| Summary: | Maintenance and Update Frequency: notPlanned Statement: 3.3.1. Krill sample collection Krill sample collection is described in detail in Ericson et al. (2018a). Briefly, krill were caught on board the FV Saga Sea (Aker Biomarine) during their 2016 fishing season (December 2015 – September 2016), from three different locations; the West Antarctic Peninsula (WAP), South Orkney Islands (SOI) and South Georgia (SG) (Figure 3.1). Twenty krill day-1 were randomly sampled from the catch by a fisheries observer (there was no selection by size or maturity stage). These samples were transported to Hobart, Tasmania on dry ice and stored at –80ºC. 3.3.2. Initial lipid extraction and fatty acid analyses Three male and three female krill were collected from the fisheries samples at 2-week intervals, for lipid extraction. Krill were individually extracted in separation funnels using a modified method of Bligh and Dyer (1959), with a solvent mixture of methanol (MeOH)/dichloromethane (CH2Cl2)/water (H2O) at 20:10:7, by vol. To separate phases, 10 mL CH2Cl2 and 10 mL saline MilliQ H2O were added the following day. The lower lipid layer was drained into a round bottomed flask and solvent was removed using a rotary evaporator, to concentrate the total lipid extract (TLE). The TLE was stored at –20 ºC in a pre-weighed glass vial with added solvent (CH2Cl2), to ensure that oxidation of the sample did not occur. These total lipid extracts (TLE) obtained from Ericson et al. (2018a) were used for the present study. Krill with a large range of selected biomarker percentages in the TLE were included. Only males were included to eliminate gender as a potential confounding variable (Clarke 1980; Mayzaud et al. 2000). Males that had < 25% TAG (as % of total lipids) were excluded, as low TAG percentages during the reproductive season may make them less suitable for dietary analysis (Stübing & Hagen 2003; Virtue et al. 1996). Total lipid extracts from 12 males from the 2016 catch were selected from summer, autumn and combined ...
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