Dominik Bahlburg, Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Bremerhaven, Bremerhaven, Germany, Mei Xue, College of Marine Living Resource Science and Management, Shanghai Ocean University, Shanghai, China, Sebastian Menze, Institute of Marine Research, Bergen, Norway, Tom J. Langbehn, University of Bergen, Bergen, Norway, Abigail J.R. Smith, Australian Antarctic Division, Kingston, Australia, Bjørn Arne Krafft, Institute for Marine Research, Bergen, Norway and Bettina Meyer, Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven, Germany