Harbour seals are Britain's most common seal species. Their welfare is affected by disturbance at haul-out sites, fishing gear entanglement, and prey depletion from overfishing.
Harbour seal welfare is significantly affected by human disturbance at haul-out sites. When seals are flushed into the water by approaching humans, dogs or boats, they expend energy unnecessarily and pups may be separated from nursing mothers. Repeated disturbance at key sites causes seals to abandon them entirely. The welfare cost of individual disturbance events is real - caloric expenditure, thermal stress and pup separation are all measurable welfare impacts. Entanglement in fishing gear causes drowning in animals that must surface to breathe. Prey depletion from overfishing creates nutritional stress that is particularly severe during the energetically demanding lactation period. The combination of these pressures means that even populations of apparently reasonable size may be experiencing significant chronic welfare compromise.