A5081148973- Ichthyology and Marine Biology
- Fish Biology and Ecology Studies
- Fish Ecology and Management Studies
- Marine animal studies overview
- Marine and fisheries research
- Turtle Biology and Conservation
- Coral and Marine Ecosystems Studies
- Marine Ecology and Invasive Species
- Identification and Quantification in Food
- Marine and coastal plant biology
- Plant Genetic and Mutation Studies
- Travel Writing and Literature
- Isotope Analysis in Ecology
- Diverse Aspects of Tourism Research
- Cruise Tourism Development and Management
- Marine Biology and Environmental Chemistry
- Coastal and Marine Management
- Genetic diversity and population structure
- Fish biology, ecology, and behavior
TogaLabs (South Africa)
2020-2025
Nelson Mandela University
2010-2024
University of Plymouth
2023
University of KwaZulu-Natal
2020
University of Fort Hare
2017
Rhodes University
2007-2013
Bayworld Centre for Research and Education
2006
Knowledge of the diet and trophic ecology apex predators is key for implementation effective ecosystem as well species-based management initiatives. Using a combination stomach content data stable isotope analysis (δ15N δ13C) current study provides information on size-based sex-specific variations in diet, position (TP) foraging habitat tiger sharks (Galeocerdo cuvier) caught KwaZulu-Natal Sharks Board bather protection program. This presents longest time-series most detailed G. cuvier...
To support sustainable growth of ocean-based economies, many countries are engaging in marine spatial planning (MSP) processes, which require robust decision-support tools. Systematic conservation (SCP) is commonly used decision-making to guide spatially efficient protected area expansion. Here we contend that SCP can also be streamline MSP negotiations by developing a coherent, integrated portfolio sites for multiple sectors depend on biodiversity being maintained good state, as...
AbstractRisk-induced fear effects exerted by top predators are pervasive in terrestrial and marine systems, with lasting impacts on ecosystem structure function. The loss of can disrupt ecosystems trigger trophic cascades, but the introduction novel apex into is not well understood. We documented emigration white sharks Carcharodon carcharias response to presence a pair killer whales, Orcinus orca, at large shark aggregation site South Africa. Between February June 2017, five carcasses...
Abstract Both the reef manta ray, Mobula alfredi and oceanic ray M. birostris , are repeatedly observed in South Africa, yet little is known about distributions of either species. In this study, we collated citizen science observations since 2003 to reveal six areas KwaZulu-Natal (KZN) Eastern Cape provinces, where rays have been sighted across multiple years. Using their unique ventral spot patterning, 184 individuals were photo-identified, comprising 139 45 . Most photo-identified...
Understanding socio-economic aspects of the tiger shark Galeocerdo cuvier diving industry, including information on participant expectations, experiences and expenditure, is necessary for effective management Aliwal Shoal Marine Protected Area east coast South Africa. Between January December 2007, a total 2 133 dives was conducted by 1 065 divers (95% CI = 946-1 198). Data were collected means administration semi-structured survey questionnaire to 197 (18.6%) dive participants. Respondents...
Understanding the movement patterns of raggedtooth sharks (Carcharias taurus) is crucial in defining habitat use and evaluating effects exploitation anthropogenic activities. Between 1984 2004, 1107 C. taurus juveniles (<1.8-m TL) 2369 maturing subadults adults (>1.8-m were tagged released along east coast South Africa. In total, 125 178 recaptured, representing recapture rates 11.2% 7.5% respectively. The average distance travelled by juvenile was 18.7 km (95% CI = 10.8–26.6 km)....
Observations of great white sharks (Carcharodon carcharias) scavenging from cetacean carcasses are rare and have only been reported in the scientific literature for large (>3.5 m total length (TL)) individuals. Between 13 October 25 November 2006, young year juvenile were observed carcass a humpback whale (Megaptera novaeangliae) Algoa Bay, South Africa. Although more than one shark scavenged carcass, simultaneous feeding was not observed. The showed clear preference soft tissue at sites...
The present study provides information on the existence of a possible inshore nursery area for white sharks (Carcharodon carcharias) in Algoa Bay, South Africa. In total, 43 flights were conducted, using Robinson R22 helicopter, between October 2010 and March 2012. A total 50 was sighted, with maximum sighting rate seven per hour 2010. majority (96.0%) observed less than 2.5 m length, immature sighted (98.0%). hurdle model, comprising logistic regression to model presence–absence log-normal...
Human activities in the oceans increase extinction risk of marine megafauna. Interventions require an understanding movement patterns and spatiotemporal overlap with threats. We analysed 33 white sharks ( Carcharodon carcharias ) satellite-tagged South Africa between 2012 2014 to investigate influence size, sex season on spatial temporal longline gillnet fisheries protected areas (MPAs). used a hidden Markov model identify ‘resident’ ‘transient’ states effect covariates transition...
Manta rays ( Mobula alfredi and M. birostris ) are poorly understood in South Africa, despite their ecological importance charismatic appeal. This study analyzed a 41-year dataset from the KwaZulu-Natal bather protection program to investigate catch per unit effort between 1981-2021. We used Generalized Additive Models probability of encounter assess annual seasonal trends, as well effect location moon phases on rates. also evaluated size composition demographics caught manta using same...
Abstract A double-tagging experiment and integrated on-site questionnaire telephone survey were used to investigate aspects of tag shedding, reporting, wounds, biofouling for the raggedtooth shark (Carcharias taurus), tagged off east coast South Africa. Between 2002 2004, 84 juvenile (<1.8 m total length, TL), 24 adult (>1.8 TL) C. taurus double-tagged. Of these, 11 six double-tagged sharks recaptured. Significantly, more tags shed from than sharks, there was also a significant...
Understanding recreational aspects of the tourism industry developing around KwaZulu-Natal sardine run is important for protection and sustainability Pondoland Marine Protected Area (MPA), on south-east coast South Africa. Between June July 2007, a total 128 people visited this area to experience using boat-based access. An onsite questionnaire survey 108 (84.4%) participants at Port St Johns Mbotyi indicated that direct value their visit was R5.47 million (95% CI = R5.14–5.82 million)....
Abstract Marine predators are vital to the healthy functioning of coastal ecosystems, but understand their roles, it is necessary elucidate movement ecology, particularly in relation one another. A decade's worth acoustic telemetry data (2011–2020) from Algoa Bay, South Africa, was investigated determine how two mesopredatory species (teleosts: dusky kob Argyrosomus japonicus , n = 11, and leervis Lichia amia 16) top predatory (sharks: ragged‐tooth sharks Carcharias taurus 45, white...
Abstract Adaptive divergence in response to environmental clines are expected be common species occupying heterogeneous environments. Despite numerous advances techniques appropriate for non‐model species, gene–environment association studies elasmobranchs still scarce. The bronze whaler or copper shark ( Carcharhinus brachyurus ) is a large coastal with wide distribution and one of the most exploited southern Africa. Here, we assessed neutral adaptive genomic diversity C. across highly...
A Cormack–Jolly–Seber model was developed to estimate abundance, survival, and probability of capture for juvenile (<1.8 m total length, TL) adult (>1.8 raggedtooth sharks (Carcharias taurus) along the east coast South Africa. Model estimates were adjusted account tag loss, nonreporting, after release mortality. The constructed using mark–recapture data from Oceanographic Research Institute Port Elizabeth Museum cooperative tagging programs 1984 2004. survival 0.56 that 0.89. ranged...
The smooth hammerhead shark Sphyrna zygaena is known to display a high degree of site fidelity specific areas along the South African coastline. This species vulnerable overfishing and steep declines have been noted globally. In this study, dual marker approach was used investigate spatial temporal genetic variation juvenile S. across south east coast Africa. Kinship individuals determined within cohorts from sampled in Mossel Bay, putative pupping ground. Significant differentiation...
Direct observations of sharks attacking mysticetes are rare. The present study provides the first direct observation dusky (Carcharhinus obscurus) a humpback whale (Megaptera novaeangliae) calf. event was witnessed on 16 July 2014 within Pondoland Marine Protected Area, South Africa, during annual sardine run. involved group ~10 to 20 ranging in length between 2 and 3m. followed loose behind attacked it while surface as well when diving. Shark bites were concentrated left-hand side whale’s...
This study provides one of the first quantitative assessments a fish community within pre-operational deep-water port system. Between September 2006 and 2007 total 4 559 fish, representing 47 species 27 different families, were caught Port Ngqura, Africa's deepest port, in 1 713 h shore-angling (2.3 angler−1 h−1) 239 boat-based angling (2.8 h−1). Catches included representative both estuarine shore fisheries. The majority (83.0%) marine most less than size-at-50% maturity (71.4%). abundantly...
Abstract Stable‐isotope analysis (SIA) provides a valuable tool to address complex questions pertaining elasmobranch ecology. Liver, metabolically active, high turnover tissue (~166 days for 95% turnover), has the potential reveal novel insights into recent feeding/movement behaviours of this diverse group. To date, limited work used tissue, but ecological application SIA in liver requires consideration preparation techniques given concentrations urea and lipid that could bias δ 13 C 15 N...
Biofouling of external tags can damage both the animal and tag. It is an inherent problem to many fish-tagging studies; however, it has received little attention. Between 2005 2007, we investigated taxonomic group wet weight sessile multicellular eukaryonts growing on 33 B-type dart recaptured from raggedtooth sharks (Carcharias taurus Rafinesque, 1810) along eastern coast South Africa. All tags, except one a shark that had been at liberty only for 13 days, contained some degree...
Abstract Identifying nearshore waters that serve as important habitats for neonate and juvenile sharks is crucial effective fisheries management. This study examined the abundance of dusky Carcharhinus obscurus within Port Ngqura, on south-east coast South Africa, between September 2006 August 2007 using a combination shore-angling catches mark-recapture data. During this period, port was non-operational still undergoing construction. A total 480 sharks, ranging in size from 50 to 123 cm...
Understanding differences in the recapture rate between different tags (A-, B- and C-types), capture methods (rock-and-surf anglers, scientific divers Natal Sharks Board protection nets) life-history stages (juvenile adult) is critical evaluating results obtained from cooperative tagging programmes (CTPs). A generalised linear modelling approach, using a log-linear model, was used to determine significant probability of these various factors data Oceanographic Research Institute Port...
The common smooth-hound shark, Mustelus mustelus, is a widely distributed demersal shark under heavy exploitation from various fisheries throughout its distribution range. To assist in the development of appropriate management strategies, authors evaluate stock structure, site fidelity and movement patterns along species' southern Africa based on combination molecular long-term tag-recapture data. Eight species-specific microsatellite markers (N = 73) two mitochondrial genes, nicotinamide...