Molecular analysis of population dynamics and phylogeography of South African seals

Marine and coastal environments are national assets which are threatened by climate change and anthropogenic threats. Large marine vertebrates such as seals move between different habitats and play an important role in the stability and functioning of the ecosystem. The Cape Fur Seal (Arctocephalus pusillus pusillus) is the only pinniped breeding in mainland South Africa. The species suffered population declines from 1600 to 1899 due to over-exploitation which induced a genetic bottleneck. Following prohibition of sealing in 1893, populations of Cape fur seals recovered to an estimated population size of 1.5 to 2 million. The species faces several threats including disease due to exposure to domestic or feral dogs, mortalities due to being caught in marine debris or in bycatch due to fishing operations, illegal killing of seals and depletion of their prey targeted by fisheries. Ecosystem changes associated with climate change has been reported to cause mass mortality events. Climate change has also been related with shifts in their prey distribution and can result in extreme weather conditions that can affect the viability of populations on small, low lying islands. In addition, vagrant seals have been recorded on the South African coast. The occurrence of pinnipeds in areas distant from their reproductive sites may be due to oceanographic anomalies in a changing environment. In this study, we will investigate population dynamics such as population structure diversity and relatedness in resident Cape Fur Seals using next generation sequencing technologies. The sample set will include approximately 200 samples that have been collected over the last 14 years. We will analyse the diets of the seals using DNA barcoding to further investigate the role these predators play in the marine ecosystem. Lastly, we will assess occurrences of rare and vagrant species that have stranded on the South African coast using sanger sequencing of mitochondrial gene regions. This project will generate genetic data which can be used to assess resident seal population demographics and diversity as well as the changes in vagrant and rare seal species migration due to the effect of changes in the marine environment. Information generated here will assist in development of conservation strategies that may have relevance to several marine mammals.