I have since been changing the look of my iBook.  I did have a background of my web gradient which is the two different blues merging into each other.  Below is what my original background for my iBook looked like;

I made this in Ai.  I used the same background that I used for my Web page.  I choose these colours to represent a coral reef.  It feels and looks vibrant.  I made the border from animal stickers that I found on the web.  I changed their colour to black and re-sized them to fit my design.  I did this because I wanted to maintain the coral reef vibe but thought this was lacking in colour.  I did have further thoughts as to if it was much more colourful it would distract from the content. This would look way too much.  I have therefore changed my background.  I have done a little research into professional presentations and presentable backgrounds to content.  For every page in my iBook will be a new background.  I am keeping the background gradient.  For my iBook I will have my reef gradient on every page followed by coral marine life around it.  These will be images acting as a type of border for my content  

My solution is below;

The animals are images from the web and I have not made them.  I have tried to keep the same theme across both the website and the iBook.  Using the same background was a great idea because it links in with using the same content.  They will be different on every page with different marine animals to add variety and to keep the up the flow of the iBook.  Content will be placed within the background but not over lapping the creatures.