The 35-year-old joined the Iron from Blackpool in 2013 and has made 119 league appearances for the League One side.
He helped them to a third-placed finish this season, before they were beaten by Millwall in the play-off semi-finals.
Bishop told the club website: "With the way the season finished, it's a sense of unfinished business and it was disappointing for all of us."

He told The Hollywood Reporter he was "super excited" and wanted "to put a different spin on it", but did not expand on what role he would play.
The film will see Jordan reunite with his Creed director Ryan Coogler.
"I'm looking forward to working with Ryan once again. It's gonna be a good time," he said.
He added he could not wait to work with Nyong'o, who won a best supporting actress Oscar for 12 Years a Slave in 2014, as well as Chadwick Boseman - who is currently on the big screen playing Black Panther in Captain America: Civil War.
Jordan played the Human Torch in last year's Fantastic Four flop reboot.  Nyong'o also played CGI character Maz Kanata in Star Wars: The Force Awakens.
Black Panther will be released in February 2018.

Philippe Bianchi told France Info radio his son, who remains in a coma, had shown "no significant progress" since crashing into a recovery vehicle last October at Suzuka.
"In general, progress needs to be made in the first six months," Bianchi said.
"It has been nine months now and Jules has still not woken up."
Frenchman Jules Bianchi, 25, continues to receive treatment for his severe injuries in hospital in his home city of Nice.
Philippe Bianchi added: "As time goes by, I am less optimistic than I might have been two or three months after the accident when we could have hoped for better progress."
Bianchi admitted that if Jules did awake from his coma, it could lead to added difficulties.
He revealed that, prior to his son's accident, the two had spoken about the condition of seven-time Formula 1 world champion Michael Schumacher, who suffered severe head injuries in a skiing accident in December 2013 and faces a long road to recovery.
Philippe Bianchi said: "If he had a severe handicap, we are convinced that is not what Jules would want.
"We talked about it. He discussed with us that if one day he had an accident like that of Michael Schumacher, that even if his only handicap was not being able to drive, he would have a lot of difficulty living. Because it was his life."
Jules Bianchi joined Marussia in 2013 and raced in 34 grands prix, scoring two championship points in last year's Monaco Grand Prix.
Marussia came close to collapse over the winter but were rescued and are racing as Manor in 2015.
Scunthorpe midfielder Neal Bishop has signed a one-year contract extension.
[NEXT_CONCEPT]
Michael B Jordan has confirmed he and Oscar-winning actress Lupita Nyong'o will be among the cast of the upcoming Marvel superhero film Black Panther.
[NEXT_CONCEPT]
Jules Bianchi's father says he is "less optimistic" that his son will recover from head injuries sustained in a crash at last year's Japanese Grand Prix.