Echosounder data to assess patterns in krill density - voyage of the RV Tangaroa, 2015

Echosounder data were collected on a multidisciplinary research voyage conducted from the RV Tangaroa, operated by New Zealand’s National Institute of Water and Atmospheric Research Limited (NIWA). The voyage lasted 42 days, departing from Wellington, New Zealand on January 29th , 2015 and returning to the same port on 11th March 2015.Active acoustic data were obtained continuously using a calibrated scientific echosounder (Simrad EK60, Horten, Norway). The echosounder operated at 38 and 120 kHz for the duration of the voyage with a pulse duration of 1.024 ms, a pulse repetition rate of one ping per second and a 7° beam width. The echosounder data here are a subset of that collected throughout the voyage and include only data from south of 65°S. This subset of data focuses on research questions pertaining to Antarctic blue whales and krill.