The Impact of Puzzle Feeders, Ice-Pops and Artificial Seaweed on Captive Harbour Seals (Phoca vitulina) Behaviour

Environmental enrichment is used in zoos and aquaria to improve animal welfare through the stimulation of naturalistic behaviours and reduction of stereotypic behaviours. This study investigated the impact of new enrichment items on the behaviour of a group of captive adult harbour seals. Data were collected in summer-autumn 2023 using continuous scan sampling and all behaviours one-zero recording method for 1-minute intervals (4 hours/day, 8 days). Under standard enrichment conditions, more than 90% of the seals’ behavioural budget was represented by naturalistic behaviours, with low levels of pattern group swimming, which occurred mainly before the two daily shows. Group swimming decreased and random swimming increased before the seal shows on days with new enrichment, but these differences were not statistically significant. The presence of new enrichment items led to a significant increase in exploration and a significant decrease in group swimming only during the morning periods when the new items were actually present in the enclosure (p<0.05, Kruskal Wallis test). During these periods the seals interacted most frequently with the submersed fish-filled puzzle feeders and least frequently with the floating artificial seaweed. This study concluded that new environmental enrichment may be beneficial even for seals displaying low levels of stereotypic behaviours as it provides more behavioural choices and helps promote active naturalistic exploratory behaviours which may alleviate captivity induced stress and improve welfare.