ORCID Profile
0000-0001-7950-193X
Current Organisation
North-West University
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Biology Centre, AS CR
Date: 11-12-2020
DOI: 10.14411/FP.2020.036
Publisher: Elsevier BV
Date: 06-2021
Publisher: Wiley
Date: 30-05-2011
Publisher: Elsevier BV
Date: 09-2023
Publisher: Biology Centre, AS CR
Date: 25-02-2019
DOI: 10.14411/FP.2019.002
Abstract: Southern Africa is considered one of the world's 'hotspots' for the ersity of cartilaginous fishes (Chondrichthyes), with currently 204 reported species. Although numerous literature records and treatises on chondrichthyan fishes are available, a paucity of information exists on the bio ersity of their parasites. Chondrichthyan fishes are parasitised by several groups of protozoan and metazoan organisms that live either permanently or temporarily on and within their hosts. Reports of parasites infecting elasmobranchs and holocephalans in South Africa are sparse and information on most parasitic groups is fragmentary or entirely lacking. Parasitic copepods constitute the best-studied group with currently 70 described species (excluding undescribed species or nomina nuda) from chondrichthyans. Given the large number of chondrichthyan species present in southern Africa, it is expected that only a mere fraction of the parasite ersity has been discovered to date and numerous species await discovery and description. This review summarises information on all groups of parasites of chondrichthyan hosts and demonstrates the current knowledge of chondrichthyan parasites in South Africa. Checklists are provided displaying the host-parasite and parasite-host data known to date.
Publisher: American Society of Parasitologists
Date: 06-2008
DOI: 10.1645/GE-1391.1
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.MARPOLBUL.2022.114142
Abstract: 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 5.8 mg/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 17.8 mg/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 s led between 2005-10 from the same region, with generally higher concentrations compared to the same species s led globally.
Publisher: Springer Science and Business Media LLC
Date: 16-10-2023
Publisher: Elsevier BV
Date: 04-2015
Abstract: Aquatic wildlife is increasingly subjected to emerging diseases often due to perturbations of the existing dynamic balance between hosts and their parasites. Accelerating changes in environmental factors, together with anthropogenic translocation of hosts and parasites, act synergistically to produce hard-to-predict disease outcomes in freshwater and marine systems. These outcomes are further complicated by the intimate links between diseases in wildlife and diseases in humans and domestic animals. Here, we explore the interactions of parasites in aquatic wildlife in terms of their bio ersity, their response to environmental change, their emerging diseases, and the contribution of humans and domestic animals to parasitic disease outcomes. This work highlights the clear need for interdisciplinary approaches to ameliorate disease impacts in aquatic wildlife systems.
Publisher: Elsevier BV
Date: 09-2020
Publisher: Elsevier BV
Date: 04-2022
Publisher: Biology Centre, AS CR
Date: 07-12-2020
DOI: 10.14411/FP.2020.035
Publisher: Elsevier BV
Date: 08-2021
Publisher: Elsevier BV
Date: 12-2022
Publisher: Oxford University Press (OUP)
Date: 10-03-2021
DOI: 10.1093/ZOOLINNEAN/ZLAB002
Abstract: The digenetic trematode family Gorgocephalidae comprises just a few species, and the literature devoted to the lineage consists of only a handful of reports. With one exception, all reports have been based on material collected in the Indo-West Pacific, an expansive marine ecoregion stretching from the east coast of Africa to Easter Island, Hawaii and French Polynesia. We collected adult and intramolluscan gorgocephalids from kyphosid fishes and littorinid gastropods from several Australian localities, and from South Africa and French Polynesia. Specimens of Gorgocephalus kyphosi and G. yaaji were collected from, or near, their type-localities, providing new morphological and molecular (COI, ITS2 and 28S) data needed for a revised understanding of species boundaries in the family. Two new species are recognized: Gorgocephalus euryaleae sp. nov. and Gorgocephalus graboides sp. nov. New definitive host records are provided for described species and three new intermediate hosts are identified. These new records are all associated with Kyphosus fishes and littorinid gastropods, reaffirming the restriction of gorgocephalids to these hosts. Most significantly, we provide evidence that G. yaaji is distributed from South Africa to French Polynesia, spanning the breadth of the Indo-West Pacific. Our findings have significant relevance regarding digenean species delineation over geographic range.
Publisher: American Society of Parasitologists
Date: 10-2009
DOI: 10.1645/GE-1920.1
Publisher: Elsevier BV
Date: 04-2013
DOI: 10.1016/J.IJPARA.2012.11.012
Abstract: Investigations to determine whether juvenile gnathiid isopods are vectors of haemogregarines between coral reef fishes were undertaken at Lizard Island, Australia. Haemogregarina balistapi parasitaemias in triggerfish, Rhinecanthus aculeatus, decreased under gnathiid-free, laboratory conditions, compared with those in tagged R. aculeatus returned to the reef. Gnathia aureamaculosa juveniles were common ectoparasites of reef R. aculeatus and laboratory reared specimens of this gnathiid were fed on R. aculeatus infected with H. balistapi. Subsequent squashes of this gnathiid contained haemogregarine gamonts similar to those seen in blood films of R. aculeatus, and haemogregarine developmental stages, including oocysts, sporozoites, meronts and merozoites. Biological transmission of H. balistapi and a second haemogregarine species, Haemogregarina bigemina, using laboratory reared gnathiids to several species of triggerfishes and surgeonfishes raised from larvae was then attempted. Investigations involved recipient fish ingesting, or being bitten by, G. aureamaculosa juveniles fed on donor fish with haemogregarines control fish were exposed to gnathiids fed on uninfected donor fish. Subsequently, no haemogregarines were detected in recipient triggerfishes and controls were negative. However, a recipient surgeonfish, Acanthurus xanthopterus, which had ingested gnathiids likely infected with donor fish H. balistapi, carried H. bigemina-like stages. A second recipient surgeonfish, which had ingested gnathiids presumed to be infected with H. bigemina, also carried haemogregarine stages. Finally, a third surgeonfish apparently carried haemogregarines after gnathiids presumed to be infected with H. bigemina had bitten this fish, although not all gnathiids were recovered during the trials and the third infected surgeonfish may have also ingested gnathiids. The study provides strong evidence that G. aureamaculosa is the definitive host of H. balistapi, to our knowledge the first such observation from a coral reef environment. Although transmission of H. balistapi has not yet been demonstrated, laboratory trials tend to support the view that G. aureamaculosa is also a potential vector of H. bigemina between surgeonfish.
Publisher: American Society of Parasitologists
Date: 2008
DOI: 10.1645/GE-1391R.1
Publisher: Springer Science and Business Media LLC
Date: 26-06-2021
DOI: 10.1007/S11230-021-09984-2
Abstract: Thirteen species of sea lice (family Caligidae) are reported from a range of elasmobranch and actinopterygian fishes caught off South Africa or obtained from public aquaria in South Africa. Two new species of Caligus Müller, 1785 are described: C. linearis n. sp. from Pomatomus saltatrix (Linnaeus) and C. tumulus n. sp. from Chrysoblephus cristiceps (Valenciennes). A supplementary description is provided for both sexes of Caligus tetrodontis Barnard, 1948 taken from Amblyrhynchotes honckenii (Bloch) and previous records of this parasite from South African fishes are critically reviewed. It is concluded that Caligus material from Arothron hispidus Linnaeus was previously misidentified as C. tetrodontis and is in urgent need of re-examination. Morphological and molecular observations on Caligus furcisetifer Redkar, Rangnekar & Murti, 1949 indicate that this copepod is phenotypically and genetically identical to Lepeophtheirus natalensis Kensley & Grindley, 1973, and the latter becomes a junior subjective synonym of C. furcisetifer . We include new geographical distribution records for Caligus longipedis Bassett-Smith, 1898, C. rufimaculatus Wilson, 1905 and Lepeophtheirus spinifer Kirtisinghe, 1937, extending into South African waters, as well as both new distribution and host records for Alebion gracilis Wilson, 1905, Caligus dakari van Beneden, 1892 and Lepeophtheirus acutus Heegaard, 1943. The molecular analysis confirmed the monophyly of the genus Caligus. The South African species of Caligus did not cluster together, but the two included South African species of Lepeophtheirus were recovered as sister taxa.
Publisher: American Society of Parasitologists
Date: 08-2006
DOI: 10.1645/GE-756R.1
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Nico J Smit.