At-sea surveys of seabirds and marine mammals, South Georgia, Antarctica, 2010-2011 ...

• Main Authors: Trathan, Philip, Collins, Martin, Black, Andrew, Ashburner, Jonathan, Wilson, Alastair
• Format: Dataset
• Language: English
• Published: NERC EDS UK Polar Data Centre 2024
• Subjects: "EARTH SCIENCE","BIOSPHERE","ECOLOGICAL DYNAMICS","SPECIES/POPULATION INTERACTIONS","SPECIES PREDATION"; "EARTH SCIENCE","OCEANS","AQUATIC SCIENCES","FISHERIES"; South Georgia; krill; winter; Antarc*; Antarctica
• Online Access: https://dx.doi.org/10.5285/a271c430-739f-44a2-9fb0-29404740a625; https://data.bas.ac.uk/full-record.php?id=GB/NERC/BAS/PDC/01819

At-sea surveys of seabirds around South Georgia were undertaken during the austral winter (May to September) in 2010 and 2011. Surveys were conducted in set transects which covered areas primarily targeted by the krill industry, and as well as areas not normally fished. Surveys consisted of simultaneous recordings of seabirds and marine mammals on the surface of the water within a continuous 300m wide strip transect on one side of the vessel, and 'snapshots' at 300m intervals. Species, positional, environmental and trip data were recorded for each survey. The aim of the project was to investigate the potential interactions between higher predators and the South Georgia krill fishery. These surveys were carried out as part of a wider Overseas Territories Environment Programme (OTEP; SGS701) funded project 'Identifying important and vulnerable marine areas for conservation at South Georgia.' Phil Trathan (BAS) applied for this grant. ... : The methodology relies on the simultaneous recording of seabirds and marine mammals on the surface of the water within a continuous 300m wide strip transect on one side of the vessel (the side offering the better viewing conditions) and 'snapshots' at 300m intervals. The 300m limit of the transect is defined using callipers with the jaw width determined using Heinemann's (1981) formula. Seabirds and marine mammals recorded in contact with the water are assigned to one of five distance bands; A 0-50m, B 50-100m, C 100-200m, D 200-300m, E >300m. This element of distance sampling within the strip transect enables the observer to assess the detectability of species at distance and where necessary correct for animals that go undetected. In the southern oceans, certain species of seabird (notably penguins and diving- petrels) and marine mammals spend much of the time below the surface and can be difficult to detect when on the surface. It is therefore important to consider sea state and visibility (for ...