Horizontal flux of secondary production in the southern ocean food web: current velocity data and the transport of krill in the South Georgia ecosystem

The transport of secondary production in the Southern Ocean food-web was investigated using a combination of physical model data and ship based biological data. The physical current velocity dataset was from FRAM and was used to derive a mean velocity field for the upper 250m of the water column. These have been combined with estimates of krill density and standing stocks to consider the flux of krill through the South Georgia area and estimate residence times. These data have been considered with estimates of local predator demand to consider the implications for calculating the precautionary catch levels suitable for the region. The study suggests that catch levels in this area have in the past being of the same order as the calculated potential yield. The work highlights the need for improved infomation the spatial food web connections, the flux of krill and residence times.