Enabling pinniped conservation by means of non-invasive genetic population analysis

Conservation and management of protected species, particularly of elusive species such as pinnipeds, is hampered by knowledge gaps. In the case of studies using genetic data these are often attributed to a lack of representative samples. Therefore, there is a pressing need for the development of minimally invasive sampling protocols suitable for genetic analyses of pinnipeds. The present study evaluated the applicability of various protocols for the collection and processing of samples from harbour seals (Phoca vitulina) and grey seals (Halichoerus grypus), encompassing seven source sample types (blood, skin, hair (plucked/moulted), urine, buccal swabs, scat) and three different extraction methods. Protocols were designed for minimally invasive sampling, but also to evaluate differences in their performance based on cost and time of execution in comparison to traditional sampling approaches. The performance of each protocol was measured following successful DNA isolation, molecular sex determination and sequencing of a mitochondrial DNA fragment (control region). Protocols using plucked hair, urine and buccal swab samples proved effective for collection from individuals in captivity, whereas scat was most applicable for non-invasive sampling in the wild. Furthermore, following a pilot study on scat samples, DNA was found to be viable for genetic analysis after exposure to ambient conditions for up to four weeks. This study provides a useful assessment of the suitability of various minimal and non-invasively collected samples for DNA isolation, amplification and mitochondrial sequencing, enabling the effective design of future sampling strategies and a significant increase of samples available for genetic analysis of pinnipeds.