South African Coast Research Articles

Mortalities of southern right whales (Eubalaena australis) and related anthropogenic factors in South African waters, 1999–2019

The southern right whale (Eubalaena australis; SRW) population in South Africa’s coastal waters has experienced marked changes since 2009, including altered feeding and migration behaviour, and decreased calving success. At the same time, anthropogenic activities in the area have increased. Based on this, an update on SRW mortalities and related anthropogenic factors is warranted. Building on the published information of Best et al. (2001a), data were collated on all SRW mortalities as well as non‐fatal ship‐strikes and entanglements along the South African coast between 1999 and 2019. A total of 97 SRW mortalities were recorded, including three that did not result in a stranding, of which the majority were classified as calves of the year. Most of these occurred on the Western Cape coast between the months of July to November, coinciding with the seasonal presence of the species in South African coastal waters. Eleven of these mortalities could be attributed to ship‐strikes whereas three mortalities related to entanglements. A total of 98 non‐fatal incidents, including 16 ship‐strikes and 82 entanglements with SRWs, were recorded in South Africa between 1999 and 2019. Ship‐strikes occurred mainly around the area of Cape Town harbour. Entanglements occurred mainly in rock‐lobster gear and bather‐protection nets in the Western Cape and KwaZulu‐Natal provinces respectively, although the latter did not occur between 2015–2019 attributable to the replacement of over 70% of the nets by drumlines, and the removal of the remaining nets during whale season. In general, the incidence of SRW mortalities and entanglements decreased post‐2007, coinciding with the decreased presence of SRWs along the South African coast. Available data show a relatively low rate of fatal entanglements and ship‐strikes, although this may be underestimated due to the opportunistic nature of the collated data. In view of the population growth rate and the increased anthropogenic activities in South African coastal waters, continued and improved monitoring (e.g. through a more systematic reporting system) of these incidents is crucial to ensure accurate knowledge‐based management decisions in the future. Possible mitigation measures aimed at reducing anthropogenic interactions are mooted.

U-Th dating, taphonomy, and taxonomy of shell middens at Klasies River main site indicate stable and systematic coastal exploitation by MIS 5c-d

The archaeological record, particularly of shellfish, from the Klasies River main site (KRM) is important in understanding the fluctuating nature of coastal occupational patterns and changing coastal ecologies. In this paper, we provide new uranium–thorium (U-Th) dates for one of the earlier phases of coastal exploitation at KRM, and the microstratigraphic analyses generate novel information about the taphonomy of shell-bearing deposits from the Later Stone Age (LSA) to the MSA I period that, in turn, provide a broader context for middening at the site. A wide range of syndepositional taphonomic processes related to human activities and post-depositional effects include burning, fragmentation and compaction, chemical alteration, and cementation. Despite such issues influencing recovery, shellfish data are informative and are presented from three layers of the Witness Baulk: Shell Midden One (SMONE), Black Occupational Soils (BOS), and Silty Black Soils (SBLS). These coarse shell midden deposits exhibit visible decalcification coupled with cementation with secondary carbonate formation in association with conditions of high moisture and soft sedimentation deformation of the underlying sediments of SBLS. This stratigraphy section is chronologically anchored for the first time using U-Th dating of speleothems associated with a hiatus after the deposition of BOS. The three ages, 110,060 ± 1,100, 109,800 ± 970, and 106,000 ± 2,100 years, place the BOS layer as the base of the SASL sub-member at over 110 ka, making the underlying middens from the LBS member even older. The zooarchaeological analyses of the three layers indicate coastal ecological changes from more sheltered conditions prior to the hiatus, with the exploitation of alikreukel and brown mussels predominating. Before 110 ka, in BOS and SBLS, more exposed coastal conditions occurred, and the diversity of exploited shellfish increased. SMONE and BOS are associated with MSA II/Mossel Bay lower lithic technology and SBLS with MSA I technology, indicating asynchronous coastal ecological and technological changes. The MIS 5c-d evidence for early coastal occupation at KRM provides details on the period during which coastal occupation became stable and systematic on the South African coast and puts the KRM amongst the handful of sites with shell-bearing deposits, occurring prior to 110 ka in South Africa.

Total mercury concentrations in sharks, skates and rays along the South African coast.

Global declines in elasmobranch populations resulting from several stressors raises conservation concern. Additionally, apex predators bioaccumulate high concentrations of total mercury (THg), due to biomagnification. Although South Africa is considered one of the top ten contributors of Hg emissions globally, information on Hg concentrations in elasmobranchs is limited. The aim of this study was to evaluate the THg concentrations in 22 species of elasmobranchs along the South African coastline. Concentrations ranged between 0.22 and 5.8mg/kg in Haploblepharus pictus (dark shysharks) and Rostroraja alba (white skates) on the south coast, respectively. Along the east coast it ranged between 0.21 and 17.8mg/kg in Mobula kuhlii (shortfin devil rays) and Sphyrna lewini (scalloped hammerheads), respectively. Mercury concentrations on the east coast were in the same range or higher compared to the same species sampled between 2005-10 from the same region, with generally higher concentrations compared to the same species sampled globally.

High element concentrations are not always equivalent to a stressful environment: differential responses of parasite taxa to natural and anthropogenic stressors.

Environmental parasitology developed as a discipline that addresses the impact of anthropogenic activities related to the occurrence and abundance of parasites, subsequently relating deviations of natural parasite distribution to environmental impact. Metals, often considered pollutants, might occur under natural conditions, where concentrations might be high due to a natural geogenic release rather than anthropogenic activities. We specifically investigated whether naturally occurring high levels of elements might negatively affect the parasite community of the intertidal klipfish, Clinus superciliosus, at different localities along the South African coast. Parasite communities and element concentrations of 55 klipfish (in muscle and liver) were examined. Our results show that parasites can disentangle anthropogenic input of elements from naturally occurring high element concentrations. Acanthocephala, Cestoda and Isopoda were associated with higher concentrations of most elements. Environmental parasitology, applicable to a wide range of systems, is scarcely used on marine ecosystems and can contribute to environmental monitoring programs.

Rostrum abnormalities in the endangered Indian Ocean humpback dolphin (Sousa plumbea) in South Africa.

Morphological abnormalities in wild animals can be indicators of the underlying health of a population and may be determined through routine photographic surveys. Here, we assess unusual rostrum conditions in Indian Ocean humpback dolphins (Sousa plumbea) inhabiting South African coastal waters to understand the rate of prevalence of abnormal rostrums and formulate hypotheses on potential causes. Photographic data were collated from systematic boat surveys and opportunistic sightings, obtained between April 1998 and March 2021 in various regions along the South African coast. Overall, 31 unique individuals were found with abnormal rostrum conditions, varying from slight misalignments to severe wounds and/or aberrant morphologies. In most cases, injuries were likely caused by natural events during the animal's life history such as interactions with sharks and/or reef-associated hunting strategies. Mark-recapture data indicated that individuals had survived with these injuries for up to 10 years. This study reports the highest incidence of rostrum abnormalities in the species. As numbers reflect only those that have survived their injuries, they are considered a minimum estimate. A better understanding of the cause(s) of these injuries is important given the endangered status of this species.

Morphological and molecular characterisation of Alella igillimpethu n. sp. (Copepoda: Siphonostomatoida: Lernaeopodidae) parasitising the southern African endemic intertidal klipfish, Clinus superciliosus.

Lernaeopodidae Milne Edwards, 1840, is an ecological and economically important fish parasite family of copepods (Crustacea: Copepoda), consisting of 48 genera with 334 valid species. To date, approximately 17genera have been documented from both teleost and elasmobranch hosts from South African marine waters. As part of parasitological surveys targeting parasites of the endemic intertidal klipfish, Clinus superciliosus (Linnaeus) (Clinidae) along the South African coast, a species of Lernaeopodidae was discovered on the gills of this host. Alella igillimpethu n. sp. is described from Clinussuperciliosus from Langebaan marina on the west coast of South Africa, with a prevalence of 42.1% and mean intensity of 2.9 (ranging from 1-13). Morphological identification was done using light and scanning electron microscopy and the species description was generated with the aid of DEscription Language for TAxonomy (DELTA) software. The mitochondrial cytochrome c oxidase subunit 1 (COI) region, as well as partial 18S and 28S ribosomal RNA genes confirmed the classification within the family Lernaeopodidae. This is the first report of Lernaeopodidae from C.superciliosus, or in fact any member of Clinidae, as well as the first molecular characterisation of any marine lernaeopodid infecting teleost fish from South Africa. This study contributes valuable genetic and morphological data for this copepod family, as well as new host and distribution records.

Metazoan parasite diversity of the endemic South African intertidal klipfish, Clinus superciliosus: Factors influencing parasite community composition.

The current trend in marine parasitology research, particularly in South Africa, is to focus on a specific parasite taxon and not on the total parasite community of a specific fish host. However, these records do not always reveal the ecological role of parasites in ecosystems. Thus, the present study aimed to determine which factors influence the parasite community composition of the endemic southern African intertidal klipfish, Clinus superciliosus (n=75). Metazoan parasites were sampled from four localities (two commercial harbours - west coast; and two relatively pristine localities - southeast coast) along the South African coast. A total of 75 klipfish were examined for parasites, where 30 distinct taxa, representing seven taxonomic groups were found: Acanthocephala (4 taxa), Cestoda (2 taxa), Crustacea (5 taxa), Digenea (11 taxa), Hirudinea (2 taxa), Monogenea (1 taxon) and Nematoda (5 taxa). Results indicated that the main driver of diversity was locality, with the highest diversity on the southeast coast, most likely due to higher water temperatures and upwelling compared to the west coast. The parasite community composition of the klipfish was significantly influenced by water temperature and parasite life cycle. These results emphasise the importance of parasitological surveys including all parasite taxa in hosts from multiple localities and seasons, to better comprehend their ecological role.

A morphological classification of coastal forelands, with examples from South Africa

Alongshore variations in the cross-shore width, and therefore volume, of sandy beaches are important because these reflect spatial variability in the operation of wave- and wind-driven processes taking place both at the shoreface and in the supratidal zone. One key geomorphic signature of variations in cross-shore beach width is the development of coastal forelands. Different foreland types have been described in the literature from very specific geomorphic contexts, but hitherto there has been no overarching classification scheme that genetically links these different foreland types, or considers them in the wider context of sandy beach dynamics. In order to achieve this aim, this study maps and inventorises 87 forelands from the South African coast (~2600 km long), and classifies these into four morphological types: salients, tombolos, cuspate forelands, and ramp forelands. These foreland types have different morphological properties, reflecting the interplay of coastal erosional and depositional processes and any antecedent conditions; and a varying balance of morphodynamic controls on their development and behaviour. These include variations in wave (and to a lesser extent wind) energy, sediment supply, and the presence of bedrock outcrops of different sizes, shapes and positions along the shoreline. Analysis of foreland morphology and dynamic behaviour, based on examples from South Africa, enables a better understanding of coastal forelands globally as integrated sediment systems and responsive to the range of forcings driving coastal change.

Seismic Surveys off the South African Coastline

Abstract In two recent South African cases, the applicants sought interim interdicts preventing the respondent companies – Shell and Searcher – from continuing with, or alternatively commencing, their seismic surveys along the eastern and the western/southwestern coasts of South Africa respectively. In both matters, rights in relation to searching for mineral or petroleum resources had been granted in terms of the Mineral and Petroleum Resources Development Act 28 of 2002. The High Courts paid special attention to the inadequate public consultation processes that had been followed and highlighted the duty of Shell and Searcher to meaningfully consult with the affected communities and individuals. In both cases, the Courts found that the requirements for an interim interdict had been met, and Shell and Searcher were accordingly prohibited from continuing with or commencing their seismic surveys of the respective portions of the South African coast, pending the outcomes of the main applications.

Estimating the economic income and social contributions derived from the South African west coast rock lobster fishery

The west coast rock lobster Jasus lalandii fishery is South Africa’s third-most-valuable fishery, although the stock is currently estimated at <2% of its pristine biomass. Recent ecologically necessary reductions in the total allowable catch (TAC) had negative economic impacts on stakeholders; however, these have not been quantified as current research into the socio-economic aspects of this fishery is limited. This study explored trends in the net seasonal income and employment opportunities of the fishery in the seasons 2016/17–2018/19 for its different sectors and representative individuals, by analysing records from the government authority and data collected from stakeholders in this fishery through interviews (n = 30) and surveys (n = 19). The results indicate that though the fishery was profitable over the three seasons, with the estimated contribution to gross national income ranging from R453 185 000 (US$33 302 714) in 2018/19 to R564 721 000 (US$41 499 039) in 2017/18, the decreasing quotas had a disproportionate negative effect on some of the representative individuals examined within the different sectors. These worrying economic trends for the different stakeholders indicate that, for effective resource recovery and equitable distribution of fishing opportunities, the socio-economic context of the fishery must be studied more extensively and must be included more directly in management decisions.

An indicator-based approach for cross-realm coastal biodiversity assessments

Ecosystem status assessments are generally separated into realm-specific analyses (terrestrial, freshwater, estuarine or marine), but without integrating these into a coherent assessment of coastal biodiversity across the land–sea interface. Trends in assessment indicators in coastal versus non-coastal areas have also rarely been considered. In this study we aimed to compile the first cross-realm national biodiversity assessment for the South African coast using three key indicators. The ecological condition, ecosystem threat status, and ecosystem protection level of coastal ecosystem types (n = 186) were determined and compared with those of non-coastal ecosystem types (n = 444). Nearly half (46.9%) of the South African coastal habitat has been degraded compared with 20% of non-coastal areas. Proportionately, there are three-times (60%) as many threatened coastal ecosystem types (or 55% by area) as there are threatened non-coastal ecosystem types (19%, 6% by area). Despite the impacted state of coastal biodiversity, protection levels are generally higher in the coastal zone (87% of ecosystem types have some protection) compared with non-coastal areas (75%), although fewer coastal ecosystem types have met their biodiversity targets (24%, vs 28% for non-coastal ecosystem types). These results illustrate the importance of using a cross-realm approach for status assessments, management and conservation of coastal biodiversity. The assessment methods described are flexible and widely applicable to other regions.

Underwater Chatter for the Win: A First Assessment of Underwater Soundscapes in Two Bays along the Eastern Cape Coast of South Africa

In 2014, the South African government launched ‘Operation Phakisa’ under which port developments play a significant role in supporting ocean economic growth. These developments will likely increase vessel traffic to and from South African ports, making it imperative to monitor for changes in underwater sound budgets with potential negative effects on marine life. However, no soundscape studies have been conducted around South Africa, resulting in an absence of baseline measurements. This study provides a first description of the underwater soundscape in St. Francis Bay and Algoa Bay, Eastern Cape. Soundscape measurements identified major soundscape contributors, temporal patterns in broadband sound levels, and underlying environmental drivers. Applicability of modelled vessel noise and wind noise maps to predict large-scale spatial variation in sound budgets was assessed. Our study shows that sounds from biological sources and wind dominated at all recording sites, with fish choruses driving temporal patterns as a function of time of year and position of the sun. Sound from vessels was present at all sites but most notable in long-term spectral levels measured in Algoa Bay. Sound propagation models predicted a further increase in the contribution of vessel noise towards shipping lanes and east Algoa Bay. Our study provides a building block to monitor for shifts in sound budgets and temporal patterns in these two bays under a developing ocean economy. Furthermore, our study raises concerns that vessel noise is likely a significant contributor in shallow waters elsewhere along the South African coast where vessel density is known to be higher (i.e., Durban and Cape Town).

Revealing different migration strategies in a Baltic Common Tern (Sterna hirundo) population with light-level geolocators

The Common Tern (Sterna hirundo) is one of Germany’s farthest migrating bird species. Ringing studies have shown the use of the East Atlantic flyway, and according to their main wintering areas at the western and southern African coasts, German and European Common Tern populations have been divided into two allohiemic groups. However, first ring recoveries of German Common Terns in Israel indicated that some of the birds breeding in eastern Germany cross central Europe and migrate along the eastern African coast. To investigate the migratory behavior of Common Terns from East Germany, we fitted 40 Common Terns breeding in a colony at the German Baltic coast with light-level geolocators. Twenty-four loggers with analyzable datasets could be retrieved, revealing two different migratory strategies within one population. Seventeen individuals (70.83%) used the eastern Atlantic flyway and spent the winter at the western African coast, the Gulf of Guinea and the southern African coast, while the other individuals (n = 7; 29.17%) crossed central Europe, migrated along the eastern African coast and overwintered in the Mozambique Channel and South African coast. We, therefore, suggest to add a third allohiemic group to complement the picture of European Common Tern migration. Moreover, our results provide new knowledge and open new questions, which can be used for future studies regarding the evolution of different migratory strategies and its consequences in relation to climate change.

Locally developed models improve the accuracy of remotely assessed metrics as a rapid tool to classify sandy beach morphodynamics.

Classification of beaches into morphodynamic states is a common approach in sandy beach studies, due to the influence of natural variables in ecological patterns and processes. The use of remote sensing for identifying beach type and monitoring changes has been commonly applied through multiple methods, which often involve expensive equipment and software processing of images. A previous study on the South African Coast developed a method to classify beaches using conditional tree inferences, based on beach morphological features estimated from public available satellite images, without the need for remote sensing processing, which allowed for a large-scale characterization. However, since the validation of this method has not been tested in other regions, its potential uses as a trans-scalar tool or dependence from local calibrations has not been evaluated. Here, we tested the validity of this method using a 200-km stretch of the Brazilian coast, encompassing a wide gradient of morphodynamic conditions. We also compared this locally derived model with the results that would be generated using the cut-off values established in the previous study. To this end, 87 beach sites were remotely assessed using an accessible software (i.e., Google Earth) and sampled for an in-situ environmental characterization and beach type classification. These sites were used to derive the predictive model of beach morphodynamics from the remotely assessed metrics, using conditional inference trees. An additional 77 beach sites, with a previously known morphodynamic type, were also remotely evaluated to test the model accuracy. Intertidal width and exposure degree were the only variables selected in the model to classify beach type, with an accuracy higher than 90% through different metrics of model validation. The only limitation was the inability in separating beach types in the reflective end of the morphodynamic continuum. Our results corroborated the usefulness of this method, highlighting the importance of a locally developed model, which substantially increased the accuracy. Although the use of more sophisticated remote sensing approaches should be preferred to assess coastal dynamics or detailed morphodynamic features (e.g., nearshore bars), the method used here provides an accessible and accurate approach to classify beach into major states at large spatial scales. As beach type can be used as a surrogate for biodiversity, environmental sensitivity and touristic preferences, the method may aid management in the identification of priority areas for conservation.

Deniz İpek Yolu: Umman’ın Dış Politikası İçin Sonuçları

This study seeks to analyze the implications of Oman’s participation in the Maritime Silk Road, which is the maritime component of the Belt and Road Initiative, announced in 2013 by the President of the People’s Republic of China, Xi Jinping. Sultan Qaboos has transformed Oman from an isolated and backward country to an active political mediator in the region. Oman’s neutral stance and diplomatic connections with every political actor in the region differentiate Oman from the rest of the Gulf countries. Geographically, Oman is situated in the intersection of the Persian Gulf, the Arabian Sea and the Indian Ocean. Historically, Oman ruled South Asian and East African coasts, extending its influence. The geographical position and historical legacy make Oman as a key country for the Maritime Silk Road. Thus, participation of Oman in the Belt and Road Initiative is invaluable in the eyes of the Chinese policymakers. Omani policymakers, who want to diversify Oman’s economy, welcome Chinese investments. However, increasing Chinese involvement in Oman’s economy might harm Oman’s sovereignty because of Chinese practice of using debts as exerting pressure on the lending states’ sovereignty. Moreover, the intensified competition between the USA and China in the Indian Ocean could compromise Oman’s neutral stance. Yet, Sultan Qaboos’ legacy is followed by Omani policymakers. While benefiting Chinese economic investments, Oman performs balancing acts against China.

Projected climate change impacts on the ecosystems of the Agulhas Bank, South Africa

Marine ecosystems are expected to be increasingly affected by climate change, impacting their physical and biogeochemical environment. Changes in primary production, temperatures and hence species distribution, may lead to critical consequences for fishery exploitation. Therefore, future projections are essential to develop sustainable strategies and climate change adaptation plans for fisheries, and fishery-dependent societies. In this study, we focus on the Agulhas Bank, a broad extension of the continental shelf of the South African coast, along which flows the western boundary Agulhas Current. The Agulhas Bank is known for being biologically productive and is an important nursery ground for many commercially exploited fish species, including the chokka squid fishery, a vital source of income for many people in the Eastern Cape Province. Squid catches manifest strong interannual fluctuations, at times causing fishery crashes. Additional impacts due to climate change will have significant socio-economic consequences for this all-important fishery. To investigate future variations of the physical and biogeochemical environment on the Agulhas Bank, we used the global ocean model NEMO-MEDUSA, forced by the high emissions scenario RCP8.5. Our simulations show a significant increase in sea surface temperature and bottom temperature, but limited changes in primary production. Projections highlight an increase in current velocity on the Agulhas Bank throughout the course of this century, induced by an onshore shift of the Agulhas current. This current shift may pose a threat to squid recruitment success as a large fraction of squid paralarvae may be removed from their shelf feeding grounds and lost to the greater ocean via the Agulhas current. The results further show that planktonic food for the paralarvae is less likely to become the main limiting factor in the future, while increasing temperatures may affect growth rates and spawning success.

Comparative phylogeography in a marine biodiversity hotspot provides novel insights into evolutionary processes across the Atlantic‐Indian Ocean transition

AbstractAimIntraspecific genetic variation is a key component of biodiversity, with higher diversity indicating greater resilience and population substructuring suggesting unique evolutionary histories. Comparative approaches, in which intraspecific genetic variation is assessed across multiple species, are powerful tools to identify evolutionary hotspots, but are still rarely applied at spatial scales relevant to conservation planning. Here, we use comparative phylogeography to understand patterns and potential drivers of genetic variation within a biodiversity and ocean warming hotspot.LocationThe South African coastline, Indian/Atlantic Oceans.MethodsA literature search was conducted to obtain mitochondrial DNA cytochrome oxidasecsubunit I and cytochromebsequence data for 17 marine fish and invertebrate species. From these data, we compared averages of haplotype and nucleotide diversity, and within‐region ΦSTbetween four biogeographic provinces in the region. Mixed linear models tested whether environmental variability, habitat preference, or geographic location significantly influence genetic variation.ResultsAverage diversity values differed between haplotype and nucleotide diversity, but both broadly displayed highest diversity levels within the South‐West bioregion, which is also a region of high levels of within‐region ΦST. Range in sea surface temperatures (SSTs) was the only significant fixed‐effect term in the haplotype diversity mixed linear models. Mean SST, stability in SSTs since the Mid‐Holocene and position within the species' geographic distribution all had no significant effect on genetic variation.Main conclusionsAlong this coastline characterized by high environmental heterogeneity, we find that variation in temperature is a prominent source of intraspecific variation. Genetic diversity differs between bioregions, but does not display higher levels within the core of each species’ range when assessed across multiple species. With elevated levels of genetic diversity, the South‐West region of the South African coast is highlighted as a conservation priority area, representing both high genetic diversity and differentiation across taxa.

Contrasting phylogeographic patterns of intertidal mites (Acari, Oribatida) along the South African shoreline

The South African coast is known to harbor four different species of intertidal oribatid mites and their distribution strongly correlates with marine ecoregions. Relatively little is known about the dispersal of these organisms and how populations of different locations are connected. To test dispersal abilities and connectivity of these South African species, we performed a morphometric and molecular genetic study. COI gene sequences of two of the widely distributed South African intertidal oribatid mite species revealed clearly contrasting patterns. Halozetes capensis, which occurs in the Agulhas Ecoregion, shows distinct genetic structuring, whereas Fortuynia elamellata micromorpha, which is distributed in the Natal Ecoregion, exhibits gene flow between all populations. The paleoenvironmental history and specific ocean current pattern are suggested to be responsible for these patterns. During the last glacial maximum, the colder climate and the weakening of the Agulhas Current possibly resulted in a bottleneck in the warm-adapted F. e. micromorpha populations, but the subsequent global warming allowed the populations to expand again. The cold-adapted H. capensis populations, on the other hand, experienced no dramatic changes during this period and thus could persist in the Agulhas Ecoregion. Considering transport on ocean currents, the Agulhas Current could be further responsible for the connectivity between the Fortuynia populations. But the deflection of this current in the Agulhas Ecoregion could support the isolation of Halozetes populations. The concomitant morphometric study demonstrated morphological homogeneity among populations of Fortuynia and thus confirms strong connectivity. The Halozetes populations, on the other hand, form two different morphological groups not reflecting geography.

Winds of change: Climate variability in a mild glacial on the east coast of South Africa, inferred from submerged aeolianites and the archaeological record of Sibudu

Here we present an optically stimulated luminescence (OSL) age estimate of 64 ± 5 ka for an offshore aeolianite and draw regional correlations (within 45 km) between the Pleistocene geological sequence offshore of the Durban Bluff, and contemporary palaeoenvironmental records from Sibudu on the South African sub-tropical east coast. Considering this age estimate within the context of high-resolution hydroacoustic data and, in particular, sub-bottom profiles, we tentatively suggest phases of dune building during marine isotope stage (MIS) 4 along the east coast of South Africa. The age and depositional characteristics of the composite Bluff-Blood Reef aeolianites suggest that dune-building events were linked to sea-level stillstands during both highstands (with deposits now preserved above water from MIS 7 and 5e) and lowstands (preserved below water, specifically, MIS 4). Aeolianite remnants of late MIS 4 age show that the wind regime during this mild glacial was dominated by winds typical of modern-day temperate latitudes; prevailing directions preserved in foresets pointing towards northerlies and southeasterlies. This is in contrast to the present-day prevailing northeasterlies and southwesterlies in the study area. We investigate the role of a narrow shelf in the characteristics of the sedimentary depositional system of the Durban Bluff and the role of southeasterlies during MIS 4 in delivering sediment to the contemporary coast. We demonstrate the value in correlating offshore and onshore Quaternary sequences, and the role that submerged deposits can play in unravelling nuances of glacial conditions on ice-free continental shelves. Broadly, the correlations that we draw between the shelf aeolianites and the archaeological record of Sibudu, supports evidence of climatic and environmental variability during MIS 4 in this area.

How developed is the South African coast? Baseline extent of South Africa's coastal and estuarine infrastructure

Coastal ecosystems are increasingly being transformed from natural to artificial owing to increasing population growth, development pressures and impacts from climate change. With the threat from sea-level rise the increase in armouring of coastlines and other coastal defence structures is a particular concern. This study used Google Earth to define and map the extent of artificial structures along the coastline and within estuaries of South Africa. Infrastructure along the coastline was mostly concentrated around major cities with 85.71 km of armouring mapped along the entire coast and 51.74 km mapped within estuaries. Jetties were the dominant infrastructure type found within estuaries and armouring was the most dominant type along the coastline. Although large sections of the coast were found to be underdeveloped, hotspots around cities show that much of these areas are affected by infrastructure. In these areas in particular, haphazard and ad hoc development can have cumulative environmental impacts. As no extensive record of structures along the coastline of South Africa has been compiled, this study provides the first baseline inventory of the extent of infrastructure within the coastal environment of South Africa. This baseline can therefore be used to record and measure changes in infrastructure development of the coastal environment and guide future coastal development practises.