<P> Cook resigned in September 2009 after working for Disney for over 38 years . Depp's faith in Pirates of the Caribbean: On Stranger Tides was somewhat shaken after the resignation, with Depp explaining that "There's a fissure, a crack in my enthusiasm at the moment . It was all born in that office". Depp also explained Cook was one of the few who accepted his portrayal of Jack Sparrow: "When things went a little sideways on the first Pirates movie and others at the studio were less than enthusiastic about my interpretation of the character, Dick was there from the first moment . He trusted me". </P> <P> During production of Dead Man's Chest and At World's End, writers Ted Elliott and Terry Rossio discovered Tim Powers' 1987 novel On Stranger Tides, which they considered a good foundation on which to base "a new chapter" in the Pirates series . Disney bought the rights to the novel in April 2007 . Rossio stated that he and Elliot had considered using Blackbeard and the Fountain of Youth in the story before reading the book, "but whenever you say those words, Powers' novel comes to mind . There was no way we could work in that field without going into territory Tim had explored ." However, they denied that it would be a straight version of the novel: "Blackbeard came from the book, and in the book there is a daughter character, too . But Jack Sparrow is not in the book, nor is Barbossa . So I wouldn't call this an adaptation ." Rossio declared the script was written to be a standalone film, "kind of a James Bond sort of thing", instead of the "designed to be a trilogy" structure of the previous installments . They hoped to "design a story that would support new characters," as characters such as Will Turner would not return . Bruckheimer added that there was a decision to "streamline the story a little bit, make it a little simpler and not have as many characters to follow", as the number of characters and subplots in At World's End caused the film to have an unwieldy length . The duo decided to employ another sea myth alluded in the previous episodes: mermaids, which are briefly referenced in the book . The mermaids' role expanded in the script, which included a vast attack sequence . </P> <P> Depp was deeply involved with the story design, frequently meeting the writers to show what he was interested in doing, and in the words of Rossio, being "involved in coming up with story lines, connecting characters, creating moments that we would then fashion, shape and then go back ." Among Depp's suggestions were turning Phillip into a missionary and having a Spanish contingent following the protagonists . Afterwards, Rob Marshall and executive producer John DeLuca met Rossio and Elliot, and did alterations of their own, including building the female lead . </P> <P> Depp signed on to return as Captain Jack Sparrow in September 2008, saying that he would come back if the script was good . Almost a year later, Disney announced that Depp would be paid $55.5 million for his role, realizing that without him the franchise would be "dead and buried ." Geoffrey Rush expressed interest in returning to his role as Barbossa, and Bruckheimer later confirmed his presence . Rush was positive on Barbossa having lost a leg, as he considered the disability made him "angrier, more forceful and resilient as a character", and had to work with the stunt team for an accurate portrayal of the limp and usage of crutch, particularly during sword fighting scenes . While the production team considered a prop pegleg to be put over Rush's leg, the tight schedule caused it to be replaced with a blue sock that was replaced digitally, with a knob on the shoe to give Rush a reference for his walk . Three other actors from the previous films returned, Kevin McNally as Joshamee Gibbs, Greg Ellis as Lt. Theodore Groves, and Damian O'Hare as Lt. Gilette . Keith Richards also had a cameo, reprising his role as Captain Teague from At World's End; he and Depp tried to persuade Mick Jagger to audition for the part of a pirate elder . Previous cast members Orlando Bloom and Keira Knightley stated that they would not reprise their roles, as they wanted to be involved in different films . They both thought the storyline involving their characters had gone as far as it could . On August 1, 2009, Bill Nighy expressed his desire to return as Davy Jones, who died in the previous film, saying the possibility to resurrect the character, but at the end, his inclusion was scrapped . On February 5, 2010, Mackenzie Crook also announced he would not be reprising his role of Ragetti, stating, "They haven't asked me . But actually I don't mind that at all . I'm a fan of the first one especially and I think the trilogy we've made is great . I'd almost like them to leave it there ." </P>

Who plays the first mermaid in pirates of the caribbean 4