Variation at site level was highly significant and moderately high
(15–16%) for apparent digestibility of both protein and fat, while site
level variation was higher (approximately 20%) for both feeding intensity
and total energy intake. A possible explanation is that localmanagement
factors and/or site-specific environmental conditions differ between sites
and that these differences have greater influence regarding feeding intensity
and total energy intake than on nutrient digestibility. In addition, this
could reflect that feed production is more standardized than feeding
management giving rise to less variation between sites. Underlyingmanagement
factors with an impact on feed utilization can be optimized and
improved if they are identified. As an example, sites with unfavorable
environmental conditions may be identified and the production may be
adjusted to carrying capacity or totally avoided as future salmon farming
sites.