Otter territory marking through sprainting (scent marking) is an important behaviour for welfare and fitness, and understanding otter territoriality helps explain population density and welfare constraints.
Individual otter welfare is significantly affected by territory quality. Otters in territories with poor water quality, depleted fish populations, or insufficient holt sites experience nutritional stress and reduced reproductive success. Territorial disputes — primarily between adult males — cause direct injury welfare harm. Road mortality during territory patrol represents a preventable welfare and conservation harm. The ecology of otter territories explains why population recovery has not been uniform across all waterways — some river systems lack the food abundance and holt availability to support the territory sizes otters require. Improving river habitat quality increases the otter population carrying capacity, enabling more individuals to hold quality territories with adequate food and shelter.