A swimming
speed of 0.5 bl s−1 was chosen as an intermediate between swimming
at 0.2 bl s−1, which is considered resting velocity (Woodward and
Smith, 1985), and the optimal swimming speed, defined as the lowest
cost of transport, which is between 1.1 and 1.2 bl s−1, depending on
rearing history (Skov et al., 2011).