Browsing Biodiversity & Conservation Biology by Author "Gibbons, Mark J."
Now showing items 1-20 of 30
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Acoustic observations of jellyfish in the Namibian Benguela
Brierley, Andrew S.; Axelson, Bjorn Erik; Buecher, Emmanuelle; Sparks, Conrad A.J.; Boyer, Helen; Gibbons, Mark J. (Inter-Research, 2001)Multi-frequency acoustic data (18, 38 and 120 kHz) were collected in conjunction with pelagic trawl sampling for gelatinous macrozooplankton during a cruise to the Namibian Benguela in September 1999. Sampling focused ... -
Beyond the jellyfish joyride and global oscillations: advancing jellyfish research
Gibbons, Mark J.; Richardson, Anthony J. (Oxford University Press, 2013)There has been debate in the literature recently about increases in jellyfish populations in response to anthropogenic change, and this has attracted widespread media interest. Despite an international collaborative ... -
Carybdea branchi, sp. nov., a new box jellyfish (Cnidaria: Cubozoa) from South Africa.
Gershwin, Lisa-Ann; Gibbons, Mark J. (Magnolia Press, 2009)A common and conspicuous member of the medusan fauna of South Africa has been the subject of repeated taxonomic confusion. After having been mistakenly identified by earlier workers as either Carybdea alata or Tamoya ... -
Creating opportunities through science symposia
Gibbons, Mark J.; Florence, Wayne K.; Musson, Maryke (South African Assn. For The Advancement Of Science, 2020)For most marine scientists, unless we work in the field of fisheries development or at the interface of science and policy, it is rare to feel that we are making an impact on the lives of people in the wider community. ... -
Diet of whale sharks Rhincodon typus inferred from stomach content and signature fatty acid analyses
Rohner, Christoph A.; Couturier, Lydie I. E.; Richardson, Anthony J.; Pierce, Simon J.; Prebble, Clare E. M.; Gibbons, Mark J.; Nichols, Peter D. (Inter Research, 2013)Whale sharks Rhincodon typus are large filter-feeders that are frequently observed feeding in surface zooplankton patches at their tropical and subtropical coastal aggregation sites. Using signature fatty acid (FA) ... -
Does phylogeny have an influence on the date of first description? A comparative study of the world's fishes
Beukes, Brandon; Witbooi, Peter Joseph; Gibbons, Mark J. (Elsevier, 2020)The process of species description is not random, and understanding the factors that influence when a species is first described (the date of first description, DoFD) allows us to target environments and/or species' traits ... -
Does phylogeny have an influence on the date of first description? A comparative study of the world's fishes
Beukes, Brandon; Witbooi, Peter; Gibbons, Mark J. (Elsevier, 2020)The process of species description is not random, and understanding the factors that in- fluence when a species is first described (the date of first description, DoFD) allows us to target environments and/or species' ... -
Environmental responses of jellyfish polyps as drivers of medusa populations off the coast of Namibia
Ziegler, L.; Gibbons, Mark J. (National Inquiry Services Centre, 2018)Jellyfish populations in the southeastern Atlantic off the coast of Namibia have increased subsequent to the decline of small pelagic fisheries at the end of the 1960s, although the environment there has also become warmer ... -
Feeding and vertical migration of the chaetognath Sagitta friderici (Ritter Zahony, 1911) in the southern Benguela during spring 1987, with notes on seasonal variability of feeding ecology
Gibbons, Mark J.; Stuart, V. (NISC and Taylor & Francis, 1994)The feeding biology and the vertical migration of Sagitta friderici were examined over 24 h at two stations in the southern Benguela during spring (October) 1987. Together with studies conducted during summer (February ... -
Hydromedusae off the Orange River Mouth, Southern Africa
Sparks, Conrad A.J.; Gibbons, Mark J. (NISC (Pty) Ltd and Taylor& Francis, 2003)A total of 242 zooplankton samples from the upper 100 m of the water column was collected discontinuously from March 1997 to January 1999 off the Orange River mouth on the west coast of southern Africa. Six species of ... -
An insight into the reproductive biology of the bearded goby Sufflogobius bibarbatus
Utne-Palm, A.C.; Locatello, L.; Mayer, I.; Gibbons, Mark J.; Rasotto, M B. (Wiley, 2013)Preliminary results obtained from histological analyses of the male reproductive organs, supplemented with field and behavioural data, indicate that Sufflogobius bibarbatus, a small, slow growing gobiid exhibiting low ... -
Jellyfication of marine ecosystems as a likely consequence of overfishing small pelagic fishes: Lessons from the Benguela
Roux, Jean-Paul; van der Lingen, Carl D.; Gibbons, Mark J.; Moroff, Nadine E.; Shannon, Lynne J.; Smith, Anthony D.M.; Cury, Philippe M. (University of Miami, Rosenstiel School of Marine and Atmospheric Science, 2013)Changes in two contrasting ecosystems of the Benguela upwelling region, one dominated at mid-trophic level by jellyfishes (Namibia, northern Benguela ecosystem, where small pelagic fish abundance has been severely depleted) ... -
Mesoscale structure of neuston assemblages across the southern Indian Ocean subtropical gyre
Gibbons, Mark J.; Parker, Yasmeen; Cedras, Riaan B.; Thibault, Delphine (Elsevier, 2022-12-28)Despite concern around plastic pollution in subtropical gyres, our understanding of the biological component of the neustonic layer (upper 20 cm of the ocean) in these areas is poor. Here we investigate the neuston ... -
A modern description of Crambionella stuhlmanni (Scyphozoa: Rhizostomeae) from St. Lucia Estuary, South Africa
Neethling, Simone; Channing, Alan; Gershwin, Lisa-Ann; Gibbons, Mark J. (Cambridge University Press, 2011)A new record of Crambionella stuhlmanni is reported from the east coast of South Africa. The material is described using quantitative morphological data, and mitochondrial (CO1) and nuclear (ITS-1) sequence data. The species ... -
New observations on the diel vertical distribution of Hydromedusae in the southern Benguela ecosystem
Buecher, Emmanuelle; Gibbons, Mark J. (NISC (Pty) Ltd and Taylor& Francis, 2003)Diel vertical migration (DVM) of six common species of hydromedusae was investigated during two drogue studies conducted in St Helena Bay on the west coast of South Africa in February 1995. Clytia spp., Obelia spp. and ... -
A new species of Magelona (Polychaeta: Magelonidae) from southern Namibia
Clarke, Dylan T.; Paterson, Gordon L. J.; Florence, Wayne K.; Gibbons, Mark J. (Iziko Museums of Cape Town, 2010)A new species of Magelonidae, Magelona debeerei sp. nov., is described and illustrated from grab-samples collected at <100moff the southwest coast of Africa. Magelona debeerei sp. nov. has previously been identified from ... -
Null models for null hypotheses in taxonomy: A test using Scyphozoa
Brown, Michael K.; Gibbons, Mark J. (Oxford University Press, 2021)Although molecular tools are becoming more important in the delineation of scyphozoan species there is, perforce, a need to substantiate new species definitions using morphological data. Access to type material is often ... -
Observations on euphausiid communities of the south coast of South Africa
Gibbons, Mark J. (NISC (Pty) Ltd and Taylor& Francis, 1995)A total of 24 species of euphausiid was collected during a survey along the South African south coast during January 1992. Communities over the Agulhas Bank were of low diversity and abundance and were dominated by Nycliphanes ... -
Observations on the ecology of Pleurobrachia pileus (Ctenophora) in the southern Benguela ecosystem
Buecher, Emmanuelle; Thibault-Botha, D.; Gibbons, Mark J. (NISC (Pty) Ltd and Taylor & Francis, 2003)The vertical distribution, abundance and size composition of a population of Pleurobrachia pileus was studied during a six-day drogue study conducted off the west coast of South Africa in February 1995. The population was ... -
Observations on the pelagic decapod Pasiphaea semispinosa in the Benguela upwelling ecosystem
Barange, M.; Macpherson, E.; Gibbons, Mark J. (NISC and Taylor & Francis, 1994)Information on vertical and horizontal distribution patterns, abundance and morphology of the decapod Pasiphaea semispinosa in the Benguela upwelling system is presented. P. semispinosa is the dominant pelagic decapod in ...