UISearchBar going to the view's top when I click on it

I have a UITableView which doesn't reach the entire view. Approximatively, the UITableView is two times smaller than the view.

Then, I add "Search Bar and Search Display Controller" to the UITableView from the Object library. So, to visualize, the searchBar appears at the screen's center.

Here's my view :

My problem : When I click into the search field to do my research, the searchBar is going to the top of the view, in place of the navigation bar ! And the transition is very awful... How can I constraint the searchBar to stay in its initial place ?