You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Dog

Context:
Dogs have lived and worked with humans in so many roles that they have earned the unique nickname, "man's best friend", a phrase used in other languages as well. They have been bred for herding livestock, hunting (e.g. pointers and hounds), rodent control, guarding, helping fishermen with nets, detection dogs, and pulling loads, in addition to their roles as companions. In 1957, a husky-terrier mix named Laika became the first animal to orbit the Earth.

Question:
Certain dogs are bred to help fishermen with what?

nets