RSPCA welfare standards for farmed Atlantic salmon 65 September 2015
* indicates an amendment
Appendix 2
Crowd intensity scale
A simple fish behaviour scale from 1-5 may be used as a guide to managing acute stress, i.e.:
Goal
1. Essentially no fins breaking the surface of the water.
Acceptable
2. Fins above the water over a small part of the surface of the crowd.
Undesirable
3. Fins and part of the fish above the water over the whole surface of the crowd. Some burrowing,
gasping and vigorous activity in parts of the crowd.
Unacceptable
4. The whole surface of the crowd vigorously burrowing, gasping and splashing.
5. Whole surface of the pen boiling with violent splashing.
Level 1: Goal - low stress, no vigorous activity
Observations:
Fish in the sides of the crowd
swimming slowly.
Normal swimming behaviour, but not
all in the same direction.
No dorsal fins on surface.
No white sides on surface.
Level 2: Acceptable - some fins on surface
Observations:
Normal swimming behaviour at suction
point, low stress.
Few dorsal fins on surface.
No white sides on surface.