Strictly speaking, no. In the UK the [Great] Cormorant and Shag are two completely different species, but it can sometimes get confusing. Our Shag is a certainly member of the cormorant family and sometimes the names can be interchangeable. For example in New Zealand all the various cormorants they have are (usually) called shags, e.g. the Great Cormorant is known as the Black Shag.Is that another word for Cormorant?