Research Publications - Shark Research Unit

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Research Publications

PUBLICATIONS

The Shark Research Unit is a prolific publisher of scientific articles, research theses, and popular articles

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ACADEMIC ARTICLES

Publication in ‘Nature’

Queiroz et al. (2019) (R. Johnson as co-author) Global spatial risk assessment of sharks under the footprint of fisheries Nature volume 572, pages461–466

Effective ocean management and the conservation of highly migratory species depend on resolving the overlap between animal movements and distributions, and fishing effort. However, this information is lacking at a global scale. Here we show, using a big-data approach that combines satellite-tracked movements of pelagic sharks and global fishing fleets, that 24% of the mean monthly space used by sharks falls under the footprint of pelagic longline fisheries. Space-use hotspots of commercially valuable sharks and of internationally protected species had the highest overlap with longlines (up to 76% and 64%, respectively), and were also associated with significant increases in fishing effort. We conclude that pelagic sharks have limited spatial refuge from current levels of fishing effort in marine areas beyond national jurisdictions (the high seas). Our results demonstrate an urgent need for conservation and management measures at high-seas hotspots of shark space use, and highlight the potential of simultaneous satellite surveillance of megafauna and fishers as a tool for near-real-time, dynamic management.

Publication in ‘Science’

Bonfil, Meyer, Scholl, Johnson, O´Brian, Oosthuizen, Swanson, Kotze, Patterson (2005) Transoceanic migration, long-distance return migration and local movement patterns in the great white shark.

The large-scale spatial dynamics and population structure of marine top predators are poorly known. We present electronic tag and photographic identification data showing a complex suite of behavioral patterns in white sharks. These include coastal return migrations and the fastest known transoceanic return migration among swimming fauna, which provide direct evidence of a link between widely separated populations in South Africa and Australia. Transoceanic return migration involved a return to the original capture location, dives to depths of 980 meters, and the tolerance of water temperatures as low as 3.4 degrees C. These findings contradict previous ideas that female white sharks do not make transoceanic migrations, and they suggest natal homing behavior.

J. Escobar (2009) Movement patterns and population dynamics of four catsharks endemic to South Africa

E. Gennari, P.Cowely, R. Johnson (2017) Performance and reliability of active acoustic biotelemetry to best track marine pelagic species in temperate coastal waters

Escobar-Porras, J. 2007. A responsibility to the marine environment. SANCOR Newsletter, Issue 185.

Jennari, Kock, Smale, Towner, Khan, Bester, Johnson, Fischer, Meÿer, Morse (2019) Antibiotic sensitivity of bacterial flora isolated from the oral cavities of live white sharks (Carcharodon carcharias) in South African waters

Morse, Mole, Bester, Johnson, Scacco, Gennari (2019). Cape fur seals adjust traversing behaviour with lunar conditions in the high white shark density waters of Mossel Bay, South Africa.

Gennari, Johnson, Cowley (2018) Performance and reliability of active acoustic biotelemetry to best track marine pelagic species in temperate coastal waters

Ryklief, Pistorius, Johnson (2014) Spatial and seasonal patterns in sighting rate and life history composition of the white shark, Carcharodon carcharias at Mossel Bay, South Africa

O. Jewell, R. Johnson, M.N. Bester (2013) Fine scale movements and activity areas of white sharks (Carcharodon carcharias) in Mossel Bay, South Africa

D. Delaney, R.Johnson, M.N.Bester (2012) Accuracy of Using Visual Identification of White Sharks to Estimate Residency Patterns.

O. Jewell, M.Wcisel, A.Towner, M.N.Bester, R.Johnson, S.Singh (2011) Effects of Smart Position Only (SPOT) Tag Deployment on White Sharks Carcharodon carcharias in South Africa.

Findlay, Meyer, Elwen, Kotze, Johnson, Truter, Uamusse, Sitoe, Wilke, Kerwath, Swanson, Staverees, Van Derwesthuizen (2011) Distribution and abundance of humpback whales, Megaptera novaeangliae, off the coast of Mozambique.

Vignon, Sasal, Johnson, Galzin (2009) Impact of shark-feeding tourism on surrounding fish populations off Moorea Island (French Polynesia).

Johnson, Bester, Dudley, Oosthuizen, Meÿer, Hancke (2009) – Coastal swimming patterns of white sharks (Carcharodon carcharias) at Mossel Bay, South Africa.

Gubili, Johnson, Oosthuizen, Kotze, Meÿer, Sims, Jones, Noble (2009) Concordance of genetic and fin photo identification in the great white shark, (Carcharodon carcharias), of Mossel Bay, South Africa.

Johnson, Keswick, Bester, Oosthuizen (2008)Encounters between white sharks and Cape fur seals in a shallow channel.

Kock, Johnson, Bester, Compagno, Cliff, Dudley, Griffiths, Kotze, Laroche, Meyer, Oosthuizen, Swanson (2006) White shark abundance: not a causative factor in numbers of shark bite incidents.

Johnson, Venter, Bester, Oosthuizen (2006) Seabird predation by white shark, (Carcharodon carcharias), and Cape fur seal, (Arctocephalus pusillus pusillus), at Dyer Island.

Oelofse, Kock, Johnson, Haskins (2006) Is there a relationship between white shark presence and the management of city estuaries and river mouths?

Johnson, Kock, Bester, Compagno, Dudley, Griffiths, Keswick, Kotze, Laroche, Meyër, Oosthuizen, Swanson, Jacobs (2006) South Africa’s White Shark cage-diving industry – is their cause for concern?

Bonfil, Meyer, Scholl, Johnson, O´Brian, Oosthuizen, Swanson, Kotze, Patterson (2005) Transoceanic migration, long-distance return migration and local movement patterns in the great white shark.

Johnson, Oosthuizen, Bester, Meyer, Swanson, Kotze (2004) Habitat utilization of the white shark in South Africa, using acoustic telemetry

R.L. Johnson (2003) Behavioural ecology of the white shark (Carcharodon carcharias) at Dyer Island, South Africa. M.Sc. thesis

Ferguson, Van Jaarsveld, Johnson, Bredenkamp, Foord, Britz (2003) Rodent induced damage to a pine plantation: a southern African case study.

Johnson, Ferguson, Van Jaarsveld, Chimimba, Bronner (2002) The effect of afforestation fragmentation on small mammal assemblages at Groenvaly grasslands.

ACADEMIC POSTERS

Escobar-Porras, J. and Macdonald, A. (2015) The blacktip sharks Carcharhinus limbatus of Aliwal Shoal. 9th Western Indian Ocean Marine Science Association, October 2015.

Escobar-Porras, J., Sauer, W.H.H. and Cowley, P.D. (2007) Movement patterns of selected endemic catsharks in South African waters. 5th Western Indian Ocean Marine Science Association, October 2007.

Johnson, Ferguson, Van Jaarsveld (2002) The effect of afforestation fragmentation on small mammal assemblages at Groenvaly grasslands. B.Sc Hons presentation – University of Pretoria

ORAL PRESENTATIONS

Escobar-Porras, J. and Macdonald, A. (2014) Population genetics in South African elasmobranchs: Are they defined by the reproductive strategy of the species?- The Blacktip Story. Sharks International, June 2014.

Escobar-Porras, J. and Macdonald, A. (2013) Population genetics in South African elasmobranchs: Are they defined by the reproductive strategy of the species? The Blacktip Story. 8th Western Indian Ocean Marine Science Association, October 2013.

Escobar-Porras, J. and Sauer, W.H.H. (2011) Elasmobranchs of southern Africa: Trends and Gaps. 7th Western Indian Ocean Marine Science Association, October 2011.

Escobar-Porras, J. and Sauer, W.H.H. (2011) Elasmobranchs of southern Africa: where are we and where should we be focusing our efforts? Southern African Shark and Ray Research Meeting, 2011. KZNSB, Umhlanga Rocks, February 2011.

Cowley, P.D., Attwood, C.G., Götz, A., Kerwath, S.E., Wood, A.D., Potts, W.M., Mackenzie, B.L., Bennett, R., Watt-Pringle, P. and Escobar-Porras, J. (2008) Movement behaviour of important fishery species in the Tsitsikamma National Park . Tsitsikamma National Park Scientists’ Symposium 2008. Storms River, TNP, July 2008. Oral presentation by PDC.

Escobar-Porras, J., Sauer, W.H.H. and Cowley, P.D. (2008) Are Catsharks as homely as tabby cats? 13th Southern African Marine Science Symposium, June 2008.

ACADEMIC CREDITS

Peter Andrew Watt-Pringle (2009) – Formal Acknowledgement of Jessica Escobar. Movement behaviour of three South African inshore sparid species in rocky intertidal and shallow subtidal habitats. M.Sc Thesis

Alistair John Green (2009) – Formal Acknowledgment of Jessica Escobar. The protein and energy requirements of the South Africa abalone, Haliotis Midae. M.Sc Thesis

Phanor H. Montoya-Maya (2014) Formal acknowledgement of Jessica Escobar. Ecological genetic connectivity between and within southeast African marginal coral reefs. P.hd. Thesis

P.A Watt-Pringle, P.D.Cowely, A. Gotz (2015) – Formal Acknowledgment of Jessica Escobar. Residency and small-scale movement behaviour of three endemic sparid fishes in their shallow rocky subtidal nursery habitat, South Africa

Alistair John Green (2009) – Formal Acknowledgment of Jessica Escobar. The protein and energy requirements of the South Africa abalone, Haliotis Midae. M.Sc Thesis

Michelle Kruger (2010) Formal Acknowledgement of Jessica Escobar. Spatio-temporal dynamics of ichthyoplankton in the Kowie Estuary, South Africa. M.Sc. Thesis

ABOUT US

The Shark Research Unit is a shark and marine research and conservation institute driven by a passionate team of shark experts. We are located in South Africa and work in two regions of priority – Aliwal Shoal and Mossel Bay.

Our core purpose is to conduct and support original shark research, conservation and education programs through strategic partnerships with marine scientists, postgraduate students, ecotourism operators and academic institutes.

Our focus extends to nurturing a new generation (of all ages) of shark scientists, professionals and enthusiasts. We achieve this through our great white shark research internship, learner outreach programs and expert guided shark edu-tours

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