Phil er rannsóknarprófessor við Environmental Research Institute við University College Cork, en hann hefur áður verið fiskieftirlitsmaður hjá Northern Regional Fisheries Board á fyrstu árum sínum. Nýlega var hann líffræðingur og teymisstjóri hjá Sjávarstofnun Írlands í frægu Burrishoole rannsóknarstöðinni í Newport, Mayo, þar sem hann hefur enn aðsetur fyrir syndir sínar.
He also did a stint on secondment with the Central Fisheries Board in Ireland as Director of Protection and Conservation. He is probably best known for his research on the genetic impacts of farm escapes salmon, which he still is very much involved, but has also been published widely in the areas of salmonid population biology and ecology, stock assessment, population genetics, evolutionary biology, and the inventory of freshwater fish habitat. His interest in the marine ecology of Atlantic salmon stems from his work on the EU SALSEA-Merge project and more recently on the Norwegian SeaSALAR project.