Pope Francis is encouraging efforts to safeguard the human rights of fishermen and mariners.

Francis tweeted that he is praying for them and their families and noted that Sunday is a day dedicated to seafarers and fishermen. Francis tweeted: "I encourage every effort to protect and safeguard their human rights."

Separately, the Vatican issued a prayer to mark the day, noting that seafarers endure difficult working conditions, including long stretches away from home and sometimes not getting paid, and face threats of piracy or terrorist attacks.

Pope Francis delivers his blessing as he recites the Angelus prayer from the window of his studio overlooking St.Peter's Square, at the Vatican, Sunday, July 14, 2019. (AP PhotoAndrew Medichini)

Pope Francis delivers his blessing as he recites the Angelus prayer from the window of his studio overlooking St.Peter's Square, at the Vatican, Sunday, July 14, 2019. (AP PhotoAndrew Medichini)

An Associated Press investigation into fishing industry practices in southeast Asia several years ago led to more than 2,000 fishing slaves being freed and fueled reform efforts to improve working conditions for those on fishing boats.

Pope Francis delivers his blessing as he recites the Angelus prayer from the window of his studio overlooking St.Peter's Square, at the Vatican, Sunday, July 14, 2019. (AP PhotoAndrew Medichini)

Pope Francis delivers his blessing as he recites the Angelus prayer from the window of his studio overlooking St.Peter's Square, at the Vatican, Sunday, July 14, 2019. (AP PhotoAndrew Medichini)

Two girls sits on adults' backs as they look at Pope Francis delivering his blessing during the Angelus noon prayer from the window of his studio overlooking St.Peter's Square, at the Vatican, Sunday, July 14, 2019. (AP PhotoAndrew Medichini)

Two girls sits on adults' backs as they look at Pope Francis delivering his blessing during the Angelus noon prayer from the window of his studio overlooking St.Peter's Square, at the Vatican, Sunday, July 14, 2019. (AP PhotoAndrew Medichini)

Pope Francis delivers his blessing as he recites the Angelus prayer from the window of his studio overlooking St.Peter's Square, at the Vatican, Sunday, July 14, 2019. (AP PhotoAndrew Medichini)

Pope Francis delivers his blessing as he recites the Angelus prayer from the window of his studio overlooking St.Peter's Square, at the Vatican, Sunday, July 14, 2019. (AP PhotoAndrew Medichini)