Cormorant is the correct name for these birds. Shag is an alternative name. There are a number of different species. I am in the city & don't have my bird book to hand so can't identify this particular one..
But whatever, it is a lovely image, well captured.
Yes Bev @tramway is correct. They are cormorants and shag is a "nickname." There are 5 species of cormorants ranging from this cute guy to quite large ones :) Love your capture!
But whatever, it is a lovely image, well captured.