Table 1 Behavioural parameters used for observations during the 12 days of conditioning and feed omission tests.
From: Positive effects of bubbles as a feeding predictor on behaviour of farmed rainbow trout
Behaviour | Observation method | Definition |
|---|---|---|
Activity | Instantaneous sampling (current activity at preselected moments in time) Ethovision XT software | Activity is calculated as a percent by taking every pixel in a given area and comparing it with the previous image. If all pixels remain the same, there is zero activity. If all pixels are different, there is 100% activity. If the animal is moving and increases its velocity (whilst keeping the same shape) there will be an increase in activity, because the pixels belonging to the animal are increasingly different as it moves faster |
Agonistic behaviours | Continuous sampling (occurrence) | Bite attempts and chases through the tank. This parameter was counted when a fish moved away from its initial position with a propulsive tail stroke, immediately followed by another fish52. An occurrence was considered to end when the fish interrupted the behaviour for at least 5 s |
Burst of accelerations | Continuous sampling (occurrence) | Sudden movement away from the initial position with propulsive tail strokes, without previous agonistic interaction53. An occurrence was considered to end when the fish interrupted the behaviour for at least 5 s |
Jumps | Continuous sampling (occurrence) | Movement towards the water surface with sudden emergence of at least half of the body out of the water53 |
