Fannie Shabangu
University of Pretoria, Zoology and Entomology, Graduate Student
Research Interests: Computer Science, Medicine, Standardization, Whale, Underwater, and 6 moreGC, Za, Marine Mammal, Detector, Baleen, and Das
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ABSTRACT South Africa’s marine ecosystem has been subjected to unfavourable anthropogenic effects brought about by mismanagement and over-exploitation. In order to manage exploited marine resources properly, knowledge is needed about... more
ABSTRACT South Africa’s marine ecosystem has been subjected to unfavourable anthropogenic effects brought about by mismanagement and over-exploitation. In order to manage exploited marine resources properly, knowledge is needed about their size and distribution, and how their exploitation can potentially impact on the remainder of the ecosystem. Hydro-acoustic methods can facilitate the study of aquatic animals and their environment without causing any significant environmental damage or change. The authors describe how hydro-acoustic technology can be used in fisheries research, oceanography and geomorphology in South African waters. They also highlight opportunities for how this technology can be further developed and identify needs and opportunities for further research in the South African context.
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Seasonal acoustic occurrences and diel singing patterns of humpback whale (Megaptera novaeangliae) songs and Antarctic minke (Balaenoptera bonaerensis) whale are described using acoustic recordings from the west coast of South Africa and... more
Seasonal acoustic occurrences and diel singing patterns of humpback whale (Megaptera novaeangliae) songs and Antarctic minke (Balaenoptera bonaerensis) whale are described using acoustic recordings from the west coast of South Africa and Maud Rise, Antarctica. Acoustic data were recorded from early 2014 to early 2017. Acoustic occurrences (i.e., presence) of humpback and minke whale sounds were identified through visual scrutiny of spectrograms of recorded data. Environmental conditions associated with humpback whale song occurrences were ranked according to their model-predicted relative importance. In South Africa, humpback whale songs were detected from June to December but peaked in September. In Antarctica, humpback whale songs were detected from March to May (singing peaked in April). Minke whale sounds were only recorded in 2014, between June and September in Antarctica and between September and November in South Africa. Humpback whales were more vocally active at night in all recording sites whereas minke whales were more vocally active during the day. This is the first study to describe the seasonal acoustic occurrences of humpback and minke whales off the west coast of South Africa. Such knowledge could be essential for the conservation and management of these species in both South Africa and Antarctica.
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Research Interests: Mechanical Engineering, Environmental Science, Oceanography, Endangered Species, Medicine, and 15 moreMultidisciplinary, Chlorophyll, Animals, PLoS one, Ecosystem, Minke whale, Interdisciplinary Engineering, Conservation of Natural Resources, Environment, Electrical And Electronic Engineering, Area Under Curve, Monte Carlo Method, Latitude, Oceans and Seas, and Longitude
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Seasonal occurrence, diel‐vocalizing patterns, and call‐types of Antarctic minke whales are described using bio‐acoustic recordings from the west coast of South Africa and the Maud Rise, Antarctica. In Antarctica, minke whale bioduck... more
Seasonal occurrence, diel‐vocalizing patterns, and call‐types of Antarctic minke whales are described using bio‐acoustic recordings from the west coast of South Africa and the Maud Rise, Antarctica. In Antarctica, minke whale bioduck calls were detected in seven of nine months of hydrophone deployment (peaking in May and September) while downsweeps were only detected in June. Bioduck calls were sporadically detected in South African waters with peak calling in September/October, and no bioducks were detected from March through August. Bioduck call occurrence was high during daytime in Antarctica but there was no diel‐vocalizing pattern in South African waters. We split bioduck B call‐type into two subtypes: B1 with 13 ± 1 pulses (Dominello & Širović, 2016) and B2 with 9 ± 1 pulses (this study). Bioduck B2 was detected both in Antarctic and South African waters, with harmonics up to 2 kHz. Similar bioduck call‐types were detected in Antarctic and South African waters, with bioduck A2 being the most common. Month of the year was the most important predictor of bioduck occurrence both in Antarctic and South African waters. This is the first study to describe the seasonal occurrence, diel‐vocalizing behavior and call‐types of Antarctic minke whales off the South African west coast and eastern Weddell Sea.
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Anthropogenic underwater noise has been shown to negatively affect marine organisms globally; yet little to no noise research has been conducted in most African waters including South Africa's. This study aimed to quantitatively... more
Anthropogenic underwater noise has been shown to negatively affect marine organisms globally; yet little to no noise research has been conducted in most African waters including South Africa's. This study aimed to quantitatively describe sources of underwater noise and effects of underwater noise on the acoustic detectability of Antarctic blue, fin, minke, humpback, and sperm whales off South Africa's west coast. Noise from vessel traffic (<35 km to the location of recorders) dominated the soundscape below 500 Hz while wind-generated noise increased with wind speed above 5 m s-1 and dominated the soundscape above 500 Hz. Acoustic detectability of humpback, minke and sperm whales decreased with increasing ambient noise levels whereas blue and fin whale acoustic detectability increased with the ambient noise levels. We provide baseline information on underwater noise sources and the effects of underwater noise on whale acoustic detectability off the west coast of South Africa.
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Abstract The world's oceans are subject to the multiple impacts of human activity and to the consequent threats to the health of many and varied ocean ecosystems. Oceans around South Africa are no exception and, with the need for... more
Abstract The world's oceans are subject to the multiple impacts of human activity and to the consequent threats to the health of many and varied ocean ecosystems. Oceans around South Africa are no exception and, with the need for economic growth in the country, anthropogenic stressors on ocean resources are rapidly increasing. In this study, we investigated 14 different anthropogenic stressors that impacted ocean health between 2003 and 2013, and their cumulative anthropogenic effects on cetaceans in the South African Exclusive Economic Zone (EEZ) and South African Marine Protected Areas (MPA), Important Marine Mammal Areas (IMMA), Ecologically or Biologically Significant Areas (EBSA) and ecoregions. We determined cetacean species richness in these five area categories using ensemble models, and identified anthropogenic impacts from relevant literature. We calculated and compared the average species richness, the average trend for each anthropogenic stressor and average cumulative impact between 2003 and 2013 in the five areas. Results highlight that climate related stressors (such as sea surface temperature and ocean acidification), together with shipping stressors, are increasing more rapidly than other stressors across the EEZ. Cetacean species richness was highest along the west coast shelf and shelf edge where sea level rise, ocean acidification, shipping, and commercial pelagic fishing with low by-catch were most pronounced. The results of this study will inform marine spatial planners and policy makers in determining priority areas for cetacean conservation and in identifying anthropogenic stressors that need to be addressed to mitigate cumulative anthropogenic impacts on cetaceans.
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Bioacoustics has emerged as a useful method of data collection and analysis for diverse animals in a wide range of environments and has helped to describe, monitor, and conserve some of Africa's species biodiversity. However, little... more
Bioacoustics has emerged as a useful method of data collection and analysis for diverse animals in a wide range of environments and has helped to describe, monitor, and conserve some of Africa's species biodiversity. However, little is known about how much it contributes to the continent's research corpus. We report results from a systematic review of bioacoustics applications in Africa that summarises the current state of the field and identifies research opportunities. Using keyword searches of bibliographic databases, scanning reference lists, and placing appeals to the bioacoustics community in Africa we identified 727 publications between 1953 and mid-2020. We documented variables ranging from publication type and author affiliation, geographic location, biome and habitat, biological groups, and research type. Most (69%) studies were focused on animal behaviour, with terrestrial species (88.6%), particularly mammals, substantially outweighing research on freshwater (4.8%) and marine (6.6%) habitats. The majority (74.3%) of authors who have contributed to this body of knowledge were non-African affiliates. Our review suggests that bioacoustics research in Africa has considerable room to expand institutionally, taxonomically, and thematically. We highlight the need and potential for more locally driven research and provide a roadmap for future bioacoustics applications across the continent.
Research Interests: Zoology and Bioacoustics
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Research Interests: Zoology and Bioacoustics
Knowledge of cetacean occurrence and behaviour in southern African waters is limited, and passive acoustic monitoring has the potential to address this gap efficiently. Seasonal acoustic occurrence and diel-vocalizing patterns of sperm... more
Knowledge of cetacean occurrence and behaviour in southern African waters is limited, and passive acoustic monitoring has the potential to address this gap efficiently. Seasonal acoustic occurrence and diel-vocalizing patterns of sperm whales in relation to environmental conditions are described here using passive acoustic monitoring data collected off the west coast of South Africa. Four autonomous acoustic recorders (AARs) were deployed on 3 oceanographic moorings from July 2014 to January 2017. Sperm whale clicks were detected year round in most recording sites, with peaks in acoustic occurrence in summer and late winter through spring. Diel-vocalizing patterns were detected in winter, spring and summer. Higher percentages of sperm whale clicks were recorded by AARs deployed at 1100 m water depth compared to those concurrently deployed at 850 and 4500 m, likely inferring that the whales exhibited some preference to water depths around 1100 m. Acoustic propagation modelling sugges...
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In southern African waters, information about species distribution and habitat preferences of many cetacean species is limited, despite the recent economic growth that may affect them. We determined the relative importance of eight... more
In southern African waters, information about species distribution and habitat preferences of many cetacean species is limited, despite the recent economic growth that may affect them. We determined the relative importance of eight environmental variables (bathymetry, distance to shore, slope, chlorophyll-a, salinity, eastwards sea water velocity, northwards sea water velocity and sea surface temperature) as drivers of seasonal habitat preferences of Bryde’s whales (Balaenoptera brydei), humpback whales (Megaptera novaeangliae), southern right whales (Eubalaena australis) and sperm whales (Physeter macrocephalus). Using presence only data from multiple sources, we constructed predictive species distribution models (SDMs) consisting of ensembles of seven algorithms for these species during both summer and winter. Predicted distribution for all cetaceans was high in southern Africa and, in particular, within the South African Exclusive Economic Zone (EEZ). Predictive models indicated ...
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A decrease in the frequency of two southeast Pacific blue whale song types was examined over decades, using acoustic data from several different sources in the eastern Pacific Ocean ranging between the Equator and Chilean Patagonia. The... more
A decrease in the frequency of two southeast Pacific blue whale song types was examined over decades, using acoustic data from several different sources in the eastern Pacific Ocean ranging between the Equator and Chilean Patagonia. The pulse rate of the song units as well as their peak frequency were measured using two different methods (summed auto-correlation and Fourier transform). The sources of error associated with each measurement were assessed. There was a linear decline in both parameters for the more common song type (southeast Pacific song type n.2) between 1997 to 2017. An abbreviated analysis, also showed a frequency decline in the scarcer southeast Pacific song type n.1 between 1970 to 2014, revealing that both song types are declining at similar rates. We discussed the use of measuring both pulse rate and peak frequency to examine the frequency decline. Finally, a comparison of the rates of frequency decline with other song types reported in the literature and a disc...
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ABSTRACT Marine mammals, and in particular Antarctic blue whales, represent an important predator component of marine ecosystems. These mammals are considered to be critically endangered due to unsustainable whaling practices in the... more
ABSTRACT Marine mammals, and in particular Antarctic blue whales, represent an important predator component of marine ecosystems. These mammals are considered to be critically endangered due to unsustainable whaling practices in the previous century. Currently, it is also difficult to monitor the species’ population recovery through the use of sighting surveys. Passive acoustic monitoring (PAM) can be used to research Antarctic blue whales because they are quite vocal and can be detected over long distances through the use of this technology. PAM also has considerable application potential to other baleen species that reside in South African waters, including fin whales (Balaenoptera physalus). It is, however, still an emerging methodology in South Africa and a number of challenges need to be addressed before it reaches the same level of maturity as visual surveys in South Africa and around the world.
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