Krill stock evaluation with data from commercial fishing vessels

Commercial krill fishing vessels can provide useful data for science and management. The use of such vessels as platforms for survey transects under scientific supervision has already been demonstrated. Here we show that acoustic data of good quality can be collected by observers on board during normal fishing operations in a relatively easy and cheap manner using the Norwegian vessel ‘Saga Sea’ in 2011 as example. A one-month subset of the acoustic data from February/March was processed within a time-frame of a week and linked to krill length data from the same period. The data from the fishing operations were very different from transect data collected just some days before. Krill concentrations were in general much higher during fishing and the length distribution was different. This was expected from the very concentrated geographical positioning of the vessel and intensive fishing during the period. The data have the potential of providing information about local krill depletion, fishing patterns and diel and seasonal behavior of krill. Based on the last years experience with the Norwegian krill fishing vessels and previous experience in own waters we advocate that increased collaboration with commercial vessels should be aimed at.