Changes in haematological parameters in relation to prey switching in a wild population of harbour seals

摘要: 1. Previous studies have found marked inter-annual variation in winter food availability, diet composition and body condition a population of harbour seals (Phoca vitulina L.) Northeast Scotland. This study aimed to determine whether there were other physiological consequences prey switching by comparing haematological parameters years when the clupeids herring sprat dominated switched alternative prey. 2. There significant differences leukocyte erythrocyte relation composition. In contrast, indices did not explain parameters, suggesting that observed changes result from energetic content prey. 3. Leukocyte counts significantly higher after ‘good’ clupeid years, although mean small. Such could resulted either immuno-suppression, for example because nutrient or contaminant levels, pathogen challenge resulting geographical variations water quality. 4. The more marked, was evidence widespread macrocytic anaemia prey. acclimation, as prey-specific foraging strategies, nutritional quality prey. 5. These results indicate generalist predators such seal may exhibit responses their diet. data highlight need consider long-term effects availability on dynamics marine top predators. particular, it is hypothesized fish-induced be responsible declines certain pinniped populations.