, showing a stratified (layered) water column for spring- summer caused by wind driven upwelling, with the water column being more or less isothermal (of equal temperatures) during the winter (Figure 5.1). The continuous monitoring of temperature also identified a 3 week break in the usual upwelling cycle during December 1999, with a consequent gradual warming of the bottom water. Once again, this “warm water” event (although the water column remained stratified indicating that the magnitude of this event was not as great as those observed during December 1974 and 1976 events) was associated with a decrease in phytoplankton production (due to reduced import of nitrate) which, in turn, impacted negatively on local mussel mariculture yields (Monteiro et al. 2000).

5.2 Salinity The salinity data time series covers much of the same period as that for water temperature and salinity data was extracted from the studies of Shannon and Stander (1977), Monteiro and Brundrit 1990, Monteiro et al. (1990) and Monteiro et al. (2000) (Fig 5.2). There was little variation in the salinity with depth in the water column and the values recorded at 10 m depth are presented in Figure 5.2. Under summer conditions when the water column is stratified, surface salinities may be slightly elevated due to evaporation and therefore salinity measurements from the deeper water more accurately reflect those of the source water. Salinities of the inshore waters along the west coast typically vary between 34.6-34.9 parts- per-thousand (ppt, or grams of salt per kilogram of sea water) (Shannon 1966), and the salinity values recorded for Saldanha Bay usually fall with in this range. During summer months when wind driven coastal upwelling within the Benguela region brings cooler South Atlantic Central Water to the surface, salinities are usually lower than during the winter months when the upwelling front breaks down and South Atlantic surface waters move against the coast (warm, surface waters are more saline due to evaporation). 35.3

35.2

35.1

34.9

Salinity (PSU) 34.8

34.7

34.6

34.5

Fig. 5.2: Time series of salinity records for Saldanha Bay

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The salinity time series shows salinity peaks in December 1974 and 1976 which reflects the warm water inflows that occurred at this time (Figure 5.2). Higher than normal salinity values were also recorded in August 1977 and July 1979 (Figure 5.2) and, although this was not reflected in the temperature time series (probably due to rapid heat loss and mixing during winter), the salinity peaks do indicate periodic inflows of surface oceanic water into Saldanha Bay.

Oceanic surface waters tend to be low in nutrients and therefore limit primary production (phytoplankton growth). These oceanic water intrusions into Saldanha Bay, that were identified from the temperature and salinity measurements, corresponded to low levels of nitrate and chlorophyll concentrations measured at the same time as salinity and temperature peaks (Monteiro and Brundrit 1990) (Figure 5.3). This highlights the impacts of the changes in physical oceanography (water temperature and salinity) in the immediate area on the biological processes (nitrate and chlorophyll) occurring within Saldanha Bay (Monteiro and Brundrit 1990). Data concerning these parameters cover a short period only (1974-1979) and as such are little use in examining effects of human development on the Bay.

34 32 30 28 ) 26

ug/l 24 22 20 18 16 14 12 10 8 concentration ( Chlorophyll 6 4 2 0 Apr-74 Jun-74 Aug-74 Oct-74 Dec-74 Feb-75 Apr-75 Jun-75 Aug-75 Oct-75 Dec-75 Feb-76 Apr-76 Jun-76 Aug-76 Oct-76 Dec-76 Feb-77 Apr-77 Jun-77 Aug-77 Oct-77 Dec-77 Feb-78 Apr-78 Jun-78 Aug-78 Oct-78 Dec-78 Feb-79 Apr-79

Chlorophyll concentrations

34 32 30 28 26 ) 24 uM 22 20 18 16 14 12 10 Nitrate concentration ( Nitrate 8 6 4 2 0 Apr-74 Jun-74 Aug-74 Oct-74 Dec-74 Feb-75 Apr-75 Jun-75 Aug-75 Oct-75 Dec-75 Feb-76 Apr-76 Jun-76 Aug-76 Oct-76 Dec-76 Feb-77 Apr-77 Jun-77 Aug-77 Oct-77 Dec-77 Feb-78 Apr-78 Jun-78 Aug-78 Oct-78 Dec-78 Feb-79 Apr-79 Jun-79 Aug-79 Oct-79

Nitrate concentrations Fig 5.3: Time series of chlorophyll and nitrate concentration measurements for Saldanha Bay.

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5.3 Dissolved oxygen Sufficient dissolved oxygen in sea water is essential for the survival of nearly all marine organisms. Low oxygen (or anoxic conditions) can be caused by excessive discharge of organic effluents (for example, from fish factory waste or municipal sewage) and microbial breakdown of this excessive organic matter depletes the oxygen in the water. The well known “black tides” and associated mass mortality of numerous marine species that occasionally occur along the west coast, result from the decay of large plankton blooms under calm conditions. Once all the oxygen in the water is depleted, anaerobic bacteria (not requiring oxygen) continue the decay process, causing the characteristic sulphurous smell. Apparent oxygen utilization (AOU - a measure of the potential available oxygen in the water that has been used by biological processes) values for Small and Big Bay over the period April 1974 - October 1982 and July 1988 are given in Monteiro et al. (1990). AOU is defined as the difference between the saturated oxygen concentration (the highest oxygen concentration that could occur at a given water temperature e.g. 5 ml/l) and the measured value (e.g. 1 ml/l) – hence positive AOU (5 ml/l – 1 ml/l = 4 ml/l) values indicate an oxygen deficit (indicated in red in Figure 5.4). More recent data on oxygen concentration in Small Bay (covering the period September 1999-February 2000) were provided by Monteiro et al. (2000). During this study, oxygen concentration at 10 m depth was recorded hourly by an instrument moored in Small Bay, these values were converted to AOU and the monthly average plotted in Figure 5.4.

There is no clear trend evident in the AOU time series, low oxygen concentrations (high AOU values) occur during both winter and summer months (Figure 5.4). Small Bay does experience a fairly regular oxygen deficit during the winter months, whilst Big Bay experiences less frequent and lower magnitude oxygen deficits. Monteiro et al (1990) attributed the oxygen deficit in Small Bay largely to anthropogenic causes, namely reduced flushing rates (due to the causeway and ore jetty construction) and discharges of organic rich effluents. The most recent data (September 1999-February 2000) indicate a persistent and increasing oxygen deficit as summer progresses (Figure 5.4). It is clear that oxygen levels within Small Bay are very low during the late summer months, likely as a result of naturally occurring conditions, however, the ecological functioning of the system could be further compromised by organic pollutants entering the Bay. There is evidence of anoxia in localised areas of Small Bay (e.g. under the mussel rafts, within the yacht basin) that is caused by excessive organic inputs. Monteiro et al (1997) identified the effluent from a pelagic fish processing factory as the source of nitrogen that resulted in an Ulva seaweed bloom in Small Bay.

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Desired Health:

Current Health:

4 Small Bay

Increasing oxygen deficit deficit Increasing oxygen 1

0 Apr-74 May-74 Jul-74 Aug-74 Sep-74 Oct-74 Dec-74 Jan-75 Feb-75 Mar-75 Apr-75 Jul-75 Oct-75 Jan-76 Mar-76 Jun-76 Sep-76 Dec-76 Mar-77 Jun-77 Aug-77 Oct-77 Dec-77 Mar-78 Jun-78 Sep-78 Jan-79 Apr-79 Jul-79 Oct-79 Jan-81 Apr-81 Jul-81 Oct-81 Jan-82 Apr-82 Jul-82 Oct-82 88 Jul Sep-99 Oct-99 Nov-99 Dec-99 Jan-00 Feb-00

-1

AOU (ml/l)

-2

-3

-4

Big Bay 1.5

0.5 Increasing oxygen deficit deficit Increasing oxygen 0 Apr-74 May- Jul-74 Aug-74 Sep-74 Oct-74 Dec-74 Jan-75 Feb-75 Mar-75 Apr-75 Jul-75 Oct-75 Jan-76 Mar-76 Jun-76 Sep-76 Dec-76 Mar-77 Jun-77 Aug-77 Oct-77 Dec-77 Mar-78 Jun-78 Sep-78 Jan-79 Apr-79 Jul-79 Oct-79 Jan-81 Apr-81 Jul-81 Oct-81 Jan-82 Apr-82 Jul-82 Oct-82 Jul 88 -0.5

-1

-1.5 AOU (ml/l)AOU -2

-2.5

-3

-3.5

Fig. 5.4: Apparent oxygen utilization (AOU) time series Small Bay and Big Bay, Saldanha Bay. (Note: Positive values in red indicate an oxygen deficit).

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5.4 Currents and waves Circulation patterns and current strengths prior to the development (1974-75) in Saldanha Bay were investigated using several techniques (drogues, dye-tracing, drift cards and sea- bed drifters). Surface currents (within the upper five meters) are complex and appeared to be dependent on wind strength and direction as well as the tidal state. Within Small Bay, currents were weak (5-15 cm.s-1) and tended to be clockwise (towards the NE) irrespective of the tidal state or the wind (Figure 5.5 A). Greater current strengths were observed within Big Bay (10-20 cm.s-1) and current direction within the main channels was dependent on the tidal state (Figure 5.5 A). The strongest tidal currents were recorded at the mouth of Langebaan Lagoon (50-100 cm.s-1), these being either enhanced or retarded by the prevailing wind direction (Figure 5.5 A). Currents within the main channels in Langebaan Lagoon were also relatively strong (20-25 cm.s-1). Outside of the main tidal channels, surface currents tended to flow in the approximate direction of the prevailing wind with velocities of 2-3 % of the wind speed (Shannon and Stander 1977). Current strength and direction at 5 m depth was similar to that at the surface, but was less dependent on wind direction and velocity and appeared to be more influenced by the tidal state. Currents at 10 m depth at the mouth of the Bay were found to be tidal (up to 10 cm. s-1, either eastwards or westwards) and in the remainder of the Bay, a slow (5 cm.s-1) southward or eastward movement, irrespective of the tidal state, was recorded.

The currents and circulation of Saldanha Bay subsequent to the construction of the Marcus Island causeway and the iron ore/oil jetty were described by Weeks et al. (1991a). Historical data of drogue tracking collected by the Sea Fisheries Research Institute during 1976-1979 were analysed in this paper. This study confirmed that wind is the primary determinant of surface currents in both Small Bay and Big Bay; although tidal flows do influence currents below the thermocline and are the dominant forcing factor in the proximity of Langebaan Lagoon. Weeks et al. (1991a) noted that because much of the drogue tracking was conducted under conditions of weak or moderate wind speeds, the surface current velocities measured (5-20cm.s-1), were probably underestimated. The authors concluded that the harbour construction had constrained water circulation within Small Bay, enhancing the general clockwise pattern and increasing current speeds along the boundaries, particularly the south-westward current flow along the iron ore/oil jetty (Figure 5.5 B). More recent data collected during strong NNE wind conditions in August 1990 revealed that greater wind velocities do indeed influence current strength and direction throughout the water column (Weeks et al. 1991b). These strong NNE winds were observed to enhance the surface flowing SSW currents along the ore jetty in Small Bay (out of the Bay), but resulted in a northward replacement flow (into the Bay) along the bottom, under both ebb and flood tides. The importance of wind as the dominant forcing factor of bottom, as well as surface, waters was further confirmed by Monteiro and Largier (1999) who described the density driven inflow-outflow of cold bottom water into Saldanha Bay during summer conditions when prevailing SSW winds cause regional scale upwelling.

Construction of the iron ore jetty and the Marcus Island causeway altered the wave exposure zones evident in the Bay. Prior to harbour development in Saldanha Bay, Flemming (1977) distinguished four wave-energy zones in the Bay, defined as being a centrally exposed zone in the area directly opposite the entrance to the Bay, two adjacent semi-exposed zones on either side and a sheltered zone in the far northern corner of the Bay (Figure 5.5 A). The iron ore jetty essentially divided the Bay into Small Bay and Big Bay and altered the wave energy and exposure patterns within the Bay. The causeway increased the extent of sheltered and semi-sheltered zones in Small Bay with no semi-exposed degree of wave energy being present in this area (Luger et al. 1999). Wave exposure in Big Bay was altered less dramatically, however, the extent of sheltered and semi-sheltered wave exposure areas increased after harbour development (Luger et al. 1999).

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 25 Anchor Environmental Consultants CC

Semi- A) B) ered d exposed eltered helt Desired Health: e 6 i-sh S er 6 Sem elt 6 Ore Jetty Sh Natural state 6

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e t E l Small Bay x e

p h o s S Desired Health: e d E x p Marcus Island o Causeway Big Bay s e

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Pre-1973 h S o Present 33 10’S 33o 10’S Flood tide Flood tide Ebb tide Ebb tide

0m 1500m 3000m 4500m 6000m 0m 1500m 3000m 4500m 6000m 17o 50’E Adapted from Shannon and Stander 1977 and Flemming 1977 17o 50’E Adapted from Weeks et al . 1991a and Luger et al . 1999 Fig.5.5: Schematic representation of the surface currents and circulation of Saldanha Bay (A) prior to the harbour development (Pre-1973) and (B) after construction of the causeway and iron-ore jetty (Present). (Source: Shannon and Stander 1977 and Weeks et al. 1991a)

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 26 Anchor Environmental Consultants CC

5.5 Microbiological monitoring Faecal pollution contained in, for example, untreated sewage or storm water runoff, may introduce disease-causing micro-organisms into coastal waters. These pathogenic micro- organisms constitute a threat to water users and consumers of seafoods. Bacterial indicators are used to detect the presence of faecal pollution. These bacterial indicators, however, only provide indirect evidence of the possible presence of water borne pathogens and may not accurately represent the risk to water users (Monteiro et al. 2000). Target limits, based on the faecal coliform count, for the harvesting of filter feeders (mussels and oysters which concentrate disease causing micro-organisms in their flesh) and for recreational water use, are provided in the Water Quality Guidelines for Use in South African Coastal Marine Waters (Department of Water Affairs and Forestry 1995a, b) and are indicated below:

Maximum acceptable count per 100ml sample: Mariculture 20 faecal coliforms in 80 % of samples 60 faecal coliforms in 95% of samples Full water contact 100 faecal coliforms in 80 % of samples (recreational use) 2 000 faecal coliforms in 95% of samples

In 1998, the Council for Scientific and Industrial Research (CSIR) were contracted by the Saldanha Bay Water Quality Forum Trust to undertake fortnightly sampling of microbiological indicators at 15 sites within Saldanha Bay. The initial report by the CSIR, covering the period February 1999 - March 2000, revealed that within Small Bay, faecal coliform counts frequently exceeded the guidelines for mariculture at 10 of 11 sampling stations. At 9 of the 11 sampling sites within Small Bay, the 80th percentile limit (100 faecal coliforms occurring in 80% of samples analysed) for full contact recreational use was also exceeded (Monteiro et al. 2000). These results indicated that there was indeed a health risk associated with the collection and consumption of filter feeding shellfish (mussels) and with recreational water use (swimming, diving etc.) within Small Bay. Much lower faecal coliform counts were recorded at stations within Big Bay, with the exception of the 80th percentile guideline for mariculture being exceeded at one station (Paradise beach), all other sites ranged within the guidelines for mariculture and recreational use (Monteiro et al. 2000). Regular monitoring of microbiological indicators within Saldanha Bay has continued and the available data now covers the period February 1999 to June 2005. This updated data set is summarized in this report in order to identify any trends over the past six years and assess the current levels of faecal pollution within Saldanha Bay.

Monitoring data for the 6 year period combined, reveal that, with the exception of station 10 (General Cargo Quay), all stations within Small Bay exceeded the target limits for mariculture while the 80th percentile limit for full contact recreation was exceeded at 6 of the 10 sites (indicated in red text in Table 5.1). Within Big Bay the faecal coliform counts were much lower, falling within the recommended limits for recreation at all sites (although 16 % of the samples exceeded the 100 faecal coliforms/100ml at the Langebaan main beach site) (Table 5.1). At the three sites closest to Langebaan, however, bacterial counts exceeded both the 80th and 95th percentile limits for mariculture (indicated in red text in Table 5.1).

Time series plots of faecal coliform counts reveal little improvement in the last six years at nearly all sites within Small Bay (Figure 5.6). Only in the vicinity of the mussel rafts (site 1) does there appear to be an improvement, with the 80th percentile limit for harvesting filter feeders only exceeded twice since January 2000 (last in July 2003 when the faecal coliform count was 23 per 100 ml), whereas it was exceeded seven times during the first year of monitoring (Figure 5.6). At all other sites within Small Bay however, the 80th percentile limit for mariculture, and at sites 3-7 and 9, the 80th percentile limit for recreation, continued to be regularly exceeded (Figure 5.6). Although there appears to be a slight decrease in the frequency with which target limits are exceeded over time, the most polluted sites are between the Yacht club basin and Hoedtjies Bay and in the vicinity of the sewage works outlet in Blue Water Bay (Figure 5.6). Big Bay has been sampled less frequently than Small Bay, but there is little change evident in the time series data for the five sampling stations within

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 27 Anchor Environmental Consultants CC

Big Bay (Figure 5.7). The 80th percentile limit for mariculture is exceeded fairly regularly at the three sites between Mykonos and Langebaan main beach, but the water is safe for recreational use on most occasions. Faecal coliform counts show an increase closer to the town of Langebaan (station15) (Figure 5.7).

Table 5.1: Levels of non-compliance to South African Water Quality Guidelines for bacterial counts (faecal coliforms) for mariculture and recreational uses for 15 sites sampled between February 1999 - June 2005 (Source: Monteiro et al 2000, CSIR - Saldanha Bay Water Quality Forum monitoring programme).

Number of Mariculture Recreation Site Station samples (n) n>20 %>20 n> 60 %>60 n>100 %>100 n>2000 %>2000 Beach at mussel rafts 1 40 10 25 8 20 7 18 0 0 Small Craft Harbour 2 73 24 33 11 15 9 12 0 0 Quay - Sea Harvest 3 99 58 59 41 41 28 28 2 2 Saldanha Yacht Club 4 112 86 77 72 64 63 56 6 5 Pepper Bay - Big Quay 5 115 94 82 71 62 56 49 10 9 Pepper Bay- "Cape Reef" 6 96 67 70 46 48 32 33 4 4 Hoedjies Bay Hotel - Beach 7 121 94 78 56 46 42 35 4 3 Beach at caravan park 8 97 53 55 27 28 18 19 5 5 Beach – Sewage outlet 9 125 111 89 85 68 72 58 11 9 General Cargo Quay 10 36 4 11 1 3 1 3 0 0 Seafarm - Portnet 11 31 5 16 1 3 1 3 0 0 Mykonos - Paradise Beach 12 35 6 17 1 3 0 0 0 0 Mykonos - harbour 13 60 14 23 8 13 6 10 1 2 Langebaan North 14 57 18 32 10 18 5 9 0 0 Langebaan Main Beach 15 68 35 51 23 34 11 16 1 1 Acceptable level of 20 5 20 5 non-compliance * Guidelines refer to the number of faecal coliforms per 100ml sea water (e.g. values in the column n > 20 refers to the number of samples where the faecal coliform count exceeded 20 per 100ml seawater). ** Values highlighted in red exceed the acceptable level of non-compliance

A seasonal trend in faecal coliform counts is expected, with peaks during holiday periods (when sewage systems may become overloaded) or during periods of high rainfall i.e. winter, when storm water discharge into the Bay is expected to be highest. This seasonal trend is however, not evident in the time series data, with peaks occurring during both winter and summer months. This makes it difficult to identify the causes of faecal pollution, although spatial patterns in faecal coliform counts do suggest that the water currents and circulation patterns play a large role in determining the concentration and persistence of bacterial indicators in different areas. It is logical that the sites along the northern shore of Small Bay, where tidal and wind driven current speeds and, hence flushing rates, tend to be the lowest within the whole Saldanha Bay-Langebaan system, have the highest concentrations of bacterial indicators. These sites being in the vicinity of the most populated and developed area (Saldanha CBD) are also closest to the most likely sources of faecal pollution (sewage outlets and storm water outflow).

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6 6 6 6 6 6 100000 6 6 6 6 6 6

80th% Filterfeeders 80th% Recreation 95th% Recreation 10000

1000

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1000 1000

0ml 1 10 r 00 ml

pe 100 100 unt per 1 o t C 0 n 10 u Co 10 1-Oct-03 2-Oct-02 4-Apr-02 4-Jun-03 9-Jun-99 5-Jun-02 8-Dec-04 3-Aug-99 7-Aug-02 30-Jul-03 22-Apr-04 30-Jun-04 27-Oct-04 27-Jan-05 29-Jun-05 22-Jan-03 16-Apr-99 19-Jan-00 30-Jan-02 31-Mar-05 26-Mar-03 28-Mar-01 12-Feb-04 27-Nov-02 17-Feb-99 23-Nov-99 14-Nov-01 12-Dec-03 25-Aug-04 28-Sep-99 26-Sep-01 20-Dec-01 23-May-01 1 Hoedjiesbaai Hotel Beach 1 0

0 4-A pr- 02 2-O ct- 02 1-O ct- 03 9-Jun-99 5-Jun-02 4-Jun-03 3-Aug-99 7-Aug-02 8-Dec-04 30-Jul-03 16-Apr-99 22-Apr-04 27-Oct-04 19-Jan-00 30-Jan-02 22-Jan-03 30-Jun-04 27-Jan-05 29-Jun-05 17-Feb- 99 28-Mar-01 26-Mar-03 12-Feb- 04 31-Mar-05 28-Sep-99 23-Nov-99 26-Sep-01 14-Nov-01 20-Dec-01 27-Nov-02 12-Dec-03 25-Aug-04 23-May-01 Pepperbay (Large quay) 3-Jul-02 2-Jul-03 6-Jul-99 2-Oct-02 1-Oct-03 4-Apr-02 5-Jun-02 4-Jun-03 9-Jun-99 2-Mar-05 7-Aug-02 4-Sep-02 3-Aug-99 1-Sep-99 1-Aug-01 5-Dec-01 8-Dec-04 30-Jul-03 28-Jul-04 8-May-02 4-May-05 30-Oct-02 30-Apr-03 22-Apr-04 16-Apr-99 26-Oct-99 11-Apr-01 31-Oct-01 27-Oct-04 22-Jan-03 21-Jan-04 30-Jun-04 19-Jan-00 16-Jan-02 30-Jan-02 12-Jan-05 27-Jan-05 29-Jun-05 26-Feb-03 26-Mar-03 12-Feb-04 11-Mar-04 17-Feb-99 17-Mar-99 16-Feb-00 28-Mar-01 27-Feb-02 31-Mar-05 27-Nov-02 12-Dec-02 27-Aug-03 20-Nov-03 12-Dec-03 28-Sep-99 23-Nov-99 23-Dec-99 26-Sep-01 14-Nov-01 20-Dec-01 25-Aug-04 22-Sep-04 25-Nov-04 26-May-04 12-May-99 23-May-01 Sewage works outlet

6 6 6 6 100000 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 100000 80th% Filterfeeders 80th% Recreation 95th% Recreation 9 10000 80th% Filterfeeders 80th% Recreation 95th% Recreation 8 10000

1000 1000 7 100 100

Count per 100 ml 6 S mall Bay 10 Count per 100 ml 10 10 5

1 4 1 3 0 0 2 4-Jun-03 1-Oct-03 4-Apr-02 5-Jun-02 2-Oct-02 9-Jun-99 7-Aug-02 3-Aug-99 8-Dec-04 30-Jul-03 29-Jun-05 22-Apr-04 30-Jun-04 27-Oct-04 27-Jan-05 22-Jan-03 30-Jan-02 16-Apr-99 19-Jan-00 31-Mar-05 26-Mar-03 28-Mar-01 12-Dec-03 12-Feb-04 25-Aug-04 27-Nov-02 26-Sep-01 14-Nov-01 20-Dec-01 17-Feb-99 28-Sep-99 23-Nov-99 23-May-01 4-Apr-02 2-Oct-02 1-Oct-03 5-Jun-02 4-Jun-03 9-Jun-99 7-Aug-02 3-Aug-99 8-Dec-04 30-Jul-03 30-Jan-02 22-Jan-03 22-Apr-04 30-Jun-04 27-Oct-04 27-Jan-05 29-Jun-05 16-Apr-99 19-Jan-00 27-Nov-02 26-Mar-03 12-Feb-04 31-Mar-05 17-Feb-99 23-Nov-99 28-Mar-01 14-Nov-01 12-Dec-03 28-Sep-99 26-Sep-01 20-Dec-01 25-Aug-04 Small quay at Sea Harvest 1 23-May-01 Caravan park

100000 100000

10000 80th% Filterfeeders 80th% Recreation 95th% Recreation 10000 80th% Filterfeeders 80th% Recreation 95th% Recreation

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Count per 100 ml 10

1 1 0 4-Apr-02 1-Oct-03 2-Oct-02 9-Jun-99 5-Jun-02 4-Jun-03 3-Aug-99 7-Aug-02 8-Dec-04 30-Jul-03 16-Apr-99 22-Apr-04 27-Oct-04 27-Jan-05 29-Jun-05 19-Jan-00 30-Jan-02 22-Jan-03 30-Jun-04 31-Mar-05 28-Mar-01 26-Mar-03 17-Feb-99 28-Sep-99 23-Nov-99 26-Sep-01 14-Nov-01 20-Dec-01 12-Dec-03 12-Feb-04 27-Nov-02 25-Aug-04 23-May-01 9-Jun-99 4-Apr-02 5-Jun-02 2-Oct-02 4-Jun-03 1-Oct-03 8-Dec-04 3-Aug-99 7-Aug-02 30-Jul-03 27-Oct-04 16-Apr-99 22-Apr-04 27-Jan-05 29-Jun-05 22-Jan-03 30-Jun-04 Small beach near mussel rafts 19-Jan-00 30-Jan-02 31-Mar-05 17-Feb-99 26-Mar-03 12-Feb-04 28-Mar-01 27-Nov-02 12-Dec-03 25-Aug-04 28-Sep-99 23-Nov-99 26-Sep-01 14-Nov-01 20-Dec-01 23-May-01 General Cargo Quay

Fig. 5.6: Faecal coliform counts at 10 sampling stations within Small Bay (Feb 99-June 2005).

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 29 Anchor Environmental Consultants CC

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100000 80th% Filterfeeders 80th% Recreation 95th% Recreation 95th% Recreation 10000 80th% Filterfeeders 80th% Recreation 10000 1000 1000 100

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Count per 100 mL 10 1 Small Bay 11 1 0 0 9-Jun-99 4-Apr-02 5-Jun-02 2-Oct-02 4-Jun-03 1-Oct-03 3-Aug-99 7-Aug-02 8-Dec-04 30-Jul-03 16-Apr-99 22-Apr-04 19-Jan-00 30-Jan-02 22-Jan-03 30-Jun-04 27-Oct-04 27-Jan-05 29-Jun-05 28-Mar-01 17-Feb-99 26-Mar-03 12-Feb-04 31-Mar-05 28-Sep-99 23-Nov-99 26-Sep-01 14-Nov-01 20-Dec-01 27-Nov-02 12-Dec-03 25-Aug-04 23-May-01 4-Apr-02 2-Oct-02 1-Oct-03 9-Jun-99 5-Jun-02 4-Jun-03 3-Aug-99 7-Aug-02 8-Dec-04

30-Jul-03 Langebaan (North street) 16-Apr-99 30-Jan-02 19-Jan-00 22-Jan-03 22-Apr-04 30-Jun-04 27-Oct-04 27-Jan-05 29-Jun-05 17-Feb-99 23-Nov-99 28-Mar-01 14-Nov-01 27-Nov-02 26-Mar-03 12-Feb-04 31-Mar-05 12 28-Sep-99 26-Sep-01 20-Dec-01 12-Dec-03 25-Aug-04 23-May-01 Seafarm dam outlet Big Bay 13

6 100000 6 100000 6 6

80th% Filterfeeders 80th% Recreation 95th% Recreation 10000 80th% Filterfeeders 80th% Recreation 95th% Recreation 10000 14 1000 1000 Langebaan 15 100 100 Lagoon

Count per 100 ml 10 Count per 100 ml 10 Overall Desired Health:

1 1 0 0 1-Oct-03 4-Apr-02 2-Oct-02 4-Jun-03 5-Jun-02 9-Jun-99 30-Jul-03 8-Dec-04 7-Aug-02 3-Aug-99 22-Apr-04 27-Oct-04 16-Apr-99 30-Jun-04 29-Jun-05 30-Jan-02 22-Jan-03 27-Jan-05 19-Jan-00 26-Mar-03 31-Mar-05 28-Mar-01 12-Feb-04 17-Feb-99 12-Dec-03 25-Aug-04 26-Sep-01 14-Nov-01 20-Dec-01 27-Nov-02 28-Sep-99 23-Nov-99 23-May-01 4-Apr-02 2-Oct-02 1-Oct-03 9-Jun-99 5-Jun-02 4-Jun-03 3-Aug-99 7-Aug-02 8-Dec-04 30-Jul-03 16-Apr-99 22-Apr-04 19-Jan-00 30-Jan-02 22-Jan-03 27-Jan-05 29-Jun-05 30-Jun-04 27-Oct-04 17-Feb-99 28-Mar-01 26-Mar-03 31-Mar-05 12-Feb-04 28-Sep-99 23-Nov-99 26-Sep-01 14-Nov-01 20-Dec-01 27-Nov-02 25-Aug-04 12-Dec-03 23-May-01 Langebaan main beach Mykonos (Paradise Beach) Fig. 5.7: Faecal coliform counts at 5 sampling stations within Big Bay (Feb 99-June 2005).

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 30 Anchor Environmental Consultants CC

5.6 Heavy Metal Contaminants There is an increasing global trend emerging in countries like USA, Australia, New Zealand and South Africa to monitor the long-term effects of water quality by assessing the impacts thereof on specific marine species or species groups. Mussels and oysters, i.e. filter feeding organisms, are considered to be suitable indicator species for the purpose of monitoring water quality as, due to their feeding process, they tend to accumulate trace metals, hydrocarbons and pesticides in their flesh. Mussels are sessile organisms (anchored in one place for their entire life) and will be affected by both short-term variability and long-term trends in water quality, at specific locations. Monitoring the contaminant levels in mussels can provide early warnings for poor water quality and dramatic changes in contaminant levels occurring.

In 1985 the Directorate: Marine and Coastal Management (MCM) of the Department of Environmental Affairs and Tourism initiated a “Mussel Watch” Programme whereby mussels (either brown mussels Perna perna or Mediterranean mussels Mytilus galloprovincialis) are collected every six months (May and October) from 26 coastal sites. The mussel samples are analysed for the trace metals Cadmium (Cd), Copper (Cu), Lead (Pb), Zinc (Zn), Iron (Fe) and Manganese (Mn), hydrocarbons and pesticides. Mussels have been collected from five stations in Saldanha Bay every six months (May and October each year) since 1997. Data from Saldanha Bay Mussel Watch programme are currently, however, only available until 2001 due to a backlog in processing of samples. These data are represented in Figure 5.8 where the maximum legal limits prescribed for each contaminant in shellfish for human consumption, as stipulated by the Foodstuffs, Cosmetics and Disinfectants Act, 1972 (Act 54 of 1972), are indicated in red text. The levels of contaminants prescribed in this Act, should be met if the quality of the water from which these organisms are harvested complies with the recommended target values for mariculture, as specified in the South African Water Quality Guidelines for Coastal Marine Waters.

Elevated levels of Cadmium reduce the ability of bivalves to efficiently filter water and extract nutrients, thereby impeding successful metabolism of food. Cadmium can also lead to injury of the gills of bivalves further reducing the effectiveness of nutrient extraction. Similarly, elevated levels of Lead result in damage to mussel gills and increased growth deficiencies and mortality. Elevated levels of Zinc are known to suppress growth of bivalves and at levels between 470 to 860 mg/l can result in mortality of the mussels (South African Water Quality Guidelines for Coastal Marine Waters, Mariculture).

Data supplied by the Mussel Watch Programme (Figure 5.8) show that concentrations of all heavy metals reported on are well below the maximum legal limits at all sites in Saldanha Bay from 1997 until 2000 or 2001. There appears to be no heavy metal accumulation in the flesh of mussels in Saldanha Bay and the quality of the water can be considered suitable for mariculture purposes. The mussel farm in Small Bay would be expected to employ stringent monitoring methods on a regular basis to ensure that exported mussels are well within the necessary safety levels.

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 31 Anchor Environmental Consultants CC

Maximum limit 3 mg/l Maximum limit 3 mg/l Maximum limit 3 mg/l

3 mg/l

Maximum limit 50 mg/l Maximum limit 50 mg/l Maximum limit 50 mg/l

Maximum limit 4 mg/l Maximum limit 4 mg/l Maximum limit 4 mg/l

)

/ g

(

n o

t a

r Maximum limit 300 mg/l

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n e

c n

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Maximum limit not listed Maximum limit not listed

Maximum limit not listed

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May Oct May May Oct May Oct May Oct 97 97 98 99 99 00 00 May Oct May May Oct May Oct 01 01 May Oct May Oct May May Oct May Oct May Oct 97 97 98 99 99 00 00 01 01 Fish factory 97 97 98 99 99 00 00 01 01 Saldanha Bay North Portnet

Maximum limit 3 mg/l Maximum limit 3 mg/l

Portnet Saldanha Bay North

Fish factory Maximum limit 50 mg/l Maximum limit 50 mg/l Small Bay

Iron ore jetty

Mussel raft 27

Maximum limit 4 mg/l )

l Maximum limit 4 mg/l

)

(

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Maximum limit 300 mg/l

Maximum limit not listed

Oct May May May Oct May Oct May Oct May Oct May May Oct May Oct May Oct 97 97 98 99 99 00 00 01 01 97 97 98 99 99 00 00 01 01 Mussel raft 27 Iron ore jetty

Fig. 5.8: Heavy metal concentrations in mussels collected from five sites in Saldanha Bay as part of the Mussel Watch Programme. Source of data: G. Kiviets, Marine and Coastal Management, Department of Environmental Affairs and Tourism

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 32 Anchor Environmental Consultants CC

5.7 Summary of Water Quality in Saldanha Bay and Langebaan Lagoon There are no long term trends evident in the water temperature, salinity and dissolved oxygen data series that solely indicate anthropogenic causes. In the absence of actual discharge of industrially heated sea water into the Bay, water temperature is unlikely to show any change that is discernable from that imposed by natural variability. Admittedly there is limited pre- development data (pre 1975), so although it is conceivable that construction of the causeway and ore/oil jetty has impeded water flow thus increasing residence time and increasing water temperatures, salinity and likely decreasing oxygen concentration, particularly in Small Bay, there is little data to support this. Given that cold, nutrient rich water influx during summer is density driven; dredging shipping channels could have facilitated this process which would be evident as a decrease in water temperature and salinity and an increase in nitrate and chlorophyll concentrations. Once again there is little evidence of this in the available data series. Natural, regional oceanographic processes (wind driven upwelling or downwelling and extensive coast–Bay exchange) rather than internal, anthropogenic causes, appear to remain the major factors affecting physical and chemical water characteristics in Saldanha Bay.

The construction of physical barriers (the iron ore/oil jetty and the Marcus Island causeway) do appear to have changed current strengths and circulation within Small Bay, resulting in increased residence time (decreased flushing rate), enhanced clockwise circulation and enhanced boundary flows. There has also been an increase in sheltered and semi-sheltered wave exposure zones in both Small and Big Bay subsequent to harbour development.

The microbiological monitoring program provides evidence that the coastal waters in Small Bay continue to have faecal coliform counts in excess of the safety guidelines for both mariculture and recreational use. Given the current importance and likely future growth of both the mariculture and tourism industries within Saldanha Bay, it is imperative that steps are taken to remedy the situation. As it is impractical to alter the hydrodynamics of Small Bay and improve flushing rates, the recommended course of action is to identify the sources of faecal pollution and take measures to reduce them (most likely by improving storm water and sewage management). Continued monitoring of bacterial indicators, in order to assess the effectiveness of adopted measures, is required. Although microbiological water quality within much of Big Bay remains acceptable, the situation in the vicinity of Langebaan town should continue to be monitored and pro-active steps implemented (e.g. upgrading of sewage and storm water facilities to keep pace with development and population growth) to ensure that the waters remain safe for recreational activities.

Data supplied by the Mussel Watch Programme (DEAT) suggest that there is no heavy metal (Cadmium, Copper, Lead, Zinc, Iron and Manganese) accumulation in the flesh of mussels sampled in Small Bay. Concentrations of these heavy metals in the flesh of mussels between 1997 and 2000 or 2001 are well below the prescribed maximum legal limits.

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 33 Anchor Environmental Consultants CC

6 SEDIMENTS

6.1 Sediment particle size (Mud – Sand – Gravel)

The types of sediments occurring in Saldanha Bay are strongly influenced by wave energy and current circulation patterns occurring in the system. High wave energy and strong currents suspend fine sediment particles (mud) which are then flushed out the Bay, leaving behind the coarser (heavier) sand or gravel particles. Reduced wave action and disturbed current patterns can result in the deposition of mud in some areas. Since 1975, several industrial developments in Saldanha Bay (iron ore jetty, multi-purpose jetty, mussel rafts and establishment of a yacht harbour) have resulted in some level of obstruction to the natural patterns of wave action and current circulation prevailing in the Bay. The extent to which changes in wave exposure and current patterns has impacted on sediment deposition and consequently on benthic macrofauna (animals living in the sediments), has been an issue of concern for many years. The quantity and distribution of different sediment grain particle sizes (gravel, sand and mud) through Saldanha Bay prescribes the status of biological communities and the extent of possible organic loading that may occur in Saldanha Bay.

Contaminants, such as trace metals and organic toxic pollutants, are predominantly associated with fine sediment particles (mud or cohesive sediments). The mud component of sediment (defined as being of grain size less than 60 µm) is closely associated with the occurrence of organic carbon and trace metals. Higher proportions of mud, relative to sand or gravel, can lead to high organic loading and trace metal contamination. It follows then that with a disturbance to natural wave action and current patterns, an increase in the proportion of mud in the sediments of Saldanha Bay, could result in higher organic loading and dangerous levels of trace metals occurring. Changes in sediment particle size in Saldanha Bay are of interest here and are summarised in Figure 6.1 and in the text that follows.

Disturbance to the sediment (e.g. dredging) can lead to re-suspension of the mud component from underlying sediments, along with the associated organic pollutants and trace metals. It may take several months or years following a dredging event before the mud component has settled out of suspension and the sand or gravel component re-established on the surface layer. Once the mud component has stabilised and is protected from wave action and currents by the overlying sand or gravel, the associated organic pollutants and trace metals become largely non-threatening to the environment.

The earliest studies reporting on the sediments of Saldanha Bay and Langebaan Lagoon were conducted by Flemming (1977) prior to large scale development of the area. Flemming (1977), however, did not report on the distribution of the mud component of the sediments in Saldanha Bay and Langebaan Lagoon as, at that time, they was considered to have an “overall low content”. The mud component in Saldanha Bay prior to development (1977) was thus considered to be negligible and the sediments comprised predominantly sand particles (size range from 1 mm to 60 µm, Figure 6.1).

The next sediment sampling to take place in Saldanha Bay for which data is available was conducted in 1989 and 1990 by Jackson and McGibbon (1991) as a result of concern for deteriorating water quality in the Bay. At the time of the Jackson and McGibbon study, the iron ore jetty had been established dividing the Bay into Small Bay and Big Bay (Figure 6.1), the multi-purpose terminal had been added to the jetty, various holiday complexes had been established on the periphery of the Bay and the mariculture industry had begun farming mussels in sheltered waters of Small Bay. The 1989 and 1990 studies revealed that sediments occurring in both Small Bay and Big Bay were still primarily comprised of sand particles but that mud now made up a noticeable, albeit small, component at most sites in the Bay (Figure 6.1). The Jackson and McGibbon (1991) study concluded that an increase in organic loading in the Bay had indeed occurred, however, this was not strongly reflected in the sediment analysis conducted at the time.

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 34 Anchor Environmental Consultants CC

6 6 6 6 6 6 6 6

Mud Sand Gravel Mud Sand Gravel 100% 100% 80% 80%

60% 60%

40% 1997 Dredge 40% 1997 Dredge 20% 20%

0% 0% 1977 1989 1990 1999 2000 2001 2004 1977 1989 1990 1999 2000 2001 2004

North channel - Small Bay Multi-purpose Quay

6 6 6 6 6 6 6 6 6 6 6 6

Mud Sand Gravel Mud Sand Gravel

100% 100% Small Bay 80% 80% 60% 60%

40% 40% 1997 Dredge Dredge 1997 Dredge 20% 20% Big Bay 0% 0% 1977 1989 1990 1999 2000 2001 2004 1977 1989 1990 1999 2000 2001 2004 Yacht club basin Channel end of ore jetty

6 6 6 6

Mud Sand Gravel Mud Sand Gravel 100% Overall Desired Health: 100% 80% 80% 60% 60% 40% Dredge 1997 Dredge

40% 1997 Dredge 20% 20% 0% 0% 1977198919901999200020012004 1977 1989 1990 1999 2000 2001 2004 Mussel farm Big Bay

Fig. 6.1: Particle grain size percentage contribution to sediments at six locations in Saldanha Bay between 1977 and 2004.

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 35 Anchor Environmental Consultants CC

The next study on sediment particle size in Saldanha Bay occurred nearly a decade later, in 1999. However, immediately preceding this (in 1997/98) an extensive area adjacent to the ore jetty was dredged (indicated by arrows in Figure 6.1), resulting in a massive disturbance to the sediment of the Bay. The 1999 study clearly shows a substantial increase in the percentage of mud particles making up the sediment composition, specifically at the Multi- purpose Quay, Channel end of the ore jetty, the Yacht club basin and the Mussel farm area (Figure 6.1). Two sites least affected by the dredging event were the North channel site in Small Bay and the site in Big Bay. The North channel site is located in shallow water where the influence of strong wave action and current velocities are expected to have facilitated in flushing out the fine sediment particles (mud) that are likely to have arisen from dredging activities. The site located in Big Bay (not dredged, represented by dashed grey arrow) remained largely unaffected by the dredging event occurring in Small Bay and is presumably mediated to some extent by the scouring action of oceanic waves impacting the site (Figure 6.1).

Subsequent studies conducted in 2000 and 2001 indicated that the mud content of the sediment remained high but that there was an unexplained influx of coarse sediment (gravel) in 2000 followed by what appears to be some recovery over the 1999 situation. The 2000 results are somewhat anomalous and may be related to some analytical error that arose when the samples were analysed. Sampling conducted in 2004 shows almost complete recovery of sediments over the 1999 situation to a majority percentage of sand in five of the six sites examined for this report (Figure 6.1). The only site where a substantial mud component remains is at the Multi-purpose Quay. The shipping channel adjacent to the Quay is the deepest section of Small Bay (artificially maintained to allow passage of vessels) and is expected to concentrate the denser (heavier) mud component of sediment occurring in the Bay.

In summary, the natural, pre-development state of sediment in Saldanha Bay comprised predominantly sand particles, however, increasing development and human impact in the Bay reduced the overall wave energy and altered the current circulation patterns. As a result, mud (cohesive sediment) began to accumulate in surface sediments in the Bay. Dredging of Small Bay in 1997/98 also re-suspended large amounts of mud from the deeper lying sediments, which then settled out in the surface sediments. These fine sediments have however gradually been washed out of the Bay or have been reburied through the course of time. The situation at present reflects that of slightly reduced wave action and current velocities with slightly higher than normal amounts of mud in the sediments. Any future dredging or other such large-scale disturbance events to the sediment in Saldanha Bay are likely to result in similar increases in the mud proportion as was evident in 1999, with accompanying increase in heavy metal content (refer to §6.3 for more details on this).

6.2 Particulate Organic Carbon (POC) and Nitrogen (PON)

Particulate organic carbon (POC) and particulate organic nitrogen (PON) can be expected to accumulate in the same areas as mud (cohesive sediment). Most organic particulate matter is of similar particle size range as that of mud particles (less than 60 µm) and settles out of the water column together, resulting in high concentrations of POC and PON in areas where mud is located. The most likely sources of organic matter in Saldanha Bay are from the natural fluctuation of phytoplankton production at sea and the associated detritus that forms from decay thereof, the fish factory waste discharge and the faecal waste concentrated beneath the mussel rafts at the mussel farm. The accumulation of organic matter (POC and PON) is most likely to be concentrated in sheltered areas where there is limited wave action and hence limited dispersal of organic matter. Elevated concentrations of PON in the sediments can indicate the presence of relatively fresh organic matter of phytoplankton origin, however, high carbon to nitrogen ratios can indicate simultaneous input of nitrogen depleted matter, possibly of fish waste origin (Monteiro et al. 1999). An accumulation of organic matter does not necessarily result in a direct negative impact on the environment, however, persistent build up can lead to increased sulphide concentrations, which develop as a result of the breakdown of organic matter. Persistent high organic loads can ultimately result in anoxic conditions which have severe negative impacts on the environment. Sulphide rich

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 36 Anchor Environmental Consultants CC sediments (anoxic sediments) are easily recognised by their black colour and distinct sulphide odour. The presence of sulphide in the sediments can lead to hydrogen sulphide, specifically toxic to the environment in the gaseous form, which occurs at low pH values.

Particulate organic carbon was measured during similar sampling events as that of sediment particle size. The percentage POC prior to any major development in and around Saldanha Bay (Pre-1974) was very low (between 0.2 and 0.5) throughout the Bay (Figure 6.2). The next available POC data (1989) was collected after construction of the iron ore jetty and the establishment of mussel farms in Small Bay. At this stage all sites monitored had considerably elevated levels of POC present with the greatest increase occurring at the Mussel farm (Figure 6.2). POC levels peaked at a record high (16.9 %) at this site in 1990. The reason for this extremely high POC percentage is uncertain. Through all subsequent years of POC monitoring (1990, 1999, 2000, 2001 and 2004), levels have remained higher than those originally reported, prior to development. All POC levels recorded in 2004 are lower than previous years, except at the Mussel farm site, suggesting some degree of recovery in Saldanha Bay. The lowest POC values occur at the North channel site in Small Bay and in Big Bay. The low POC values recorded here are due to the shallow water and/or high wave action and current patterns experienced at these sites resulting in a considerable amount of POC being flushed out. POC values are highest at the Yacht club basin and the Mussel farm, both sheltered sites (Figure 6.2).

No historical PON values were attainable for the purposes of this report, however, data from 1999 to 2004 of the percentage organic nitrogen measured at selected sites within Small and Big Bay indicates that the highest levels of organic nitrogen in Saldanha Bay, were recorded at the Yacht Club basin and near the Mussel rafts (Figure 6.3). This is predicted to be as a result of fish factory waste discharge and faecal waste concentrating beneath the mussel rafts.

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 37 Anchor Environmental Consultants CC

6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6

Small Bay

Big Bay

6 6 6 6 6 6 6 6 6 6 6 6

Overall Desired Health:

Fig. 6.2: Particulate Organic Carbon (POC) percentage occurring in sediments of Saldanha Bay at six locations between 1974 and 2004

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 38 Anchor Environmental Consultants CC

6 6 6 0.7 6 6 6 6 6 6 6 6 6 Small Bay 0.6

0.5

0.4

% PON 0.3 Big Bay 0.2 0.1

0 1999 2000 2001 2004

Channel end of ore jetty

6 6 6 6 Overall Desired Health:

Figure 6.3. Particulate Organic Nitrogen (PON) percentage occurring in sediments of Saldanha Bay at six locations between 1999 and 2004.

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 39 Anchor Environmental Consultants CC

6.3 Trace metals

Several trace metals naturally occur in the marine environment, some of which are important in fulfilling various physiological roles. Disturbance to the natural environment by either anthropogenic or natural factors can lead to an increase in trace metal concentrations occurring in the sediment. An increase in trace metal concentrations above certain established safety thresholds can result in negative impacts on various marine organisms, especially filter feeders like mussels that tend to accumulate trace metals in their flesh. High concentrations of trace metals can also render some marine species unsuitable for human consumption. Trace metals are strongly associated with the cohesive fraction of sediment (i.e. the mud component) and with Particulate Organic Carbon (POC). Trace metals occurring in sediments are generally inert (non-threatening) when buried in the sediment but can become toxic to the environment when they are converted to the more soluble form of metal sulphides. Metal sulphides are known to form as a result of natural re-suspension of the sediment (strong wave action resulting from storms) and from anthropogenic induced disturbance events like dredging activities.

The concentrations of twelve different trace metals have been evaluated on various occasions in Saldanha Bay, however, the overall fluctuations in concentrations are similarly reflected by several key metals throughout the time period. For the purposes of this report, four trace metals, those having the greatest potential impact on the environment, were selected from the group to represent the status of trace metals in Saldanha Bay. The metals reported on here are thus Cadmium (Cd), Lead (Pb), Copper (Cu) and Nickel (Ni).

The earliest trace metal concentrations recorded in Saldanha Bay were sampled in 1980, prior to the time at which ore concentrate was first exported from the ore jetty. The sites sampled were 2 km north of the Multi-purpose Quay (Small Bay) and 3 km south of the Multi- purpose Quay (Big Bay) and trace metals reported on included Lead (Pb), Cadmium (Cd) and Copper (Cu). Concentrations of these metals in 1980 were very low, well below the health and safety thresholds (Figure 6.4 A-D). Subsequent sampling of trace metals in Saldanha Bay (for which data is available) only took place nearly 20 years later in 1999. During the interim period between these sampling events, a considerable volume of ore had been exported from the Bay, areas of Saldanha Bay had been dredged (1997/98), and the mussel farm and the small craft harbour (yacht club basin) had been established (1984). As a result of these activities, the concentrations of trace metals in 1999 were very much higher (up to 60 fold higher) at all stations monitored (Figure 6.4 A-D). This reflects the accumulation of trace metals in the intervening 20 years, much of which had recently been re-suspended during the dredging event and had settled in the surficial (surface) sediments in the Bay. The levels of Cadmium recorded in 1999 at the Mussel farm and the Yacht club basin far exceeded the safety threshold of 1.5 mg/kg established by the internationally accepted London Convention regulations. Fortunately safety thresholds set by the London Convention for Lead, Copper and Nickel were not exceeded in 1999, however, concentrations were considerably higher than had previously been recorded at all stations, especially the Mussel farm and Yacht club basin (Figure 6.4 A-D). Annual monitoring of trace metals was implemented and by the following year (2000), concentrations of most trace metals in Saldanha Bay were considerably lower, although nowhere approaching levels measured in 1980 (Figure 6.4 A-D). This closely mirrors changes in the proportion of mud in the sediments, and most likely reflects the removal or burial of these fine sediments together with the trace metal contaminants from the Bay, by wave action. Exceptions to this observed decrease in trace metal concentrations were evident at the Multi-purpose Quay site where concentrations of Lead, Copper and Nickel, which increased between 1999 and 2000. Subsequent monitoring events between 2001 and 2004 (most recent), have revealed that trace metal concentrations have continued to decrease in Saldanha Bay (Figure 6.4 A-D) and are much reduced from the exceptionally high concentrations recorded in 1999.

The dramatic increase in trace metal concentrations, especially those of Cadmium and Lead, after the start of exporting ore concentrate from the jetty in Saldanha Bay, lead to concern for the safety and health of marine organisms, specifically those being farmed for human

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 40 Anchor Environmental Consultants CC consumption (mussels and oysters). Of particular concern were the concentrations of Cadmium which exceeded the safety levels established by the London Convention (Figure 6.4 A-D). Both Lead and Copper concentrates are exported from Saldanha Bay and it was hypothesised that the overall increase of trace metal concentration was directly associated with the export of these metals. Detailed studies examining the origin of the trace metals present in the Bay revealed that other trace metals occurring in Saldanha Bay are mostly of natural origin, except for the area adjacent to the Multi-purpose Quay where elevated concentrations are associated with ore dust fall-out occurring during loading and unloading activities. Cadmium concentrations have been found to occur in naturally high concentrations in the organic rich sediments of the near shore zone of the southern Benguela (including Saldanha Bay area).

In summary, elevated trace metal concentrations recorded in Saldanha Bay in 1999 were ascribed to be an accumulation of these metals in the sediments of the Bay over the preceding 20 years, much of which was re-suspended as a result of dredging operations and had settled in the surface layers. Construction of the Marcus Island causeway and the ore jetty had contributed to this process by reducing wave action and modifying circulation patterns prevailing in the Bay. Subsequent monitoring has revealed a substantial overall decrease in the concentrations of trace metals in the Bay, suggesting that a disturbance, like dredging which remobilises the fine sediments and re-suspends trace metals, can severely affect the health of the Bay and that it takes between three to six years before the contaminated sediments are removed from the Bay by natural processes. It was also shown that trace metal concentrations were elevated near the Multi-purpose Quay as a result of lead and copper ore dust entering the environment during export activities.

6.4 Hydrocarbons

Hydrocarbon contamination of the sediment in Saldanha Bay were measured in 1999 and although all other contaminant (POC and trace metals) were at extremely elevated levels during this time, hydrocarbons were considered very low and did not pose an ecological risk to the environment. No poly-cyclic or poly-nuclear compounds (of highest ecological threat) or pesticides were detected in sediments of Saldanha Bay. As a result, hydrocarbon monitoring has not been continued through subsequent studies.

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Cadmium

London Convention safety threshold = 1.5 mg/kg London Convention safety threshold = 1.5 mg/kg

6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6

Small Bay

London Convention safety threshold = 1.5 mg/kg London Convention safety threshold = 1.5 mg/kg

Big Bay

6 6 6 6

Overall Desired Health: London Convention safety threshold = 1.5 mg/kg

Fig. 6.4 A: Concentrations of Cadmium (Cd) in mg/kg recorded at six sites in Saldanha Bay between 1980 and 2004. Red line represents the safety levels of Cadmium in sediments set by the London Convention (1.5 mg/kg).

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 42 Anchor Environmental Consultants CC

London Convention safety threshold = 100 mg/kg London Convention safety threshold = 100 mg/kg

6 6 Lead 6 6

London Convention safety threshold = 100 mg/kg

6 6 6 London Convention safety threshold = 100 mg/kg 6

Small Bay

Big Bay

London Convention safety threshold = 100 mg/kg London Convention safety threshold = 100 mg/kg 6 6 6 6

Overall Desired Health:

Fig. 6.4 B: Concentrations of Lead (Pb) in mg/kg recorded at six sites in Saldanha Bay between 1980 and 2004. Red line represents the safety levels of Lead in sediments set by the London Convention (100 mg/kg).

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 43 Anchor Environmental Consultants CC

London Convention safety threshold = 50 mg/kg London Convention safety threshold = 50 mg/kg Copper 6 6 6 6

London Convention safety threshold = 50 mg/kg London Convention safety threshold = 50 mg/kg

6 6 6 6 6 6 6 6

Small Bay

Big Bay

London Convention safety threshold = 50 mg/kg London Convention safety threshold = 50 mg/kg

6 6 6 6

Overall Desired Health:

Fig. 6.4 C: Concentrations of Copper (Cu) in mg/kg recorded at six sites in Saldanha Bay between 1980 and 2004. Red line represents the safety levels of Copper in sediments set by the London Convention (50 mg/kg).

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 44 Anchor Environmental Consultants CC

London Convention safety threshold = 50 mg/kg London Convention safety threshold = 50 mg/kg Nickel 6 6 6 6

b e

a a

N o N

London Convention safety threshold = 50 mg/kg London Convention safety threshold = 50 mg/kg

6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 Small Bay

Big Bay

o N

London Convention safety threshold = 50 mg/kg

London Convention safety threshold = 50 mg/kg 6 6 6 6

6 6 6 6

Overall Desired Health: a

o N

Fig. 6.4 D. Concentrations of Nickel (Ni) in mg/kg recorded at six sites in Saldanha Bay between 1980 and 2004. Red line represents the safety levels of Nickel in sediments set by the London Convention (50 mg/kg).

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6.5 Summary of sediment health status of Saldanha Bay

The overall health of sediments in Saldanha Bay have been monitored through three closely related aspects, namely; 1) sediment particle size composition, 2) Concentrations of Particulate Organic Matter (Particulate Organic Carbon or POC, and Particulate Organic Nitrogen or PON) and 3) trace metal concentrations. The latter two components (organic matter and trace metals) tend to be present in higher concentrations with an increasing cohesive fraction (mud) of sediment (i.e. a greater percentage of mud component results in higher concentrations of both organic matter and trace metals). The earliest records from Saldanha Bay (pre-development) indicate that the major component of the sediment comprised of sand particles, with an associated low concentration of POC, PON and trace metals. Construction of the Marcus Island causeway and ore jetty in the 1970’s led to a disruption (reduction) in water movement and circulation in the Bay, accompanied by an increase in the fine particulate fraction (mud) in the sediments of the Bay. This was also accompanied by a significant increase in concentrations of trace metals in the sediment (either from natural or anthropogenic sources) over the same period. Small Bay was dredged extensively in 1997/98 resulting in a massive disturbance to the sediment during which the mud fraction, together with the associated trace metals, was re-suspended and subsequently settled in the surface layers of the sediment. Subsequent to the dredging (1999), the percentage of mud present in Saldanha Bay was dramatically higher with a concomitant increase in organic matter and trace metal concentrations. Frequent sediment health monitoring (2000, 2001 and 2004) has revealed an overall decrease in mud component and an increase in sand and gravel component since this time. This has been associated with an overall decrease in POC and trace metal concentrations over the same time period. Trace metals concentrations in the sediments in Saldanha Bay have improved dramatically since the extremely high levels recorded in 1999. However, concentrations are still elevated somewhat over natural levels. Two areas of concern in the Bay (still having comparatively high percentage mud component) are the Yacht club basin and the Multi-purpose Quay. Concentrations of organic nitrogen in the Bay appear to be increasing with time, however, the increase is not directly associated with dredging events alone. The highest nitrogen concentrations are evident at the Yacht club basin and the Mussel rafts, both areas where high nitrogen load is expected due to fish factory waste effluent and faecal pellets waste, respectively.

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 46 Anchor Environmental Consultants CC

7 BENTHIC MACROFAUNA

Soft-bottom benthic macrofauna (animals living in the sediment that are larger than 1 mm) are the biological component most frequently monitored to detect changes in the health of the marine environment as a result of anthropogenic impacts. Benthic macrofauna are considered to be suitable biotic components to detect impacts of pollution, largely because these species tend to live for several years and their community composition responds noticeably to changes in environment quality over time. They are also relatively non-mobile (as compared with fish and birds) and thus tend to be directly affected by pollution.

Species abundance and biomass (the numbers and mass of species making up the benthic community) and species diversity (how many different species are present) are two measures of benthic macrofauna community health most commonly used to interpret the health of the environment. It is generally predicted that with an increase in disturbance in the environment (e.g. as a result of dredging or increase in effluent discharge) the numbers of large, competitive species (Crustacean species like prawns and crabs) would decrease, while smaller, opportunistic species like amphipods and polychaete worms would increase in numbers. However, other more subtle effects can occur in response to changes in water quality. For example, increasing pollution and organic loading of the environment has been known to result in an increase in deposit feeders like polychaete worms (Polydora sp.) and a decrease in suspension feeders like the sea pen Virgularia schultzei. A combination of impacts like dredging and nutrient loading, as is applicable in Saldanha Bay, can result in variable responses amongst the species making up the benthic macrofauna community. In general a high number of different species occurring in a system (high species diversity) is reflective of a healthy environment.

The oldest records of benthic macrofauna species occurring in Saldanha Bay date back to the 1940’s, prior to the construction of the iron-ore jetty and Marcus Island causeway. Available data from this study is, however, not comparable with subsequent studies and as such cannot be used for establishing conditions in the environment prior to any of the major developments that occurred in the Bay. The earliest records available with data that are comparable with subsequent studies come from a study conducted by Moldan (1978) in 1975 where the effects of dredging in Saldanha Bay on the benthic macrofauna were evaluated. Unfortunately, this study only provided comparative benthic macrofauna data after the majority of Saldanha Bay (Small Bay and Big Bay) had been dredged. A similar study conducted by Christie and Moldan (1977) in 1975 examined the benthic macrofauna in Langebaan Lagoon, using a diver-operated suction sampler, and the results thereof provide a useful description of baseline conditions present in the Lagoon from this time.

Several subsequent studies, conducted in the period 1975-1990, examined the benthic macrofauna communities of Saldanha Bay and/or Langebaan Lagoon, but are also, regrettably not comparable with any of the earlier or subsequent studies. Recent studies conducted by the CSIR in 1999 (Bickerton 1999) and Anchor Environmental Consultants in 2004 (Anchor Environmental Consultants 2004), do, however, provide comparative benthic macrofauna data from Saldanha Bay (1999 and 2004) and Langebaan Lagoon (2004 only). In the intervening years between the 1975 and 1999 studies, significant development took place in Saldanha Bay (previously described in this report) including ore export and dredging of Small Bay in 1997/98. The 1999 study was conducted approximately 12 months after dredging and is representative of a recovering benthic community. Direct comparisons between earlier studies are further complicated due to different equipment being used in 1975 than in 1999 and 2004. The study conducted in 1975 in Saldanha Bay (Moldan 1978) made use of a modified von Veen grab sampler weighted to 20 kg which sampled an area of 0.2 m2 from the surface fraction of sediment whilst that of 1999 and 2004 made use of a diver-operated suction sampler which sampled an area of 0.12 m2 to a depth of 30 cm. The former sampling technique (von Veen grab) would be expected to sample a smaller proportion of benthic macrofauna due to its limited ability to penetrate the sediment beyond the surface layers. The suction sampler effectively sampled to a depth of 30 cm, which is the range in which larger species, like prawns and crabs, are expected to occur. The study conducted in 1975 in Langebaan Lagoon (Christie and Moldan 1977) and that conducted in 2004 (Anchor Environmental Consultants 2004) both made use of a diver-operated suction sampler which sampled an area of 0.12m2. However, in 1975 a depth of 60 cm was sampled while in 2004 a depth of only 30 cm was sampled. Thus, considering the differences in sampling techniques employed, it is likely that the changes reflected by the data between the 1975 and 1999/2004 in Saldanha Bay and Langebaan Lagoon are a function both of

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 47 Anchor Environmental Consultants CC real changes that occurred in the Bay and an artefact of differences in sampling methodology. The exact location of sites sampled during 1975 and 1999/2004 studies also differed slightly (Figure 7.1), however, the broad distribution of sites throughout the sampling area ensures that the data collected are representative of Small Bay, Big Bay and Langebaan Lagoon and such can be compared with one another.

Benthic Macrofauna Small Bay Ore Jetty Sampling Stations

General Cargo Yacht Club Quay Basin Sampled in 1975 Sampled in 1999 and 2004 Sampled in 2004 Marcus Island Sea Harvest Mussel Farm Causeway Big Bay

33o 3’S

Langebaan Lagoon

33o 10’S

0m 1500m 3000m 4500m 6000m

o 17 50’E Fig. 7.1. Benthic macrofauna sampling stations in 1975, 1999 and 2004.

The study conducted in 1975 reported on the biomass (mass of species occurring) of benthic macrofauna species classified into broad categories of either Phylum (Echinodermata), Subphylum (Crustacea), Order (Pennatulacea and Echiuroidea) or Class (Gastropoda and Polychaeta). In order to allow comparisons between this data and that from more recent years, the same broad species groupings have been retained for the purposes of this report. To facilitate interpretation of the results presented, Table 7.1 lists the dominant species that represent the broad categories reported on here.

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Table 7.1. Dominant species contributing to the Phylum, Sub-phylum, Order or Class as reported from benthic macrofauna studies conducted in 1975, 1999 and 2004. Phylum/Sub- Common name Scientific name phylum/Order/Class Echiuroidea Tongue worm Ochaetostoma capense Pennatulacea Sea pen Virgularia schultzei Sea cucumber Holothuroidea spp. Echinodermata Brittle stars Ophiuroidea spp. White mussel Tellina gilchristi Pelecypoda White mussel Macoma crawfordii Mediterranean mussel Choromytilus meridionalis Plough shell Bullia annulata Gastropoda Whelk Nassarius spp. Mud prawn Upogebia capensis Sand prawn Callianassa kraussi Three-legged crab Thaumastoplax spiralis Crustacea Crown crab Hymenosoma orbiculare Amphipods Various species Isopods Various species Polychaetes Worms Various species

The biomass (bar graphs in wet mass g/m2) and percentage composition (pie charts) of the benthic macrofauna occurring in Small Bay, Big Bay and Langebaan Lagoon from each study (1975, 1999 and 2004) are represented in Figure 7.2. Two very stark differences were evident in the benthic fauna in Saldanha Bay between the 1975 and 1999/2004 surveys, with changes evident in Small Bay being of greater contrast than those in Big Bay. In Small Bay, overall biomass (bar graphs) in 1975 was less than 5% of that in 1999/2004, while species diversity (pie charts) was very much higher in 1975 as opposed to the latter period. Bivalves (which are filter feeders) overwhelmingly dominated the biomass in 1975 (>60% of the total biomass) but made up only a very small proportion in 1999 (6%) and even less in 2004 (0.5%). Crustaceans on the other hand, changed from making up a very small proportion of the biomass in 1975 (<2%) to more than 70% in the 1999 and 2004 surveys. Other important changes in the fauna included the loss of the echinoderm and sea pen communities between 1975 and 1999, and a major reduction in the biomass of Gastropods and Polychaete worms present.

Similar, but correspondingly smaller changes were evident in Big Bay between 1975 and 1999/2004 (Figure 7.2). Overall biomass (bar graphs) increased by at least 3-fold from 1975 to 1999, and more than doubled again between 1999 and 2004. The contribution by tongue worms, echinoderms, bivalves, gastropods and polychaete worms all declined between 1975 and 1999/2004 (pie charts), while the contribution by crustaceans increased dramatically across the same time period (accounting for most of the increase in overall biomass between 1975 and 1999, and between 1999 and 2004). The contribution by sea pens in Big Bay by contrast declined between 1975 and 1999, but seem to have recovered again somewhat between 1999 and 2004.

In contrast to the situation in both Small and Big Bay, overall biomass (bar graphs, Figure 7.2) in Langebaan Lagoon declined sharply between 1975 and 2004 (by about 60%). The sharp decline in species diversity (pie charts) was similar, however, to the trend noted in the Bay. The change in biomass was linked to a loss or reduction in the abundance of many of the important taxa present in 1975 (bivalves, polychaete worms, gastropods, echinoderms, and sea pens), but with little change evident in the biomass of crustaceans present.

The abundance of benthic invertebrates occurring in Small Bay and Big Bay was reduced substantially after dredging events (Figure 7.3). Subsequent sampling shows variable abundance and changing composition of benthic macrofauna in Small and Big Bay. The abundance of benthic macrofauna in Langebaan Lagoon is only represented by one sampling event and little can be established from this. The species diversity is however, very low with only three species occurring.

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 49 Anchor Environmental Consultants CC

(Tongue worm)

(Sea pen) (Bivalves)

Desired Health:

8 4

/ 7

g 9

1 s

g 1

r g

W e

r D

m /

s 7 s 9

a 1 Desired Health:

e r

W D

Desired Health:

/ g

s s

Fig. 7.2 Biomass (wet mass represented by bars) and percentage composition (species diversity represented by pie charts) of benthic macrofauna occurring in Small Bay, Big Bay and Langebaan Lagoon, Saldanha Bay during 1975, 1999 and 2004. Arrows indicate dredging events.

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It is not clear how much the change in benthic invertebrate abundance and diversity is related to anthropogenic changes that have occurred in the Bay versus changes in sampling techniques used. The sampling method used in Small Bay and Big Bay in 1975 (von Veen grab) would be expected to sample less crustaceans compared to the diver operated suction sampler (used in 1999 and 2004). Crustaceans burrow several centimetres below the surface of the sediment, beyond the reach of the von Veen grab sampler but certainly included by the suction sampler. Taking into account the expected increase in crustaceans due to different sampling techniques used in 1999/2004, there has nonetheless been a significant decrease in benthic macrofauna species diversity in Small Bay and Big Bay since 1975. The decrease in biomass evident in Langebaan Lagoon since 1975 could be attributed to a 50 % reduced sample being taken in 2004 (suction sampler depth to 60 cm in 1975 and only 30 cm in 2004), however, the decreased species diversity is likely as a result of negative impacts on the environment. It is most likely that the changes observed in the benthic macrofauna biomass and species diversity are at least partially related to changes imposed on the environment.

The suspension feeding sea pen (Order: Pennatulacea Virgularia schultzei) has historically been viewed as a good indicator of environmental health. This species comprises a long, thin colony of polyps arranged around a brittle central axis which projects out of the sand to a height of approximately 20 cm. Due to its delicate nature, the sea pen is readily eliminated from areas where conditions are no longer favourable. The sea pen was recorded in Small Bay, Big Bay and Langebaan Lagoon (in low numbers) in 1975, however, was not encountered in any sampling events again until 2004. The disappearance of sea pens from Saldanha Bay is likely to be related to declines in water and sediment quality over the same period, as noted earlier, and the subsequent reappearance in Big Bay to an improvement in conditions in this area. The absence of sea pens in Small Bay suggests that environmental conditions here remain unfavourable for colonisation by this species (most likely a function of reduced water circulation in this part of the Bay). Similarly, the loss of the echinoderm fauna (also considered to be highly sensitive to disturbance) as well as some of the other historically important groups (e.g. bivalves) in the Bay and Lagoon is also indicative of reduced water and sediment quality in the Bay as a whole. The overall increase in biomass in the Bay and a corresponding decrease in the Lagoon may be related to the increase in particulate organic carbon in the Bay which would serve as an important food source for particulate feeders such as the crustaceans (the group that accounted for most of the observed increase in biomass).

The decrease in species diversity in Langebaan Lagoon is of particular cause for concern. Previous reports have suggested that development in Small and Big Bay had no evident impacts on the environmental attributes of Langebaan Lagoon but these results brings this conclusion into question. Continued, regular monitoring of the benthic macrofauna biomass, abundance and species diversity in Saldanha Bay and Langebaan Lagoon is strongly recommended to further quantify the impacts on and recovery of the environment.

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(Tongue worm)

(Sea pen) (Bivalves)

500 Desired Health:

450

8 4 400 9

9 1

350

300 e

d e

250 D r

200 D 150

Numbers occuring 100 50 0 1960's 1999 2001 2004 Small Bay

900

800 g n 700

uri 4

c 7

c Desired Health:

600 9 1

500 g d

e r 400 D

Number 300 200

100

0 1960's 1999 2001 2004 Big Bay ? 140

120

100

Numbers occuring 20

0 1960's199920012004 Langebaan Lagoon

Fig. 7.3. Abundance (numbers of macrofauna indicated by bars) and percentage composition (species diversity represented by pie charts) of benthic macrofauna occurring in Small Bay, Big Bay and Langebaan Lagoon, Saldanha Bay during 1960s, 1999, 2001 and 2004. Arrows indicate dredging events.

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Isopod spp. Amphipod spp.

Polychaete spp. Polychaete spp.

Whelks (Nucella spp.) White mussels (Donax spp)

Plate 1: Benthic macrofauna species frequently found to occur in Saldanha Bay and Langebaan Lagoon, photographs by: Charles Griffiths.

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Sea cucumber (Holothuroidea spp.)

Brittle star Ophiuroidea spp.

Sand prawn (Callianassa craussi) Mud prawn (Upogebia capensis)

Plate 2: Benthic macrofauna species frequently found to occur in Saldanha Bay and Langebaan Lagoon, photographs by: Charles Griffiths.

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8 INTERTIDAL INVERTEBRATES (ROCKY SHORES)

8.1 Historical studies Despite the known changes that have taken place within the Saldanha Bay system over the last fifty years, almost no historical data exists on the state of rocky-shores in the area. Species presence/absence data was collected by undergraduate students of the University of Cape Town at Lynch Point Schaapen Island between 1965 and 1974 (Griffith pers. comm). The accuracy and reliability of this data is, however, questionable and therefore has not been included in this report. Robinson et al. (2004) assessed the distribution and status of marine alien species within the Saldanha Bay/Langebaan Lagoon system. As part of this work, the biomass supported by intertidal mussels was quantified around the Bay. However, only a single study by Robinson et al. (in press) has considered intertidal community structure in the area. In particular they assess changes in community composition on the rocky-shores of Marcus Island between 1980 and 2001, focusing on the impact of the Mediterranean mussel, Mytilus galloprovincialis. It is upon the latter study that this report will focus.

Several alien invasive species have been recorded within Saldanha Bay in recent times (Robinson et al. 2005). Presently, the only such species affecting rocky-shores in the system is the Mediterranean mussel (M. galloprovincialis). First identified in Saldanha Bay in 1979 (Branch and Steffani 2004), this species has not only become a dominant space occupier on rocky intertidal shores (Robinson et al. 2005), but is also the subject of extensive mariculture operations within the Bay (Boyd and Heasman 1998).

In 1980 researchers at the University of Cape Town sampled the distribution and abundance of intertidal invertebrates at Marcus Island. This study was conducted before the invasion of the Mediterranean mussel was recognized, although this species was most likely already present in low numbers. In 2001, sampling was repeated in order to assess the impact of the mussel invasion on community structure (Robinson et al. in press). In the original survey, seven intertidal zones were identified and sampled. They were (in descending order of tidal height): The Porphyra zone, consisting of beds of the alga Porphyra capensis. The Ulva zone, characterized by mixed beds of the algae Ulva capensis and Ulva linza. The Granularis zone, dominated by the limpet Scutellastra granularis. The algal turf zone, covered by a moss-like red algae community dominated by Caulacanthus ustulatus. The Gigartina zone, characterized by the algae Gigartina radula and Pterosiphonia cloiophylla. The Aulacomya zone, dominated by the ribbed mussel Aulacomya ater. The Choromytilus zone, consisting of beds of the black mussel Choromytilus meridionalis.

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Figure 8.1. Porphyra zone on the high shore showing dominant species Porphyra capensis, Lynch Point, Langebaan Lagoon.

Figure 8.2. Ulva zone at Lynch Point showing Ulva spp. (green seaweed) with some Porphyra capensis (brown seaweed) interspersed, Langebaan Lagoon. Photo taken at high tide.

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Figure 8.3. Scutellastra granularis, the species dominant in the Granularis zone.

Algal turf zone

Choromytilus zone

Figure 8.4. Rocky intertidal zonation patterns at Lynch Point, Langebaan Lagoon showing clear demarcations of Algal turf zone and Choromytilus zone.

Upon re-sampling the shore at Marcus Island in 2001, only six of the original seven intertidal zones could be detected. The algal turf zone had disappeared and thus could not be resampled. The disappearance of a whole zone represents a major change in community structure on the rocky shore.

The faunal communities occurring in all six sampling zones differed significantly between 1980 and 2001 (Figure 8.5; Robinson et al. in press). In the Porphyra zone differences in communities were mainly due to declines in the number of isopods (Exosphaeroma varicolor). In both the Ulva and Granularis zones, changes in the abundance of the nudibranch (sea

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 57 Anchor Environmental Consultants CC slug, Onchidella capensis) were responsible for the differences observed between 1980 and 2001. In the Gigartina zone, two species of gastropods (Aetoniella nigra and Tricolia neritina) had declined in numbers dramatically between 1980 and 2001. Both species occurred in large numbers in 1980 (i.e. mean densities of 14 771.m-2 and 5 729.m-2 respectively), but were absent in 2001. Within the Aulacomya zone, the abundance of ribbed mussel, for which this zone was named (Aulacomya ater), had also been greatly reduced between 1980 and 2001. Similarly, the changes observed in the Choromytilus zone were primarily as a result of the disappearance of the indigenous black mussel Choromytilus meridionalis. The following text and Table 8.1 summarises the resulting changes occurring in the intertidal rocky shores of Marcus Island between 1980 and 2001, and the consequent responses by the fauna in each zone.

The change in community structure in the Porphyra zone between 1980 and 2001 are considered unlikely to be as a result of the mussel invasion, as no Mediterranean mussels were recorded in this zone in 2001, which is too high upshore for mussels to survive. Crustaceans and insect larvae dominated both sets of samples and minor changes in their abundance here can most likely be attributed to seasonal variation in abundance of the algae Porphyra capensis (Griffin et al. 1999) the dominant alga in the zone.

Prior to the arrival of Mediterranean mussels, both the Ulva and Granularis zones were patchy environments, consisting mainly of bare rock interspaced with patches of algae and large limpets. However, following the invasion, the relatively bare rock surface was converted to a less patchy and more profiled mussel bed (Robinson et al. in press). The change in dominant species in these zones dramatically altered the habitat type which accounts for the changes in communities occurring here between 1980 and 2001.

Unlike the indigenous black mussels, Mediterranean mussels develop multi-layered beds (McQuaid and Phillips 2000) and consequently, the invasion resulted in a structural modification in the Gigartina zone. Although extreme declines in the numbers of the gastropods were recorded in 2001 compared to 1980, it remains unclear as to whether this was as a consequence of natural variation, or a reflection of changes induced by the invasion of Mediterranean mussels.

As the Aulacomya zone was previously characterised by the presence of mussel beds, the invasion of Mediterranean mussels was unlikely to have greatly altered this habitat in the zone. The changes in community structure in this zone were caused by a decline in ribbed mussel which was readily out-competed by the invading Mediterranean mussel (Griffiths et al. 1992).

The Choromytilus zone was originally characterized by the presence of substantial beds of the indigenous black mussel. The arrival of the Mediterranean mussels thus did not replace the type of habitat in this zone, but altered it from a single-layered mussel bed, typical of black mussels, to multi-layered mussel beds (Griffiths et al. 1992). The changes in community structure in this zone are considered to be as a result of decreased abundance of black mussel and increasing abundance of Mediterranean mussel.

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Figure 8.5. Multi-dimensional scaling of species abundance for all sampling zones in 1980 (○) and 2001 (●). (Robinson et al. in press). The further away the data points for each year and the lower the stress values, in each zone, the more different the species composition is between years.

Table 8.1. A summary of changes within the various sampling zones following the invasion of the Mediterranean mussel (Robinson et al. in press).

Zone 1980 (before invasion) 2001 (after invasion) Response Porphyra • Few species Unchanged Unchanged • Patchy environment community Ulva & • Bare rock with few large • Mussel bed Granularis limpets • More uniform Different community • Patchy environment environment Gigartina • Some bare rock • Mix of seaweeds and Different community • Uniform environment mussel beds Aulacomya • Very uniform environment • Dominated by larger Different community • Dominated by small mussels multilayered mussels Choromytilus • Very uniform environment • Remains uniform • Dominated by large mussels • Still large mussels but Different community different species

In summary, studies conducted in 1980 and again in 2001 on the intertidal fauna occurring at Marcus Island, Saldanha Bay show that strong links occur between the invasion of the Mediterranean mussel and changes in the intertidal rocky shore communities (Robinson et al. in press). The effects of the invasion were, however, not spread evenly across the intertidal zone. The upper-most tidal zone (Porphyra zone) remained free of mussels, and was thus not

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 59 Anchor Environmental Consultants CC affected by the arrival of this invasive mussel. The zones lowest on the shore (Aulacomya and Choromytilus) still supported large numbers of mussels (although of a different species), and thus have not been greatly altered. It is the mid-to-low intertidal zones that have been most affected by the invasion of the Mediterranean mussel. Historically the mid-to-low zones were open-rock habitats, dominated by limpets and algae, however, in 2001 these zones supported dense mussel beds that changed the physical stress occurring here, increased the complexity and reduced the patchiness of the mussel beds, thus, dramatically altering the intertidal community structure on Marcus Island.

8.2 Baseline study conducted in 2005 A review of the existing data on Saldanha Bay’s rocky intertidal communities has revealed a severe lack of information (see previous section), and the need for a monitoring programme was identified. This study forms the first part of the rocky intertidal monitoring programme.

To assess the nature and extent of unfavourable anthropogenic effects on the intertidal ecosystem, a ‘reference ’or ‘baseline’ is needed, depicting the types of organisms occurring and the degree of natural variability. Any changes detected during future monitoring can be evaluated against the established baseline conditions. However, existing pollution from fish factories and changes in physical oceanography are likely to have already affected the intertidal communities and potentially changed their structures from their original pristine states. It is thus impossible to establish a baseline dataset before any anthropogenic impacts on the Bay (anthropogenic impacts started in the early 1970’s), however, the data gathered during this study, and future studies of this type, can nonetheless serve as a reference guideline against which future changes can be assessed.

Eight rocky shore sites were selected in Saldanha Bay for establishing a baseline data set on rocky intertidal communities (Figure 8.6). A description of these sites, their wave exposure degree and their GPS readings (WGS84) are listed below in order from most sheltered site to most exposed site: Site name Exposure Description of site Latitude Longitude gradient Dive School (DS) Very sheltered Gentle slope, small 33º00.58 S 17º56.93 E (most sheltered boulders interspersed with site) sandy gravel Jetty (J) Very sheltered Steeper slope with boulders 33º00.49 S 17º56.84 E Iron Ore Jetty (IO) Very sheltered Very steep slope with 33º00.50 S 18º00.01 E medium sized broken boulders piled up against jetty Schaapen Island Sheltered Located in a bay on east 33º05.45 S 18º01.49 E Sheltered (SS) side of island, mostly flat with some rocky sections Schaapen Island Semi-exposed Steep slope with ragged 33º05.40 S 18º01.48 E Exposed (SE) to exposed topography on west of island Lynch Point (L) Semi-exposed Smooth surface with deep 33º02.68 S 18º02.26 E crevices North Bay (NB) Semi-exposed Flat high and mid-shore 33º02.01 S 17º56.11 E to exposed Low shore has large boulders Marcus Island (M ) Exposed Very flat 33º02.58 S 17º58.03 E (most exposed site)

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Rocky intertidal sampling sites

Jetty Small Bay Iron ore jetty Small craft Dive School harbour

Causeway Big Bay North Bay Lynch Point Marcus Island

Schaapen Island Exposed

Langebaan Lagoon

Figure 8.6. Location of eight intertidal rocky shore sites for monitoring during 2005 in Saldanha Bay.

The rocky intertidal can be divided into different zones according to shore height level (Branch and Branch, 1981). Each shore height zone is distinguishable by their different biological communities, which are largely a result of the different exposure times to air. The high shore is exposed longest to air, and generally has a low species diversity and cover (Fig 8.7A). Further down the shore, diversity starts to increase, and the mid shore is characterised by limpets and barnacles (also called the balanoid zone, Fig. 8.7B). At the low shore, the force of the wave action becomes important and determines the composition of the biological communities. On sheltered and moderately exposed shores, algae are dominant (Fig. 8.7C), whereas on more exposed shores, the rock may be almost entirely covered by filter-feeders, particularly mussels (Fig. 8.7D).

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A B

C D

Figure 8.7. Different rocky intertidal communities at varying shore height zones in Saldanha Bay and Langebaan Lagoon: A) High shore, B) Mid shore, C) Sheltered low shore and D) Exposed low shore.

Sampling of the rocky intertidal communities at Saldanha Bay took place from 16th to 19th October 2005. At each study site, the rocky intertidal area was divided into three shore height zones: the high, mid and low shore. In each of these three shore height zones, six 100 x 50- cm quadrats were randomly placed on the shore and the percentage cover of all species recorded as primary (occurring on the rock) and secondary (occurring on other benthic fauna or flora) cover, and individual mobile organisms counted to calculate densities within the quadrat area. The quadrat was subdivided into smaller squares, to aid in the estimation of the percentage cover (Figure 8.8). Finally, the primary and secondary cover data for both mobile and sessile organisms were combined and down-scaled to 100%.

Intertidal species were categorized into five trophic groups (according to their method of feeding); a) grazers, mostly limpet species; b) filter-feeders, particularly sessile suspension feeders such as mussels; c) predators, such as carnivorous whelks and anemones; d) crustose algae; and e) foliose algae, further divided into e1) red foliose, e2) green foliose, and e3) brown foliose algae.

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Figure 8.8. The quadrat divided into smaller squares to aid in percentage cover estimates when recording the fauna and flora composition of the rocky intertidal.

Appendix I provides a full list of the species, their percentage cover and, were applicable, their densities for each quadrat at each site.

The data collected from the eight rocky intertidal sites were statistically analysed using the PRIMER V5.2.2 computer programme. The details of these statistical analyses and the results thereof are reported on in Appendix II. In summary, interpretation of the statistical analysis suggests that the rocky intertidal communities at the two most sheltered sites (Dive School and Jetty) are very similar, as are the communities occurring at the most exposed sites (North Bay and Marcus Island). The rocky intertidal communities occurring at the two sites on Schaapen Island (both sheltered and exposed) also appear to be very similar (see Appendix II for more detail).

8.2.1 Findings of the Baseline Survey 2005 All eight study sites differed noticeably in their community structure, which is most likely a result of their different exposure to wave action and their different topography. Many studies have found that the level of wave force is an important factor in determining what species occur where (McQuaid and Branch 1984, 1985, McQuaid et al. 1985). Wave action can also significantly influence the distribution, density, size, behaviour and/or competitive ability of species (Steffani and Branch 2003a, b). A high degree of wave action is favoured by filter feeders, like mussels, as there is an increased concentration and delivery of particulate food matter. It is to be expected that an area having high wave energy (exposed shore) will have high biomass of filter feeders. Sheltered shores, on the other hand, having low wave action, have lower overall biomass of filter feeders and are usually dominated by algae (seaweeds). This was indeed the situation established at the rocky intertidal study sites in Saldanha Bay. The exposed sites, like North Bay and Marcus Island, were dominated by the mussel Mytilus galloprovincialis, a filter feeder, whereas the sheltered sites, like Dive School and Jetty, had greater proportions of algae (Figure 8.9).

The type of substratum (rock layer) can also influence the type and abundance of species occurring on the shore, particularly at boulder beaches where the number of different species

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occurring tends to be lower due to the instability of boulders. The slope of a shore also influences the type and abundance of species occurring.

The two sites surveyed in Small Bay, Dive School and Jetty, were both found to be very poor in densities of fauna and flora occurring here (Figure 8.9). The construction of the Marcus Island causeway has lead to reduced wave action in Small Bay (Monteiro et al. 1990, Weeks et al. 1991), turning these shores into sheltered boulder beaches. Unfortunately no historical data exists that could verify the notion of a change in community structure at these sites, but it is very likely that the sheltering effect of the causeway has negatively affected the intertidal communities along the Small Bay shoreline and changed their compositions.

There is a paucity of information on rocky intertidal communities in Saldanha Bay, however, several reports have suggested that since the Mediterranean mussel Mytilus galloprovincialis has invaded the West Coast, the composition of the rocky intertidal fauna and flora have been drastically altered (Robinson et al. in press, Griffiths et al. 1992). The general trend along the entire West Coast is towards an increasing dominance of Mytilus galloprovincialis and the findings of this baseline study of the state of the rocky intertidal communities of Saldanha Bay, supports this same trend.

This study provides a reference data set against which potential future changes in rocky intertidal community composition can be measured and their severity evaluated. It is thus recommended that an annual rocky intertidal monitoring programme in Saldanha Bay be established, where the same study sites are sampled, making use of the same sampling strategy to allow future comparisons in data collected.

A B

C D

Fig. 8.9. Four rocky intertidal sites surveyed in 2005: A) Dive School, B) Jetty, C) Marcus Island and D) North Bay.

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9 FISH COMMUNITY COMPOSITION AND ABUNDANCE

The waters of Saldanha Bay and Langebaan Lagoon support an abundant and diverse fish fauna. Commercial exploitation of the fish within the Bay and Lagoon began as early as the late 1600’s by which time the Dutch colonists had established beach-seine fishing operations in the region (Poggenpoel 1996). These fishers targeted harders and other shoaling species such as white steenbras and white stumpnose, with much of the catch dried and salted for supply to the Dutch East India Company boats, troops and slaves at the Castle in Cape Town (Griffiths et al. 2004). Commercial netfishing continues in the area today, and although beach-seines are no longer used, gill-net permit-holders target harders and landed an estimated 590 tons per annum, valued at approximately R 1.8 million, in 1998-1999 (Hutchings and Lamberth 2002a). Species such as white stumpnose, white steenbras, kob, elf, steentjie, yellowtail and smoothhound shark support a large shore angling and recreational boat fishery which contributes significantly to the tourism appeal and regional economy of Saldanha Bay and Langebaan. In addition to the importance of the area for commercial and recreational fisheries, the sheltered, nutrient rich and sun-warmed waters of the Bay provide a refuge from the cold, rough seas of the adjacent coast and constitute an important nursery area for the juveniles of many fish species that are integral to ecosystem functioning. In 1976 the importance of Langebaan Lagoon to the health of the marine environment was acknowledged with the area being declared a protected zone and later a Marine Protected Area (MPA, Figure 1.1). The Langebaan Lagoon MPA was divided into three zones where fishing is allowed in zone A only, power boats are excluded from zones B and C and all boats are excluded from zone C (see Figure 1.1).

Despite the importance and long history of fisheries in the Bay and Lagoon, scientific data on the fish community in the area are limited to a few studies, mostly by students and staff of the University of Cape Town. Gill net sampling, with the aim of quantifying by-catch in the commercial and illegal gill net fishery, was undertaken during 1998-99 (Hutchings and Lamberth 2002b). A once-off survey for small cryptic species utilizing rotenone (a fish specific, biodegradable toxin that prevents the uptake of oxygen by small fish) was conducted during April 2001 (Anchor Environmental Consultants, Ballast Water Project). More recently, experimental seine-net sampling of sandy shore fishes was conducted over limited periods during 1986-1987 (UCT unpublished data), 1994 (Clark 1997) and 2005 (this study). The data from these three sampling methods (gill netting, seine netting, and rotenone) are summarized below. Of these methods, only the seine net data set allows for comparative analyses over time. Current research on the fish fauna of Saldanha Bay includes acoustic tracking of white stumpnose within Langebaan Lagoon (C. Attwood, Marine and Coastal Mangement, personal communication) and monitoring of recreational angler catches (P. Nel, West Coast National Parks, personal communication). The results of these studies are not yet available, but will make a valuable contribution to the understanding of the fish and fisheries of the region in the future.

9.1 Seine net surveys Experimental seine netting during all three surveys (UCT unpublished data, Clark 1997, this study) was conducted at various sites using a beach-seine net, 30 m long, 2 m deep, with a stretched mesh size of 12 mm. Replicate hauls (3-5) were conducted approximately 50 m apart at each site during daylight hours. Areas swept by the net were calculated as the distance offshore multiplied by the mean width of the haul. All fish captured were identified and abundance calculated as the number of fish per square meter sampled. Sampling during 1986-87 was only conducted within the Lagoon, whilst replicate hauls were made at 8 and 11 different sites during 1994 and 2005 surveys respectively. For the purposes of this report, sites were grouped into three main areas, namely Small Bay, Big Bay and Langebaan Lagoon. The original data (numerical and mass data) for all sites sampled during this study (October 2005) are included in this report as Appendix III).

Thirty-two fish species were recorded during the three seine-net surveys conducted during 1986-87, 1994 and 2005. The complete species list and abundance of each species caught

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 65 Anchor Environmental Consultants CC in Small Bay, Big Bay and the Lagoon during each of the different surveys is shown in Table 9.1. Harders, silversides and gobies numerically dominated the catches for all three surveys combined. Overall species richness and abundance was highest in Langebaan Lagoon (21 species) and lowest in Big Bay (15 species). The trend of increasing fish diversity and abundance with decreasing wave exposure (within Langebaan Lagoon and Small Bay) identified by Clark (1997) appears to hold for both of the more recent surveys. Overall the number of species captured showed little change over time (Figure 9.1). The actual species composition in the different areas between the three surveys did however show substantial change (Table 9.1). Out of the 20 species recorded in Small Bay, only 11 occurred in the two recent surveys, whilst 10 out of the 15 species recorded in Big Bay occurred in both surveys and only eight of the 18 species found in the Lagoon occurred in recent catches. Of concern is the apparent disappearance of pipefish during the most recent survey, but it is encouraging to note the return of white steenbras (a heavily overexploited linefish species that was historically abundant in the region) in Small Bay during the most recent survey (Table 9.1)

1986-87 1994 2005 18 2250m2 2 2 16 7200m 7125m 2 14 4500m2 5400m 18000m2 7200m2 12 10

ofNumber species 4

2 0 Small Bay Big Bay Lagoon

Overall Desired Health: Fig. 9.1. Number of fish species caught during seine net surveys in Saldanha Bay and Langebaan Lagoon. The total area netted in each region is indicated above the bars.

3 1986-87 1994 2005 ? ) -2 2.5 ?

1.5

Fish abundance (No.m abundance Fish 0.5

0 Small Bay Big Bay Lagoon Overall Desired Health:

Fig. 9.2. Fish abundance during seine net surveys conducted in Saldanha Bay and Langebaan Lagoon.

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Overall fish abundance in Small Bay and Langebaan Lagoon during the most recent survey was substantially less than during earlier surveys (Figure 9.2). This is most likely related to the selectivity of the seine net sampling gear and the season during which the sampling was conducted. The small mesh seine-net samples small fish species and juveniles most effectively. The earlier surveys were conducted during April (autumn) whilst the 2005 survey took place during October (spring). As most juvenile species annually recruit to nearshore environments during summer and natural mortality rates of juvenile marine fish are high, the abundance of many species is expected to decrease over time. Temporal trends in the abundance of the five most frequently caught species within Small Bay, Big Bay and Langebaan Lagoon are shown in Figure 9.3. Large decreases in the abundance of silversides, and white stumpnose and a small decrease in the abundance of harders are evident in Small Bay, whilst the density of gobies increased. This may be indicative of low oxygen conditions within Small Bay. Within Big Bay, the abundance of harders, Cape soles and eagle rays decreased, and white stumpnose and gurnards increased (Figure 9.3). As in Small Bay, the number of silverside decreased dramatically within Langebaan Lagoon in the 2005 sample, suggesting that the low abundance of this species is due to a general current small population size rather than any specific water quality problems within Small Bay. Although the abundance of harders and Knysna sand gobies was substantially reduced between 1994 and 2005, densities during the latter period were similar to those recorded during 1986-87. The number of Caffrogobius (gobies) remained similar during all three survey periods, whilst super klipvis became progressively scarcer and were not recorded in 2005.

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Goby (Caffrogobius spp.)

Super klipvis (Clinus superciliosus)

Gurnard (Chelidonichthys kumu) Goby (Psammogobius knysnaensis)

Estuarine herring (Gilchristella aestuaria)

Silverside (Atherina breviceps) Elf (Pomatomus saltatrix)

Cape stumpnose (Rhabdosargus holubi)

White stumpnose (Rhabdosargus globiceps)

Plate 3: Fish species occurring in Saldanha Bay and Langebaan Lagoon. Photographs by Charles Griffiths.

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Table 9.1: Abundance of fish species (number.m-2) during three seine-net surveys in Saldanha Bay and Langebaan lagoon. SPECIES SMALL BAY BIG BAY LANGEBAAN LAGOON

Scientific name Common name 1994 2005 1994 2005 1986-87 1994 2005 Abundance (number per m2) Atherina breviceps Silverside 1.3084 0.0410 0.0004 0.0033 1.1916 1.2131 0.0524 Liza richardsonii Harder 0.6951 0.5847 0.3049 0.2703 0.2452 0.7135 0.3452 Psammogobius knysnaensis Knysna sand gobi 0.0958 0.4908 0.1411 Caffrogobius sp. Goby 0.0160 0.1294 0.0888 0.1030 0.1336 Heteromyctus capensis Cape sole 0.0049 0.0017 0.1016 0.0019 0.0011 0.0014 Clinus superciliosus Super klipvis 0.0080 0.0028 0.0698 0.0079 0.0006 Rhabdosargus globiceps White stumpnose 0.0618 0.0067 0.0042 0.0276 0.0009 0.0069 0.0001 Diplodus sargus capensis Black tail 0.0022 0.0178 0.0120 Lithognathus lithognathus White steenbras 0.0079 Clinus latipennis False Bay Klipvis 0.0051 0.0011 0.0163 Rhinobatos annulatus Sandshark 0.0009 0.0013 0.0082 0.0030 0.0204 Cheilidonichtyes capensis Gurnard 0.0022 0.0082 0.0029 0.0106 0.0025 0.0038 Spondyliosoma emarginatum Steentjie 0.0013 0.0092 0.0004 Myliobatis aquila Eagle ray 0.0013 0.0004 0.0069 Gilchristella aestuaria Estuarine herring 0.0026 Sygnathus acus Pipe fish 0.0022 0.0002 0.0063 0.0007 Callorhynchus capensis St Joseph 0.0022 Mustelus mustelus Smoothhound shark 0.0027 0.0018 0.0002 Rhabdosargus holubi Cape stumpnose 0.0013 Etrumeus terres Red eye sardine 0.0009 Poroderma africana Striped catshark 0.0009 Pomatomus saltatrix Elf 0.0009 0.0007 0.0002 0.0001 Solea bleekeri Blackhand sole 0.0004 Lichia amia Leervis 0.0003 Cancelloxus longior Klipvis sp. 0.0002 0.0002 Blennophis Klipvis sp. 0.0002 0.0001 Clinus agilis Klipvis sp. 0.0001 Trachurus trachurus Horse mackerel 0.0001 Gonorhynchus gonhorynchus Beaked sand eel 0.0001 Rhinobatos blockii Bluntnose guitar fish 0.0001 Sarpa salpa Streepie 0.0001 Total 2.11 0.81 0.44 0.34 1.71 2.56 0.69 Number of species 32 16 15 13 13 9 15 12 Number of hauls 98 5 12 10 9 30 20 12 Total area sampled(m2) 51675 2250 7200 4500 5400 18000 7125 7200

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1.40 1994 2005

1.20

1.00

) Desired Health: Small Bay -2 0.80

0.60 (no.m

0.40

Big Bay 0.20

0.00 Silverside Harder Nude goby White Black tail stumpnose Fish abundance-Small Bay

1994 2005 0.35

0.30

0.25 )

-2 0.20 Desired Health:

0.15 (no.m 0.10

0.05

0.00 Harder Cape sole White Eagle ray Gurnard stumpnose

Fish abundance-Big Bay Langebaan Lagoon

1.40 1986-87 1994 2005

1.20

1.00 ) 0.80 Desired Health:

0.60 (no.m

0.40

0.20

0.00 Silverside Harder Knysna sand Caffro goby sp. Super klipvis gobi 0m 1500m 3000m 4500m 6000m Fish abundance-Langebaan Lagoon 17o 50’E

Fig. 9.3: Abundance of the five most common fish species seine-netted within Saldanha Bay during three surveys (1986-87, 1994, 2005).

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9.2 Gill net sampling

Small mesh (48-51 mm stretched mesh) and large mesh (145-178mm) gill nets, 75 m long, 4 m deep, were deployed from a rowing boat beyond the surf zone and allowed a soak time of at least one hour. All fish caught were identified and catch rates (CPUE: number of fish per net-hour) calculated. A total of 18 fish species were recorded in 35 gill net sets made in Saldanha Bay during 1998-99 (Table 9.2). Harders, the legal target species of the commercial gill-net fishery, were by far the most frequently caught species, with hound shark, a valuable elasmobranch species, also contributing significantly to catches (Table 9.2). Eagle rays, St Joseph sharks, white stumpnose, horse mackerel and sandsharks were the next most frequently caught species (Table 9.2). Species not recorded in seine net catches included biscuit skates, barbel, fingerfin, shy sharks and thresher shark.

Table 9.2: Fish species recorded in 35 experimental gill net sets conducted in Saldanha Bay during 1998- 99. SPECIES CPUE (No.net-hour-1) 51mm 145-178mm Liza richardsonii Harder 15.98 Mustelus mustelus Smoothhound shark 3.39 0.90 Myliobatis aquila Eagle ray 1.79 Callorhynchus capensis St Joseph 0.33 Rhabdosargus globiceps White stumpnose 0.51 Trachurus trachurus Horse mackerel 0.37 Rhinobatos annulatus Sandshark 0.22 0.09 Diplodus sargus capensis Black tail 0.15 Solea bleekeri Blackhand sole 0.12 *Raja straeleni Biscuit skate 0.10 0.09 Spondyliosoma emarginatum Steentjie 0.07 Pomatomus saltatrix Elf 0.05 Poroderma africana Striped catshark 0.05 *Galeicthys feliceps Barbel 0.02 0.03 *Argyrosomus inodorus Kob 0.02 *Chirodactylus brachydactylus Twotone fingerfin 0.02 *Haploblepharus pictus Dark shy shark 0.02 *Alopias vulpinus Thresher shark 0.03

Total CPUE 21.1 3.3 Number of species 16 8 Total soak time (hours) 41 33.5 Number of sets 18 17 * denotes species not recorded in seine net catches

9.3 Rotenone sampling of cryptic fishes Cryptic fishes were sampled in and around the port of Saldanha Bay between 21 April and 24 April 2001. The fish were sampled by divers using the anaesthetic rotenone. Where possible, the area to be sampled was enclosed within a plastic sheet measuring 3m x 3m, and weighted on the edge with chain. This precaution is used to reduce dilution of the rotenone before it has had its full effect on the fish, and to reduce the chance of fishes escaping from the sample area. A total of eleven stations were sampled, covering a range of habitat types, including boulder, sand, mud, and mixed boulder/sand. These stations also spanned a wide range of cover types which fish utilize for hiding or camouflaging themselves. These included "bare sand" with prawn holes, rock crevices or holes between boulders, the alga Gracilaria, drift or dislodged algae, kelp, and clumps of pods of the seasquirt Pyura.

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Sites thus represented a diversity of bottom topography and cover types, in an attempt to capture the greatest diversity of fish species.

A total of 214 fish representing 19 species and 10 families were collected from the eleven samples (Table 9.3). The number of species captured differed between samples, ranging from a minimum of one to a maximum of nine (mean = 3.82 species per sample). Similarly, the number of individuals also differed widely between samples, and ranged between one and 55 (mean = 19.45 individuals per sample). The five most abundant species captured in all the samples (Table 9.3) were the clingfish Apletodon pellegrini, the klipfish Clinus superciliosus, the blenny Parablennius cornutus, the goby Caffrogobius saldanha, and the pipefish Syngnathus acus. Less than ten individuals of each of the remaining 14 species were captured. Rotenone sampling of cryptic fishes captured a further 10 species that were not recorded during seine-net or gill-net surveys, bringing the total to 48 species recorded during scientific surveys.

Table 9.3. The numbers of fish of 19 species captured in 11 rotenone samples in Saldanha Bay in April 2001. SPECIES COMMON NAME NUMBER CAUGHT

*Apletodon pellegrini Chubby clingfish 44 *Batrichthys apiatus Toad fish 5 Caffrogobius caffer Banded goby 1 Caffrogobius nudiceps Barehead goby 2 *Caffrogobius saldanha Goby sp. 32 *Chorisochismus dentex Rocksucker 1 *Clinoporus biporosus Klipvis sp 2 *Clinus acuminatus Klipvis sp. 2 Clinus agilis Klipvis sp. 7 Clinus superciliosus Klipvis sp. 40 *Clinus venustris Klipvis sp. 1 *Cremnochorites capensis Cape triplefin 3 *Galeichthys ater Barbel 1 Goby sp. Goby sp. 4 Haploblepharus pictus Dark shyshark 1 *Parablennius cornutus Blenny sp. 40 Psammogobius knysnaensis Knysna sand goby 2 Spondyliosoma emarginatum Steentjie 1 Syngnathus acus Pipe fish 25 TotaL 214 Number of species 19 * denotes species not recorded in seine or gill net samples

9.4 Overall status of fish in Saldanha Bay and Langebaan Lagoon The current available scientific data on fish communities within Saldanha Bay and Langebaan provide a good baseline from which future changes can be assessed. A few species captured during seine-net surveys showed large changes in abundance at various sites, but given the limited data set it is not possible to assess the implications of these changes i.e. whether these changes are a result of natural or anthropogenic processes. Unfortunately the time series data is currently inadequate to assess any temporal changes (through time) and this highlights the need for continued and improved monitoring. Fish communities naturally exhibit a large amount of annual (due to natural and anthropogenic induced changes in population size and distribution over time) and inter-annual (seasonal) variability. Furthermore, the efficiency of sampling methods and the distributions of different species varies greatly under different environmental conditions, e.g. in clean cold conditions, passive sampling gears such as gill nets catch fewer fish than when the water is warm and dirty. It is recommended that the seine-net surveys be continued as a monitoring method. Not only is it the most comprehensive existing data base (spanning three time periods) but, because a

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known area is sampled it allows for the calculation of abundance and biomass. Seine-netting is very effective at sampling juveniles of many species that inhabit near shore surf-zones and gives an indication of the health of the environment as well as of the adult stock. The frequency of sampling should also be increased, as “once off” surveys do not allow identification of natural seasonal or inter-annual variations. At the very least, the timing of future surveys should be standardized (late summer-autumn is probably best as there are already data from two earlier surveys that were conducted in April). Trends in the abundance and composition of larger species and adults, which are important to the fisheries within the Bay, but not vulnerable to capture using experimental seine-netting, can be monitored in a cost-effective manner by sampling fishers’ catches (as is currently undertaken by the National Parks in Langebaan).

Harders (Liza richardsonii) Pipefish (Sygnathus acus)

Blackhand sole (Solea bleekeri) Eagle ray (Myliobatus aquila)

White steenbras (Lithognathus lithognathus) Sandshark (Rhinobatus annulatus)

Plate 4: Fish species occurring in Saldanha Bay and Langebaan Lagoon. Photographs by Charles Griffiths.

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10 BIRDS

10.1 Introduction

Together with the five islands within the Bay, Saldanha Bay and Langebaan Lagoon provide a wide variety and extensive habitat for a multitude of waterbirds. This includes sheltered deepwater marine habitats associated with Saldanha Bay itself, the sheltered beaches of the Bay, islands as breeding refuges for seabirds, the rocky shorelines of the islands in the mouth of the Bay, and the extensive intertidal saltmarshes, mud- and sandflats of the sheltered Langebaan Lagoon. Langebaan Lagoon comprises 1750 ha of intertidal mud- and sandflats and 600 ha of saltmarshes (Summers 1977). Beds of the sea grass, Zostera capensis and, to a lesser extent, the red seaweed, Gracilaria sp., are patchily distributed over the sandflats. There are also small saltpans and drainage channels which add habitat diversity around the lagoon. Although there is no river flowing into the Lagoon, it has many estuarine characteristics due to the supply of fresh groundwater into the head of the lagoon.

The sheltered Bay and lagoon are not only extensive in area but are rare habitats on the generally very exposed West Coast of South Africa. There are only four other large estuarine systems which provide sheltered habitat comparable to Langebaan Lagoon for birds along the West Coast – the Orange, Olifants and Berg River and Rietvlei/Diep estuarine systems. There are no comparable sheltered bays and relatively few offshore islands. Indeed, these habitats are even of significance at a national scale. While South Africa’s coastline has numerous estuaries (at least 258), it has few very large sheltered coastal habitats such as bays, lagoons or estuaries. Indeed, the Langebaan-Saldanha area is comparable in extent to systems such as Kosi, St Lucia and the Knysna estuary.

Thus unsurprisingly, the area is of tremendous importance in terms of the diversity and abundance of waterbird populations it supports. A total of 53 species of seabirds have been recorded from within the boundaries of the West Coast National Park and 11 species are known to breed on the islands within the Bay.

10.2 Birds of Saldanha Bay and the Islands

10.2.1 National importance of Saldanha Bay and the islands for birds

Saldanha Bay and the islands are important not so much for the diversity of birds they support, but for the sheer numbers of birds of a few species in particular.

The islands of Malgas, Marcus, Jutten, Schaapen and Vondeling are important seabird breeding colonies, this cluster of islands forming one of only a few such breeding areas along the West Coast of South Africa. Uniquely situated at the mouth of a sheltered bay, Saldanha Bay forms part of the feeding range for many of the seabirds using the islands. The islands support nationally important breeding populations of African Penguin (a red data species), Cape Gannet, four species of marine cormorants, Kelp and Hartlaub’s Gulls and Swift Terns. The use of Saldanha Bay by these birds means that these important aggregations are at risk from oil pollution events.

In addition to seabird breeding colonies, the islands also support important populations of the rare and endemic African Black Oystercatcher. These birds are resident on the islands, but are thought to form a source area for mainland coastal populations through dispersal of young birds.

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10.2.2 Ecology and status of the principle bird groups

The African Penguin Spheniscus demersus is endemic to southern Africa, with all known breeding colonies situated within South Africa and Namibia (Whittington et al. 2005a). The species is currently classified as vulnerable under IUCN’s ‘red data list’ criteria (Whittington et al. 2005). The population decreased by at least 90% in the 20th century with present trends differing between colonies (Whittington et al. 2005b).

Breeding pairs of African Penguins have been counted at Malgas, Marcus, Jutten and Vondeling Islands from 1987 to 2005 (Figure 10.1). At three of the four islands there has been an overall decrease in population size during this period. Vondeling Island is the only island to show an increase in breeding pairs over this time period. Malgas Marcus 2500 Jutten Vondeling Total 2000 Desired health:

1500

1000

500

Number of breeding pairs breeding Numberof

0 Photo: B.M. Clark African penguin 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 Year Figure 10.1. Changes in African Penguin populations at islands in Saldanha Bay (Data source: Rob Crawford, Marine & Coastal Management).

The changes in population size are believed to be linked to patterns of immigration and emigration, particularly of young birds, on the different islands along the West Coast (Whittington et al. 2005), with birds tending to move to Robben and Dassen Islands in recent years. Although there is a tendency for young birds to disperse to colonies in the vicinity of their birth colony that are unrelated to shifts in the distribution of prey (Whittington et al 2005b), the overall decline on the Saldanha Bay islands may be partly due to changing patterns of dominance among the main prey species. African penguins prey almost exclusively on small clupeoid fish (e.g. anchovy). Diet samples taken from penguins at Marcus and Jutten Islands showed that the diet of African penguins in the Southern Benguela from 1984 to 1993 was dominated by anchovy (Laugksch and Adams, 1993). During periods when anchovy are dominant, food is more consistently available to penguins on the western Agulhas Bank than at other times (older anchovy remain there throughout the year and sardines are available in the region in the early part of the year). Penguin colonies closest to the Agulhas Bank would benefit during periods of anchovy dominance while those colonies between Lüderitz and Table Bay (including Saldanha Bay) would be faced with a diminished food supply as the anchovy population contracts to the north off Namibia and the south off South Africa (Whittington et al 2005b). The reduced abundance of anchovy may explain the decrease in the African penguin population evident from 1987 to 1993.

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The Kelp Gull, Larus dominicanus, breeds exclusively on offshore islands, apart from one mainland site. The Islands in Saldanha Bay support a significant proportion of South Africa’s breeding population. Within this area, the majority breed on Schaapen and Jutten Islands with a small but consistent sized population on Malgas Island. Small numbers of breeding kelp gulls have only been recorded on Marcus Island in 1978, 1985 and 1990. Overall, the number of Kelp gulls on the islands has been steadily increasing (Figure 10.2), probably due to the increase in availability of food as a result of the introduction and spread of the invasive alien mussel species Mytilus galloprovincialus. This does not necessarily represent a good impact on the ecosystem as Kelp Gulls are known to eat the eggs of several other bird species (e.g. Cape Cormorants).

Malgas Photo: Les Underhill 12000 Marcus Jutten Schaapen 10000 Total 8000

6000 4000

2000 0 Number of Breeding Pairs Kelp Gull 1978 1985 1986 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

1987:No data Year 1979-1984:No data Figure 10.2. Changes in breeding population of Kelp gulls at Malgas, Marcus, Jutten and Schaapen Islands (Data source: Rob Crawford, Marine & Coastal Management).

Hartlaub's Gull, Larus hartlaubIii, 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. The numbers breeding on the different islands are highly erratic, as are the total numbers in the Bay. However, there is no upward or downward trend over time (Figure 10.3).

Malgas Marcus 3500 Jutten Schaapen Photo: Les Underhill Vondeling 3000 Total 2500

2000 1500 1000

500 Number of breeding pairs 0 Hartlaub’s Gull

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 Year Figure 10.3. Changes in breeding population of Hartlaub’s Gulls at Malgas, Marcus, Jutten, Schaapen and Vondeling Islands (Data source: Rob Crawford, Marine & Coastal Management).

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The Swift Tern, Sterna bergii, also known as Greater Crested Tern, 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 is the most important prey species. Jutten Island is the most important island for breeding Swift Terns, but breeding numbers are erratic at all the islands (Figure 10.4). No long term trends are discernible.

3500 Malgas Marcus Jutten Photo: H.D. Oschaleus 3000 Schaapen Vondeling 2500

2000

1500

1000

Number of breeding pairs breeding of Number 500

Swift Tern 0

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 Year Figure 10.4. Changes in breeding population of Swift Terns at Malgas, Marcus, Jutten, Schaapen and Vondeling islands (Data source: Rob Crawford, Marine & Coastal Management)

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 at Lambert's Bay; Malgas Island in Saldanha Bay), and one (Bird Island) at Port Elizabeth. They feed out at sea, but are normally restricted to the continental shelf, up to 100 km from the coast. There have been some fluctuations in population density from year to year but overall the population has shown a small decrease over time (Figure 10.5).

3.50 Photo: B.M. Clark

3.00

2.50

2.00

1.50

1.00 Mean Density (n/m2) 0.50

0.00 Cape Gannet colony

1956/57 1994/95 1995/96 1996/97 1997/98 1998/99 1999/00 2000/01 2001/02 2003/04 2004/05 Year Figure 10.5. Mean density of Cape gannets at Malgas Island, Saldanha Bay (Data source: Rob Crawford, Marine & Coastal Management). Cape gannets will often forage more than 100 kilometres away from their nesting site (Adams and Navarro, 2005). This means that very few will actually feed in Saldanha Bay. Therefore, choice of nesting area is more influenced by protection from predators. The quality of water in Saldanha Bay should therefore not have a significant effect on the Cape Gannet population.

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Cape Cormorants, Phalacrocorax capensis, are endemic to southern Africa, where they are abundant on the west coast but less common on the east coast of southern Africa, occurring as far as Seal Island in Algoa Bay. They breed between Ilha dos Tigres, Angola, and Seal Island in Algoa Bay, South Africa. They generally feed within 10-15 km of the shoreline, preying on Pelagic Goby Sufflogobius bibarbatus, Cape Anchovy Engraulis capensis, Pilchard Sardinops occelatus and Cape Horse Mackerel Trachurus trachurus (du Toit, 2004).

The population on Malgas Island has been relatively stable since 1988 showing some fluctuation. The population at Vondeling and Schaapen Islands show gradual increasing trends since 1988 and there has been an overall decreasing trend on Jutten Island although the population shows large fluctuations on a year to year basis (Figure 10.6).

Malgas 18000 Jutten Photo: M. du Toit Desired health: Vondeling 16000 Schaapen 14000 12000 10000

8000

6000

4000

2000

0 Number pairs breeding of

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 Cape Cormorant

Year Figure 10.6. Changes in breeding population of Cape Cormorants at Saldanha Bay islands (Data source: Rob Crawford, Marine & Coastal Management)

Large interannual fluctuations in breeding numbers due to breeding failure, nest desertion and mass mortality are related to the abundance of anchovy, for which they compete with commercial fisheries. This makes it difficult to accurately determine population trends. In addition, mortality results from disease, with tens of thousands of birds dying during outbreaks of avian cholera. Cape Cormorants are also vulnerable to oiling, and are difficult to catch and clean. Discarded fishing gear and marine debris entangle and kill many birds. Kelp Gulls prey on Cape Cormorant eggs and chicks; which is exacerbated by human disturbance, especially during the early stages of breeding, and the increase in gull numbers (du Toit, 2004).

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Bank Cormorants, Phalacrocorax neglectus, are endemic to 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).

Count data suggest an overall decrease in the population at Malgas Island, which was previously the most important island for this species. Data suggest that many of these birds moved to the other islands (Figure 10.7), but there has also been a decline in total numbers since a peak in 1991 (Figure 10.7).

Photo: M. du Toit 350 Malgas Marcus Jutten 300 Desired health: Vondeling Schaapen Total 250 200

150

100

Number of breeding pairs Number breeding of 0 Bank Cormorant

1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 Figure 10.7. Changes in breeding Yearpopulation of Bank Cormorants at Saldanha Bay islands (Data source: Rob Crawford, Marine & Coastal Management). No breeding has been recorded on Schaapen Island.

Declines are mainly attributed to scarcity of prey. Eggs and chicks are taken by Kelp Gulls and Great White Pelicans. Human disturbance exacerbates this predation. Increased predation has been attributed to the loss of four colonies in other parts of South Africa and Namibia. The birds are known to occasionally drown in rock-lobster traps, and nests are often lost to rough seas. Oiling also poses a threat to this vulnerable species.

Crowned Cormorants, Phalacrocorax coronatus, are endemic to Namibia and South Africa occurring between the Bird Rock Guano Platform in southern Namibia and Quoin Rock, South Africa. They generally occur within 10 km from the coastline, and occasionally in estuaries and sewage works up to 500 m from the sea. Crowned Cormorants feed on slow-moving benthic fish and invertebrates, which they forage for in shallow coastal waters and among kelp beds (du Toit, 2004).

There are no Crowned Cormorants breeding on Malgas Island, which is dominated by Cape Cormorants and Bank Cormorants. Populations on Jutten, Marcus and Vondeling Islands have increased, while the population on Schaapen Island has remained fairly stable (Figure 10.8). This suggests that the Crowned Cormorant population is not threatened by lack of food or predation in the Saldanha Bay area.

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450 Marc us Jutten 400 Schaapen Photo: M. du Toit Vondeling 350 Total

300 250 200 150

100

Number of breeding pairs Number breeding of 50 0

1978 1979 1980 1981 1985 1986 1987 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 Crowned Cormorant No data No data Year Figure 10.8. Changes in breeding population of Crowned Cormorants at Saldanha Bay islands (Data source: Rob Crawford, Marine & Coastal Management). No breeding has been recorded on Malgas Island.

White-breasted Cormorant, Phalacrocorax carbo lucidus, 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 surface-dwelling prey, such as sparid fishes (e.g. Steentjies and White stumpnose, du Toit, 2004).

No breeding pairs have been counted on Malgas Island since the 1920’s and a low number of breeding pairs were counted on Marcus and Jutten Islands intermittently between 1973 and 1987 (Figure 8.9). In 1995, 130 breeding pairs were present on Schaapen Island but this population declined to 45 pairs by 2003, only two pairs were seen in 2004 and none were counted in 2005 (Figure 10.9). Vondeling Island had just a few (between two and nine) breeding pairs of birds using the island intermittently between 1987 and 1997 (Figure 10.9).

Human disturbance poses a serious threat at breeding sites. These cormorants are more susceptible to disturbance than the other marine cormorants, and leave their nests for extended periods if disturbed, exposing eggs and chicks to Kelp Gull predation. Other mortality factors include Avian Cholera, oil pollution, discarded fishing line and hunting inland (du Toit, 2004). Due to Schaapen Islands close proximity to the town of Langebaan and high boating and recreational use of the area, it is possible that the decline in White-breasted cormorants is largely due to increased levels of human disturbance. 140 Marc us Jutten Desired health: Schaapen 120 Vondeling Photo: P. Ryan

100

20 Number of breeding pairs 0

1973 1974 1975 1976 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 White breasted cormorant Year Figure 10.9. Changes in breeding population of White-breasted Cormorants at Saldana Bay islands (Data source: Rob Crawford, Marine & Coastal Management).

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African Black Oystercatchers, Haematopus moquini, are endemic to southern Africa and are listed as a Red Data species. They breed in rocky intertidal and sandy beach areas from Namibia to the southern KwaZulu-Natal coast. The islands in Saldanha Bay support an important number of these birds. They breed on all five islands, where their populations have been monitored by the Percy FitzPatrick Institute, University of Cape Town. They are most numerous on Jutten and Malgas Islands, where their populations currently fluctuate around 190-250 birds and 90-160 birds, respectively. Their numbers have increased dramatically over the past 25 years. In the early 1980s, numbers were in the range of 50-200 on Jutten and 25-60 on Malgas Islands (Figure 10.10). Numbers were relatively stable until the early 1990s. The steady increase in Oystercatcher numbers over the past decade is thought to be linked primarily to the introduction and proliferation of the alien mussel Mytilus galloprovincialis. African Black Oystercatchers are resident on the islands, feeding in the rocky intertidal. While the mussels arrived and became important in the diet between the late 1980s and the early 1990s, the effects on population only began to show much later because of the age at first breeding and slow breeding rate of these birds. The population has stabilised in the recent years and the carrying capacity of the islands has probably been reached. Oystercatchers are unlikely to be affected by water quality in Saldanha Bay except in as much as it affects intertidal invertebrate abundance. Like most of the birds described above, they are, however, vulnerable to catastrophic events such as oil spills.

Photo: Kathy Calf 250 Jutten Island Malgas Island 200

150

100

Adult numbers 50

0 8 0 2 4 0 4 /9 /9 /0 /0 9/80 9 1 3/9 9 3 African Black Oystercatcher 7 81/82 83/84 85/86 87/8 8 9 9 95/96 97/98 9 01/02 0 Year Figure 10.10. Changes in the numbers of African Black Oystercatchers Haematopus moquini on Jutten and Malgas Islands, 1979-2005. Lines represent 3-year moving averages. Source: Hockey PAR 2006. Oystercatcher Conservation Programme: Final Report. Unpublished report to WWF-SA (not to be cited).

10.3 Birds of Langebaan Lagoon

10.3.1 National importance of Langebaan Lagoon for birds

Langebaan Lagoon supports a total of about 27 000 waterbirds during summer and about 9500 during winter. Sixty-seven species of waterbirds are regularly recorded at Langebaan Lagoon. About half of the waterbird species are waders, of which 17 are regular migrants from the Palearctic region of Eurasia; these make up 98% of the summer wader population by numbers. Important non-waders which utilise the system are Kelp and Hartlaub's Gulls, Greater Flamingo, Sacred Ibis and Common Tern. Resident waterbird species which utilise the rocky and sandy coastlines include the African Black Oystercatcher and the Whitefronted Plover, both of which breed in the area.

The thousands of migratory waders supported by Langebaan Lagoon during the austral summer make it the most important ‘wintering’ area for these birds in South Africa (Underhill

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1987). Since Langebaan Lagoon regularly supports over 20 000 waders it is recognised as an internationally important site under the Ramsar Convention on Wetlands of International Importance, to which South Africa is a signatory. With regard to density and biomass of waders, Langebaan Lagoon compares favourably to other internationally important coastal wetlands in West Africa and Europe.

The true importance of Langebaan Lagoon for waders cannot be assessed without recourse to a comparison with wader populations at other wetlands in southern Africa. During the summer of 1976 to 1977, the wader populations at all coastal wetlands in the south-western Cape were counted (Siegfried, 1977). The total population was estimated at 119 000 birds of which 37 000 occurred at Langebaan. Only one other coastal wetland, the Berg River estuary, contained more than 10 000 waders. Thus, Langebaan Lagoon held approximately one third of all the waders in the south-western Cape (Siegfried, 1977). Studies were extended to Namibia (then South West Africa) in the summer of 1976-77. Walvis Bay Lagoon contained up to 29 000 waders and Sandvis had approximately 12 000 waders. Therefore, it was determined that Langebaan Lagoon was the most important wetland for waders on the west coast of southern Africa (Siegfried, 1977). Although not strictly an estuary, Langebaan Lagoon is ranked fourth of all South African estuaries, in terms of its conservation importance for waterbirds (Turpie 1995).

In 1985, Langebaan Lagoon was declared a National Park, and recreational activities such as boating, angling and swimming have since been strictly controlled within the Lagoon.

10.3.2 The main groups of birds and their use of habitats and food

The waterbirds of Langebaan Lagoon can be divided into nine different taxonomic orders (Table 10.1), the most species rich being the Charadriiformes, which include the waders, gulls and terns. Table 10.1 also shows the more commonly used groupings of waterbirds, each of which is described in more detail below. Their relative contribution to the bird numbers on the estuary differs substantially in summer and winter, due to the prevalence of migratory birds in summer (Figure 10.1). Waders account for 86% of the birds on Langebaan Lagoon during summer, nearly all of these being migratory. In winter, resident wader numbers increase slightly, and numbers of flamingos increase substantially.

Table 10.1 Taxonomic composition of waterbirds in Langebaan Lagoon (excluding rare or vagrant species) Common groupings Order SA Migrant Resident Waterfowl Podicipediformes (Grebes) 1 Anseriformes (Ducks, geese) 8 Gruiformes (Rails, crakes, gallinules, coots) 3 Cormorants, darters, Pelecaniformes (Cormorants, darters, pelicans) 6 pelicans Wading birds Ciconiiformes (Herons, egrets, ibises, spoonbill, 9 etc.) Phoenicopteriformes (Flamingos) 2 Birds of prey Falconiformes (Birds of prey) 3 Waders Charadriiformes: Waders 8 17 Gulls Gulls 2 Terns Terns 2 4 Kingfishers Alcediniformes (Kingfishers) 2 Total 46 21

Waders are the most important group of birds on Langebaan Lagoon in terms of numbers. The influx of waders into the area during summer accounts for most of the seasonal change in community composition. Most of the Palaearctic migrants depart quite synchronously

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around early April, but the immature birds of many of these species remain behind and do not don the breeding plumage of the rest of the flock. The resident species take advantage of relief in competition for resources and use this period to breed. The migrants return more gradually in spring, with birds beginning to trickle in from August, and numbers rising rapidly during September to November.

Waders feed on invertebrates that mainly live in intertidal areas, at low tide, both by day and night (Turpie and Hockey 1995). They feed on a whole range of crustaceans, polychaete worms and gastropods, and adapting their foraging techniques to suit the type of prey available. Among the waders, plovers stand apart from the rest in that they have insensitive, robust bills and rely on their large eyes for locating prey visually. Oystercatchers have similar characteristics, using their strong bills to prise open shellfish. Most other waders have soft, highly sensitive bills and can locate prey by touch as well as visually. Those feeding by sight tend to defend feeding territories. Pelicans Waterfowl Cormorants Flamingos 0.2% Cormorants 0.4% 0.6% 3.9% Pelicans 1.9% Other Herons, Other 0.6% 1.1% Waterfowl egrets, ibises 0.3% 1.4% Palearctic 1% waders Gulls, terns 27.8% 6.8%

Resident waders Flamingos 1.3% 41.0% Resident waders 5.9%

Palearctic Gulls, terns waders 14.1% 85.0% Herons, egrets, ibises Winter Summer 6.3% Figure 10.11. Numerical composition of the birds on Langebaan Lagoon during summer and winter

Waders require undisturbed sandflats in order to feed at low tide and undisturbed roosting sites at high tide. In the 1970s it was determined that the most important sandflats, in terms of the density of waders they support, were in Rietbaai, in the upper section of Langebaan Lagoon, and at the mouth, near Oesterwal. The important roosting sites were the saltmarshes, particularly between Bottelary and Geelbek (Summers, 1977).

Gulls and terns are common throughout the area. Although their diversity is relatively low, they make up for this in overall biomass, and form an important group. Both Kelp Gulls and Hartlaub’s Gulls occur commonly in the lagoon.

Cormorants, darters and pelicans are common as a group, but are dominated by the marine cormorants which breed on the Saldanha Bay islands. Pelicans visit the bay and lagoon to feed, but they breed beyond the area at Dassen Island. Darters are uncommon, and are more typical of lower salinities and habitats with emergent vegetation which is relatively uncommon in the study area.

Waterfowl occur in fairly large numbers because of the sheer size of the study area, but they are not as dense as they might be in freshwater wetland habitats or nearby areas such as the Berg River floodplain.

Other birds that commonly occur on the lagoon include birds of prey such as African Fish Eagle, Osprey and African Marsh Harrier, and species such as Pied Kingfisher and Cape Wagtail.

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10.3.3 Interannual variability in bird numbers

Irregular waterbird surveys were conducted at Langebaan Lagoon from 1934, but, due to the large size of the lagoon, these early counts were confined to small areas. It was not until 1975 that annual summer and winter surveys of the total population of waders at high tide were conducted by members of the Western Cape Water Study Group (WCWSG) (Underhill, 1987). An analysis of the numbers of waders over the period 1975 to 1980 showed stable summer populations, but large year to year variations in the number of Palearctic migrants that overwintered (Robertson, 1981).

Langebaan Lagoon and an adjacent sandy beach facing the Atlantic Ocean were surveyed each summer (January or February) and winter (June or July) between winter 1975 and winter 1986, yielding census data for waders over 11 summers and 12 winters and non- waders over nine summers and 10 winters (Underhill 1986). Counts were made at high tide when waders congregate to roost on saltmarshes and sand spits. The species composition from the 1975 to 1986 counts conformed quite closely with the results of earlier surveys (Underhill 1986).

Langebaan has been monitored continuously by the Wader Study Group up to 1991, but the unpublished data are not publicly available. Since 1992, the Lagoon has been monitored biannually by the Co-ordinated Waterbird Counts (CWAC), organised by the Avian Demography Unity at the University of Cape Town.

The above data sets provide the opportunity to examine the long term trends in bird numbers at Langebaan Lagoon up to the present day. This reveals a dramatic downward trend in the numbers of Palearctic waders at the Lagoon (Figure 10.2). While this may echo global trends in certain wader populations due to disturbance of their breeding grounds, what is of more concern is that the trend appears to be echoed by resident waders (Figure 10.93). This suggests that conditions at Langebaan Lagoon are at least partially to blame. The most likely problems are that of siltation of the system reducing the area of suitable (e.g. muddy) intertidal foraging habitat and human disturbance, which has been shown to have a dramatic impact on bird numbers in other estuaries (Turpie and Love 2000).

45000 40000

35000 Desired health: 30000 25000

20000

15000

Number birds of 10000

5000

1976 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 Year Figure 10.12. Long term trends in the numbers of migratory waders on Langebaan Lagoon

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1400 1200 Desired health: 1000 800

600 400

Number birds of 200

1976 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 Year Figure 10.93. Long term trends in the numbers of resident waders on Langebaan Lagoon

10.4 Overall status of birds in Saldanha Bay and Langebaan Lagoon Populations of two cormorant species, namely, Bank Cormorants and White-breasted Cormorants, that utilise islands within the Saldanha Bay region for shelter and breeding have decreased since early to mid-1990’s. Construction of the causeway linking Marcus Island to the mainland and increased human disturbance have been attributed to be the cause of reduced populations of these species. All other species of seabirds investigated in this study in the Saldanha Bay region appear to have healthy populations with either stable numbers or increasing numbers.

Decreasing numbers of migrant waders utilising Langebaan Lagoon reflects a global trend of this nature, largely due to increasing disturbance to breeding grounds of many species. Of greater concern, however, is the decreasing populations of resident waterbirds present in Langebaan Lagoon throughout the year. This long-term trend is most likely due to unfavourable conditions persisting in Langebaan Lagoon as a result of anthropogenic impacts. Bird counts in the region will continue to be conducted by outside organisations, however, it is highly recommended that the status of key species be monitored and used as an indication of environmental conditions in the area.

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11 MANAGEMENT AND MONITORING RECOMMENDATIONS

Monitoring of aquatic health in Saldanha Bay and Langebaan Lagoon has escalated considerably in recent years owing to concerns over declining health in the Bay. This section provides a summary of the state of health of Saldanha Bay and Langebaan Lagoon as reflected by the various environmental parameters reported on (Table 11.1). It also briefly describes current monitoring efforts and provides recommendations as to management actions that need to be implemented in order to mitigate some of the threats that have been detected. It also provides recommendations on how existing monitoring activities may need to be modified in the future to accommodate changes in the state of the Bay.

11.1 Water Quality

11.1.1 Temperature, Salinity and Dissolved Oxygen From a water quality perspective, key physico-chemical changes that have resulted from anthropogenic impacts on the Bay include modification in circulation patterns and wave exposure gradients in the Bay, leading to a reduction in water movement and exchange between the Bay and the adjacent marine environment. Concentrations of faecal coliforms in the nearshore waters are of great concern, particularly in Small Bay where concentrations frequently exceed safety limits and associated pathogens may present a significant risk to human health.

There is currently no continuous monitoring of physico-chemical parameters (temperature, salinity and dissolved oxygen) taking place in Saldanha Bay whereby the data are readily accessible to the Saldanha Bay Water Quality Trust. It is strongly recommended that such continuous (at least hourly) monitoring should be implemented at a minimum of three locations in the Bay, these being two stations in Small Bay (one specifically in the Yacht Club Basin), and one station in Big Bay using similar methodology and station locations to that employed by the CSIR (1999). It should be possible to download this data remotely and it should be analysed on a regular basis. Furthermore, it would be beneficial to obtain such data from both surface and bottom waters (i.e. 1 m and 10 m) to enable ongoing comparisons with historical data.

11.1.2 Chlorophyll a and Nutrients There is currently no regular monitoring of chlorophyll a or nutrient concentrations (specifically nitrogen and ammonia) taking place in Saldanha Bay. It is strongly recommended that monthly monitoring of these parameters be implemented at a minimum of the same three stations identified for temperature, salinity and oxygen monitoring. This requires manual samples to be collected on a monthly basis and sent for laboratory analysis. Ongoing data analysis and interpretation should form a part of such monitoring programs.

11.1.3 Currents and waves Long term changes in the patterns of current flow and wave energy should be quantified through a formal dedicated study to be conducted approximately every five years.

11.1.4 Microbiological monitoring (Faecal coliform) Water samples are currently analysed fortnightly for faecal coliform and E. coli concentrations from 18 stations in Saldanha Bay and Langebaan Lagoon. This level of monitoring should continue as such with regular analysis and interpretation of data taking place.

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11.2 Sediments

11.2.1 Particle size, Particulate Organic Carbon and Trace metals Sediment monitoring in the Bay has revealed that key heavy metal contaminants (Cd, Pb, Cu, Ni) have accumulated in the sediments to the extent that they pose a significant risk during dredging events. These contaminants are typically associated with the finer sediment fraction and tend to be re-suspended during major dredging events and can more readily be taken up by living organisms.

Sediment monitoring (particle size, particulate organic carbon and trace metals) should continue to be conducted biannually at the same suite of stations that have been monitored during 1999 and 2004 with additional stations to be monitored in Langebaan Lagoon. Dredging in the Bay should be avoided if at all possible, and appropriate precautions need to be taken when dredging become necessary to ensure that suspended trace metals do not reach cultured organisms in the Bay.

11.2.2 Hydrocarbons Poly-cyclic, poly-nuclear compounds, and pesticides were considered to pose no threat during analysis conducted in 1999, however, it is recommended that these pollutants should be monitored approximately every five years.

11.3 Benthic macrofauna Abundance and biomass of benthic macrofauna are currently monitored biannually at the same stations as those for sediment monitoring. This regularity (biannually) and intensity of benthic macrofauna monitoring should continue at all of the current stations but it is recommended that the number of stations monitored in Langebaan Lagoon be increased to at least 10 stations (currently only five stations have been sampled).

11.4 Rocky intertidal Key changes in the rocky intertidal ecosystem reflect the regional invasion by the Mediterranean mussel (Mytilus meridionalis) which has significantly altered natural community structure in the lower intertidal, particularly in wave exposed areas.

The intertidal transects (and the quadrats along those transects) that were established in the survey initiated in 2005 should continue to be monitored biannually for the next four years (i.e. two additional surveys) but could then be reduced in frequency to once every five years thereafter.

11.5 Fish Available data on fish communities in the Bay are not sufficient to discern any real long term changes but there is some evidence to suggest that tolerant species are becoming more abundant while more sensitive species are declining in abundance.

Fish sampling surveys should be conducted biannually at the same sites selected during the 2005 study for the next four years (i.e. two additional surveys) but could then be reduced in frequency to once every five years thereafter. This sampling should be confined to the same seasonal period each year for comparative purposes. Additional data on daily catch records from anglers (West Coast National Park and fishing clubs) should also be sourced, collated and analysed. Such information would be invaluable in contributing to an understanding of the overall health of fish populations in the Bay.

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11.6 Birds An alarming decrease in the abundance of both resident and migrant waders utilising Langebaan Lagoon is evident over the past decade and is believed to be a function of increased human utilisation of the area and possible reduction in available food. Similar declines are evident in some bird species breeding on the offshore islands in the Bay. This is believed to be a function of reductions in their food supply (largely pelagic fish e.g. pilchard) outside of the Bay and human disturbance within the Bay. Encouraging increases in numbers of African Black Oystercatchers have been observed on some of the islands in the Bay and is believed to be related to the proliferation of alien mussels on rocky shores in the area, which constitute an important food source for these birds.

Populations of key bird species are currently monitored annually on the offshore islands within the Saldanha Bay area, whilst bird populations in Langebaan Lagoon are monitored twice per annum. These bird counts are conducted as part of an ongoing monitoring programme, managed by the Avian Demography Unit of the University of Cape Town. The data from these surveys should be regularly obtained from this organisation and examined on a biannual basis.

In summary, the environmental monitoring currently implemented in Saldanha Bay and Langebaan Lagoon (e.g. sediment, benthic macrofauna and birds) should continue with some small adjustments or additions, however, monitoring of other environmental parameters that are not currently assessed on a regular basis (e.g. temperature, oxygen, rocky intertidal and fish populations) require structured, maintained monitoring to be implemented.

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Table 11.1. Tabulated summary of Environmental parameters reported on in the State of the Bay: Saldanha Bay and Langebaan Lagoon. Parameter monitored Time period Anthropogenic induced impact WATER QUALITY Physical aspects 1974-2000 • No clears change attributable to development (temperature, salinity, dissolved oxygen, nutrients and chlorophyll) Current circulation patterns 1977 vs. 1991 • Reduced wave energy, and impaired circulation and and current strengths rate of exchange in Small Bay • Increased current strength alongside obstructions (e.g. ore jetty) Microbiological (faecal 1999-2005 • Faecal coliform counts in Small Bay frequently coliform) exceed safety levels. 6 6 • Big Bay and Langebaan Lagoon mostly remain 6 6 within safety levels for faecal coliform pollution Heavy metal contaminants in 1997-2001 • Concentrations of Cadmium, Copper, Lead, Zinc, water Iron and Manganese in mussel flesh currently well below required safety levels (positive) but this may change following any future dredging events owing to elevated metal concentration in sediments. SEDIMENTS Particle size 1977-2004 • Mud component of sediments has increased as a (mud/sand/gravel) result of reduced water movement and dredging (negative impact) but has recovered somewhat since the last dredging event (1999). Particulate Organic Carbon 1974-2004 • Elevated levels of POC evident at Yacht club basin (POC) and Mussel farm (negative impacts). Trace metal contaminants in 1980-2004 • Cadmium, Lead, Copper and Nickel are currently sediments elevated considerably above historic levels but have been at extremely high levels in the recent past following major dredging (1999). BENTHIC MACROFAUNA Species biomass 1975 vs. 1999 • Increased biomass of benthic macrofauna in Small and 2004 Bay and Big Bay • Decreased biomass of benthic macrofauna in Langebaan Lagoon Species diversity 1975 vs. 1999 • Decreased species diversity at all sites and 2004 ROCKY INTERTIDAL Impact of alien mussel 1980 vs. 2001 • Displacement of local mussel species from the lower introduction shore leading to decreased species diversity (negative). Establishment of rocky 2005 • Baseline conditions established against which to intertidal baseline conditions measure future changes. FISH Community composition and 1986/87, • Baseline conditions established against which to abundance 1994, 2005 measure future changes. 1998/99 • Anthropogenic induced changes not clearly 2001 discernable from available data, but some indications of a loss of sensitive species. BIRDS Population numbers of key 1977-2004 • Decreasing populations of Bank and White-breasted species in Saldanha Bay and Cormorants attributed to construction of causeway islands and increasing human disturbance. Population numbers of key 1976-2004 • Alarming decrease in both resident and migrant species in Langebaan waders utilising Langebaan Lagoon, attributed to Lagoon diminishing feeding grounds and human disturbance.

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12 REFERENCES

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McQUAID, C.D. and T.E. PHILLIPS 2000 – Limited wind-driven dispersal of intertidal mussel larvae: in situ evidence from the plankton and the spread of the invasive species Mytilus galloprovincialis in South Africa. Marine Ecology Progress Series 201: 211- 220. MIYAMOTO, Y. and T. NODA 2004 – Effects of mussels on competitively inferior species: competitive exclusion to facilitation. Marine Ecology Progress Series 276: 293-298. MOLDAN, A. 1978. A Study of the Effects of dredging on the benthic macrofauna in Saldanha Bay. South African Journal of Science 74: 106-108. MONTEIRO, P.M.S., McGIBBON, S. and J.L. HENRY 1990 – A decade of change in Saldanha Bay: natural or anthropogenic? South African Journal of Science 86: 454- 456. MONTEIRO, P.M.S, WARWICK, P. A., PASCALL, A. AND M. FRANCK 2000 – Saldanha Bay Water Quality Monitoring Programme. Parts 1 & 2. CSIR. MONTEIRO, P.M.S and G. B. BRUNDRIT -1990 – Interannual chlorophyll variability in Soutyh Africa’s Saldanha Bay system, 1974-1979. South African Journal of marine Science 9: 281-288. MONTEIRO, P.M.S and J.L. LARGIER 1999 – Thermal stratification in Saldanha Bay (South Africa) and subtidal, density-driven exchange with the coastal waters of the Benguela Upwelling System. Estuarine and Coastal Shelf Science 49: 877-890. MONTEIRO, P.M.S, ANDERSON, R. J., and s. WOODBOURNE 1997 – 15N as a tool to demonstrate the contribution of fish-waste-derived nitrogen to an Ulva bloom in Saldanha Bay, South Africa. South African Journal of marine Science. 18: 1-10. NEVARRO, R. 2000. Avian Demography Unit, Dept of Statistical Sciences, University of Cape Town. http://web.uct.ac.za/depts/stats/adu/species/sp053_00.htm PETRAITIS, P. S. 1991. Recruitment of the mussel Mytilus edulis L. on sheltered and exposed shores in Maine, USA. Journal of Experimental Marine Biology and Ecology 147:65-80. PHILLIPS, D.J.H. & P.S. Rainbow. 1994. Biomonitoring of trace aquatic contaminants. Chapman & Hall, London. PHILLIPS, D.J.H. 1980. Quantative aquatic biological indicators: their use to monitor trace metal and organochlorine pollution. Applied Science Publishers, London. PRINGLE, J.S. and COOPER, J. 1975. The Palearctic wader population at Langebaan Lagoon. Ostrich 46:213-218. POGGENPOEL, C. E. 1996- The exploitation of fish during the Holocene in the south-western Cape, South Africa. M. A. thesis, University of Cape Town: xxii+225p. ROBERTSON, H.G. 1981. Annual summer and winter fluctuations of Palearctic and resident waders (Charadrii) at Langebaan Lagoon, South Africa, 1975-1979. In: COOPER, J. (Ed.) Proceedings of the Symposium on Birds of the Sea and Shore, 1979. Cape Town: African Seabird Group. Pp.335-345. ROBINSON T.B., BRANCH, G.M., GRIFFITHS C.L. and A. GOVENDER In press – Effects of the invasive mussel Mytilus galloprovincialis on rocky intertidal community structure. Biological Invasions ROBINSON T.B., GRIFFITHS C.L. and N. KRUGER 2004 – Distribution and status of marine alien invasive species in and bordering the West Coast National Park. Koedoe 47: 79-87. ROBINSON T.B., GRIFFITHS C.L., MCQUAID, C.D. and M. RIUS 2005 – Marine alien species of South Africa – status and impacts. African Journal of Marine Science 27: 297-306. SHANNON, L.V. and G.H. STANDER 1977 – Physical and chemical characteristics of water in Saldanha Bay and Langebaan Lagoon. Transactions of the Royal Society of South Africa 42: 441-459. SHANNON, L.V. 1966 – Hydrology of the south and west coasts of South Africa. Investl. Rep. Div. Sea Fish. S. Afr. 58: 1-52. SIEGFRIED, W.R. 1977. Wading Bird Studies at Langebaan Lagoon. Interim Report submitted March 1977. SOUSA, W. P. 1979. Disturbance in marine intertidal boulder fields: the non-equilibrium maintenance of species diversity. Ecology. 60:1225-1239. STEFFANI, C. N., and G. M. BRANCH. 2003a. Spatial comparisons of populations of an indigenous limpet Scutellastra argenvillei and the alien mussel Mytilus

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galloprovincialis along a gradient of wave energy. African Journal of marine Science. 25:195-212. STEFFANI, C. N., and G. M. BRANCH. 2003b. Temporal changes in an intercation between an indigenous limpet Scutellastra argenvillei and an alien mussel Mytilus galloprovincialis: effects of wave exposure. African Journal of marine Science. 25:213-229. STENTON-DOZEY, J. M. E, JACKSON, L. F. and BUSBY, A. J. 1999. Impact of mussel culture on macrobenthic community structure in Saldanha Bay, South Africa. Marine Pollution Bulletin 39: 357-366. STENTON-DOZEY, J., PROBYN, T. and BUSBY, A. 2001. Impact of mussel (Mytilus galloprovincialis) raft-culture on benthic macrofauna, in situ oxygen uptake and nutrient fluxes in Saldanha Bay, South Africa. Canadian Journal of Fisheries and Aquatic Science 58: 1021-1031. SUMMERS, R.W. 1977. Distribution, abundance and energy relationships of waders (Aves: Charadrii) at Langebaan Lagoon. Transactions of the Royal Society of South Africa, 42, Parts 3&4, May, 1977. SUMMERS, R.W. and KALEJTA-SUMMERS, B. 1996. Seasonal use of sandflats and saltmarshes by waders at low and high tide at Langebaan Lagoon, South Africa. Ostrich 67:72-79. SUMMERS, R.W., COOPER, J. and PRINGLE, J.S. 1977. Distribution and numbers of coastal waders (Charadrii) in the South-western Cape, South Africa, Summer 1975- 76. Ostrich 48: 85-97. TALJAARD, S and MONTEIRO, P M S. 2002. Saldanha Bay Marine Water Quality Management Plan. Phase I: Situation Assessment. Report to the Saldanha Bay Water Quality Forum Trust. CSIR Report ENV-S-C TAYLOR, P.B., NAVARRO, R.A. 1999. Langebaan Lagoon, Langebaan, Western Cape. In: TOTAL CWAC Report: Co-ordinated Waterbird Counts in South Africa, 1992-97. Taylor, P.B., Navarro, R.A., Wren-Sargent, M., Harrison, J.A., and Kieswetter, S.L. p.160. Avian Demography Unit, Cape Town. TURPIE, J.K. and LOVE, V.C. 2000. Avifauna and human disturbance on and around Thesen Island, Knysna estuary: implications for the island's marina development and management plan. Report to Chris Mulder & Associates. TURPIE, J.K. 1995. Prioritizing South African estuaries for conservation: a practical example using waterbirds. Biological Conservation 74: 175-185. UNDERHILL, L.G. 1987. Waders (Charadrii) and other waterbirds at Langebaan Lagoon, South Africa, 1975-1986. Ostrich, 58(4): 145-155. UNDERWOOD, A. J., and P. JERNAKOFF. 1984. The effects of tidal heights, wave- exposure, seasonality and rocky-pools on grazing, and the distribution of intertidal macroalgae in New South Wales. J. Exp. Mar. Biol. Ecol. 75:71-96. UNIT FOR MARINE STUDIES 2000 – South Africa’s maritime industries. Published by M.E.R.I.T. WEEKS, S. J., A. J. BOYD, P. M. S. MONTEIRO, and G.B. BRUNDRIT. 1991a The currents and circulation in Saldanha Bay after 1975 deduced from historical measurements of drogues. South African Journal of marine Science. 11: 525-535. WEEKS, S. J., P. M. S. MONTEIRO, G. NELSON, R. M. COOPER. 1991. South African Journal of Marine Science 11, 579-583. WHITTINGTON, P.A., RANDALL, R.M., RANDALL, B.M. WOLFAARDT, A.C., CRAWFORD, R.J.M., KLAGES, N.T.W., BARTLETT, P.A., CHESSELET, Y.J. and JONES, R. 2005(a). Patterns of movements of the African penguin in South Africa and Namibia. African Journal of Marine Science, 27(1): 215-229. WHITTINGTON, P.A., RANDALL, R.M., WOLFAARDT, A.C., KLAGES, N.T.W., RANDALL, B.M., BARTLETT, P.A., CHESSELET, Y.J. and JONES, R. 2005(b). Patterns of immigration to and emigration from breeding colonies by African penguins. African Journal of Marine Science, 27(1): 205-213.

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APPENDIX I:

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 94 Anchor Environmental Consultants CC

Table 1: Percentage cover of benthic species at the eight study sites in the Saldanha Bay region. Primary and secondary data are combined and scaled to 100%.

Dive School, High Shore Mid Shore Low Shore 123456123456123456 Rock 97 94.5 94.5 82 93.5 88 62.7 69 68.7 48 56.9 67.3 79.1 76.9 60.6 73.8 70.7 71.1 Sand/Gravel 0 0 0 10 3 8 9.95 0 9.95 14.9 9.9 9.9 0 0 0 0 0 0 Fissurella mutabilis 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.5 0.49 0.49 Helcion pectunculus 000000000000000000 Crepidula porcellana 0 0 0 0 0 0 0.5 0.49 0.5 0.99 0.99 0.99 0.97 0.96 0.96 0.5 1.95 0.98 Scutellastra argenvillei 000000000000000000 Scutellastra barbara 000000000000000000 Scutellastra cochlear 000000000000000000 Cymbula granatina 0000000000.50000.960000 Scutellastra granularis 000000000000000000 Cymbula miniata 000000000000000000 Siphonaria capensis 000.50.5000.50.4900.500000000 Siphonaria serrata 1 0.5 0.5 0.5 0 0 0.5 1.97 0.5 0.99 0 0.5 0.49 0 0.96 0 0 0 Patiriella exigua 0 0 0 0 0 0 0.5 0.99 0.5 0.99 0.99 1.98 0.97 1.44 2.88 1.49 1.46 1.47 Parechinus angulosus 0 0 0 0 0 0 0 0 0 0 0 0 0.97 0.96 0.96 0.99 0.98 4.9 Chiton nigrovirescens 0000.500000000000000 Acanthochiton garnoti 000000000000000000 Littorina africana knysnaensis 000000000000000000 Oxystele tigrina 0000000000.994.950000000 Oxystele variegata 1 1 2 2 1 1 1 0.99 1 0.99 0.99 0.99 0 0 0.48 0 0 0 Burnupena spp. 0 0 0 0 0 0 0.5 0.49 1 0.99 3.96 1.98 1.94 0.96 1.92 0.99 2.93 1.47 Burnupena papyracea 000000000000000000 Nucella cingulata 000000000000000000 Nucella dubia 000000000000000000 Nucella squamosa 000000000000000000 Clionella sinuata 000000000000000000 Pentacta doliolum 00000000000000.4800.50.490 Austromegabalanus cylindricus 000000000000000000 Balanus amphitrite 000000000000000000 Chthamalus dentatus 00.50.50.50200.490000000000 Notomegabalanus algicola 00000000000000000.490 Tetraclita serrata 000000000000000000 Aulacomya ater 0 0 0 0 0 0 0 0 0 0 0.5 0 1.94 4.81 0.96 3.96 4.88 3.92 Mytilus galloprovincialis 0 0 2 0 1 0 0 0 1 1.98 1.98 2.97 9.71 2.88 0.96 3.96 3.9 1.96 Choromytilus meridionalis 0 0 0 0 1 1 3.98 0 0 0 0.99 0.99 0.97 4.81 19.2 9.9 9.76 9.8 Notomegabalanus algicola 000000001000000000 Gunnarea capensis 000000000000000000 Dendropoma corallinaceus 000000000000000000 Encrusting Bryozoa 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Sponge 0 1 0 0.5 0 0 1 1.97 4.98 9.9 0 0 0 0 4.81 0 0 0 Bunodactis reynaudi 0 0 0 0 0 0 0 0 0 0 0.99 0.5 0 0 0 0.99 0 0 Actinia equina 0.5 0 0 0.5 0 0 1 0 0 0 0 0 0 0 0.96 1.98 0.98 0 Anthothoe stimpsoni 0 0 0 0 0 0 0 0 0 0.99 0 0.99 1.94 0 0.96 0 0 0 Pseudactinia flagellifera 0 0 0 0 0 0 0 0 0 0 0 0 0.97 1.92 0 0 0.98 1.96 Bunodosoma capensis 000000000000000000.98 Pyura stolonifera 000000000000000000 Diatoms 000000000000000000 Coralline (crustose) 000000000000000000 Hildenbrandia lecanellierii 000200000000000000 Ralfsia verrucosa 0 2 0 0 0 0 1.99 0.99 1 1.98 0.99 0.99 0 0.96 1.92 0 0 0 Aeodes orbitosa 000000000000000000 Aristothamnion collabens 000000000000000000 Botryoglossum platycarpum 000000000000000000 Caulacanthus ustulatus 000000000000000000 Ceramium spp 000000000000000000 Cladophora spp. 000000000000000000 Champia lumbricalis 000000000000000000 Champia compressa 000000000000000000 Codium extricatum 000000000000000000 Coralline (upright) 000000000000000000 Gigartina scutellata 000000000000000000 Gigartina radula 0000000000.50000.960.96000 Gigartina stiriata 000000000000000000 Gymnogongrus glomeratus 000000000000000000 Iridaea capensis 000000000000000000 Laethesia difformis 000000000000000000 Laminaria pallida 000000000000000000 Nothogenia erinacea 0.50000010000.990000000 Plocamium spp. 000000000000000000 Porphyra capensis 00000000.490000000000 Splachnidium rugosum 000000000000000000 Ulva spp. 0 0.5 0 1 0.5 0 14.9 19.7 9.95 14.9 14.9 9.9 0 0.96 0.48 0.5 0 0.98 Red foliose algae 0 0 0 0 0 0 0 1.97 0 0 0 0 0 0 0 0 0 0 Cochlear Garden 000000000000000000

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 95 Anchor Environmental Consultants CC

Table 1: continued.

Jetty, High Shore Mid Shore Low Shore 123456123456123456 Rock 98.5 98.5 98.5 92.5 97.5 98 92 62 72 92.5 87.6 76 71.4 73.8 87.6 82.1 71.7 82.2 Sand/Gravel 0 0 0 0 0 0 0 10 15 0 1.99 0 0 4.95 0 0 0 0 Fissurella mutabilis 00000000000000.50000 Helcion pectunculus 000000000000000000 Crepidula porcellana 0 0 0 0 0 0 0 0 0 0 0.5 0 0.99 0.99 0.5 0.5 0.94 0.5 Scutellastra argenvillei 000000000000000000 Scutellastra barbara 000000000000000000 Scutellastra cochlear 000000000000000000 Cymbula granatina 000000000000000000 Scutellastra granularis 000000000000000000 Cymbula miniata 000000000000000000 Siphonaria capensis 000000000000000000 Siphonaria serrata 000000000000000000 Patiriella exigua 0 0 0 0 0 0 0 0.5 0.5 0.5 0 1 0.99 0.99 0 1 0 0.5 Parechinus angulosus 0000000000000.9900000 Chiton nigrovirescens 000000000000000000 Acanthochiton garnoti 000000000000000000 Littorina africana knysnaensis 000000000000000000 Oxystele tigrina 000000000001000000.99 Oxystele variegata 0.50.50.50.510.51 10.50.50.50 00.510.500.5 Burnupena spp. 0 0 0 0 0 0 0.5 0 0 0 0 0.5 0.99 0.99 0 0 0.47 0.5 Burnupena papyracea 000000000000000000 Nucella cingulata 000000000000000000 Nucella dubia 000000000000000000 Nucella squamosa 000000000000000000 Clionella sinuata 000000000000000000 Pentacta doliolum 000000000000000000 Austromegabalanus cylindricus 000000000000000000 Balanus amphitrite 000000000000000000 Chthamalus dentatus 00.50.500.50.500.50000000000 Notomegabalanus algicola 0000000000.500000000 Tetraclita serrata 000000000000000000 Aulacomya ater 00000000000.50.50.9900.5100 Mytilus galloprovincialis 0.5 0 0 0.5 0 0.5 1 0.5 0 0 0.5 1 1.97 0.99 0 0 0 0 Choromytilus meridionalis 00000000101114.814.90.59.9514.29.9 Notomegabalanus algicola 000.50.50.50.50.500000000000 Gunnarea capensis 000000000000000000 Dendropoma corallinaceus 000000000000000000 Encrusting Bryozoa 000000000000000000 Sponge 0000000000004.9300000 Bunodactis reynaudi 00000000000000000.470 Actinia equina 0.50.500000.500000000000 Anthothoe stimpsoni 0000000.50000000.50000 Pseudactinia flagellifera 000000000000000000 Bunodosoma capensis 0000000000000.9900000 Pyura stolonifera 000000000000000000 Diatoms 000000000000000000 Coralline (crustose) 000000000000000000 Hildenbrandia lecanellierii 000000000000000000 Ralfsia verrucosa 00000000.5000.53000000.5 Aeodes orbitosa 000000000000000000 Aristothamnion collabens 000000000000000000 Botryoglossum platycarpum 000000000000000000 Caulacanthus ustulatus 000000000000000000 Ceramium spp 000000000000000000 Cladophora spp. 00000000000000004.720.99 Champia lumbricalis 000000000000000000 Champia compressa 000000000000000000 Codium extricatum 000000000000000000 Coralline (upright) 000000000000000000 Gigartina scutellata 000000000000000000 Gigartina radula 00000000000000.990000 Gigartina stiriata 000000000000.5000000 Gymnogongrus glomeratus 000000000000000000 Iridaea capensis 000000000000000000 Laethesia difformis 000000000000000000 Laminaria pallida 000000000000000000 Nothogenia erinacea 000000000000.5000000 Plocamium spp. 000000000000000000 Porphyra capensis 00010.50000000000000 Splachnidium rugosum 000000000000000000 Ulva spp. 0 0 0 5 0 0 4 25 11 6 6.97 15 0.99 0 9.95 4.98 7.55 3.47 Red foliose algae 000000000000000000 Cochlear Garden 000000000000000000

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Table 1: continued.

Iron Ore Jetty, High Shore Mid Shore Low Shore 123456123456123456 Rock 99.5 99.5 99.5 99.5 99 99 23.3 9.8 1.98 19.9 14.8 39.6 14.4 59.7 40.3 43.2 70.2 9.66 Sand/Gravel 000000000000000000 Fissurella mutabilis 0000000000000.4800000 Helcion pectunculus 000000000000000000 Crepidula porcellana 0000000.470.49000.490.500.46000.460.48 Scutellastra argenvillei 000000000000000000 Scutellastra barbara 00000000000000.930.930.4700 Scutellastra cochlear 00000000000000.460000 Cymbula granatina 00000000.49000.49003.74.631.883.670.48 Scutellastra granularis 0000000.933.431.4911.483.4700000.920.48 Cymbula miniata 000000000000000000 Siphonaria capensis 0000000.470.980.50.501.980000.4700.48 Siphonaria serrata 0000000000.50.4900.4800000 Patiriella exigua 00000000.490.50.50.490.50.4800.930.470.460.48 Parechinus angulosus 000000000000000000 Chiton nigrovirescens 000000000000000000 Acanthochiton garnoti 00000000.49000000000.460.48 Littorina africana knysnaensis 0.50.50.50.50.50.50.47000.500000000 Oxystele tigrina 000000000000.5000000 Oxystele variegata 00000000.490.50.50.490.5000000 Burnupena spp. 0000000.470.980.510.490.50.480.460.460.940.460.97 Burnupena papyracea 00000000000000001.830.48 Nucella cingulata 000000000000000.46000 Nucella dubia 00000000.490000.50.4800000 Nucella squamosa 0000000000000000.4700 Clionella sinuata 000000000000000000 Pentacta doliolum 000000000000000000 Austromegabalanus cylindricus 000000000000000000 Balanus amphitrite 000000000000000000 Chthamalus dentatus 0 0 0 0 0.5 0.5 66.5 47.5 90.6 75.1 72.4 51 0.48 0 2.78 3.29 0.92 2.42 Notomegabalanus algicola 00000000000000.930000 Tetraclita serrata 00000000000.49000.933.79.390.924.83 Aulacomya ater 00000000.49000000.4600.470.460 Mytilus galloprovincialis 0000000.4732.43.9607.880.990.4800.4632.94.5964.7 Choromytilus meridionalis 000000000000000000 Notomegabalanus algicola 000000000000000000 Gunnarea capensis 0000000000000.4800000 Dendropoma corallinaceus 000000000000000000 Encrusting Bryozoa 000000000000000000 Sponge 00000000.980000000000 Bunodactis reynaudi 00000000.49000000000.460 Actinia equina 000000000000000000 Anthothoe stimpsoni 000000000000000.93000 Pseudactinia flagellifera 000000000000000000 Bunodosoma capensis 000000000000001.85000 Pyura stolonifera 000000000000001.85000 Diatoms 000000000000000000 Coralline (crustose) 0000000000000.9613.923.11.880.460.48 Hildenbrandia lecanellierii 000000000000000000 Ralfsia verrucosa 000000000000000000 Aeodes orbitosa 000000000000000000 Aristothamnion collabens 0000000000003.850.9300.470.460 Botryoglossum platycarpum 000000000000000000 Caulacanthus ustulatus 0000000000000.961.394.630.9400 Ceramium spp 00000000000001.851.8501.830 Cladophora spp. 000000000000000000 Champia lumbricalis 000000000000000000 Champia compressa 00000000000000001.830 Codium extricatum 000000000000000000 Coralline (upright) 000000000000000000 Gigartina scutellata 000000000000000000 Gigartina radula 0000000000006.731.853.240.470.460.97 Gigartina stiriata 000000000000000000 Gymnogongrus glomeratus 00000000000009.264.63000 Iridaea capensis 000000000000000000 Laethesia difformis 000000000000000000 Laminaria pallida 000000000000000000 Nothogenia erinacea 0000000000000.4800.93000 Plocamium spp. 00000000000000.4600.4700.48 Porphyra capensis 0000000.47000.5000.4800000.48 Splachnidium rugosum 000000000000000000 Ulva spp. 0000006.510000068.31.392.311.419.1710.6 Red foliose algae 00000000000000.9300.4700.97 Cochlear Garden 000000000000000000

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 97 Anchor Environmental Consultants CC

Table 1: continued.

Schaapen Island Sheltered, High Shore Mid Shore Low Shore 123456123456123456 Rock 97 97.5 97.5 98 96.5 95.5 34.2 85 87.5 53.5 79.1 15 4.95 26.7 67.6 29.1 19.9 29.6 Sand/Gravel 0 0 0 0 0 0005172.915000000 Fissurella mutabilis 0000000000000.990.50.490.490.50.49 Helcion pectunculus 000000000000000000 Crepidula porcellana 0000000.50000.4900.50.500.490.50.49 Scutellastra argenvillei 000000000000000000 Scutellastra barbara 00000000000000000.50 Scutellastra cochlear 000000000000000000 Cymbula granatina 10000001211.940000.981.9400.99 Scutellastra granularis 000000000000000000 Cymbula miniata 000000000000000000 Siphonaria capensis 000000000000000000 Siphonaria serrata 00.50.50.50.50.50.50.50.50.50.4900000.4900 Patiriella exigua 0000001.981010.49200.990.980.491.990.99 Parechinus angulosus 000000000000000000 Chiton nigrovirescens 000000000000000000 Acanthochiton garnoti 0000000000000.500.49000 Littorina africana knysnaensis 000000000000000000 Oxystele tigrina 0000000.5000000.990.990.980.9710.49 Oxystele variegata 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0 0.5 0.5 0.49 0.5 0 0.5 0 0.49 0 0 Burnupena spp. 0 0 0 0 0 0 1.98 0 0.5 0.5 0.49 0.5 0.5 0 0 0 0.5 0.49 Burnupena papyracea 000000000000000000 Nucella cingulata 000000000000000000 Nucella dubia 000000000000000000 Nucella squamosa 000000000000000000 Clionella sinuata 0000000000.50.490.5000000 Pentacta doliolum 000000000000000000 Austromegabalanus cylindricus 000000000000000000 Balanus amphitrite 000000000000000000 Chthamalus dentatus 0.50.50.50.50.52000000000000 Notomegabalanus algicola 000000000000000000 Tetraclita serrata 000000000000000000 Aulacomya ater 00000000000000.50.490.490.50.49 Mytilus galloprovincialis 0000000.500000000000 Choromytilus meridionalis 0000000000000000.490.50 Notomegabalanus algicola 00000000000.970000000 Gunnarea capensis 000000000000000000 Dendropoma corallinaceus 0000000000000.500000 Encrusting Bryozoa 0000000000000.990.50.49010 Sponge 00000.509.91000.9710000.9700 Bunodactis reynaudi 000000000.500000.50000 Actinia equina 0.50.5000.50.5000000000000 Anthothoe stimpsoni 0.5000000.50000.4900.50000.50.49 Pseudactinia flagellifera 000000000000000000 Bunodosoma capensis 000000000000000000 Pyura stolonifera 000000000000000000 Diatoms 000000000000000000 Coralline (crustose) 0000000.990000066.362.419.656.862.255.7 Hildenbrandia lecanellierii 0000002.97130.50.490001.9600.51.97 Ralfsia verrucosa 000.5000000000002.450.4912.96 Aeodes orbitosa 00000000000000.50.490.970.50.99 Aristothamnion collabens 000000000000000000 Botryoglossum platycarpum 000000000000000000 Caulacanthus ustulatus 0000000.990.50000000000 Ceramium spp 000000000000000000 Cladophora spp. 0000000.50000000000.50 Champia lumbricalis 000000000000000000 Champia compressa 000000000000000000 Codium extricatum 0000001.9800000000000 Coralline (upright) 0000000.5000000.50.500.4900 Gigartina scutellata 000000000000000000 Gigartina radula 0000000.50000014.92.970.492.915.971.97 Gigartina stiriata 000000000000000000 Gymnogongrus glomeratus 0000000000000.50000.50 Iridaea capensis 000000000000000000 Laethesia difformis 0000000.5000000.5000.4900 Laminaria pallida 000000000000000000 Nothogenia erinacea 000000000000000.49000 Plocamium spp. 000000000000000000 Porphyra capensis 00000.50.5000000000000 Splachnidium rugosum 00000000000000.50.980.4910.49 Ulva spp. 0 0.5 0.5 0.5 0.5 0.5 39.6 10 0.5 25 10.2 75.5 6.93 1.49 0.98 0.97 0.5 1.48 Red foliose algae 0000000.500000000000 Cochlear Garden 000000000000000000

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 98 Anchor Environmental Consultants CC

Table 1: continued.

Schaapen Island Exposed, High Shore Mid Shore Low Shore 123456123456123456 Rock 89.5 88 94 89 81.5 93.5 62.6 51.2 85.2 89.6 83.7 63.2 62.4 76.4 28.3 64.6 65.9 70.9 Sand/Gravel 000000000000000000 Fissurella mutabilis 0 0 0 0 0 0 0 0 0.49 0 0 0 0 0 0 0.48 0.49 0.49 Helcion pectunculus 000000000000000000 Crepidula porcellana 000000000000.5000.47000 Scutellastra argenvillei 000000000000000000 Scutellastra barbara 0000000000000.4700.940.480.490.49 Scutellastra cochlear 000000000000000000 Cymbula granatina 1 0 0 0 0 0 1.97 0 1.97 1 1.98 1.99 4.69 3.85 0.47 2.87 3.9 2.96 Scutellastra granularis 000000000000000000 Cymbula miniata 000000000000000000 Siphonaria capensis 0 0.5 0 0 0 0.5 0.49 0.5 0 0 0 0 0 0 0 0 0 0 Siphonaria serrata 0 0.5 0 0 0 0.5 0.49 1 0.49 0.5 0 0 0 0 0 0 0 0 Patiriella exigua 0 0 0 0 0 0.5 0.49 0.5 0 0 0 0.5 0 0 0.94 0.48 0 0.49 Parechinus angulosus 000000000000000000 Chiton nigrovirescens 000000000000000000 Acanthochiton garnoti 000000000000000000 Littorina africana knysnaensis 000000000000000000 Oxystele tigrina 0 0 0 0 0 0 0 0.5 0.49 0 0.5 0.5 5.63 2.88 7.55 2.39 1.46 0.49 Oxystele variegata 0 0 0 0 0.5 0.5 0.49 0.5 0 0 0.5 0 0 0 0 0 0 0 Burnupena spp. 0.5 0 0 0.5 0.5 0.5 0.99 1 0.49 1 0.5 1 0.47 0.48 0.94 0.48 0.49 0.49 Burnupena papyracea 000000000000000000 Nucella cingulata 000000000000000000 Nucella dubia 00000.50000000000000 Nucella squamosa 000000000000000000 Clionella sinuata 0000000000.500000000 Pentacta doliolum 000000000000000000 Austromegabalanus cylindricus 000000000000000000 Balanus amphitrite 000000000000000000 Chthamalus dentatus 5 1 3.98 0.5 2 0.5 0 0 0 0 0 0.5 0 0 0 0 0 0 Notomegabalanus algicola 000000000000000000 Tetraclita serrata 000000000000000000 Aulacomya ater 0000000000000.470.480.4700.491.97 Mytilus galloprovincialis 0 0 0 0 0 0 0.49 0 0 0 0 0 0 0 0 0.48 0 0 Choromytilus meridionalis 000000000000000000 Notomegabalanus algicola 000000000000000000 Gunnarea capensis 000000000000000000 Dendropoma corallinaceus 000000000000000000 Encrusting Bryozoa 000000000000000000 Sponge 0 0 0 0 0 0 0.99 3.98 3.94 0 0 0 1.88 0 0 0 0.49 0 Bunodactis reynaudi 000000000000.50.47000.4801.97 Actinia equina 000000000.490.500000000 Anthothoe stimpsoni 0 0 0 0 0 0 0.99 1.99 0.49 0.5 0.5 0 0.47 0.48 1.89 9.57 11.7 1.97 Pseudactinia flagellifera 00000000000000.480000 Bunodosoma capensis 000000000000001.8900.981.97 Pyura stolonifera 000000000000000000 Diatoms 000000000000000000 Coralline (crustose) 0 0 0 0 0 0 1.97 1 0.99 0 0 1 14.6 6.73 49.5 7.66 9.76 12.3 Hildenbrandia lecanellierii 000002.990.9900.99000000000 Ralfsia verrucosa 0 0 0 0 0 0 0.99 0 0 1 0 0 0 0.48 0 0.48 0 0 Aeodes orbitosa 0 0 0 0 0 0 0 0 0 0 0 0 1.88 2.88 1.89 0.96 0.98 0.99 Aristothamnion collabens 000000000000000000 Botryoglossum platycarpum 000000000000000000 Caulacanthus ustulatus 0000002.4611.9014.951.99000000 Ceramium spp 0 0 0 0 0 0 0 0 0 0 0 0 0 0.96 0.47 0.48 0 0 Cladophora spp. 0 0 0 0 0 0 4.43 4.98 0 1 0.99 1 0.94 0 0 0.48 0 0 Champia lumbricalis 000000000000000000 Champia compressa 000000000000000000 Codium extricatum 000000000000000000 Coralline (upright) 0000000000000000.9600.49 Gigartina scutellata 000000000000000000 Gigartina radula 0000000.49100.500.50.470.481.892.870.980.49 Gigartina stiriata 000000000000000000 Gymnogongrus glomeratus 0 0 0 0 0 0 0 0 0 0 0 0 1.88 1.92 0.47 0.96 0 0.49 Iridaea capensis 000000000.490.50.50000000 Laethesia difformis 0000000000000000.960.490 Laminaria pallida 000000000000000000 Nothogenia erinacea 00000001.991.4810.990000000 Plocamium spp. 000000000000000000 Porphyra capensis 4101101500000000000.4800 Splachnidium rugosum 0000000.4900000000000 Ulva spp. 0 0 1 0 0 0.5 12.3 14.9 1.97 1.49 4.95 26.9 0.47 0.48 0.94 0.48 0.49 0 Red foliose algae 0 0 0 0 0 0 5.91 2.99 0 0 0 0 2.82 0.96 0.94 0.96 0.98 0.99 Cochlear Garden 000000000000000000

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 99 Anchor Environmental Consultants CC

Table 1: continued.

Lynch Point, High Shore Mid Shore Low Shore 123456123456123456 Rock 95.5 97.5 97.5 97 97.5 96.5 30 39.6 65.5 87 81 15 0 6.72 36.4 54.7 8.33 0 Sand/Gravel 000000000000000000 Fissurella mutabilis 00000000000000.420.410.430.420 Helcion pectunculus 000000000000000000 Crepidula porcellana 00000000000000.420.410.430.420 Scutellastra argenvillei 0000000000000.470.8400.8600.84 Scutellastra barbara 000000000000000.41000 Scutellastra cochlear 0000000000002.820.840000.84 Cymbula granatina 0000000000.500000000 Scutellastra granularis 1 1 1 1.49 1 1 1 1.98 2 0.5 3 5 0.47 0.84 0 0.86 2.08 0.84 Cymbula miniata 0000000000000.4701.6500.420.42 Siphonaria capensis 0000000.50.99120.50.5000000 Siphonaria serrata 00000000.50.5000000000 Patiriella exigua 00000000000.50000000 Parechinus angulosus 000000000000000000 Chiton nigrovirescens 000000000000000000 Acanthochiton garnoti 000000000000000000 Littorina africana knysnaensis 1 0.5 0.5 0.5 0.5 0.5 0.5 0.99 0 0 0 1 0 0 0 0 0 0 Oxystele tigrina 000000000000000000 Oxystele variegata 0.5 0.5 0.5 0.5 0.5 1 0.5 0.5 0.5 0 0.5 0.5 0 0 0 0 0 0 Burnupena spp. 0000000.500.500000.420.830.860.830 Burnupena papyracea 000000000000000000 Nucella cingulata 0000000.500000000000 Nucella dubia 0000000.50.50000.5000000 Nucella squamosa 000000000000000000 Clionella sinuata 000000000000000000 Pentacta doliolum 000000000000000000 Austromegabalanus cylindricus 000000000000000000 Balanus amphitrite 00000000000000000.420 Chthamalus dentatus 2 0.5 0.5 0.5 0.5 1 54 44.1 25 10 10 65.5 12.2 21 9.09 7.33 14.2 76.5 Notomegabalanus algicola 0000000000000003.4500 Tetraclita serrata 000000000000000000 Aulacomya ater 0000000000000.470.4200.4300 Mytilus galloprovincialis 000000129.9503129.3947.924.817.2654.2 Choromytilus meridionalis 000000000000000000 Notomegabalanus algicola 000000000000000000 Gunnarea capensis 000000000000000000 Dendropoma corallinaceus 000000000000000000 Encrusting Bryozoa 000000000000000000 Sponge 00000000000000.4203.4500 Bunodactis reynaudi 00000000000000.424.131.722.080 Actinia equina 000000000000000000 Anthothoe stimpsoni 000000000000000000 Pseudactinia flagellifera 000000000000000000 Bunodosoma capensis 000000000000000.410.4300 Pyura stolonifera 000000000000008.260.860.830 Diatoms 000000000000000000 Coralline (crustose) 0 0 0 0 0 0 0 0 0 0 0 0 62 8.82 3.31 0.43 0.42 1.68 Hildenbrandia lecanellierii 000000000000000000 Ralfsia verrucosa 00000000001000.4200.430.420 Aeodes orbitosa 0000000000000.941.6800.430.422.52 Aristothamnion collabens 000000000000000.4100.420 Botryoglossum platycarpum 00000000000000000.420 Caulacanthus ustulatus 00000000.990000000.830.860.420 Ceramium spp 00000000000002.10.830.4304.62 Cladophora spp. 0000000000000.4700.410.8600.42 Champia lumbricalis 00000000000000000.830 Champia compressa 000000000000000000 Codium extricatum 000000000000000000 Coralline (upright) 0 0 0 0 0 0 0 0 0 0 0 0 2.35 0.42 2.89 0.86 0.42 1.68 Gigartina scutellata 000000000000000000 Gigartina radula 000000000000000.4100.420 Gigartina stiriata 000000000000001.650.4300 Gymnogongrus glomeratus 0000000000000.4700000 Iridaea capensis 000000000000000000 Laethesia difformis 000000000000000000 Laminaria pallida 0000000000001.8800.83000 Nothogenia erinacea 0000000000000000.4300 Plocamium spp. 0000000000005.635.040.830.4304.62 Porphyra capensis 000000000000000000 Splachnidium rugosum 000000000000000000 Ulva spp. 0 0 0 0 0 0 0 0 0 0 0.5 0 0 0.84 0.83 1.29 0.83 0.84 Red foliose algae 000000000000000000 Cochlear Garden 000000000000000000

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 100 Anchor Environmental Consultants CC

Table 1: continued.

North Bay, High Shore Mid Shore Low Shore 123456123456123456 Rock 89 97.5 93.5 81.5 69.5 67.5 86.1 83 92.6 85.5 77.6 83.2 15.1 50 67.1 63.6 46.6 51.2 Sand/Gravel 000000000000000000 Fissurella mutabilis 00000000000000000.480.48 Helcion pectunculus 00.500.5000.50.50000000000 Crepidula porcellana 000000000000000000.48 Scutellastra argenvillei 000000000000000000 Scutellastra barbara 0000000000000.940.4700.4700 Scutellastra cochlear 0000000000006.62.80000.96 Cymbula granatina 000000020.9910.950.991.893.740.973.743.851.91 Scutellastra granularis 0000002.9731.9822.863.961.8907.738.411.924.78 Cymbula miniata 000000000000000000 Siphonaria capensis 00.50.50.5010.50.50.5000000000 Siphonaria serrata 00.500.500.500.50.50.50.480000000 Patiriella exigua 00000000000.480000.480.4700 Parechinus angulosus 000000000000000000 Chiton nigrovirescens 000000000000000000 Acanthochiton garnoti 000000000000000000 Littorina africana knysnaensis 0.501110000000000000 Oxystele tigrina 00000000.50000000000 Oxystele variegata 000.50000.50.500.5000.9400000 Burnupena spp. 0 0 0 0.5 0.5 0.5 0 0 0 0.5 0.48 0.5 0.47 0 0 0.47 1.92 1.91 Burnupena papyracea 000000000000000000 Nucella cingulata 000000000000000000.48 Nucella dubia 000000000000000000 Nucella squamosa 000000000000000000 Clionella sinuata 000000000000000000 Pentacta doliolum 000000000000000000 Austromegabalanus cylindricus 00000000000000.930000 Balanus amphitrite 000000000000000000 Chthamalus dentatus 0.50.53540.500000.480.5000000 Notomegabalanus algicola 000000000000000000 Tetraclita serrata 00000000.500.50.480000000 Aulacomya ater 0000000.50.500.50.950.999.433.742.9000 Mytilus galloprovincialis 00.50.50.50000001.93.969.430.9314.51419.221.1 Choromytilus meridionalis 00000000.50100000000 Notomegabalanus algicola 000000000000000000 Gunnarea capensis 00000000000000.470000 Dendropoma corallinaceus 000000000000000000 Encrusting Bryozoa 000000000000000000 Sponge 0000004.952051.92.974.720.930.9700.481.91 Bunodactis reynaudi 00000000.500.5000.4700.4801.922.87 Actinia equina 000000020.5000000000 Anthothoe stimpsoni 000000000000000000 Pseudactinia flagellifera 000000000000000000 Bunodosoma capensis 0000000000000.470.470000.48 Pyura stolonifera 000000000000000000 Diatoms 000000000000000000 Coralline (crustose) 0000000.99200.52.380.529.224.30.971.875.293.35 Hildenbrandia lecanellierii 000000000000000000 Ralfsia verrucosa 00000000000000000.480.96 Aeodes orbitosa 00000000000.48000.470.4800.480 Aristothamnion collabens 00000000000.4800000.9300 Botryoglossum platycarpum 000000000000000000 Caulacanthus ustulatus 0000001.980.50.990.51.430.50.940002.880.48 Ceramium spp 00000000000.9501.891.870000 Cladophora spp. 00000000000.950.99000.4800.480.96 Champia lumbricalis 00000000000.4803.774.67009.620.48 Champia compressa 000000000000000000 Codium extricatum 000000000000000000 Coralline (upright) 00000000000.4800.4700.4800.482.87 Gigartina scutellata 000000000000000000 Gigartina radula 0000000000.51.90.59.430.47000.480.48 Gigartina stiriata 000000000000000000 Gymnogongrus glomeratus 00000000.50.5000000000 Iridaea capensis 0000000000000002.800 Laethesia difformis 000000000000000000 Laminaria pallida 0000000000000.470.47000.480.48 Nothogenia erinacea 000000000000000000 Plocamium spp. 000000000000000000 Porphyra capensis 1001102530000000000.480.930.480 Splachnidium rugosum 000000000000000000 Ulva spp. 0000000.990.50.9911.90.501.871.931.42.40.96 Red foliose algae 000000000.50000.470.9300.9300 Cochlear Garden 0000000000000.940.470000.48

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 101 Anchor Environmental Consultants CC

Table 1: continued.

Marcus Island, High Shore Mid Shore Low Shore 123456123456123456 Rock 99 99.5 99 92 94 97 52.5 50.7 57.7 13 76.2 72.6 1.78 8.51 4.44 7.21 0.93 8.65 Sand/Gravel 000000000000000000 Fissurella mutabilis 00000000000000.430.4400.470.48 Helcion pectunculus 000000000000000000 Crepidula porcellana 0000000000000.4400000 Scutellastra argenvillei 000000000000000000 Scutellastra barbara 000000000000000000 Scutellastra cochlear 000000000000000000 Cymbula granatina 00000000000001.7000.470 Scutellastra granularis 0 0 0 0 0 0 4.57 4.48 4.41 4.35 4.95 5.58 0.89 0 0 0.45 0 0 Cymbula miniata 000000000000000000 Siphonaria capensis 0 0 0 0 0 0 1.83 1.79 2.64 0.43 1.98 2.79 0 0 0 0 0 0 Siphonaria serrata 0 0 0 0 0 0 0.46 0.45 0.44 0 0.5 0.47 0 0 0 0 0 0 Patiriella exigua 0 0 0 0 0 0 0 0 0 0 0 0 0.44 0.43 0.44 0.45 0.47 0.48 Parechinus angulosus 000000000000000000 Chiton nigrovirescens 000000000000000000 Acanthochiton garnoti 000000000000000000 Littorina africana knysnaensis 000000000000000000 Oxystele tigrina 000000000000000000 Oxystele variegata 000000000000000000 Burnupena spp. 0 0 0 0 0 0 0 0 0 0.43 0 0 0.44 0.43 0.89 0.45 0.47 0.48 Burnupena papyracea 000000000000000000 Nucella cingulata 000000000000000000 Nucella dubia 000000000000000000 Nucella squamosa 0000000000000.4400000 Clionella sinuata 000000000000000000 Pentacta doliolum 000000000000000000 Austromegabalanus cylindricus 000000000000000000 Balanus amphitrite 000000000000000000 Chthamalus dentatus 0 0 0 0 0 0 7.76 1.35 1.32 2.17 2.48 2.33 0.44 0 0 0 0.47 0 Notomegabalanus algicola 000000000000000000 Tetraclita serrata 000000000000000000 Aulacomya ater 0000000000000.891.79.781.802.88 Mytilus galloprovincialis 0 0 0 0 0 0 22.8 31.4 22 66.5 6.93 9.3 4.44 8.51 44.4 18 16.8 33.7 Choromytilus meridionalis 000000000000000000 Notomegabalanus algicola 000000000000000000 Gunnarea capensis 000000000000000000 Dendropoma corallinaceus 000000000000000000 Encrusting Bryozoa 000000000000000000 Sponge 00000000000000.432.6700.930 Bunodactis reynaudi 0 0 0 0 0 0 0.46 0 0 0.43 0 0 4.44 0.85 3.56 0.9 0 1.92 Actinia equina 0000000.4600000000000 Anthothoe stimpsoni 000000000000000000 Pseudactinia flagellifera 000000000000000000 Bunodosoma capensis 000000000000000000 Pyura stolonifera 000000000000000000 Diatoms 000000000000000000 Coralline (crustose) 0 0 0 0 0 0 0 0 0 0 0 0 0.89 0.43 0 0.45 0 0.48 Hildenbrandia lecanellierii 000000000000000000 Ralfsia verrucosa 0000000000000.441.70.890.90.470 Aeodes orbitosa 0000000000001.780000.930 Aristothamnion collabens 00000000000000.4300.4500.48 Botryoglossum platycarpum 000000000000000000 Caulacanthus ustulatus 0 0 0 0 0 0 0.91 2.69 1.76 8.7 0.5 0 0 2.13 0.44 0.45 0 0 Ceramium spp 000000000000000000 Cladophora spp. 0 0 0 0 0 0 0 0 0 3.48 0 0 0.44 0.43 0.89 0.45 0.47 0 Champia lumbricalis 000000000000000000 Champia compressa 000000000000000000 Codium extricatum 000000000000000000 Coralline (upright) 0 0 0 0 0 0 0 0 0 0 0 0 1.78 2.13 0.44 0 1.4 0.96 Gigartina scutellata 000000000000000000 Gigartina radula 0000000000002.671.73.561.83.742.88 Gigartina stiriata 0 0 0 0 0 0 0 0 0 0 0 0 66.7 55.3 21.3 57.7 66.4 40.9 Gymnogongrus glomeratus 000000000000000000 Iridaea capensis 0000000000003.564.262.671.80.930.96 Laethesia difformis 00000000000000.430.44000 Laminaria pallida 000000000000000000 Nothogenia erinacea 000000000000000000 Plocamium spp. 000000000000000000 Porphyra capensis 1 0.5 1 8 6 3 1.83 0.9 0.88 0 0.5 0 0.89 0.43 0.44 0.45 0.47 0 Splachnidium rugosum 000000000000000000 Ulva spp. 0 0 0 0 0 0 6.39 6.28 8.81 0.43 5.94 6.98 6.22 7.66 2.22 6.31 4.21 4.81 Red foliose algae 000000000000000000 Cochlear Garden 000000000000000000

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 102 Anchor Environmental Consultants CC

APPENDIX II:

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 103 Anchor Environmental Consultants CC

Detailed descriptions of rocky intertidal fauna and flora occurring at eight sampling stations in Saldanha Bay, 2005.

1) Dive School (DS) The high shore at the sheltered site Dive School was occupied by a total of 13 different species, which increased to 23 and 22 for the mid and low shore, respectively. At the mostly barren high shore (<10% cover) grazers were the main trophic group, whereas green foliose algae dominated the mid shore, and filter-feeders the low shore. Generally, though, the floral and faunal cover was sparse and never exceeded 30% (Figure 1).

Percentage cover cover Percentage 5

Red Filter Green Brown Foliose Foliose Foliose Grazers Algae Feeders Predators

Encrusting High Mid Low Figure 1: Percentage contribution of the different functional groups to the community assemblages at the high, mid and low shore at the Dive School (DS) site. Where the percentage cover is not adding up to 100%, the remaining cover is bare rock surface and/or gravel/sand.

Quadrats at the high shore were 43% similar to each other, and the main species were the winkle Oxystele variegata, the ‘false’ limpet Siphonaria serrata, and the barnacle Chthamalus dentatus. The mid-shore quadrats had a slightly higher similarity of 67%, with a flora-dominated community, specifically the green alga Ulva spp. and the crustose alga Ralfsia verrucosa. The fauna was represented by O. variegata and the scavenging whelk Burnupena spp. The low shore was characterised by the indigenous mussels Choromytilus meridionalis, Aulacomya ater, and the alien mussel Mytilus galloprovincialis. Mobile species that contributed to the spatial coverage were the cushion star Patiriella exigua, the whelk Burnupena spp., the urchin Parechinus angulosus and the slipper limpet Crepidula porcellana. The average similarity among the quadrats was 67%.

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 104 Anchor Environmental Consultants CC

-2 30 25

20 15 10 .0.5m Numbers 5 0 High Mid Low

Oxystele variegata Siphonaria serrata

Crepidula porcellana Patiriella exigua Burnupena spp.

Figure 2: Abundances (numbers/0.5m2) of the five most common mobile species at each shore height (High, Mid, Low) at the Dive School (DS) site.

In terms of numerical abundances of mobile organisms, the high shore was dominated by Oxystele variegata, and to a lesser degree by Siphonaria serrata (Figure 2). In contrast, the low shore had high densities of Crepidula porcellana, Patiriella exigua and Burnupena spp. The assemblage of mobile species at the mid shore consisted of a mixture of these high and low shore species.

2) Jetty (J) At the site Jetty, the high-shore community consisted of seven species, 17 species occurred at the mid shore and 18 at the low shore. Grazers, filter-feeders and green foliose algae contributed equally to the cover at the high shore albeit at very low percentages (Figure 3). In contrast, the mid shore was clearly dominated by green foliose algae, and the low shore by filter-feeders and some green foliose algae. Similar to the site Dive School, the intertidal community cover was generally low, usually well under 20%.

The high shore samples had a similarity of 78%, which was due to the percentage cover of Oxystele variegata, and the barnacles Chthamalus dentatus and Notomegabalanus algicola. At the mid shore, characterising species were the green foliose alga Ulva spp., O. variegata and Patiriella exigua, while the low shore was defined by the black mussel Choromytilus meridionalis, the slipper limpet Crepidula porcellana, and Ulva spp. (63% and 53% similarity for the mid and low shore, respectively). The winkle Oxystele variegata occurred in high densities at the high and the mid shore, but was replaced at the low shore by Crepidula porcellana, Patiriella exigua, and Burnupena spp. (Figure 4).

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 105 Anchor Environmental Consultants CC

Percentage cover cover Percentage

Red Filter Green Brown Foliose Foliose Foliose Grazers Algae Feeders Predators Encrusting High Mid Low Figure 3: Percentage contribution of the different functional groups to the community assemblages at the high, mid and low shore at the Jetty (J) site. Where the percentage cover is not adding up to 100%, the remaining cover is bare rock surface and/or gravel/sand. 16 14

-2 12 10 8

6 4 Numbers .0.5m Numbers 2

0 High Mid Low

Oxystele variegata Patiriella exigua

Burnupena spp. Crepidula porcellana Oxystele tigrina

Figure 4: Abundances (numbers/0.5m2) of the five most common mobile species at each shore height (High, Mid, Low) at the Jetty (J) site.

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 106 Anchor Environmental Consultants CC

3) Iron Ore Jetty (IO) Species numbers at the very steep Iron Ore Jetty site increased drastically from a mere two at the high shore, to 20 at the mid shore and 37 at the low shore. The commoner one of the two species at the high shore was a grazer, whereas the low and particularly the mid shore were dominated by filter-feeders (Figure 5). In contrast to the nearly bare high shore (<1% cover), the intertidal community cover at the mid shore was with an average of 80% high, but decreased to 60% at the low shore.

cover Percentage

Red Filter Green

Brown Foliose Foliose Foliose Grazers Algae Feeders Predators Encrusting High Mid Low Figure 5: Percentage contribution of the different functional groups to the community assemblages at the high, mid and low shore at the Iron Ore Jetty (IO) site. Where the percentage cover is not adding up to 100%, the remaining cover is bare rock surface and/or gravel/sand.

The high shore quadrats revealed a 82% similarity in percentage cover with the only species present being Littorina africana knysnaensis and the barnacle Chthamalus dentatus. At the mid shore, the similarity among the samples was 67%, and the important species were C. dentatus, S. granularis, the scavenging whelk Burnupena spp. and the alien mussel Mytilus galloprovincialis. The low shore was more variable with a similarity of only 48%. Dominant species were the green alga Ulva spp. and crustose algae, and to a lesser degree Burnupena spp., M. galloprovincialis and the barnacle Tetraclita serrata.

The single grazer at the high was the tiny snail L. africana knysnaensis, with average densities of 45 individuals/0.5m2 (Figure 6). Although in reduced density, it extended down to the mid shore where it was joined by the limpets Siphonaria capensis and Scutellastra granularis, and P. exigua and Burnupena spp. The latter species were also present at the low shore, but in lower numbers.

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60 -2 50

40 30

Numbers .0.5m 10 0

High Mid Low

Littorina africana knysnaensis Siphonaria capensis

Scutellastra granularis Patiriella exigua

Burnupena spp. Figure 6: Abundances (numbers/0.5m2) of the five most common mobile species at each shore height (High, Mid, Low) at the Iron Ore Jetty (IO) site.

4) Schaapen Island Sheltered (SS) Total species numbers at the site Schaapen Island Sheltered increased from ten at the high shore to 23 at the mid shore and to 29 at the low shore. Cover at the high shore was low (10%), and consisted of grazers and filter-feeders (Figure 7). The mid shore was primarily covered by green foliose algae (~35%), while the 70% cover at the low shore was dominated by sheets of crustose algae mixed with some red foliose algae.

cover Percentage 0

Red Filter Green

Brown Foliose Foliose Foliose Grazers Algae Feeders

Predators Encrusting High Mid Low

Figure 7: Percentage contribution of the different functional groups to the community assemblages at the high, mid and low shore at the Schaapen Island Sheltered (SS) site. Where the percentage cover is not adding up to 100%, the remaining cover is bare rock surface and/or gravel/sand. The similarity among the samples was 70% at the high shore, and 55% and 62% at the mid and low shore, respectively. The main species at the high shore were Chthamalus dentatus, Oxystele variegata, Ulva spp. and Siphonaria capensis. Ulva spp. was also dominant at the mid shore together with a crustose alga (Hildenbrandia lecanellierii), P. exigua, Siphonaria serrata, Burnupena spp., and O. variegata. The low shore was primarily characterised by crustose algae, and further by Ulva spp., the red alga Gigartina radula, and the snail Oxystele tigrina.

Densities of mobile species are low at the high shore, but increase towards the mid and low shore (Figure 8). Common at the mid shore are P. exigua, S. serrata, O.°variegata, and Burnupena spp. P. exigua is also abundant at the low shore, but the other grazers are replaced by O. tigrina.

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18 16 14

-2 12 10 8

.0.5m Numbers 4 2 0 High Mid Low

Siphonaria serrata Patiriella exigua Oxystele variegata

Burnupena spp. Oxystele tigrina Figure 8: Abundances (numbers/0.5m2) of the five most common mobile species at each shore height (High, Mid, Low) at the Schaapen Island Sheltered (SS) site.

5) Schaapen Island Exposed (SE) The macrofaunal community at the high shore at Schaapen Island Exposed was represented by a total of eleven species, which covered 10% of the rock. The species number increased to 27 at the mid shore and the cover to ~30%, whereas the low shore harboured 26 species and had a 40% cover. Red foliose algae contributed mainly to the cover at the high shore, and green foliose at the mid shore. The low shore was mostly covered by crustose algae, followed by grazers, predators and some red foliose algae (Figure 9).

Most common species at the high shore were the typical high shore alga Porphyra capensis, the barnacle Chthamalus dentatus, and to a lesser degree the whelk Burnupena spp. The assemblages in the sample quadrats had a overall similarity of 50%. The floral cover at the mid shore was characterised by Ulva spp. and the red alga Caulacanthus ustulatus, and Burnupena spp. and the limpet Cymbula granatina contributed to the faunal cover. The similarity among the quadrats was 53%. The low shore had a higher similarity of 68%, and was dominated by crustose algae, and the red foliose alga Aeodes orbitosa. Burnupena spp. and C. granatina extended down to the low shore, and were joined by the anemone Anthothoe stimpsoni and the snail Oxystele tigrina.

5 cover Percentage

Red Filter Green Brown Foliose Foliose Foliose

Grazers Algae Feeders Predators

Encrusting High Mid Low

Figure 9: Percentage contribution of the different functional groups to the community assemblages at the high, mid and low shore at the Schaapen Island Exposed (SE) site. Where the percentage cover is not adding up to 100%, the remaining cover is bare rock surface and/or gravel/sand.

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-2 20

.0.5m Numbers 5

0 High Mid Low

Siphonaria serrata Burnupena spp.

Patiriella exigua Cymbula granatina Oxystele tigrina

Figure 10: Abundances (numbers/0.5m2) of the five most common mobile species at each shore height (High, Mid, Low) at the Schaapen Island Exposed (SE) site. In terms of numerical abundance of mobile species, the high shore was relatively low populated with only >5 individuals/0.5m2 for Siphonaria serrata and Burnupena spp., respectively (Figure 10). Both species increased in densities at the mid shore, but were absent from or less common at the low shore. In the latter zone, O. tigrina reached densities of close to 20/0.5m2.

6) Lynch Point (L) At Lynch Point, species numbers increased drastically with decreasing shore height, from 4 at the high shore, to 14 at the mid shore and 34 at the low shore. Percentage cover followed this pattern with only 3% cover at the high shore, increasing to 47% and 82% at the mid and low shore, respectively. Grazers dominated the high shore, whereas filter-feeders characterised the mid and low shore. At the low shore, crustose and red foliose algae played also a role (Figure 11). 60 50

cover Percentage 10

Red Filter Green Brown Foliose Foliose Foliose Grazers Algae Feeders Predators Encrusting High Mid Low Figure 11: Percentage contribution of the different functional groups to the community assemblages at the high, mid and low shore at the Lynch Point (L) site. Where the percentage cover is not adding up to 100%, the remaining cover is bare rock surface and/or gravel/sand.

The high shore assemblage showed little spatial variability (high similarity of 93%), with typical species being Scutellastra granularis, Chthamalus dentatus, Littorina africana knysnaensis, and Oxystele variegata. The mid shore was more variable with a similarity of 66%, and the communities were again characterised by C. dentatus and S. granularis, and additionally by Mytilus galloprovincialis, Siphonaria capensis, and Oxystele variegata. Chthamalus dentatus and

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M. galloprovincialis continued down to the low shore, co-occurring with some encrusting algae. The similarity among the sample quadrats was 52%.

-2 35 30 25 20 15

Numbers .0.5m 10

5 0 High Mid Low

Littorina africana knysnaensis Oxystele variegata Scutellastra granularis Burnupena spp. Scutellastra cochlear

Figure 12: Abundances (numbers/0.5m2) of the five most common mobile species at each shore height (High, Mid, Low) at the Lynch Point (L) site.

The grazer abundance at the high shore consisted of Littorina africana knysnaensis, Scutellastra granularis, and Oxystele variegata (Figure 12). All three species extended into the mid shore, but O. variegata in reduced density. S. granularis was also abundant at the low shore, in conjunction with Burnupena spp. and Scutellastra cochlear.

7) North Bay (NB) At the semi-exposed site North Bay, the high shore contained a total of nine species, which increased to 29 and 33 at the mid and low shore, respectively. The 17% cover of macrofaunal organisms at the high shore exceeded that on the mid shore where the cover was only 15%. The low shore had a cover of 51%. The high shore was dominated by red foliose algae, and the mid shore by filter-feeders and grazers (Figure 13). The main functional group at the low shore was that of the filter-feeders, but encrusting algae, grazers and red foliose algae contributed also to the cover.

The group of red foliose algae at the high shore was represented by the high shore alga Porphyra capensis. Other common less important species were Chthamalus dentatus, Littorina africana knysnaensis, and Siphonaria capensis. Similarity among the sample quadrats was relatively low with 56%. Scutellastra granularis, Cymbula granatina, a sponge and the red alga Caulacanthus ustulatus were the main species at the mid shore, whereas the low shore was characterised by Mytilus galloprovincialis, crustose algae, and again S. granularis and C. granatina. The spatial variability was with 50% similar in both shore heights.

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5 Percentage cover cover Percentage

Red Filter Green Brown Foliose Foliose Foliose Grazers Algae Feeders Predators Encrusting High Mid Low Figure 13: Percentage contribution of the different functional groups to the community assemblages at the high, mid and low shore at the North Bay (NB) site. Where the percentage cover is not adding up to 100%, the remaining cover is bare rock surface and/or gravel/sand.

45 40 35 -2 30 25 20 15

Numbers .0.5m 10

5 0 High Mid Low

Littorina africana knysnaensis Siphonaria capensis Burnupena spp. Scutellastra cochlear Scutellastra granularis Figure 14: Abundances (numbers/0.5m2) of the five most common mobile species at each shore height (High, Mid, Low) at the North Bay (NB) site.

The high shore had high densities of Littorina africana knysnaensis, interspersed with the less abundant Siphonaria capensis (Figure 14). The mid shore was characterised by Scutellastra granularis, which extended down into the low shore, where it was joined by Scutellastra cochlear and Burnupena spp.

8) Marcus Island (M) Only one species was present at the high shore at the Marcus Island site, which consequently had a cover of only 3%. Twelve species occurred at the mid shore covering 46% of the rock, and the nearly complete cover of 95% at the low shore was accomplished by 25 different species. The distinguishing group at the high shore were red foliose algae, filter-feeders at the mid shore, and red foliose and filter-feeders at the low shore (Figure 15).

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70 60

50 40

cover Percentage 10

Red Filter Green Brown Foliose Foliose Foliose Grazers Algae

Feeders Predators

Encrusting High Mid Low Figure 15: Percentage contribution of the different functional groups to the community assemblages at the high, mid and low shore at the Marcus Island (M) site. Where the percentage cover is not adding up to 100%, the remaining cover is bare rock surface and/or gravel/sand.

40 35

-2 30

20 15 10 .0.5m Numbers 5 0 High Mid Low

Siphonaria capensis Siphonaria serrata Scutellastra granularis Burnupena spp. Fissurella mutabilis

Figure 16: Abundances (numbers/0.5m2) of the five most common mobile species at each shore height (High, Mid, Low) at the Marcus Island (M) site. The alga Porphyra capensis was the only species at the high shore and the similarity in its cover among the quadrats was relatively high (83%). Mytilus galloprovincialis was the dominant species covering the mid shore, followed by Scutellastra granularis, Chthamalus dentatus, and Ulva spp. The spatial variability in community structure was relatively low in this height zone (75% similarity). At the low shore, the cover consisted primarily of the red alga Gigartina stiriata, Mytilus galloprovincialis, and to a lesser extent of Ulva spp. and another red alga Gigartina radula. Again, variability was relatively low (71% similarity).

No mobile organisms occurred at the high shore, but the limpets Siphonaria capensis and Scutellastra granularis both reached relatively high densities at the mid shore (Figure 16). Burnupena spp. and the keyhole limpet Fissurella mutabilis were present at the low shore.

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There was great variation in the densities of fauna and flora occurring at each of the study sites. This is illustrated by the abundances of the eleven most common mobile species at the study sites depicted in Figure 17. The slipper limpet Crepidula porcellana and the winkle Oxystele variegata, and to a lesser degree the cushion star Patiriella exigua (all grazers), tend to be more common at the sheltered sites and decrease in abundance with increasing wave exposure. The larger limpets like Scutellastra granularis and S. cochlear, on the other hand, are more abundant at the exposed sites. No obvious trend was apparent for the other mobile invertebrates, and they are either relatively evenly distributed at the various sites (e.g. whelk Burnupena spp.) or only occur at some of the sites (e.g. winkle Littorina africana knysnaensis and winkle Oxystele tigrina).

70 70

60 Scutellastra granularis Oxystele variegata 60 -2 -2 50 50 40 40 30 30 20 20

0.5m Numbers . 10 10 0.5m Numbers . 0 0 16 DS J IO SS SE L NB M Scutellastra cochlear Oxystele tigrina 30 -2 14 -2 12 10 20 8 6 10 4 Numbers . 0.5m Numbers . 0.5m Numbers . 2 0 0 DS J IO SS SE L NB M 5 Cymbula granatina Littorina africana knysnaensis

-2 80 -2 4 60 3 40 2 Numbers . 0.5m Numbers . 1 20 0.5m Numbers . 0 0 DSSiphonaria J capensis IO SS SE L NB M DS J IO SS SEPatiriella L NB exigua M 30 -2 60 -2 20 40

20 10 0.5m Numbers . 0.5m Numbers . 0 0 DS J IO SS SE L NB M DS J IO SS SE L NB M 16 Siphonaria serrata Burnupena spp. 25

-2 14 -2 12 20 10 15 8 6 10 4 Numbers . 0.5m 5 Numbers . 0.5m 2 0 0 25 Crepidula porcellana DS J IO SS SE L NB M

-2 20 15 10

0.5m Numbers . 5

0 DS J IO SS SE L NB M

Figure 17. Abundance of eleven most common mobile species occurring on the rocky intertidal area at eight sites (depicted by coding on the x-axis) in Saldanha Bay.

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Statistical analyses of rocky intertidal data collected in Saldanha Bay, 2005 Table 2: Total species number, total percentage cover, species richness, evenness, and diversity measure for the intertidal macrofaunal communities at the eight study sites in the Saldanha Bay region. For a general comparison among the eight rocky shore sites, the averaged data from each series of quadrats (1-6) were combined across the shore heights and scaled to 100% (percentage cover of rock and sand/gravel omitted for calculations of diversity measures).

Species Percentage Species Evenness J' Shannon- DS1 17 17.1 5.638 0.831 2.353 DS2 22 19.9 7.025 0.801 2.477 DS3 18 22.1 5.491 0.800 2.313 DS4 25 23.8 7.573 0.815 2.622 DS5 18 22.0 5.501 0.820 2.369 DS6 18 18.6 5.819 0.859 2.481 J1 15 12.7 5.510 0.774 2.095 J2 13 16.9 4.242 0.597 1.532 J3 8 9.0 3.189 0.442 0.918 J4 10 11.0 3.758 0.634 1.460 J5 14 13.7 4.960 0.707 1.865 J6 16 14.6 5.594 0.685 1.899 IO1 22 54.3 5.258 0.459 1.420 IO2 33 43.7 8.474 0.618 2.162 IO3 26 52.7 6.304 0.524 1.708 IO4 26 45.8 6.537 0.475 1.547 IO5 24 38.7 6.292 0.505 1.606 IO6 26 50.6 6.372 0.493 1.605 L1 23 58.2 5.414 0.535 1.676 L2 29 52.1 7.084 0.544 1.833 L3 28 33.5 7.686 0.683 2.275 L4 31 20.4 9.946 0.750 2.575 L5 28 37.7 7.438 0.482 1.607 L6 22 62.8 5.072 0.412 1.274 M1 27 48.9 6.684 0.611 2.015 M2 29 47.1 7.268 0.589 1.984 M3 26 46.3 6.519 0.611 1.990 M4 21 62.6 4.835 0.546 1.661 M5 24 42.9 6.117 0.564 1.794 M6 20 40.6 5.130 0.622 1.863 NB1 28 36.6 7.501 0.768 2.560 NB2 33 23.2 10.182 0.747 2.613 NB3 25 15.6 8.738 0.746 2.401 NB4 27 23.1 8.275 0.797 2.627 NB5 34 35.4 9.251 0.754 2.659 NB6 30 32.7 8.315 0.686 2.332 SS1 27 54.6 6.499 0.561 1.848 SS2 22 30.3 6.159 0.438 1.354 SS3 22 14.1 7.932 0.692 2.138 SS4 24 34.1 6.516 0.486 1.545 SS5 29 33.9 7.950 0.516 1.739 SS6 23 51.6 5.577 0.451 1.413 SE1 32 28.5 9.254 0.832 2.885 SE2 29 28.1 8.393 0.830 2.793 SE3 28 30.8 7.876 0.617 2.057 SE4 33 19.0 10.877 0.812 2.840 SE5 25 23.0 7.655 0.787 2.533 SE6 27 24.1 8.169 0.719 2.370

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Table 3: Tukey tests following a significant one-way ANOVA test (ANOVA: F7,40 = 11.38, p = <0.001) comparing the Shannon-Wiener diversity indices for each combination of the eight study sites in the Saldanha Bay region. Significant p values (<0.05) are highlighted in red. Average Shannon-Wiener indices are given in brackets behind the abbreviated site names in the first row. DS J IO L M NB SS SE (2.436) (1.628) (1.675) (1.873) (1.884) (2.532) (1.673) (2.580) DS 0.001 0.002 0.042 0.049 0.999 0.002 0.990 J 0.001 1.000 0.840 0.809 0.000 1.000 0.000 IO 0.002 1.000 0.940 0.922 0.000 1.000 0.000 L 0.042 0.840 0.940 1.000 0.010 0.937 0.004 M 0.049 0.809 0.922 1.000 0.012 0.918 0.005 NB 0.999 0.000 0.000 0.010 0.012 0.000 1.000 SS 0.002 1.000 1.000 0.937 0.918 0.000 0.000 SE 0.990 0.000 0.000 0.004 0.005 1.000 0.000

Table 4: One-way ANOSIM test followed by pairwise testing comparing the intertidal communities at the eight rocky shore study sites in the Saldanha Bay region. The data per site are combined across the shore heights. Number of permutations is 462 for all pairwise tests. The ANOSIM test established significant differences in intertidal community structure among all sites. Sites R Statistic Significance Level Global Test 0.944 0.001 Pairwise Tests DS vs J 0.65 0.002 DS vs IO 0.996 0.002 DS vs L 1 0.002 Ds vs M 1 0.002 DS vs NB 0.998 0.002 DS vs SS 0.952 0.002 DS vs SE 1 0.002 J vs IO 1 0.002 J vs L 1 0.002 J vs M 1 0.002 J vs NB 1 0.002 J vs SS 0.981 0.002 J vs SE 1 0.002 IO vs L 0.756 0.002 IO vs M 0.974 0.002 IO vs NB 0.843 0.002 IO vs SS 1 0.002 IO vs SE 0.993 0.002 L vs M 0.926 0.002 L vs NB 0.93 0.002 L vs SS 1 0.002 L vs SE 1 0.002 M vs NB 0.867 0.002 M vs SS 1 0.002 M vs SE 1 0.002 NB vs SS 0.996 0.002 NB vs SE 0.946 0.002 SS vs SE 0.785 0.002

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Table 5: Kruskal-Wallis analyses testing for differences in densities of the eleven most common mobile species among the eight study sites in the Saldanha Bay region. Significant differences are highlighted in red.

Scutellastra granularis Multiple Comparisons p values (2-tailed); Scutellastra granularis (Mobile Combine Independent (grouping) variable: Sites Kruskal-Wallis test: H ( 7, N= 48) =41.87903 p =.0000 Depend.: DS J IO L M NB SS SE Scutellastra granularis R:12.500 R:12.500 R:32.333 R:40.417 R:34.167 R:39.083 R:12.500 R:12.500 DS 1.000 0.396 0.015 0.206 0.028 1.000 1.000 J 1.000 0.396 0.015 0.206 0.028 1.000 1.000 IO 0.396 0.396 1.000 1.000 1.000 0.396 0.396 L 0.015 0.015 1.000 1.000 1.000 0.015 0.015 M 0.206 0.206 1.000 1.000 1.000 0.206 0.206 NB 0.028 0.028 1.000 1.000 1.000 0.028 0.028 SS 1.000 1.000 0.396 0.015 0.206 0.028 1.000 SE 1.000 1.000 0.396 0.015 0.206 0.028 1.000

Scutellastra cochlear Multiple Comparisons p values (2-tailed); Scutellastra cochlear (Mobile Combine Independent (grouping) variable: Sites Kruskal-Wallis test: H ( 7, N= 48) =17.41292 p =.0149 Depend.: DS J IO L M NB SS SE Scutellastra cochlear R:21.000 R:21.000 R:24.500 R:33.333 R:21.000 R:33.167 R:21.000 R:21.00 DS 1.000 1.000 1.000 1.000 1.000 1.000 1.000 J 1.000 1.000 1.000 1.000 1.000 1.000 1.000 IO 1.000 1.000 1.000 1.000 1.000 1.000 1.000 L 1.000 1.000 1.000 1.000 1.000 1.000 1.000 M 1.000 1.000 1.000 1.000 1.000 1.000 1.000 NB 1.000 1.000 1.000 1.000 1.000 1.000 1.000 SS 1.000 1.000 1.000 1.000 1.000 1.000 1.000 SE 1.000 1.000 1.000 1.000 1.000 1.000 1.000

Cymbula granatina Multiple Comparisons p values (2-tailed); Cymbula granatina (Mobile Combined Independent (grouping) variable: Sites Kruskal-Wallis test: H ( 7, N= 48) =37.38538 p =.0000 Depend.: DS J IO L M NB SS SE Cymbula granatina R:14.833 R:10.000 R:32.083 R:12.417 R:16.000 R:40.833 R:29.083 R:40.75 DS 1.000 0.919 1.000 1.000 0.036 1.000 0.038 J 1.000 0.176 1.000 1.000 0.004 0.510 0.004 IO 0.919 0.176 0.419 1.000 1.000 1.000 1.000 L 1.000 1.000 0.419 1.000 0.012 1.000 0.013 M 1.000 1.000 1.000 1.000 0.059 1.000 0.062 NB 0.036 0.004 1.000 0.012 0.059 1.000 1.000 SS 1.000 0.510 1.000 1.000 1.000 1.000 1.000 SE 0.038 0.004 1.000 0.013 0.062 1.000 1.000

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Siphonaria capensis Multiple Comparisons p values (2-tailed); Siphonaria capensis (Mobile Combined Independent (grouping) variable: Sites Kruskal-Wallis test: H ( 7, N= 48) =31.92155 p =.0000 Depend.: DS J IO L M NB SS SE Siphonaria capensis R:20.500 R:10.000 R:36.667 R:29.000 R:42.417 R:28.583 R:10.000 R:18.83 DS 1.000 1.000 1.000 0.188 1.000 1.000 1.000 J 1.000 0.027 0.525 0.002 0.602 1.000 1.000 IO 1.000 0.027 1.000 1.000 1.000 0.027 0.766 L 1.000 0.525 1.000 1.000 1.000 0.525 1.000 M 0.188 0.002 1.000 1.000 1.000 0.002 0.099 NB 1.000 0.602 1.000 1.000 1.000 0.602 1.000 SS 1.000 1.000 0.027 0.525 0.002 0.602 1.000 SE 1.000 1.000 0.766 1.000 0.099 1.000 1.000

Siphonaria serrata Multiple Comparisons p values (2-tailed); Siphonaria serrata (Mobile Combined) Independent (grouping) variable: Sites Kruskal-Wallis test: H ( 7, N= 48) =19.49906 p =.0068 Depend.: DS J IO L M NB SS SE Siphonaria serrata R:32.833 R:9.0000 R:20.667 R:13.833 R:25.333 R:27.500 R:33.917 R:32.917 DS 0.089 1.000 0.525 1.000 1.000 1.000 1.000 J 0.089 1.000 1.000 1.000 0.619 0.057 0.086 IO 1.000 1.000 1.000 1.000 1.000 1.000 1.000 L 0.525 1.000 1.000 1.000 1.000 0.363 0.510 M 1.000 1.000 1.000 1.000 1.000 1.000 1.000 NB 1.000 0.619 1.000 1.000 1.000 1.000 1.000 SS 1.000 0.057 1.000 0.363 1.000 1.000 1.000 SE 1.000 0.086 1.000 0.510 1.000 1.000 1.000

Oxystele tigrina Multiple Comparisons p values (2-tailed); Oxystele tigrina (Mobile Combined) Independent (grouping) variable: Sites Kruskal-Wallis test: H ( 7, N= 48) =34.03525 p =.0000 Depend.: DS J IO L M NB SS SE Oxystele tigrina R:24.000 R:19.667 R:18.750 R:16.000 R:16.000 R:18.750 R:39.750 R:43.083 DS 1.000 1.000 1.000 1.000 1.000 1.000 0.510 J 1.000 1.000 1.000 1.000 1.000 0.363 0.105 IO 1.000 1.000 1.000 1.000 1.000 0.262 0.073 L 1.000 1.000 1.000 1.000 1.000 0.092 0.023 M 1.000 1.000 1.000 1.000 1.000 0.092 0.023 NB 1.000 1.000 1.000 1.000 1.000 0.262 0.073 SS 1.000 0.363 0.262 0.092 0.092 0.262 1.000 SE 0.510 0.105 0.073 0.023 0.023 0.073 1.000

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Oxystele variegata Multiple Comparisons p values (2-tailed); Oxystele variegata (Mobile Combined) Independent (grouping) variable: Sites Kruskal-Wallis test: H ( 7, N= 48) =37.87023 p =.0000 Depend.: DS J IO L M NB SS SE Oxystele variegata R:45.500 R:36.917 R:21.250 R:34.083 R:6.0000 R:15.000 R:21.917 R:15.333 DS 1.000 0.076 1.000 0.000 0.005 0.099 0.005 J 1.000 1.000 1.000 0.004 0.188 1.000 0.212 IO 0.076 1.000 1.000 1.000 1.000 1.000 1.000 L 1.000 1.000 1.000 0.014 0.510 1.000 0.570 M 0.000 0.004 1.000 0.014 1.000 1.000 1.000 NB 0.005 0.188 1.000 0.510 1.000 1.000 1.000 SS 0.099 1.000 1.000 1.000 1.000 1.000 1.000 SE 0.005 0.212 1.000 0.570 1.000 1.000 1.000

Burnupena spp. Multiple Comparisons p values (2-tailed); Burnupena spp. (Mobile Combined) Independent (grouping) variable: Sites Kruskal-Wallis test: H ( 7, N= 48) =16.86680 p =.0183 Depend.: DS J IO L M NB SS SE Burnupena spp. R:41.000 R:15.667 R:24.250 R:22.833 R:20.917 R:18.917 R:17.667 R:34.750 DS 0.048 1.0 0.689 0.363 0.176 0.109 1.000 J 0.048 1.000 1.000 1.000 1.000 1.000 0.510 IO 1.000 1.000 1.000 1.000 1.000 1.000 1.000 L 0.689 1.000 1.000 1.000 1.000 1.000 1.000 M 0.363 1.000 1.000 1.000 1.000 1.000 1.000 NB 0.176 1.000 1.000 1.000 1.000 1.000 1.000 SS 0.109 1.000 1.000 1.000 1.000 1.000 0.968 SE 1.000 0.510 1.000 1.000 1.000 1.000 0.968

Littorina africana knysnaensis Multiple Comparisons p values (2-tailed); Littorina africana knysnaensis (Mobile Co Independent (grouping) variable: Sites Kruskal-Wallis test: H ( 7, N= 48) =39.25789 p =.0000 Depend.: DS J IO L M NB SS SE Littorina africana knysnaensis R:16.500 R:16.500 R:42.833 R:37.750 R:16.500 R:32.917 R:16.500 R:16.50 DS 1.000 0.031 0.240 1.000 1.000 1.000 1.000 J 1.000 0.031 0.240 1.000 1.000 1.000 1.000 IO 0.031 0.031 1.000 0.031 1.000 0.031 0.031 L 0.240 0.240 1.000 0.240 1.000 0.240 0.240 M 1.000 1.000 0.031 0.240 1.000 1.000 1.000 NB 1.000 1.000 1.000 1.000 1.000 1.000 1.000 SS 1.000 1.000 0.031 0.240 1.000 1.000 1.000 SE 1.000 1.000 0.031 0.240 1.000 1.000 1.000

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 119 Anchor Environmental Consultants CC

Patiriella exigua Multiple Comparisons p values (2-tailed); Patiriella exigua (Mobile Combined) Independent (grouping) variable: Sites Kruskal-Wallis test: H ( 7, N= 48) =36.47725 p =.0000 Depend.: DS J IO L M NB SS SE Patiriella exigua R:42.250 R:23.500 R:29.250 R:7.0000 R:19.000 R:11.000 R:42.083 R:21.917 DS 0.570 1.000 0.000 0.113 0.003 1.000 0.333 J 0.570 1.000 1.000 1.000 1.000 0.602 1.000 IO 1.000 1.000 0.165 1.000 0.671 1.000 1.000 L 0.000 1.000 0.165 1.000 1.000 0.000 1.000 M 0.113 1.000 1.000 1.000 1.000 0.120 1.000 NB 0.003 1.000 0.671 1.000 1.000 0.003 1.000 SS 1.000 0.602 1.000 0.000 0.120 0.003 0.353 SE 0.333 1.000 1.000 1.000 1.000 1.000 0.353 Crepidula porcellana Multiple Comparisons p values (2-tailed); Crepidula porcellana (Mobile Combined) Independent (grouping) variable: Sites Kruskal-Wallis test: H ( 7, N= 48) =30.71998 p =.0001 Depend.: DS J IO L M NB SS SE Crepidula porcellana R:44.417 R:34.333 R:22.083 R:23.750 R:11.917 R:12.583 R:31.750 R:15.167 DS 1.000 0.160 0.296 0.002 0.002 1.000 0.008 J 1.000 1.000 1.000 0.155 0.200 1.000 0.496 IO 0.160 1.000 1.000 1.000 1.000 1.000 1.000 L 0.296 1.000 1.000 1.000 1.000 1.000 1.000 M 0.002 0.155 1.000 1.000 1.000 0.396 1.000 NB 0.002 0.200 1.000 1.000 1.000 0.496 1.000 SS 1.000 1.000 1.000 1.000 0.396 0.496 1.000 SE 0.008 0.496 1.000 1.000 1.000 1.000 1.000

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 120 Anchor Environmental Consultants CC

APPENDIX III:

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 121

Table 1: Number of fish caught in seine net hauls in Saldanha Bay and Langebaan Lagoon, October 2005 Site number 1234657891011 Site name Bluewater Bluewater Bluewater Camp Camp Camp Small Boat Small Boat Small Boat Hoedtjies- Hoedtjies- Bay Bay Bay Site Site Site Harbour Harbour Harbour baai baai Replicate 12312312312 Date 17-Oct-05 17-Oct-05 17-Oct-05 17-Oct-05 17-Oct-05 17-Oct-05 17-Oct-05 17-Oct-05 17-Oct-05 17-Oct-05 17-Oct-05 Time 14:00 14:00 14:00 15:00 15:00 15:00 12:00 12:00 12:00 13:00 13:00 Area (m2) 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 Liza richardsonii harder 125 497 1011 138 17 2400 1 4 17 Psammogobius knysnaensis Knysna sand gobi Caffrogobius caffer Goby Caffrogobius nudiceps nude goby 102 745 Atherina breviceps silverside2313571398 18940 Rhabdosargus globiceps white stumpnose 3 17 16 12 Cheilidonichtyes capensis gurnard 10 3 11 10 12 1 1 9 Clinus latipennis False Bay Klipvis Diplodus sargus capensis Blacktail 1 1 9 27 7 8 7 1 65 Spondyliosoma emarginatum Steentjie 1 54 11 Lithognathus lithognathus White steenbras 12 20 5 Heteromyctus capensis Cape sole 84 Rhinobatos annulatus Sandshark, guitar fish 3 1 1 1 3 Clinus superciliosus super klipvis 1 1 1 12 3 Gilchristella aestuaria estuarine round herring 15 4 Rhabdosargus holubi Cape stumpnose 9 Myliobatos aquila eagle ray 1 2 Blennophis Klipvis sp. Cancelloxus longior Snake eel Pomatomus saltatrix elf Rhinobatos blockii bluntnose guitar fish Gonorhynchus gonhorynchus Beaked sand eel 1 Mustelus mustelus smoothhound Total 159 519 1045 265 98 2446 84 6 12 229 888

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Table 1 contd. Site number 12 13 14 15 16 17 18 19 20 21 22 23 24 Site name Hoedtjies- Schaapen Schaapen Schaapen Strand Strand Strand Lynch Lynch Lynch Seafarm Seafarm Seafarm baai Island Island Island looper looper looper Point Point Point dam dam dam Replicate 3213123123123 Date 17-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 Time 13:00 08:00 08:00 08:00 09:30 09:30 09:30 12:00 12:00 12:00 14:00 14:00 14:00 Area (m2) 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 Liza richardsonii 1093 573 135 242 299 331 17 298 8 90 66 108 Psammogobius knysnaensis 40 17 37 Caffrogobius caffer Caffrogobius nudiceps 84 Atherina breviceps 65 521 1941 Rhabdosargus globiceps 134 12 3 Cheilidonichtyes capensis 2 5111081928 2 Clinus latipennis 50 26 41 2 2 1 1 Diplodus sargus capensis 2 Spondyliosoma emarginatum 11 Lithognathus lithognathus 20 Heteromyctus capensis 522 24 2 2 Rhinobatos annulatus 13 1 2 Clinus superciliosus 2 Gilchristella aestuaria Rhabdosargus holubi Myliobatos aquila Blennophis 1 Cancelloxus longior 1 Pomatomus saltatrix 1 Rhinobatos blockii Gonorhynchus gonhorynchus Mustelus mustelus 1 Total 116 1198 629 230 255 324 363 21 307 12 242 81 116

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Table 1 contd. Site number 25 26 27 28 29 30 31 32 35 36 37 38 Site name Tsaars- Tsaars- Tsaars- Kraal- Kraal- Kraal- Church- Church- Church- Geel- Geel- Geel- bank bank bank baai baai baai haven haven haven bek bek bek Replicate 123123123123 Date 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 Time 10:00 10:00 10:00 12:00 12:00 12:00 13:00 13:00 13:00 14:00 14:00 14:00 All Area (m2) 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 sites Liza richardsonii 3 48 95 156 79 17 88 80 93 77 8206 Psammogobius knysnaensis 226 58 6 256 142 225 7 2 1016 Caffrogobius caffer 840461153 1 951 Caffrogobius nudiceps 11 942 Atherina breviceps 16 4 2 9 19 3 58 72 184 690 Rhabdosargus globiceps 1 198 Cheilidonichtyes capensis 1 143 Clinus latipennis 411 129 Diplodus sargus capensis 128 Spondyliosoma emarginatum 1 69 Lithognathus lithognathus 57 Heteromyctus capensis 1 32 Rhinobatos annulatus 25 Clinus superciliosus 4 24 Gilchristella aestuaria 19 Rhabdosargus holubi 9 Myliobatos aquila 3 Blennophis 1 2 Cancelloxus longior 1 Pomatomus saltatrix 1 Rhinobatos blockii 1 1 Gonorhynchus gonhorynchus 1 Mustelus mustelus 1 Total 7 50 1 1183 264 98 320 179 316 138 172 275 11798

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Table 2: Mass of fish caught in seine net hauls in Saldanha Bay and Langebaan Lagoon, October 2005 Site number 1234657891011 Site name Bluewater Bluewater Bluewater Camp Camp Camp Small Boat Small Boat Small Boat Hoedtjies- Hoedtjies- Bay Bay Bay Site Site Site Harbour Harbour Harbour baai baai Replicate 12312312312 Date 17-Oct-05 17-Oct-05 17-Oct-05 17-Oct-05 17-Oct-05 17-Oct-05 17-Oct-05 17-Oct-05 17-Oct-05 17-Oct-05 17-Oct-05 Time 14:00 14:00 14:00 15:00 15:00 15:00 12:00 12:00 12:00 13:00 13:00 Area (m2) 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 Rhinobatos annulatus Sandshark, guitar fish 8100 1700 3200 2200 8700 Liza richardsonii harder 212 1332 1438 207 20 1968 1 5 22 Myliobatos aquila eagle ray 4100 2200 Atherina breviceps silverside 5 3 6 76 109 1 7 148 140 Psammogobius knysnaensis Knysna sand gobi Mustelus mustelus smoothhound Caffrogobius nudiceps nude goby 42 413 Caffrogobius caffer Goby Diplodus sargus capensis Black Tail 0 1 10 38 10 9 12 1 104 Lithognathus lithognathus White steenbras 23 13 Rhabdosargus globiceps white stumpnose 6 31 25 32 Rhabdosargus holubi Cape stumpnose 16 74 Heteromyctus capensis Cape sole 12 4 Spondyliosoma emarginatum Steentjie 2 41 13 Cheilidonichtyes capensis gurnard52 4421 04 Clinus latipennis False Bay Klipvis Clinus superciliosus super klipvis 4 3 0 10 2 Gilchristella aestuaria estuarine round herring 21 5 Pomatomus saltatrix elf Cancelloxus longior Snake eel Gonorhynchus gonhorynchus Beaked sand eel 2 Blennophis Klipvis sp. Total 222.2 5446.0 9584.1 2053.4 198.6 4200.8 3288.9 5.6 19.5 2479.6 9398.9

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 125

Table 2 contd. Site number 12 13 14 15 16 17 18 19 20 21 22 23 24 Site name Hoedtjies- Schaapen Schaapen Schaapen Strand Strand Strand Lynch Lynch Lynch Seafarm Seafarm Seafarm baai Island Island Island looper looper looper Point Point Point dam dam dam Replicate 3213123123123 Date 17-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 18-Oct-05 Time 13:00 08:00 08:00 08:00 09:30 09:30 09:30 12:00 12:00 12:00 14:00 14:00 14:00 Area (m2) 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 Rhinobatos annulatus Liza richardsonii 293.7 258.2 343.2 1164.9 992.7 305.8 840.1 1068.7 1196.4 433.6 5167.8 411.7 Myliobatos aquila Atherina breviceps 27 47.8 88 486.4 0.1 3.7 40.2 28 14.1 75.1 42.3 Psammogobius knysnaensis 2.6 3.2 12 11.7 40.1 Mustelus mustelus 800 Caffrogobius nudiceps 24 7 Caffrogobius caffer 1.8 Diplodus sargus capensis 1.9 Lithognathus lithognathus 79.5 Rhabdosargus globiceps Rhabdosargus holubi Heteromyctus capensis 1.4 11.1 5.1 10.9 20.6 Spondyliosoma emarginatum 1.2 3 Cheilidonichtyes capensis 1.4 1.1 7.7 6.7 2.3 4.5 14.7 Clinus latipennis 12.3 11.6 18.6 0.3 2.1 Clinus superciliosus 3 Gilchristella aestuaria Pomatomus saltatrix 6 Cancelloxus longior 3.1 Gonorhynchus gonhorynchus Blennophis Total 136.8 341.5 350.6 839.8 1191.8 1034.8 380.0 884.1 1117.2 1231.7 1256.8 5242.9 454.0

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 126

Table 2 contd. Site number 25 26 27 28 29 30 31 32 35 36 37 38 Site name Tsaars- Tsaars- Tsaars- Kraal- Kraal- Kraal- Church- Church- Church- Geel- Geel- Geel- bank bank bank baai baai baai haven haven haven bek bek bek Replicate 123123123123 Date 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 19-Oct-05 Time 10:00 10:00 10:00 12:00 12:00 12:00 13:00 13:00 13:00 14:00 14:00 14:00 All Area (m2) 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 600 m2 sites Rhinobatos annulatus 39000 2700 7800 73400.0 Liza richardsonii 220.4 227.1 180.9 4 1367.2 246.5 445.4 179.4 27.7 142.8 20720.8 Myliobatos aquila 6300.0 Atherina breviceps 0.4 2.1 0.4 <0.1 13.7 70.7 6.1 1441.4 Psammogobius knysnaensis 184 57.1 7.6 281.7 224.8 216.1 1040.5 Mustelus mustelus 800.0 Caffrogobius nudiceps 486.4 Caffrogobius caffer 376.9 17.4 3.9 19.2 419.2 Diplodus sargus capensis 186.9 Lithognathus lithognathus 114.8 Rhabdosargus globiceps 10.1 0.1 <0.1 104.0 Rhabdosargus holubi 90.0 Heteromyctus capensis 7 16.1 0.3 88.5 Spondyliosoma emarginatum 0.6 60.9 Cheilidonichtyes capensis 0.4 0.3 60.0 Clinus latipennis 0.5110.21.1 48.7 Clinus superciliosus 4 27.1 Gilchristella aestuaria 25.5 Pomatomus saltatrix 6.0 Cancelloxus longior 3.1 Gonorhynchus gonhorynchus 1.6 Blennophis 0.2 0.2 0.4 Total 39228.2 2937.7 7998.1 5.0 1368.0 1.1 813.4 520.3 190.9 314.6 323.5 365.0 104625.8

State of the Bay: Saldanha Bay and Langebaan Lagoon (Technical Report) 127