Ospreys are specialist fish hunters whose welfare during the breeding season depends on adequate fish populations and undisturbed access to productive fishing areas near nesting sites.
Osprey welfare during breeding is directly linked to fish availability near the nest site. A male osprey that cannot catch sufficient fish to provision the female and growing chicks faces the welfare stress of repeated unsuccessful diving and eventual breeding failure. Fish population depletion in catchments near osprey nests — from overfishing, otter predation on stocked fisheries, or water quality issues — reduces fishing success rates and increases energy expenditure. River and lake management that maintains healthy fish populations, combined with legal protection of osprey fishing areas from disturbance, provides the welfare-positive environment breeding ospreys need. Monitoring of nest productivity provides an indirect indicator of fish population health in the surrounding area.