Slobodan Paparella from the Adriatic island of Lastovo said he was fed up with being embarrassed in front of his fishing pals.
He said that most days when he went fishing he would catch only the odd fish - but that his Irish setter Lipi would jump into the water and use her jaws to catch dozens of fish.
Paparalla said the last straw was when he tried to reel in a 15lb fish but lost it at the least second - only to see Lipi jump in and catch the fish with one bite and bring it back to shore.
He said: "The other fishermen were all laughing at me. I have no choice but to sell the dog because it keeps humiliating me."