Wordpress site with high rebound rate to correct

I am looking for a high experienced wordpress developer to help me understand why my new wordpress website has a high rebound rate (65 to 75%) from visitors while before the migration the rate was under 30%.
In relation, the number of pages seen per users is less than 2 and visitors
I need the developper to make an analysis, propose solutons concerning the theme and then able to fix.
www.mygolfmedia.com