Isabelle S Giddy, University of Cape Town, Oceanography, Cape Town, South Africa; University of Gothenburg, Gothenburg, Sweden, Sarah-Anne Nicholson, Council for Scientific and Industrial Research, Cape Town, South Africa, Marcel du Plessis, University of Cape Town, Department of Oceanography, Cape Town, South Africa, Sebastiaan Swart, University of Gothenburg, Department of Marine Sciences, Gothenburg, Sweden and Andrew F Thompson, California Institute of Technology, Physical Oceanography, Pasadena, CA, United States