Stephen Kirkman

Stephen Kirkman
Oceans and Coasts · Department of Environmental Affairs

PhD Zoology

About

138
Publications
51,273
Reads
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3,270
Citations
Citations since 2016
58 Research Items
1729 Citations
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300

Publications

Publications (138)
Article
Full-text available
While marine top predators can play a critical role in ecosystem structure and dynamics through their effects on prey populations, how the predators function in this role is often not well understood. In the Benguela region of southern Africa, the Cape fur seal (Arctocephalus pusillus pusillus) population constitutes the largest marine top predator...
Article
Full-text available
We reviewed 140 papers to assess the ecological effectiveness of South Africa’s marine protected areas (MPAs). Evidence was assessed for coverage and representivity, protection of important biodiversity areas, other recognised elements of effectiveness, connectivity, and ecological effects—from the scale of individual MPAs to the MPA network scale....
Data
Supplementary Table S1: NEOLI features, as defined by Edgar et al. (2014), showing how scoring was conducted for marine protected areas (MPAs) in the South African context. No-take = extent that regulations restrict fishing; Enforced = extent of compliance with regulations that restrict fishing, both through overt policing and through community sup...
Technical Report
Full-text available
Reports on research, monitoring and related activities of the Department of Forestry, Fisheries and the Environment's Chief Directorate: Oceans and Coastal Research, in support of the Departmental mandate of conserving and managing South Africa’s coastal and marine environment.
Article
As countries commit to developing their ocean-based economies sustainably, it is critical to secure the underlying marine biodiversity and ecological processes. Ecosystem-based Marine Spatial Planning (MSP) can support achieving this; however, because competition for ocean space is increasing, biodiversity prioritisation must be spatially efficient...
Article
Full-text available
Identifying key sites of marine biodiversity value and implementing the required practical spatial management measures is critical for safeguarding marine biodiversity and maintaining essential ecological processes, especially in the face of accelerating global change and expanding ocean economies. Delineating Ecologically or Biologically Significa...
Article
Full-text available
Predators can impact prey via predation or risk effects, which can initiate trophic cascades. Given widespread population declines of apex predators, understanding and predicting the associated ecological consequences is a priority. When predation risk is relatively unpredictable or uncontrollable by prey, the loss of predators is hypothesized to r...
Article
Full-text available
Aim Climate change will likely lead to a significant redistribution of biodiversity in marine ecosystems. We examine the potential redistribution of a community of marine predators by comparing current and future habitat distribution projections. We examine relative changes among species, indicative of potential future community-level changes and c...
Article
Full-text available
Research on the socioeconomic aspects of marine protected areas (MPAs) in South Africa is reviewed to guide evaluation and integration. After a brief international review, we used declaration notices and management plans to determine the extent to which social and economic objectives have been included in the purpose statements of MPAs. We then rev...
Article
Full-text available
Many marine species exhibit fine-scale population structure despite high mobility and a lack of physical barriers to dispersal, but the evolutionary drivers of differentiation in these systems are generally poorly understood. Here we investigate the potential role of habitat transitions and seasonal prey distributions on the evolution of population...
Article
The phylogeny and systematics of fur seals and sea lions (Otariidae) have long been studied with diverse data types, including an increasing amount of molecular data. However, only a few phylogenetic relationships have reached acceptance because of strong gene-tree species tree discordance. Divergence times estimates in the group also vary largely...
Technical Report
Full-text available
The Oceans and Coasts Annual Science Report, 2020, previously known as the State of the Oceans and Coasts around South Africa report card, covers environmental monitoring results and research highlights achieved during the 2020 calendar year. Also presented are various tools and technologies that have been developed or utilised in support of the sc...
Chapter
Marine animal forests, although among the most diverse ecosystems worldwide, remain obscure in terms of their diversity and functioning. Their spatial extent, diversity and function within the larger marine ecosystems remain poorly known; mainly due to a lack of traditional taxonomic expertise and the challenges associated with non-destructive samp...
Article
Full-text available
Coastally distributed dolphin species are vulnerable to a variety of anthropogenic pressures, yet a lack of abundance data often prevents data-driven conservation management strategies from being implemented. We investigated the abundance of Indo-Pacific bottlenose dolphins (Tursiops aduncus) along the south coast of South Africa, from the Goukamma...
Article
Knowledge of animal foraging behaviour has implications for management and conservation. While Cape fur seals Arctocephalus pusillus pusillus comprise a major proportion of the southern African marine predator biomass, little is known about their at-sea movements. We investigated foraging distribution, habitat use and diving behaviour for 35 adult...
Article
Fisheries resources of the Benguela Current Large Marine Ecosystem (BCLME) are critically important to the socio-economic well-being of the people of Angola, Namibia and South Africa. Their high degree of environmental vulnerability underscores the importance of maintaining a healthy ecosystem by increasing its resilience to the impacts of anthropo...
Preprint
Full-text available
A bstract The phylogeny and systematics of fur seals and sea lions (Otariidae) have long been studied with diverse data types, including an increasing amount of molecular data. However, only a few phylogenetic relationships have reached acceptance pointing at strong gene-tree species tree discordance. Divergence times in the group also vary largely...
Article
Sub-optimal levels of ocean health were determined for four sub-Saharan African Large Marine Ecosystems (LMEs), based on Global Environmental Facility (GEF) Transboundary Waters Assessment Program (TWAP) assessments. Various ecosystem health and pollution indices that were considered reflect coastal degradation that is ubiquitous in many areas of t...
Technical Report
Full-text available
South Africa’s Oceans and Coasts Annual Science Report, 2019, presents results of research and monitoring conducted by the Department’s Chief Directorate: Oceans and Coastal Research on a number of physical, biological and chemical aspects of oceans and coasts (including estuaries) around South Africa, in the Southern Ocean, or other parts of the A...
Article
Biodiversity maps are an important component of ecosystem-based management and conservation. In the past, biodiversity maps were largely generated using patchy occurrence data from a range of data sources. Currently, substantial species occurrence data are readily available for large parts of the world and are accessible programmatically. Consideri...
Preprint
Full-text available
We investigated the abundance of Indo-Pacific bottlenose dolphins ( Tursiops aduncus ) along the south coast of South Africa, from the Goukamma Marine Protected Area (MPA) to the Tsitsikamma MPA, between 2014 and 2016. During this period, 662.3h of boat-based photo-identification survey effort was carried out, and the sighting histories of 817 iden...
Technical Report
Full-text available
The National Biodiversity Assessment (NBA) is a tool used to monitor and report on the state of biodiversity in South Africa. The NBA 2018 was a collaborative effort to synthesise the best available science on ecosystems, species and genes. Ecosystems were assessed using two headline indicators: threat status and protection level. A revised nationa...
Technical Report
Full-text available
Previously referred to as the “State of the Oceans and Coasts around South Africa Report Card". Consists of research and monitoring report cards for 2018 by multiple different authors, edited by Kirkman, Huggett and Crawford. This is the low resolution, web-site version
Article
Full-text available
Over the past three decades, marine resource management has shifted conceptually from top-down sectoral approaches towards the more systems-oriented multi-stakeholder frameworks of integrated coastal management and ecosystem-based conservation. However, the successful implementation of such frameworks is commonly hindered by a lack of cross-discipl...
Article
Coasts are among our most valuable natural assets but are under intense pressure from human use and climate change. Despite this, coasts – as a coherent ecological unit – have been poorly included in conservation plans, largely because they are inadequately delineated. There are usually gaps and overlaps at the edges of the separate terrestrial-, e...
Article
Full-text available
The Indian Ocean humpback dolphin (Sousa plumbea; G. Cuvier, 1829) is the most endangered marine mammal species in South Africa, and the overall decline of its abundance and group size may affect the social organization of the species, potentially accentuating its vulnerability. Understanding the social organization is therefore particularly releva...
Chapter
Full-text available
Marine Spatial Planning (MSP) intends to create an improved, rational use of the ocean to reduce conflict among competing uses to achieve social, economic and environmental objectives. Systematic Conservation Planning (SCP) can contribute to MSP because it is also spatially explicit, deliberately seeks to reduce conflict and generates an evidence-b...
Chapter
Some major physical and oceanographic features of the Angolan marine system include a narrow continental shelf, the warm, southward flowing Angola Current, the plume of the Congo River in the north and the Angola-Benguela Front in the south. Depth, substrate types and latitude have been shown to account for species differences in demersal faunal as...
Article
Full-text available
The distribution and habitat use of the Indo-Pacific bottlenose dolphin Tursiops aduncus along the south coast of South Africa was investigated using bi-monthly boat-based surveys, from 2013 to 2016, over a distance of 145 km between the Goukamma and Tsitsikamma marine protected areas (MPAs). Survey effort totalled 6 239 km and 750.6 hours. Encount...
Conference Paper
Full-text available
The systematics and phylogeny of Otariidae have been extensively studied for over two centuries. Yet, several relationships, in particular, the monophyly within Arctocephalus, remain unclear. Recent molecular phylogenies only used few concatenated mitochondrial or nuclear genes. Here we reconstructed the Otariidae phylogeny based on whole-genome se...
Article
Full-text available
Effective ecosystem-based management requires estimates of abundance and population trends of species of interest. Trend analyses are often limited due to sparse or short-term abundance estimates for populations that can be logistically difficult to monitor over time. Therefore it is critical to assess regularly the quality of the metrics in long-t...
Article
The Betty's Bay Marine Protected Area (MPA) was established to protect endangered species like the African penguin (Spheniscus demersus), abalone (Haliotis midae) and the west coast rock lobster (Jasus lalandii). Very little is known about the effects their protection has had on other assemblages within the MPA. To this end, a photo-quadratic surve...
Article
The distribution of marine predators is driven by the distribution and abundance of their prey; areas preferred by multiple marine predator species should therefore indicate areas of ecological significance. The Southern Ocean supports large populations of seabirds and marine mammals and is undergoing rapid environmental change. The management and...
Article
Full-text available
Predators can impact ecosystems through consumptive or risk effects on prey. Physiologically, risk effects can be mediated by energetic mechanisms or stress responses. The predation-stress hypothesis predicts that risk induces stress in prey, which can affect survival and reproduction. However, empirical support for this hypothesis is both mixed an...
Article
Full-text available
The Indian Ocean humpback dolphin was recently uplisted to 'Endangered' in the recent South African National Red List assessment. Abundance estimates are available from a number of localized study sites, but knowledge of movement patterns and population linkage between these sites is poor. A national research collaboration, the SouSA project, was e...
Article
Full-text available
Southern Hemisphere humpback whales (Megaptera novaeangliae) generally undertake annual migrations from polar summer feeding grounds to winter calving and nursery grounds in subtropical and tropical coastal waters. Evidence for such migrations arises from seasonality of historic whaling catches by latitude, Discovery and natural mark returns, and r...
Data
Dedicated and incidental sightings of “super-groups” of humpback whales reported in this study. (DOCX)
Article
Full-text available
Foraging behaviour of marine top predators is increasingly being used to identify areas of ecological importance. This is largely enabled by the ability of many such species to forage extensively in search of prey that is often concentrated in oceanographically productive areas. To identify important habitat in the Southern Indian Ocean within and...
Data
Generalised boosted regression model response curves for the different predictors of behavioural activity of the twelve adult Subantarctic fur seal Arctocephalus tropicalis females tagged at Prince Edward Island in March 2011 and tracked between then and February 2012. Distance represents distance from the study colony, Distance8 is the distance fr...
Data
Switching state space model predicted tracks of adult Subantarctic fur seal Arctocephalus tropicalis females tagged at Prince Edward Island in March 2011, overlaid on seasonal averages of sea surface temperature (°C) for (A) Autumn (March-May; n = 12 seals), (B) Winter (June-August; n = 8 seals), (C) Spring (September-November; n = 6 seals), (D) Su...
Data
The performance of the random forest model in terms of correctly predicting suitable foraging habitat (assumed to be associated with area restricted search) for Subantarctic fur seals Arctocephalus tropicalis at Prince Edward Island, on the training set, based on the Area Under the Curve (AUC) of the Receiver Operating Characteristic (ROC) curve. S...
Data
Foraging habitat suitability (preferred areas for ARS) in the study domain for Subantarctic fur seals Arctocephalus tropicalis in each of the four seasons as predicted by a generalised boosted regression model with behavioural state (travelling or area restricted search) as a function of geographical and environmental variables. The dashed lines sh...
Data
Switching state space model predicted tracks of adult Subantarctic fur seal Arctocephalus tropicalis females tagged at Prince Edward Island in March 2011, overlaid on seasonal averages of chlorophyll-a for (A) Autumn (March-May; n = 12 seals), (B) Winter (June-August; n = 8 seals), (C) Spring (September-November; n = 6 seals), (D) Summer (December-...
Data
The performance of the generalised boosted regression model in terms of correctly predicting suitable foraging habitat (assumed to be associated with area restricted search) for Subantarctic fur seals Arctocephalus tropicalis at Prince Edward Island, on the training set, based on the Area Under Curve (AUC) of the Receiver Operating Characteristic (...
Article
Full-text available
The three countries of the Benguela Current Large Marine Ecosystem (BCLME), namely Angola, Namibia and South Africa, have committed to implementing ecosystem-based management (EBM) including an ecosystem approach to fisheries (EAF) in the region, to put in practice the principles of sustainable development in ocean-related matters. There is also re...
Article
Full-text available
Effective conservation management requires information on wildlife abundance and distribution. Platforms of opportunity, including whale-watching vessels (WWV), can provide inexpensive and valuable information particularly in data deficient areas. This study analyzed over 5,500 cetacean encounters from more than 2,500 trips over 10 years by a WWV i...
Article
Full-text available
Using long-term survey data, changes in demersal fau-nal communities in the Benguela Current Large Mar-ine Ecosystem were analysed at community and population levels to provide a comparative overview of the occurrence and timing of regime shifts. For South Africa, the timing of a community-level shift observed in the early 1990s, and of a lesser sh...
Article
Full-text available
The NansClim project (2010-2013) represented a regional collaboration to assess the effects of climate on Benguela dynamics. Based on in situ (since the 1960s in Namibia and South Africa and 1985 in Angola) and satellite (since the 1980s) observations, the project focussed on four subsystems, namely the Angola subtropical, northern Benguela upwelli...
Article
Biodiversity is changing at an unprecedented rate on a global scale as a complex response to several anthropogenic changes, in addition to the background natural environmental variability and cycles. In the Benguela Current Large Marine Ecosystem region (BCLME), aspects of demersal fish species diversity were studied between 1985 and 2010 in three...
Conference Paper
Repeated pup censuses for the Australian fur seal (Arctocephalus pusillus doriferus) have been performed across the species’ range every five years since 2002 to monitor population trends. Live pup numbers were estimated at 20 pupping sites using one of the following methods: capture-mark-resight, direct count, or count from aerial photograph. From...