Food distributed in such a way that each individual
can get sufficient food is a requirement for the keeping
of farm animals. Farmed fish are usually subject to
great competition when food is provided for them.
Observations of salmon in cages during food provision
show that the largest and fastest fish get a disproportionate amount of food, and a high proportion of
smaller individuals that are less able to compete are
found at the edges of the cage. Observations during
diving showed that smaller animals were at the cage
edge all the way down to the bottom of the cage, 15 to
20 m below the surface (D. M. Broom pers. obs.). If food
was made available on demand for salmon, they swam
more slowly and exhibited less fighting behaviour than
when it was supplied by broadcasting, i.e. in a way
that led to much competition.