RSTS demersal fish surveys 2006, 2010, 2013 and associated environmental covariates

Brief description

This dataset contains presence-absence records of the demersal fish sampled during the 2006, 2010 and 2013 Random Stratified Trawl Surveys surrounding Heard and MacDonald Islands on the Kerguelen Plateau. It also contains spatially matched climatological variables from satellite and modelled data that represent sea floor and sea surface conditions likely to affect the distribution of demersal fish. KP_Fish_Env.csv: contains the data used in the bioregionalisation analyses KP_Fish_Field_Descriptions.xlxs: contains descriptions of field headers in KP_Fish_Env.csv and details about the matched environmental data.

Lineage

Progress Code: completed

Statement: Surveys were conducted on a commercial trawling vessel by a trained scientific observer. This dataset consists of a subset of the RSTS trawls and contains 524 trawls between 100 and 1200 m depth and evenly spread across four surveys in 2006, 2010 and 2013. Otter bottom trawls were towed for ~ 30 minutes (Nowara, Lamb and Welsford 2014) and trawls on the shelf were conducted during the daytime to capture icefish which diurnally aggregate near the seafloor. All fish species caught in trawls were recorded. Species nomenclature was based on names published in appendix 5 of the Biogeographic Atlas of the Southern Ocean (Duhamel et al. 2014) and common names based on Gon and Heemstra (1990). Species that are primarily pelagic were removed from analyses and some species were aggregated (e.g. Paraliparis spp., Macrourus spp. and Muraenolepis spp.) Data are presence-absence for the twenty species that occur in at least 10 trawls (2% sites) that were used in the bioregionalisation analyses. Spatially matched, environmental variables representing seafloor conditions include depth, slope, seafloor temperatures, seafloor current and seafloor nitrate. Those representing sea surface conditions include surface temperature, chlorophyll-a standard deviation and sea surface height standard deviation. Variables are derived from a number of sources (as detailed in the worksheets) at spatial resolution of 0.1 degree. Spatial matching was performed using the mid-point of each trawl. References: Duhamel, G., Hulley, P.A., Causse, R., Koubbi, P., Vacchi, M., Pruvost, P., ... Van de Putte, A.P. (2014) Biogeographic patterns of fish. Biogeographic Atlas of the Southern Ocean (eds C. De Broyer, P. Koubbi, H.J. Griffiths, B. Raymond, C. d'Udekem d'Acoz, A.P. Van de Putte, B. Danis, B. David, S. Grant, J. Gutt, C. Held, G. Hosie, F. Huettmann, A. Post and Y. Ropert-Coudert), pp. 328-362. Scientific Committee on Antarctic Research, Cambridge UK. Gon, O. and Heemstra, P.C. (1990) Fishes of the Southern Ocean. J.L.B. Smith Institute of Ichthyology, Grahamstown, R.S.A. Nowara, G.B., Lamb, T.D. and Welsford, D.C. (2014) The 2014 annual random stratified trawl survey in the waters of Heard Island (Division 58.5.2) to estimate the abundance of Dissostichus eleginoides and Champsocephalus gunnari. CCAMLR Document

Notes

Purpose
This dataset was used as an example dataset in the paper: Hill et al. (2020) Determining Marine Bioregions: A comparison of quantitative approaches, Methods in Ecology and Evolution. Different analytical approaches to determining bioregions were compared using both this dataset and a synthetic dataset.