Salmon Fishing in the Yemen is a 2011 British romantic comedy-drama film directed by Lasse Hallstrom and starring Ewan McGregor, Emily Blunt, Kristin Scott Thomas and Amr Waked. Based on the 2007 novel of the same name by Paul Torday, and a screenplay by Simon Beaufoy, the film is about a fisheries expert who is recruited by a consultant to help realize a sheikh's vision of bringing the sport of fly fishing to the Yemen desert, initiating an upstream journey of faith to make the impossible possible. The film was shot on location in London, Scotland, and Morocco from August to October 2010. The film premiered at the 2011 Toronto International Film Festival. The film received generally positive reviews upon its release, and earned $34,564,651 in revenue worldwide.
Based on the above text, what's the best answer to this question: is salmon fishing in yemen based on a true story?

Options:
-no
-yes
no