In terms of their heritage, they were originally bred by Portuguese fisherman to assist by herding fish into nets, retrieving working tools and even carrying messages and small items from ship to shore! (mypetneedsthat.com)
It is trained to retrieve and fix broken nets as well as herd fishes to go to fisherman's nets. (puppiesdogs.org)
As the name implies, the Portuguese Water Dog is a native to Portugal and is a working class breed that were originally bred to help herd fish into fishermen's nets, retrieve lost tackle and broken nets. (dogdojo.org)